From 6797ec6ed396f65916fe816f8b2b49114253dd86 Mon Sep 17 00:00:00 2001
From: Scott Shawcroft <scott@tannewt.org>
Date: Fri, 5 Jul 2019 19:01:54 -0700
Subject: Add support for grayscale displays that are < 8 bit depth.

This also improves Palette so it stores the original RGB888 colors.

Lastly, it adds I2CDisplay as a display bus to talk over I2C. Particularly
useful for the SSD1306.

Fixes #1828. Fixes #1956
---
 shared-module/displayio/ColorConverter.c |  35 +++++--
 shared-module/displayio/ColorConverter.h |   4 +
 shared-module/displayio/Display.c        | 173 ++++++++++++++++++++++---------
 shared-module/displayio/Display.h        |   4 +-
 shared-module/displayio/FourWire.c       |  21 +++-
 shared-module/displayio/FourWire.h       |   6 +-
 shared-module/displayio/Group.c          |   6 +-
 shared-module/displayio/Group.h          |   3 +-
 shared-module/displayio/I2CDisplay.c     | 105 +++++++++++++++++++
 shared-module/displayio/I2CDisplay.h     |  41 ++++++++
 shared-module/displayio/Palette.c        |  50 ++++-----
 shared-module/displayio/Palette.h        |  19 +++-
 shared-module/displayio/TileGrid.c       |  50 ++++++---
 shared-module/displayio/TileGrid.h       |   3 +-
 shared-module/displayio/__init__.c       | 135 +++++++++++++++---------
 shared-module/displayio/__init__.h       |   2 +
 16 files changed, 496 insertions(+), 161 deletions(-)
 create mode 100644 shared-module/displayio/I2CDisplay.c
 create mode 100644 shared-module/displayio/I2CDisplay.h

(limited to 'shared-module/displayio')

diff --git a/shared-module/displayio/ColorConverter.c b/shared-module/displayio/ColorConverter.c
index 3928e115a..563d40c51 100644
--- a/shared-module/displayio/ColorConverter.c
+++ b/shared-module/displayio/ColorConverter.c
@@ -29,15 +29,36 @@
 void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self) {
 }
 
-bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, uint32_t input_color, uint16_t* output_color) {
-    // TODO(tannewt): Validate the color input against the input format.
-    uint32_t r5 = (input_color >> 19);
-    uint32_t g6 = (input_color >> 10) & 0x3f;
-    uint32_t b5 = (input_color >> 3) & 0x1f;
+uint16_t displayio_colorconverter_compute_rgb565(uint32_t color_rgb888) {
+    uint32_t r5 = (color_rgb888 >> 19);
+    uint32_t g6 = (color_rgb888 >> 10) & 0x3f;
+    uint32_t b5 = (color_rgb888 >> 3) & 0x1f;
     uint32_t packed = r5 << 11 | g6 << 5 | b5;
     // swap bytes
-    *output_color = __builtin_bswap16(packed);
-    return true;
+    return __builtin_bswap16(packed);
+}
+
+uint8_t displayio_colorconverter_compute_luma(uint32_t color_rgb888) {
+    uint32_t r8 = (color_rgb888 >> 16);
+    uint32_t g8 = (color_rgb888 >> 8) & 0xff;
+    uint32_t b8 = color_rgb888 & 0xff;
+    return (r8 * 19) / 255 + (g8 * 182) / 255 + (b8 + 54) / 255;
+}
+
+bool displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
+    if (colorspace->depth == 16) {
+        *output_color = displayio_colorconverter_compute_rgb565(input_color);
+        return true;
+    } else if (colorspace->grayscale && colorspace->depth <= 8) {
+        uint8_t luma = displayio_colorconverter_compute_luma(input_color);
+        *output_color = luma >> (8 - colorspace->depth);
+        return true;
+    }
+    return false;
+}
+
+bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
+    return displayio_colorconverter_convert(self, colorspace, input_color, output_color);
 }
 
 // Currently no refresh logic is needed for a ColorConverter.
diff --git a/shared-module/displayio/ColorConverter.h b/shared-module/displayio/ColorConverter.h
index 7f3c1a0a0..c48b98e6d 100644
--- a/shared-module/displayio/ColorConverter.h
+++ b/shared-module/displayio/ColorConverter.h
@@ -31,6 +31,7 @@
 #include <stdint.h>
 
 #include "py/obj.h"
+#include "shared-module/displayio/Palette.h"
 
 typedef struct {
     mp_obj_base_t base;
@@ -38,5 +39,8 @@ typedef struct {
 
 bool displayio_colorconverter_needs_refresh(displayio_colorconverter_t *self);
 void displayio_colorconverter_finish_refresh(displayio_colorconverter_t *self);
+bool displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color);
+uint16_t displayio_colorconverter_compute_rgb565(uint32_t color_rgb888);
+uint8_t displayio_colorconverter_compute_luma(uint32_t color_rgb888);
 
 #endif // MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_COLORCONVERTER_H
diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index 0ae88300a..9aee70e32 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -28,6 +28,7 @@
 
 #include "py/runtime.h"
 #include "shared-bindings/displayio/FourWire.h"
+#include "shared-bindings/displayio/I2CDisplay.h"
 #include "shared-bindings/displayio/ParallelBus.h"
 #include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/time/__init__.h"
@@ -35,6 +36,7 @@
 #include "supervisor/shared/display.h"
 
 #include <stdint.h>
+#include <string.h>
 
 #include "tick.h"
 
@@ -42,11 +44,14 @@
 
 void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         mp_obj_t bus, uint16_t width, uint16_t height, int16_t colstart, int16_t rowstart, uint16_t rotation,
-        uint16_t color_depth, uint8_t set_column_command, uint8_t set_row_command,
+        uint16_t color_depth, bool grayscale, bool pixels_in_byte_share_row,
+        uint8_t set_column_command, uint8_t set_row_command,
         uint8_t write_ram_command, uint8_t set_vertical_scroll, uint8_t* init_sequence, uint16_t init_sequence_len,
-        const mcu_pin_obj_t* backlight_pin, mp_float_t brightness, bool auto_brightness,
+        const mcu_pin_obj_t* backlight_pin, uint16_t brightness_command, mp_float_t brightness, bool auto_brightness,
         bool single_byte_bounds, bool data_as_commands) {
-    self->color_depth = color_depth;
+    self->colorspace.depth = color_depth;
+    self->colorspace.grayscale = grayscale;
+    self->colorspace.pixels_in_byte_share_row = pixels_in_byte_share_row;
     self->set_column_command = set_column_command;
     self->set_row_command = set_row_command;
     self->write_ram_command = write_ram_command;
@@ -54,6 +59,7 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     self->current_group = NULL;
     self->colstart = colstart;
     self->rowstart = rowstart;
+    self->brightness_command = brightness_command;
     self->auto_brightness = auto_brightness;
     self->data_as_commands = data_as_commands;
     self->single_byte_bounds = single_byte_bounds;
@@ -66,6 +72,10 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         self->begin_transaction = common_hal_displayio_fourwire_begin_transaction;
         self->send = common_hal_displayio_fourwire_send;
         self->end_transaction = common_hal_displayio_fourwire_end_transaction;
+    } else if (MP_OBJ_IS_TYPE(bus, &displayio_i2cdisplay_type)) {
+        self->begin_transaction = common_hal_displayio_i2cdisplay_begin_transaction;
+        self->send = common_hal_displayio_i2cdisplay_send;
+        self->end_transaction = common_hal_displayio_i2cdisplay_end_transaction;
     } else {
         mp_raise_ValueError(translate("Unsupported display bus type"));
     }
@@ -83,13 +93,13 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         bool delay = (data_size & DELAY) != 0;
         data_size &= ~DELAY;
         uint8_t *data = cmd + 2;
-        self->send(self->bus, true, cmd, 1);
         if (self->data_as_commands) {
-            // Loop through each parameter to force a CS toggle
-            for (uint32_t j=0; j < data_size; j++) {
-                self->send(self->bus, true, data + j, 1);
-            }
+            uint8_t full_command[data_size + 1];
+            full_command[0] = cmd[0];
+            memcpy(full_command + 1, data, data_size);
+            self->send(self->bus, true, full_command, data_size + 1);
         } else {
+            self->send(self->bus, true, cmd, 1);
             self->send(self->bus, false, data, data_size);
         }
         uint16_t delay_length_ms = 10;
@@ -141,11 +151,13 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         } else {
             self->backlight_pwm.base.type = &pulseio_pwmout_type;
             common_hal_pulseio_pwmout_never_reset(&self->backlight_pwm);
-            if (!self->auto_brightness) {
-                common_hal_displayio_display_set_brightness(self, brightness);
-            }
         }
     }
+    if (!self->auto_brightness && (self->backlight_inout.base.type != &mp_type_NoneType || brightness_command <= 0xff)) {
+        common_hal_displayio_display_set_brightness(self, brightness);
+    } else {
+        self->current_brightness = -1.0;
+    }
 
     self->area.x1 = 0;
     self->area.y1 = 0;
@@ -234,17 +246,7 @@ void common_hal_displayio_display_set_auto_brightness(displayio_display_obj_t* s
 }
 
 mp_float_t common_hal_displayio_display_get_brightness(displayio_display_obj_t* self) {
-    if (self->backlight_pwm.base.type == &pulseio_pwmout_type) {
-        uint16_t duty_cycle = common_hal_pulseio_pwmout_get_duty_cycle(&self->backlight_pwm);
-        return duty_cycle / ((mp_float_t) 0xffff);
-    } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
-        if (common_hal_digitalio_digitalinout_get_value(&self->backlight_inout)) {
-            return 1.0;
-        } else {
-            return 0.0;
-        }
-    }
-    return -1.0;
+    return self->current_brightness;
 }
 
 bool common_hal_displayio_display_set_brightness(displayio_display_obj_t* self, mp_float_t brightness) {
@@ -256,8 +258,26 @@ bool common_hal_displayio_display_set_brightness(displayio_display_obj_t* self,
     } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
         common_hal_digitalio_digitalinout_set_value(&self->backlight_inout, brightness > 0.99);
         ok = true;
+    } else if (self->brightness_command < 0x100) {
+        ok = self->begin_transaction(self->bus);
+        if (ok) {
+            if (self->data_as_commands) {
+                uint8_t set_brightness[2] = {self->brightness_command, (uint8_t) (0xff * brightness)};
+                self->send(self->bus, true, set_brightness, 2);
+            } else {
+                uint8_t command = self->brightness_command;
+                uint8_t hex_brightness = 0xff * brightness;
+                self->send(self->bus, true, &command, 1);
+                self->send(self->bus, false, &hex_brightness, 1);
+            }
+            self->end_transaction(self->bus);
+        }
+
     }
     self->updating_backlight = false;
+    if (ok) {
+        self->current_brightness = brightness;
+    }
     return ok;
 }
 
@@ -269,35 +289,67 @@ void displayio_display_end_transaction(displayio_display_obj_t* self) {
     self->end_transaction(self->bus);
 }
 
-void displayio_display_set_region_to_update(displayio_display_obj_t* self, uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1) {
-    self->send(self->bus, true, &self->set_column_command, 1);
-    bool isCommand = self->data_as_commands;
-    if (self->single_byte_bounds) {
-        uint8_t data[2];
-        data[0] = x0 + self->colstart;
-        data[1] = x1 - 1 + self->colstart;
-        self->send(self->bus, isCommand, (uint8_t*) data, 2);
-    } else {
-        uint16_t data[2];
-        data[0] = __builtin_bswap16(x0 + self->colstart);
-        data[1] = __builtin_bswap16(x1 - 1 + self->colstart);
-        self->send(self->bus, isCommand, (uint8_t*) data, 4);
+void displayio_display_set_region_to_update(displayio_display_obj_t* self, displayio_area_t* area) {
+    uint16_t x1 = area->x1;
+    uint16_t x2 = area->x2;
+    uint16_t y1 = area->y1;
+    uint16_t y2 = area->y2;
+    // Collapse down the dimension where multiple pixels are in a byte.
+    if (self->colorspace.depth < 8) {
+        uint8_t pixels_per_byte = 8 / self->colorspace.depth;
+        if (self->colorspace.pixels_in_byte_share_row) {
+            x1 /= pixels_per_byte;
+            x2 /= pixels_per_byte;
+        } else {
+            y1 /= pixels_per_byte;
+            y2 /= pixels_per_byte;
+        }
+    }
+
+    // Set column.
+    uint8_t data[5];
+    data[0] = self->set_column_command;
+    uint8_t data_length = 1;
+    if (!self->data_as_commands) {
+        self->send(self->bus, true, data, 1);
+        data_length = 0;
     }
-    self->send(self->bus, true, &self->set_row_command, 1);
     if (self->single_byte_bounds) {
-        uint8_t data[2];
-        data[0] = y0 + self->rowstart;
-        data[1] = y1 - 1 + self->rowstart;
-        self->send(self->bus, isCommand, (uint8_t*) data, 2);
+        data[data_length] = x1 + self->colstart;
+        data[data_length + 1] = x2 - 1 + self->colstart;
+        data_length += 2;
     } else {
-        uint16_t data[2];
-        data[0] = __builtin_bswap16(y0  + self->rowstart);
-        data[1] = __builtin_bswap16(y1 - 1 + self->rowstart);
-        self->send(self->bus, isCommand, (uint8_t*) data, 4);
+        x1 += self->colstart;
+        x2 += self->colstart - 1;
+        data[data_length] = x1 >> 8;
+        data[data_length + 1] = x1 & 0xff;
+        data[data_length + 2] = x2 >> 8;
+        data[data_length + 3] = x2 & 0xff;
+        data_length += 4;
     }
+    self->send(self->bus, self->data_as_commands, data, data_length);
+
+    // Set row.
+    data[0] = self->set_row_command;
+    data_length = 1;
     if (!self->data_as_commands) {
-        self->send(self->bus, true, &self->write_ram_command, 1);
+        self->send(self->bus, true, data, 1);
+        data_length = 0;
     }
+    if (self->single_byte_bounds) {
+        data[data_length] = y1 + self->rowstart;
+        data[data_length + 1] = y2 - 1 + self->rowstart;
+        data_length += 2;
+    } else {
+        y1 += self->rowstart;
+        y2 += self->rowstart - 1;
+        data[data_length] = y1 >> 8;
+        data[data_length + 1] = y1 & 0xff;
+        data[data_length + 2] = y2 >> 8;
+        data[data_length + 3] = y2 & 0xff;
+        data_length += 4;
+    }
+    self->send(self->bus, self->data_as_commands, data, data_length);
 }
 
 void displayio_display_start_refresh(displayio_display_obj_t* self) {
@@ -322,6 +374,9 @@ void displayio_display_finish_refresh(displayio_display_obj_t* self) {
 }
 
 void displayio_display_send_pixels(displayio_display_obj_t* self, uint8_t* pixels, uint32_t length) {
+    if (!self->data_as_commands) {
+        self->send(self->bus, true, &self->write_ram_command, 1);
+    }
     self->send(self->bus, false, pixels, length);
 }
 
@@ -349,9 +404,33 @@ void release_display(displayio_display_obj_t* self) {
 }
 
 bool displayio_display_fill_area(displayio_display_obj_t *self, displayio_area_t* area, uint32_t* mask, uint32_t *buffer) {
-    return displayio_group_fill_area(self->current_group, area, mask, buffer);
+    return displayio_group_fill_area(self->current_group, &self->colorspace, area, mask, buffer);
 }
 
 bool displayio_display_clip_area(displayio_display_obj_t *self, const displayio_area_t* area, displayio_area_t* clipped) {
-    return displayio_area_compute_overlap(&self->area, area, clipped);
+    bool overlaps = displayio_area_compute_overlap(&self->area, area, clipped);
+    if (!overlaps) {
+        return false;
+    }
+    // Expand the area if we have multiple pixels per byte and we need to byte
+    // align the bounds.
+    if (self->colorspace.depth < 8) {
+        uint8_t pixels_per_byte = 8 / self->colorspace.depth;
+        if (self->colorspace.pixels_in_byte_share_row) {
+            if (clipped->x1 % pixels_per_byte != 0) {
+                clipped->x1 -= clipped->x1 % pixels_per_byte;
+            }
+            if (clipped->x2 % pixels_per_byte != 0) {
+                clipped->x2 += pixels_per_byte - clipped->x2 % pixels_per_byte;
+            }
+        } else {
+            if (clipped->y1 % pixels_per_byte != 0) {
+                clipped->y1 -= clipped->y1 % pixels_per_byte;
+            }
+            if (clipped->y2 % pixels_per_byte != 0) {
+                clipped->y2 += pixels_per_byte - clipped->y2 % pixels_per_byte;
+            }
+        }
+    }
+    return true;
 }
diff --git a/shared-module/displayio/Display.h b/shared-module/displayio/Display.h
index fa8902ced..96d1c06d5 100644
--- a/shared-module/displayio/Display.h
+++ b/shared-module/displayio/Display.h
@@ -52,11 +52,13 @@ typedef struct {
     uint64_t last_backlight_refresh;
     displayio_buffer_transform_t transform;
     displayio_area_t area;
+    mp_float_t current_brightness;
     uint16_t width;
     uint16_t height;
-    uint16_t color_depth;
+    _displayio_colorspace_t colorspace;
     int16_t colstart;
     int16_t rowstart;
+    uint16_t brightness_command;
     uint8_t set_column_command;
     uint8_t set_row_command;
     uint8_t write_ram_command;
diff --git a/shared-module/displayio/FourWire.c b/shared-module/displayio/FourWire.c
index d38da56fc..913635db8 100644
--- a/shared-module/displayio/FourWire.c
+++ b/shared-module/displayio/FourWire.c
@@ -59,6 +59,11 @@ void common_hal_displayio_fourwire_construct(displayio_fourwire_obj_t* self,
         common_hal_digitalio_digitalinout_construct(&self->reset, reset);
         common_hal_digitalio_digitalinout_switch_to_output(&self->reset, true, DRIVE_MODE_PUSH_PULL);
         never_reset_pin_number(reset->number);
+
+        common_hal_digitalio_digitalinout_set_value(&self->reset, false);
+        common_hal_mcu_delay_us(10);
+        common_hal_digitalio_digitalinout_set_value(&self->reset, true);
+        common_hal_mcu_delay_us(10);
     }
 
     never_reset_pin_number(command->number);
@@ -88,13 +93,19 @@ bool common_hal_displayio_fourwire_begin_transaction(mp_obj_t obj) {
 
 void common_hal_displayio_fourwire_send(mp_obj_t obj, bool command, uint8_t *data, uint32_t data_length) {
     displayio_fourwire_obj_t* self = MP_OBJ_TO_PTR(obj);
+    common_hal_digitalio_digitalinout_set_value(&self->command, !command);
     if (command) {
-        common_hal_digitalio_digitalinout_set_value(&self->chip_select, true);
-        common_hal_mcu_delay_us(1);
-        common_hal_digitalio_digitalinout_set_value(&self->chip_select, false);
+        // Toggle chip select after each command byte in case the display driver
+        // IC latches commands based on it.
+        for (size_t i = 0; i < data_length; i++) {
+            common_hal_busio_spi_write(self->bus, &data[i], 1);
+            common_hal_digitalio_digitalinout_set_value(&self->chip_select, true);
+            common_hal_mcu_delay_us(1);
+            common_hal_digitalio_digitalinout_set_value(&self->chip_select, false);
+        }
+    } else {
+        common_hal_busio_spi_write(self->bus, data, data_length);
     }
-    common_hal_digitalio_digitalinout_set_value(&self->command, !command);
-    common_hal_busio_spi_write(self->bus, data, data_length);
 }
 
 void common_hal_displayio_fourwire_end_transaction(mp_obj_t obj) {
diff --git a/shared-module/displayio/FourWire.h b/shared-module/displayio/FourWire.h
index 743139e62..a4260a3ac 100644
--- a/shared-module/displayio/FourWire.h
+++ b/shared-module/displayio/FourWire.h
@@ -24,8 +24,8 @@
  * THE SOFTWARE.
  */
 
-#ifndef MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_DISPLAYIO_FOURWIRE_H
-#define MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_DISPLAYIO_FOURWIRE_H
+#ifndef MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_FOURWIRE_H
+#define MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_FOURWIRE_H
 
 #include "common-hal/busio/SPI.h"
 #include "common-hal/digitalio/DigitalInOut.h"
@@ -43,4 +43,4 @@ typedef struct {
     uint8_t phase;
 } displayio_fourwire_obj_t;
 
-#endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_DISPLAYIO_FOURWIRE_H
+#endif // MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_FOURWIRE_H
diff --git a/shared-module/displayio/Group.c b/shared-module/displayio/Group.c
index 15060e87b..38418a029 100644
--- a/shared-module/displayio/Group.c
+++ b/shared-module/displayio/Group.c
@@ -270,19 +270,19 @@ void displayio_group_construct(displayio_group_t* self, displayio_group_child_t*
     self->in_group = false;
 }
 
-bool displayio_group_fill_area(displayio_group_t *self, const displayio_area_t* area, uint32_t* mask, uint32_t* buffer) {
+bool displayio_group_fill_area(displayio_group_t *self, const _displayio_colorspace_t* colorspace, const displayio_area_t* area, uint32_t* mask, uint32_t* buffer) {
     // Track if any of the layers finishes filling in the given area. We can ignore any remaining
     // layers at that point.
     bool full_coverage = false;
     for (int32_t i = self->size - 1; i >= 0 ; i--) {
         mp_obj_t layer = self->children[i].native;
         if (MP_OBJ_IS_TYPE(layer, &displayio_tilegrid_type)) {
-            if (displayio_tilegrid_fill_area(layer, area, mask, buffer)) {
+            if (displayio_tilegrid_fill_area(layer, colorspace, area, mask, buffer)) {
                 full_coverage = true;
                 break;
             }
         } else if (MP_OBJ_IS_TYPE(layer, &displayio_group_type)) {
-            if (displayio_group_fill_area(layer, area, mask, buffer)) {
+            if (displayio_group_fill_area(layer, colorspace, area, mask, buffer)) {
                 full_coverage = true;
                 break;
             }
diff --git a/shared-module/displayio/Group.h b/shared-module/displayio/Group.h
index 7ce19a4cd..4e2308e56 100644
--- a/shared-module/displayio/Group.h
+++ b/shared-module/displayio/Group.h
@@ -32,6 +32,7 @@
 
 #include "py/obj.h"
 #include "shared-module/displayio/area.h"
+#include "shared-module/displayio/Palette.h"
 
 typedef struct {
     mp_obj_t native;
@@ -54,7 +55,7 @@ typedef struct {
 
 void displayio_group_construct(displayio_group_t* self, displayio_group_child_t* child_array, uint32_t max_size, uint32_t scale, mp_int_t x, mp_int_t y);
 bool displayio_group_get_previous_area(displayio_group_t *group, displayio_area_t* area);
-bool displayio_group_fill_area(displayio_group_t *group, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer);
+bool displayio_group_fill_area(displayio_group_t *group, const _displayio_colorspace_t* colorspace, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer);
 void displayio_group_update_transform(displayio_group_t *group, const displayio_buffer_transform_t* parent_transform);
 void displayio_group_finish_refresh(displayio_group_t *self);
 displayio_area_t* displayio_group_get_refresh_areas(displayio_group_t *self, displayio_area_t* tail);
diff --git a/shared-module/displayio/I2CDisplay.c b/shared-module/displayio/I2CDisplay.c
new file mode 100644
index 000000000..9d8949528
--- /dev/null
+++ b/shared-module/displayio/I2CDisplay.c
@@ -0,0 +1,105 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/displayio/I2CDisplay.h"
+
+#include <stdint.h>
+#include <string.h>
+
+#include "py/gc.h"
+#include "py/runtime.h"
+#include "shared-bindings/busio/I2C.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/microcontroller/__init__.h"
+#include "shared-bindings/time/__init__.h"
+
+#include "tick.h"
+
+void common_hal_displayio_i2cdisplay_construct(displayio_i2cdisplay_obj_t* self,
+    busio_i2c_obj_t* i2c, uint16_t device_address, const mcu_pin_obj_t* reset) {
+
+    // Probe the bus to see if a device acknowledges the given address.
+    if (!common_hal_busio_i2c_probe(i2c, device_address)) {
+        mp_raise_ValueError_varg(translate("Unable to find I2C Display at %x"), device_address);
+    }
+
+        // Write to the device and return 0 on success or an appropriate error code from mperrno.h
+    self->bus = i2c;
+    common_hal_busio_i2c_never_reset(self->bus);
+    // Our object is statically allocated off the heap so make sure the bus object lives to the end
+    // of the heap as well.
+    gc_never_free(self->bus);
+
+    self->address = device_address;
+
+    if (reset != NULL) {
+        common_hal_digitalio_digitalinout_construct(&self->reset, reset);
+        common_hal_digitalio_digitalinout_switch_to_output(&self->reset, true, DRIVE_MODE_PUSH_PULL);
+        never_reset_pin_number(reset->number);
+
+        common_hal_digitalio_digitalinout_set_value(&self->reset, false);
+        common_hal_mcu_delay_us(1);
+        common_hal_digitalio_digitalinout_set_value(&self->reset, true);
+    }
+}
+
+void common_hal_displayio_i2cdisplay_deinit(displayio_i2cdisplay_obj_t* self) {
+    if (self->bus == &self->inline_bus) {
+        common_hal_busio_i2c_deinit(self->bus);
+    }
+
+    reset_pin_number(self->reset.pin->number);
+}
+
+bool common_hal_displayio_i2cdisplay_begin_transaction(mp_obj_t obj) {
+    displayio_i2cdisplay_obj_t* self = MP_OBJ_TO_PTR(obj);
+    if (!common_hal_busio_i2c_try_lock(self->bus)) {
+        return false;
+    }
+    return true;
+}
+
+void common_hal_displayio_i2cdisplay_send(mp_obj_t obj, bool command, uint8_t *data, uint32_t data_length) {
+    displayio_i2cdisplay_obj_t* self = MP_OBJ_TO_PTR(obj);
+    if (command) {
+        uint8_t command_bytes[2 * data_length];
+        for (uint32_t i = 0; i < data_length; i++) {
+            command_bytes[2 * i] = 0x80;
+            command_bytes[2 * i + 1] = data[i];
+        }
+        common_hal_busio_i2c_write(self->bus, self->address, command_bytes, 2 * data_length, true);
+    } else {
+        uint8_t data_bytes[data_length + 1];
+        data_bytes[0] = 0x40;
+        memcpy(data_bytes + 1, data, data_length);
+        common_hal_busio_i2c_write(self->bus, self->address, data_bytes, data_length + 1, true);
+    }
+}
+
+void common_hal_displayio_i2cdisplay_end_transaction(mp_obj_t obj) {
+    displayio_i2cdisplay_obj_t* self = MP_OBJ_TO_PTR(obj);
+    common_hal_busio_i2c_unlock(self->bus);
+}
diff --git a/shared-module/displayio/I2CDisplay.h b/shared-module/displayio/I2CDisplay.h
new file mode 100644
index 000000000..4636c3f73
--- /dev/null
+++ b/shared-module/displayio/I2CDisplay.h
@@ -0,0 +1,41 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_I2CDISPLAY_H
+#define MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_I2CDISPLAY_H
+
+#include "common-hal/busio/I2C.h"
+#include "common-hal/digitalio/DigitalInOut.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    busio_i2c_obj_t* bus;
+    busio_i2c_obj_t inline_bus;
+    digitalio_digitalinout_obj_t reset;
+    uint16_t address;
+} displayio_i2cdisplay_obj_t;
+
+#endif // MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_I2CDISPLAY_H
diff --git a/shared-module/displayio/Palette.c b/shared-module/displayio/Palette.c
index 8dc6e766b..444151b3c 100644
--- a/shared-module/displayio/Palette.c
+++ b/shared-module/displayio/Palette.c
@@ -26,49 +26,49 @@
 
 #include "shared-bindings/displayio/Palette.h"
 
+#include "shared-module/displayio/ColorConverter.h"
+
 void common_hal_displayio_palette_construct(displayio_palette_t* self, uint16_t color_count) {
     self->color_count = color_count;
-    self->colors = (uint32_t *) m_malloc(color_count * sizeof(uint16_t), false);
-    uint32_t opaque_byte_count = color_count / 8;
-    if (color_count % 8 > 0) {
-        opaque_byte_count += 1;
-    }
-    self->opaque = (uint32_t *) m_malloc(opaque_byte_count, false);
+    self->colors = (_displayio_color_t *) m_malloc(color_count * sizeof(_displayio_color_t), false);
 }
 
 void common_hal_displayio_palette_make_opaque(displayio_palette_t* self, uint32_t palette_index) {
-    self->opaque[palette_index / 32] &= ~(0x1 << (palette_index % 32));
+    self->colors[palette_index].transparent = false;
 }
 
 void common_hal_displayio_palette_make_transparent(displayio_palette_t* self, uint32_t palette_index) {
-    self->opaque[palette_index / 32] |= (0x1 << (palette_index % 32));
+    self->colors[palette_index].transparent = true;
+}
+
+uint32_t common_hal_displayio_palette_get_len(displayio_palette_t* self) {
+    return self->color_count;
 }
 
 void common_hal_displayio_palette_set_color(displayio_palette_t* self, uint32_t palette_index, uint32_t color) {
-    uint32_t shift = (palette_index % 2) * 16;
-    uint32_t masked = self->colors[palette_index / 2] & ~(0xffff << shift);
-    uint32_t r5 = (color >> 19);
-    uint32_t g6 = (color >> 10) & 0x3f;
-    uint32_t b5 = (color >> 3) & 0x1f;
-    uint32_t packed = r5 << 11 | g6 << 5 | b5;
-    // swap bytes
-    packed = __builtin_bswap16(packed);
-    uint32_t final_color = masked | packed << shift;
-    if (self->colors[palette_index / 2] == final_color) {
+    if (self->colors[palette_index].rgb888 == color) {
         return;
     }
-    self->colors[palette_index / 2] = final_color;
+    self->colors[palette_index].rgb888 = color;
+    self->colors[palette_index].luma = displayio_colorconverter_compute_luma(color);
+    self->colors[palette_index].rgb565 = displayio_colorconverter_compute_rgb565(color);
     self->needs_refresh = true;
 }
 
-bool displayio_palette_get_color(displayio_palette_t *self, uint32_t palette_index, uint16_t* color) {
-    if (palette_index > self->color_count) {
-        return false;
+uint32_t common_hal_displayio_palette_get_color(displayio_palette_t* self, uint32_t palette_index) {
+    return self->colors[palette_index].rgb888;
+}
+
+bool displayio_palette_get_color(displayio_palette_t *self, const _displayio_colorspace_t* colorspace, uint32_t palette_index, uint32_t* color) {
+    if (palette_index > self->color_count || self->colors[palette_index].transparent) {
+        return false; // returns opaque
     }
-    if ((self->opaque[palette_index / 32] & (0x1 << (palette_index % 32))) != 0) {
-        return false;
+
+    if (colorspace->grayscale) {
+        *color = self->colors[palette_index].luma >> (8 - colorspace->depth);
+    } else {
+        *color = self->colors[palette_index].rgb565;
     }
-    *color = (self->colors[palette_index / 2] >> (16 * (palette_index % 2))) & 0xffff;
 
     return true;
 }
diff --git a/shared-module/displayio/Palette.h b/shared-module/displayio/Palette.h
index 3813e8bdd..6f5e2774c 100644
--- a/shared-module/displayio/Palette.h
+++ b/shared-module/displayio/Palette.h
@@ -32,15 +32,28 @@
 
 #include "py/obj.h"
 
+typedef struct {
+    uint8_t depth;
+    bool grayscale;
+    bool pixels_in_byte_share_row;
+    uint8_t hue;
+} _displayio_colorspace_t;
+
+typedef struct {
+    uint32_t rgb888;
+    uint16_t rgb565;
+    uint8_t luma;
+    bool transparent; // This may have additional bits added later for blending.
+} _displayio_color_t;
+
 typedef struct {
     mp_obj_base_t base;
-    uint32_t* opaque;
-    uint32_t* colors;
+    _displayio_color_t* colors;
     uint32_t color_count;
     bool needs_refresh;
 } displayio_palette_t;
 
-bool displayio_palette_get_color(displayio_palette_t *palette, uint32_t palette_index, uint16_t* color);
+bool displayio_palette_get_color(displayio_palette_t *palette, const _displayio_colorspace_t* colorspace, uint32_t palette_index, uint32_t* color);
 bool displayio_palette_needs_refresh(displayio_palette_t *self);
 void displayio_palette_finish_refresh(displayio_palette_t *self);
 
diff --git a/shared-module/displayio/TileGrid.c b/shared-module/displayio/TileGrid.c
index 0cd00e0ce..77e6daf6f 100644
--- a/shared-module/displayio/TileGrid.c
+++ b/shared-module/displayio/TileGrid.c
@@ -291,7 +291,7 @@ void common_hal_displayio_tilegrid_set_top_left(displayio_tilegrid_t *self, uint
     self->full_change = true;
 }
 
-bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer) {
+bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_colorspace_t* colorspace, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer) {
     // If no tiles are present we have no impact.
     uint8_t* tiles = self->tiles;
     if (self->inline_tiles) {
@@ -371,12 +371,13 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const displayio_ar
         y_shift = temp_shift;
     }
 
+    uint8_t pixels_per_byte = 8 / colorspace->depth;
     for (int16_t y = start_y; y < end_y; y++) {
-        int16_t row_start = start + (y - start_y + y_shift) * y_stride;
+        int16_t row_start = start + (y - start_y + y_shift) * y_stride; // in pixels
         int16_t local_y = y / self->absolute_transform->scale;
         for (int16_t x = start_x; x < end_x; x++) {
             // Compute the destination pixel in the buffer and mask based on the transformations.
-            int16_t offset = row_start + (x - start_x + x_shift) * x_stride;
+            int16_t offset = row_start + (x - start_x + x_shift) * x_stride; // in pixels
 
             // This is super useful for debugging out range accesses. Uncomment to use.
             // if (offset < 0 || offset >= (int32_t) displayio_area_size(area)) {
@@ -404,23 +405,38 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const displayio_ar
                 value = common_hal_displayio_ondiskbitmap_get_pixel(self->bitmap, tile_x, tile_y);
             }
 
-            uint16_t* pixel = ((uint16_t*) buffer) + offset;
+            uint32_t pixel;
+            bool opaque = true;
             if (self->pixel_shader == mp_const_none) {
-                *pixel = value;
-                return true;
+                pixel = value;
             } else if (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_palette_type)) {
-                if (!displayio_palette_get_color(self->pixel_shader, value, pixel)) {
-                    // A pixel is transparent so we haven't fully covered the area ourselves.
-                    full_coverage = false;
-                } else {
-                    mask[offset / 32] |= 1 << (offset % 32);
-                }
+                opaque = displayio_palette_get_color(self->pixel_shader, colorspace, value, &pixel);
             } else if (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_colorconverter_type)) {
-                if (!common_hal_displayio_colorconverter_convert(self->pixel_shader, value, pixel)) {
-                    // A pixel is transparent so we haven't fully covered the area ourselves.
-                    full_coverage = false;
-                } else {
-                    mask[offset / 32] |= 1 << (offset % 32);
+                opaque = displayio_colorconverter_convert(self->pixel_shader, colorspace, value, &pixel);
+            }
+            if (!opaque) {
+                // A pixel is transparent so we haven't fully covered the area ourselves.
+                full_coverage = false;
+            } else {
+                mask[offset / 32] |= 1 << (offset % 32);
+                if (colorspace->depth == 16) {
+                    *(((uint16_t*) buffer) + offset) = pixel;
+                } else if (colorspace->depth == 8) {
+                    *(((uint8_t*) buffer) + offset) = pixel;
+                } else if (colorspace->depth < 8) {
+                    // Reorder the offsets to pack multiple rows into a byte (meaning they share a column).
+                    if (!colorspace->pixels_in_byte_share_row) {
+                        uint16_t width = displayio_area_width(area);
+                        uint16_t row = offset / width;
+                        uint16_t col = offset % width;
+                        // Dividing by pixels_per_byte does truncated division even if we multiply it back out.
+                        offset = col * pixels_per_byte + (row / pixels_per_byte) * pixels_per_byte * width + row % pixels_per_byte;
+                        // Also useful for validating that the bitpacking worked correctly.
+                        // if (offset > displayio_area_size(area)) {
+                        //     asm("bkpt");
+                        // }
+                    }
+                    ((uint8_t*)buffer)[offset / pixels_per_byte] |= pixel << ((offset % pixels_per_byte) * colorspace->depth);
                 }
             }
         }
diff --git a/shared-module/displayio/TileGrid.h b/shared-module/displayio/TileGrid.h
index 4d97eccc2..fb6033e9c 100644
--- a/shared-module/displayio/TileGrid.h
+++ b/shared-module/displayio/TileGrid.h
@@ -32,6 +32,7 @@
 
 #include "py/obj.h"
 #include "shared-module/displayio/area.h"
+#include "shared-module/displayio/Palette.h"
 
 typedef struct {
     mp_obj_base_t base;
@@ -71,7 +72,7 @@ displayio_area_t* displayio_tilegrid_get_refresh_areas(displayio_tilegrid_t *sel
 
 // Area is always in absolute screen coordinates. Update transform is used to inform TileGrids how
 // they relate to it.
-bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer);
+bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_colorspace_t* colorspace, const displayio_area_t* area, uint32_t* mask, uint32_t *buffer);
 void displayio_tilegrid_update_transform(displayio_tilegrid_t *group, const displayio_buffer_transform_t* parent_transform);
 
 // Fills in area with the maximum bounds of all related pixels in the last rendered frame. Returns
diff --git a/shared-module/displayio/__init__.c b/shared-module/displayio/__init__.c
index b6709e0eb..97060aaeb 100644
--- a/shared-module/displayio/__init__.c
+++ b/shared-module/displayio/__init__.c
@@ -19,9 +19,10 @@
 #include "supervisor/usb.h"
 
 primary_display_t displays[CIRCUITPY_DISPLAY_LIMIT];
+uint32_t frame_count = 0;
 
 bool refresh_area(displayio_display_obj_t* display, const displayio_area_t* area) {
-    uint16_t buffer_size = 512;
+    uint16_t buffer_size = 128; // In uint32_ts
 
     displayio_area_t clipped;
     // Clip the area to the display by overlapping the areas. If there is no overlap then we're done.
@@ -30,15 +31,36 @@ bool refresh_area(displayio_display_obj_t* display, const displayio_area_t* area
     }
     uint16_t subrectangles = 1;
     uint16_t rows_per_buffer = displayio_area_height(&clipped);
-    if (displayio_area_size(area) > buffer_size) {
-        rows_per_buffer = buffer_size / displayio_area_width(&clipped);
+    uint8_t pixels_per_word = (sizeof(uint32_t) * 8) / display->colorspace.depth;
+    uint16_t pixels_per_buffer = displayio_area_size(&clipped);
+    if (displayio_area_size(&clipped) > buffer_size * pixels_per_word) {
+        rows_per_buffer = buffer_size * pixels_per_word / displayio_area_width(&clipped);
+        if (rows_per_buffer == 0) {
+            rows_per_buffer = 1;
+        }
+        // If pixels are packed by column then ensure rows_per_buffer is on a byte boundary.
+        if (display->colorspace.depth < 8 && !display->colorspace.pixels_in_byte_share_row) {
+            uint8_t pixels_per_byte = 8 / display->colorspace.depth;
+            if (rows_per_buffer % pixels_per_byte != 0) {
+                rows_per_buffer -= rows_per_buffer % pixels_per_byte;
+            }
+        }
         subrectangles = displayio_area_height(&clipped) / rows_per_buffer;
         if (displayio_area_height(&clipped) % rows_per_buffer != 0) {
             subrectangles++;
         }
-        buffer_size = rows_per_buffer * displayio_area_width(&clipped);
+        pixels_per_buffer = rows_per_buffer * displayio_area_width(&clipped);
+        buffer_size = pixels_per_buffer / pixels_per_word;
+        if (pixels_per_buffer % pixels_per_word) {
+            buffer_size += 1;
+        }
     }
-    uint32_t buffer[buffer_size / 2];
+
+    // Allocated and shared as a uint32_t array so the compiler knows the
+    // alignment everywhere.
+    uint32_t buffer[buffer_size];
+    volatile uint32_t mask_length = (pixels_per_buffer / 32) + 1;
+    uint32_t mask[mask_length];
     uint16_t remaining_rows = displayio_area_height(&clipped);
 
     for (uint16_t j = 0; j < subrectangles; j++) {
@@ -54,37 +76,30 @@ bool refresh_area(displayio_display_obj_t* display, const displayio_area_t* area
         remaining_rows -= rows_per_buffer;
 
         displayio_display_begin_transaction(display);
-        displayio_display_set_region_to_update(display, subrectangle.x1, subrectangle.y1,
-                                                        subrectangle.x2, subrectangle.y2);
+        displayio_display_set_region_to_update(display, &subrectangle);
         displayio_display_end_transaction(display);
 
-        uint32_t mask[(buffer_size / 32) + 1];
-        for (uint16_t k = 0; k < (buffer_size / 32) + 1; k++) {
-            mask[k] = 0x00000000;
+        uint16_t subrectangle_size_bytes;
+        if (display->colorspace.depth >= 8) {
+            subrectangle_size_bytes = displayio_area_size(&subrectangle) * (display->colorspace.depth / 8);
+        } else {
+            subrectangle_size_bytes = displayio_area_size(&subrectangle) / (8 / display->colorspace.depth);
         }
 
-        bool full_coverage = displayio_display_fill_area(display, &subrectangle, mask, buffer);
-        if (!full_coverage) {
-            uint32_t index = 0;
-            uint32_t current_mask = 0;
-            for (int16_t y = subrectangle.y1; y < subrectangle.y2; y++) {
-                for (int16_t x = subrectangle.x1; x < subrectangle.x2; x++) {
-                    if (index % 32 == 0) {
-                        current_mask = mask[index / 32];
-                    }
-                    if ((current_mask & (1 << (index % 32))) == 0) {
-                        ((uint16_t*) buffer)[index] = 0x0000;
-                    }
-                    index++;
-                }
-            }
+        for (uint16_t k = 0; k < mask_length; k++) {
+            mask[k] = 0x00000000;
+        }
+        for (uint16_t k = 0; k < buffer_size; k++) {
+            buffer[k] = 0x00000000;
         }
 
+        displayio_display_fill_area(display, &subrectangle, mask, buffer);
+
         if (!displayio_display_begin_transaction(display)) {
             // Can't acquire display bus; skip the rest of the data. Try next display.
             return false;
         }
-        displayio_display_send_pixels(display, (uint8_t*) buffer, displayio_area_size(&subrectangle) * sizeof(uint16_t));
+        displayio_display_send_pixels(display, (uint8_t*) buffer, subrectangle_size_bytes);
         displayio_display_end_transaction(display);
 
         // TODO(tannewt): Make refresh displays faster so we don't starve other
@@ -96,7 +111,6 @@ bool refresh_area(displayio_display_obj_t* display, const displayio_area_t* area
 
 // Check for recursive calls to displayio_refresh_displays.
 bool refresh_displays_in_progress = false;
-uint32_t frame_count = 0;
 
 void displayio_refresh_displays(void) {
     if (mp_hal_is_interrupted()) {
@@ -153,6 +167,8 @@ void common_hal_displayio_release_displays(void) {
             continue;
         } else if (bus_type == &displayio_fourwire_type) {
             common_hal_displayio_fourwire_deinit(&displays[i].fourwire_bus);
+        } else if (bus_type == &displayio_i2cdisplay_type) {
+            common_hal_displayio_i2cdisplay_deinit(&displays[i].i2cdisplay_bus);
         } else if (bus_type == &displayio_parallelbus_type) {
             common_hal_displayio_parallelbus_deinit(&displays[i].parallel_bus);
         }
@@ -169,30 +185,53 @@ void common_hal_displayio_release_displays(void) {
 void reset_displays(void) {
     // The SPI buses used by FourWires may be allocated on the heap so we need to move them inline.
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
-        if (displays[i].fourwire_bus.base.type != &displayio_fourwire_type) {
-            continue;
-        }
-        displayio_fourwire_obj_t* fourwire = &displays[i].fourwire_bus;
-        if (((uint32_t) fourwire->bus) < ((uint32_t) &displays) ||
-            ((uint32_t) fourwire->bus) > ((uint32_t) &displays + CIRCUITPY_DISPLAY_LIMIT)) {
-            busio_spi_obj_t* original_spi = fourwire->bus;
-            #if BOARD_SPI
-                // We don't need to move original_spi if it is the board.SPI object because it is
-                // statically allocated already. (Doing so would also make it impossible to reference in
-                // a subsequent VM run.)
-                if (original_spi == common_hal_board_get_spi()) {
-                    continue;
+        if (displays[i].fourwire_bus.base.type == &displayio_fourwire_type) {
+            displayio_fourwire_obj_t* fourwire = &displays[i].fourwire_bus;
+            if (((uint32_t) fourwire->bus) < ((uint32_t) &displays) ||
+                ((uint32_t) fourwire->bus) > ((uint32_t) &displays + CIRCUITPY_DISPLAY_LIMIT)) {
+                busio_spi_obj_t* original_spi = fourwire->bus;
+                #if BOARD_SPI
+                    // We don't need to move original_spi if it is the board.SPI object because it is
+                    // statically allocated already. (Doing so would also make it impossible to reference in
+                    // a subsequent VM run.)
+                    if (original_spi == common_hal_board_get_spi()) {
+                        continue;
+                    }
+                #endif
+                memcpy(&fourwire->inline_bus, original_spi, sizeof(busio_spi_obj_t));
+                fourwire->bus = &fourwire->inline_bus;
+                // Check for other displays that use the same spi bus and swap them too.
+                for (uint8_t j = i + 1; j < CIRCUITPY_DISPLAY_LIMIT; j++) {
+                    if (displays[i].fourwire_bus.base.type == &displayio_fourwire_type &&
+                            displays[i].fourwire_bus.bus == original_spi) {
+                        displays[i].fourwire_bus.bus = &fourwire->inline_bus;
+                    }
                 }
-            #endif
-            memcpy(&fourwire->inline_bus, original_spi, sizeof(busio_spi_obj_t));
-            fourwire->bus = &fourwire->inline_bus;
-            // Check for other displays that use the same spi bus and swap them too.
-            for (uint8_t j = i + 1; j < CIRCUITPY_DISPLAY_LIMIT; j++) {
-                if (displays[i].fourwire_bus.bus == original_spi) {
-                    displays[i].fourwire_bus.bus = &fourwire->inline_bus;
+            }
+        } else if (displays[i].i2cdisplay_bus.base.type == &displayio_i2cdisplay_type) {
+                displayio_i2cdisplay_obj_t* i2c = &displays[i].i2cdisplay_bus;
+                if (((uint32_t) i2c->bus) < ((uint32_t) &displays) ||
+                    ((uint32_t) i2c->bus) > ((uint32_t) &displays + CIRCUITPY_DISPLAY_LIMIT)) {
+                    busio_i2c_obj_t* original_i2c = i2c->bus;
+                    #if BOARD_I2C
+                        // We don't need to move original_i2c if it is the board.SPI object because it is
+                        // statically allocated already. (Doing so would also make it impossible to reference in
+                        // a subsequent VM run.)
+                        if (original_i2c == common_hal_board_get_i2c()) {
+                            continue;
+                        }
+                    #endif
+                    memcpy(&i2c->inline_bus, original_i2c, sizeof(busio_i2c_obj_t));
+                    i2c->bus = &i2c->inline_bus;
+                    // Check for other displays that use the same i2c bus and swap them too.
+                    for (uint8_t j = i + 1; j < CIRCUITPY_DISPLAY_LIMIT; j++) {
+                        if (displays[i].i2cdisplay_bus.base.type == &displayio_i2cdisplay_type &&
+                                displays[i].i2cdisplay_bus.bus == original_i2c) {
+                            displays[i].i2cdisplay_bus.bus = &i2c->inline_bus;
+                        }
+                    }
                 }
             }
-        }
     }
 
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
diff --git a/shared-module/displayio/__init__.h b/shared-module/displayio/__init__.h
index 18c1a4f4a..caa5ce36d 100644
--- a/shared-module/displayio/__init__.h
+++ b/shared-module/displayio/__init__.h
@@ -30,11 +30,13 @@
 #include "shared-bindings/displayio/Display.h"
 #include "shared-bindings/displayio/FourWire.h"
 #include "shared-bindings/displayio/Group.h"
+#include "shared-bindings/displayio/I2CDisplay.h"
 #include "shared-bindings/displayio/ParallelBus.h"
 
 typedef struct {
     union {
         displayio_fourwire_obj_t fourwire_bus;
+        displayio_i2cdisplay_obj_t i2cdisplay_bus;
         displayio_parallelbus_obj_t parallel_bus;
     };
     displayio_display_obj_t display;
-- 
cgit v1.2.3


From 1d1b8703b6c108b72a1abda9312646895f542672 Mon Sep 17 00:00:00 2001
From: Scott Shawcroft <scott@tannewt.org>
Date: Fri, 19 Jul 2019 16:05:13 -0700
Subject: Review feedback including NO_BRIGHTNESS_COMMAND macro

---
 locale/ID.po                                       | 13 +++++++--
 locale/circuitpython.pot                           | 13 +++++++--
 locale/de_DE.po                                    | 13 +++++++--
 locale/en_US.po                                    | 13 +++++++--
 locale/en_x_pirate.po                              | 13 +++++++--
 locale/es.po                                       | 13 +++++++--
 locale/fil.po                                      | 13 +++++++--
 locale/fr.po                                       | 13 +++++++--
 locale/it_IT.po                                    | 13 +++++++--
 locale/pl.po                                       | 13 +++++++--
 locale/pt_BR.po                                    | 13 +++++++--
 locale/zh_Latn_pinyin.po                           | 13 +++++++--
 .../atmel-samd/boards/hallowing_m0_express/board.c |  2 +-
 ports/atmel-samd/boards/pybadge/board.c            |  2 +-
 ports/atmel-samd/boards/pybadge_airlift/board.c    |  2 +-
 ports/atmel-samd/boards/pygamer/board.c            |  2 +-
 ports/atmel-samd/boards/pygamer_advance/board.c    |  2 +-
 ports/atmel-samd/boards/pyportal/board.c           |  2 +-
 ports/atmel-samd/boards/ugame10/board.c            |  2 +-
 shared-bindings/displayio/ColorConverter.c         |  2 ++
 shared-bindings/displayio/ColorConverter.h         |  2 +-
 shared-bindings/displayio/Display.c                | 10 +++++--
 shared-bindings/displayio/Display.h                |  2 ++
 shared-bindings/displayio/I2CDisplay.c             |  2 +-
 shared-bindings/displayio/Palette.c                |  2 +-
 shared-module/displayio/ColorConverter.c           |  4 +--
 shared-module/displayio/Display.c                  | 32 ++++++++++------------
 shared-module/displayio/Palette.h                  |  2 ++
 shared-module/displayio/TileGrid.c                 |  2 +-
 29 files changed, 161 insertions(+), 69 deletions(-)

(limited to 'shared-module/displayio')

diff --git a/locale/ID.po b/locale/ID.po
index 5e555a025..b211d5379 100644
--- a/locale/ID.po
+++ b/locale/ID.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -312,6 +312,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr "Kedua pin harus mendukung hardware interrut"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -443,8 +447,11 @@ msgstr "Clock unit sedang digunakan"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 67271258a..d91e2b3ac 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -308,6 +308,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -433,8 +437,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/de_DE.po b/locale/de_DE.po
index b0ebf9bcb..748833147 100644
--- a/locale/de_DE.po
+++ b/locale/de_DE.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: Pascal Deneaux\n"
 "Language-Team: Sebastian Plamauer, Pascal Deneaux\n"
@@ -312,6 +312,10 @@ msgstr "Bit depth muss ein Vielfaches von 8 sein."
 msgid "Both pins must support hardware interrupts"
 msgstr "Beide pins müssen Hardware Interrupts unterstützen"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Die Helligkeit muss zwischen 0 und 255 liegen"
@@ -437,8 +441,11 @@ msgstr "Clock unit wird benutzt"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Der Befehl muss ein int zwischen 0 und 255 sein"
 
diff --git a/locale/en_US.po b/locale/en_US.po
index 91fd15ac8..38074de98 100644
--- a/locale/en_US.po
+++ b/locale/en_US.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -308,6 +308,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -433,8 +437,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/en_x_pirate.po b/locale/en_x_pirate.po
index 5f0ab319f..9bee12d2a 100644
--- a/locale/en_x_pirate.po
+++ b/locale/en_x_pirate.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: \n"
 "Language-Team: @sommersoft, @MrCertainly\n"
@@ -312,6 +312,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -437,8 +441,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/es.po b/locale/es.po
index ff44238df..33cdfe348 100644
--- a/locale/es.po
+++ b/locale/es.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-08-24 22:56-0500\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -316,6 +316,10 @@ msgstr "Bits depth debe ser múltiplo de 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Ambos pines deben soportar interrupciones por hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "El brillo debe estar entro 0 y 255"
@@ -441,8 +445,11 @@ msgstr "Clock unit está siendo utilizado"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Entrada de columna debe ser digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Command debe estar entre 0 y 255."
 
diff --git a/locale/fil.po b/locale/fil.po
index 4693cde64..4f05812f7 100644
--- a/locale/fil.po
+++ b/locale/fil.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-12-20 22:15-0800\n"
 "Last-Translator: Timothy <me@timothygarcia.ca>\n"
 "Language-Team: fil\n"
@@ -314,6 +314,10 @@ msgstr "Bit depth ay dapat multiple ng 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Ang parehong mga pin ay dapat na sumusuporta sa hardware interrupts"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Ang liwanag ay dapat sa gitna ng 0 o 255"
@@ -441,8 +445,11 @@ msgstr "Clock unit ginagamit"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "Sa gitna ng 0 o 255 dapat ang bytes."
diff --git a/locale/fr.po b/locale/fr.po
index db2b659dd..a948630ee 100644
--- a/locale/fr.po
+++ b/locale/fr.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: 0.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-04-14 20:05+0100\n"
 "Last-Translator: Pierrick Couturier <arofarn@arofarn.info>\n"
 "Language-Team: fr\n"
@@ -319,6 +319,10 @@ msgstr "La profondeur de bit doit être un multiple de 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Les deux entrées doivent supporter les interruptions matérielles"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "La luminosité doit être entre 0 et 255"
@@ -447,8 +451,11 @@ msgstr "Horloge en cours d'utilisation"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "L'entrée 'Column' doit être un digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "La commande doit être un entier entre 0 et 255"
diff --git a/locale/it_IT.po b/locale/it_IT.po
index 0e717f15b..40a685f75 100644
--- a/locale/it_IT.po
+++ b/locale/it_IT.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-10-02 16:27+0200\n"
 "Last-Translator: Enrico Paganin <enrico.paganin@mail.com>\n"
 "Language-Team: \n"
@@ -314,6 +314,10 @@ msgstr "La profondità di bit deve essere multipla di 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Entrambi i pin devono supportare gli interrupt hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "La luminosità deve essere compreso tra 0 e 255"
@@ -442,8 +446,11 @@ msgstr "Unità di clock in uso"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "I byte devono essere compresi tra 0 e 255"
diff --git a/locale/pl.po b/locale/pl.po
index 2bc1a7557..896785126 100644
--- a/locale/pl.po
+++ b/locale/pl.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-03-19 18:37-0700\n"
 "Last-Translator: Radomir Dopieralski <circuitpython@sheep.art.pl>\n"
 "Language-Team: pl\n"
@@ -311,6 +311,10 @@ msgstr "Głębia musi być wielokrotnością 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Obie nóżki muszą wspierać przerwania sprzętowe"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Jasność musi być pomiędzy 0 a 255"
@@ -436,8 +440,11 @@ msgstr "Jednostka zegara w użyciu"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Kolumny muszą być typu digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Komenda musi być int pomiędzy 0 a 255"
 
diff --git a/locale/pt_BR.po b/locale/pt_BR.po
index 7af2e3d60..7e052bfb7 100644
--- a/locale/pt_BR.po
+++ b/locale/pt_BR.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-10-02 21:14-0000\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -311,6 +311,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr "Ambos os pinos devem suportar interrupções de hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "O brilho deve estar entre 0 e 255"
@@ -438,8 +442,11 @@ msgstr "Unidade de Clock em uso"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "Os bytes devem estar entre 0 e 255."
diff --git a/locale/zh_Latn_pinyin.po b/locale/zh_Latn_pinyin.po
index 7f6e80236..258a4d3df 100644
--- a/locale/zh_Latn_pinyin.po
+++ b/locale/zh_Latn_pinyin.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: circuitpython-cn\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-04-13 10:10-0700\n"
 "Last-Translator: hexthat\n"
 "Language-Team: Chinese Hanyu Pinyin\n"
@@ -312,6 +312,10 @@ msgstr "Bǐtè shēndù bìxū shì 8 bèi yǐshàng."
 msgid "Both pins must support hardware interrupts"
 msgstr "Liǎng gè yǐn jiǎo dōu bìxū zhīchí yìngjiàn zhōngduàn"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Liàngdù bìxū jiè yú 0 dào 255 zhī jiān"
@@ -437,8 +441,11 @@ msgstr "Shǐyòng shízhōng dānwèi"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Liè tiáomù bìxū shì digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Mìnglìng bìxū shì 0 dào 255 zhī jiān de int"
 
diff --git a/ports/atmel-samd/boards/hallowing_m0_express/board.c b/ports/atmel-samd/boards/hallowing_m0_express/board.c
index 1bbbfbaf8..be1741c87 100644
--- a/ports/atmel-samd/boards/hallowing_m0_express/board.c
+++ b/ports/atmel-samd/boards/hallowing_m0_express/board.c
@@ -100,7 +100,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA00,
-        0x100, // Brightness command. Only available when <= 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pybadge/board.c b/ports/atmel-samd/boards/pybadge/board.c
index 7e6c11dd4..c9dca0329 100644
--- a/ports/atmel-samd/boards/pybadge/board.c
+++ b/ports/atmel-samd/boards/pybadge/board.c
@@ -102,7 +102,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // no brightness command
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pybadge_airlift/board.c b/ports/atmel-samd/boards/pybadge_airlift/board.c
index d7f291d7d..eeab3f2b2 100644
--- a/ports/atmel-samd/boards/pybadge_airlift/board.c
+++ b/ports/atmel-samd/boards/pybadge_airlift/board.c
@@ -80,7 +80,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // brightness command, only valid <= 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pygamer/board.c b/ports/atmel-samd/boards/pygamer/board.c
index e59b7c458..d413c8e34 100644
--- a/ports/atmel-samd/boards/pygamer/board.c
+++ b/ports/atmel-samd/boards/pygamer/board.c
@@ -102,7 +102,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // Brightness command. Only available when < 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pygamer_advance/board.c b/ports/atmel-samd/boards/pygamer_advance/board.c
index b23353998..498a29db2 100644
--- a/ports/atmel-samd/boards/pygamer_advance/board.c
+++ b/ports/atmel-samd/boards/pygamer_advance/board.c
@@ -80,7 +80,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // Brightness command. Only available when < 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pyportal/board.c b/ports/atmel-samd/boards/pyportal/board.c
index 7fffb764f..938072158 100644
--- a/ports/atmel-samd/boards/pyportal/board.c
+++ b/ports/atmel-samd/boards/pyportal/board.c
@@ -92,7 +92,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PB31, // Backlight pin
-        0x100, // Brightness command > 0xff is none s
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/ugame10/board.c b/ports/atmel-samd/boards/ugame10/board.c
index 27a03ad91..15e22a72c 100644
--- a/ports/atmel-samd/boards/ugame10/board.c
+++ b/ports/atmel-samd/boards/ugame10/board.c
@@ -100,7 +100,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         NULL,
-        0x100, // brightness command. Only valid <=0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness
         false, // auto_brightness
         false, // single_byte_bounds
diff --git a/shared-bindings/displayio/ColorConverter.c b/shared-bindings/displayio/ColorConverter.c
index e170e0340..d9524870d 100644
--- a/shared-bindings/displayio/ColorConverter.c
+++ b/shared-bindings/displayio/ColorConverter.c
@@ -62,6 +62,8 @@ STATIC mp_obj_t displayio_colorconverter_make_new(const mp_obj_type_t *type, siz
 
 //|   .. method:: convert(color)
 //|
+//|   Converts the given RGB888 color to RGB565
+//|
 STATIC mp_obj_t displayio_colorconverter_obj_convert(mp_obj_t self_in, mp_obj_t color_obj) {
     displayio_colorconverter_t *self = MP_OBJ_TO_PTR(self_in);
 
diff --git a/shared-bindings/displayio/ColorConverter.h b/shared-bindings/displayio/ColorConverter.h
index 8f61e6642..24895500e 100644
--- a/shared-bindings/displayio/ColorConverter.h
+++ b/shared-bindings/displayio/ColorConverter.h
@@ -34,6 +34,6 @@
 extern const mp_obj_type_t displayio_colorconverter_type;
 
 void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self);
-bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *colorconverter, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color);
+void common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *colorconverter, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color);
 
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYIO_COLORCONVERTER_H
diff --git a/shared-bindings/displayio/Display.c b/shared-bindings/displayio/Display.c
index 2586e562f..361a37ece 100644
--- a/shared-bindings/displayio/Display.c
+++ b/shared-bindings/displayio/Display.c
@@ -119,7 +119,7 @@ STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_a
         { MP_QSTR_write_ram_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2c} },
         { MP_QSTR_set_vertical_scroll, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x0} },
         { MP_QSTR_backlight_pin, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
-        { MP_QSTR_brightness_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x100} },
+        { MP_QSTR_brightness_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = NO_BRIGHTNESS_COMMAND} },
         { MP_QSTR_brightness, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_OBJ_NEW_SMALL_INT(1)} },
         { MP_QSTR_auto_brightness, MP_ARG_BOOL | MP_ARG_KW_ONLY, {.u_bool = false} },
         { MP_QSTR_single_byte_bounds, MP_ARG_BOOL | MP_ARG_KW_ONLY, {.u_bool = false} },
@@ -242,10 +242,14 @@ STATIC mp_obj_t displayio_display_obj_get_brightness(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_get_brightness_obj, displayio_display_obj_get_brightness);
 
-STATIC mp_obj_t displayio_display_obj_set_brightness(mp_obj_t self_in, mp_obj_t brightness) {
+STATIC mp_obj_t displayio_display_obj_set_brightness(mp_obj_t self_in, mp_obj_t brightness_obj) {
     displayio_display_obj_t *self = native_display(self_in);
     common_hal_displayio_display_set_auto_brightness(self, false);
-    bool ok = common_hal_displayio_display_set_brightness(self, mp_obj_get_float(brightness));
+    mp_float_t brightness = mp_obj_get_float(brightness_obj);
+    if (brightness < 0 || brightness > 1.0) {
+        mp_raise_ValueError(translate("Brightness must be 0-1.0"));
+    }
+    bool ok = common_hal_displayio_display_set_brightness(self, brightness);
     if (!ok) {
         mp_raise_RuntimeError(translate("Brightness not adjustable"));
     }
diff --git a/shared-bindings/displayio/Display.h b/shared-bindings/displayio/Display.h
index a60a0cf5a..e765e6f25 100644
--- a/shared-bindings/displayio/Display.h
+++ b/shared-bindings/displayio/Display.h
@@ -36,6 +36,8 @@ extern const mp_obj_type_t displayio_display_type;
 
 #define DELAY 0x80
 
+#define NO_BRIGHTNESS_COMMAND 0x100
+
 void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     mp_obj_t bus, uint16_t width, uint16_t height,
     int16_t colstart, int16_t rowstart, uint16_t rotation, uint16_t color_depth, bool grayscale, bool pixels_in_byte_share_row,
diff --git a/shared-bindings/displayio/I2CDisplay.c b/shared-bindings/displayio/I2CDisplay.c
index 2aac49b4d..1f74e8c9e 100644
--- a/shared-bindings/displayio/I2CDisplay.c
+++ b/shared-bindings/displayio/I2CDisplay.c
@@ -103,7 +103,7 @@ STATIC mp_obj_t displayio_i2cdisplay_make_new(const mp_obj_type_t *type, size_t
 STATIC mp_obj_t displayio_i2cdisplay_obj_send(mp_obj_t self, mp_obj_t command_obj, mp_obj_t data_obj) {
     mp_int_t command_int = MP_OBJ_SMALL_INT_VALUE(command_obj);
     if (!MP_OBJ_IS_SMALL_INT(command_obj) || command_int > 255 || command_int < 0) {
-        mp_raise_ValueError(translate("Command must be an int between 0 and 255"));
+        mp_raise_ValueError(translate("Command must be 0-255"));
     }
     uint8_t command = command_int;
     mp_buffer_info_t bufinfo;
diff --git a/shared-bindings/displayio/Palette.c b/shared-bindings/displayio/Palette.c
index 974cadb02..dda58e3c5 100644
--- a/shared-bindings/displayio/Palette.c
+++ b/shared-bindings/displayio/Palette.c
@@ -74,7 +74,7 @@ STATIC mp_obj_t displayio_palette_make_new(const mp_obj_type_t *type, size_t n_a
 STATIC mp_obj_t group_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
     displayio_palette_t *self = MP_OBJ_TO_PTR(self_in);
     switch (op) {
-        case MP_UNARY_OP_BOOL: return mp_obj_new_bool(true);
+        case MP_UNARY_OP_BOOL: return mp_const_true;
         case MP_UNARY_OP_LEN:
             return MP_OBJ_NEW_SMALL_INT(common_hal_displayio_palette_get_len(self));
         default: return MP_OBJ_NULL; // op not supported
diff --git a/shared-module/displayio/ColorConverter.c b/shared-module/displayio/ColorConverter.c
index 563d40c51..6b9bd5840 100644
--- a/shared-module/displayio/ColorConverter.c
+++ b/shared-module/displayio/ColorConverter.c
@@ -57,8 +57,8 @@ bool displayio_colorconverter_convert(displayio_colorconverter_t *self, const _d
     return false;
 }
 
-bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
-    return displayio_colorconverter_convert(self, colorspace, input_color, output_color);
+void common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
+    displayio_colorconverter_convert(self, colorspace, input_color, output_color);
 }
 
 // Currently no refresh logic is needed for a ColorConverter.
diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index 9aee70e32..a8515b9e5 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -153,7 +153,8 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
             common_hal_pulseio_pwmout_never_reset(&self->backlight_pwm);
         }
     }
-    if (!self->auto_brightness && (self->backlight_inout.base.type != &mp_type_NoneType || brightness_command <= 0xff)) {
+    if (!self->auto_brightness && (self->backlight_inout.base.type != &mp_type_NoneType ||
+                                   brightness_command != NO_BRIGHTNESS_COMMAND)) {
         common_hal_displayio_display_set_brightness(self, brightness);
     } else {
         self->current_brightness = -1.0;
@@ -258,7 +259,7 @@ bool common_hal_displayio_display_set_brightness(displayio_display_obj_t* self,
     } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
         common_hal_digitalio_digitalinout_set_value(&self->backlight_inout, brightness > 0.99);
         ok = true;
-    } else if (self->brightness_command < 0x100) {
+    } else if (self->brightness_command != NO_BRIGHTNESS_COMMAND) {
         ok = self->begin_transaction(self->bus);
         if (ok) {
             if (self->data_as_commands) {
@@ -315,17 +316,16 @@ void displayio_display_set_region_to_update(displayio_display_obj_t* self, displ
         data_length = 0;
     }
     if (self->single_byte_bounds) {
-        data[data_length] = x1 + self->colstart;
-        data[data_length + 1] = x2 - 1 + self->colstart;
+        data[data_length++] = x1 + self->colstart;
+        data[data_length++] = x2 - 1 + self->colstart;
         data_length += 2;
     } else {
         x1 += self->colstart;
         x2 += self->colstart - 1;
-        data[data_length] = x1 >> 8;
-        data[data_length + 1] = x1 & 0xff;
-        data[data_length + 2] = x2 >> 8;
-        data[data_length + 3] = x2 & 0xff;
-        data_length += 4;
+        data[data_length++] = x1 >> 8;
+        data[data_length++] = x1 & 0xff;
+        data[data_length++] = x2 >> 8;
+        data[data_length++] = x2 & 0xff;
     }
     self->send(self->bus, self->data_as_commands, data, data_length);
 
@@ -337,17 +337,15 @@ void displayio_display_set_region_to_update(displayio_display_obj_t* self, displ
         data_length = 0;
     }
     if (self->single_byte_bounds) {
-        data[data_length] = y1 + self->rowstart;
-        data[data_length + 1] = y2 - 1 + self->rowstart;
-        data_length += 2;
+        data[data_length++] = y1 + self->rowstart;
+        data[data_length++] = y2 - 1 + self->rowstart;
     } else {
         y1 += self->rowstart;
         y2 += self->rowstart - 1;
-        data[data_length] = y1 >> 8;
-        data[data_length + 1] = y1 & 0xff;
-        data[data_length + 2] = y2 >> 8;
-        data[data_length + 3] = y2 & 0xff;
-        data_length += 4;
+        data[data_length++] = y1 >> 8;
+        data[data_length++] = y1 & 0xff;
+        data[data_length++] = y2 >> 8;
+        data[data_length++] = y2 & 0xff;
     }
     self->send(self->bus, self->data_as_commands, data, data_length);
 }
diff --git a/shared-module/displayio/Palette.h b/shared-module/displayio/Palette.h
index 6f5e2774c..19c05baf5 100644
--- a/shared-module/displayio/Palette.h
+++ b/shared-module/displayio/Palette.h
@@ -53,6 +53,8 @@ typedef struct {
     bool needs_refresh;
 } displayio_palette_t;
 
+// Returns false if color fetch did not succeed (out of range or transparent).
+// Returns true if color is opaque, and sets color.
 bool displayio_palette_get_color(displayio_palette_t *palette, const _displayio_colorspace_t* colorspace, uint32_t palette_index, uint32_t* color);
 bool displayio_palette_needs_refresh(displayio_palette_t *self);
 void displayio_palette_finish_refresh(displayio_palette_t *self);
diff --git a/shared-module/displayio/TileGrid.c b/shared-module/displayio/TileGrid.c
index 77e6daf6f..88873d3a9 100644
--- a/shared-module/displayio/TileGrid.c
+++ b/shared-module/displayio/TileGrid.c
@@ -379,7 +379,7 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_c
             // Compute the destination pixel in the buffer and mask based on the transformations.
             int16_t offset = row_start + (x - start_x + x_shift) * x_stride; // in pixels
 
-            // This is super useful for debugging out range accesses. Uncomment to use.
+            // This is super useful for debugging out of range accesses. Uncomment to use.
             // if (offset < 0 || offset >= (int32_t) displayio_area_size(area)) {
             //     asm("bkpt");
             // }
-- 
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