Added Single Byte Boundaries option for certain displays

2 files changed, 19 insertions, 8 deletions

diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index 8ebe4b543..3936f3b17 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -44,7 +44,7 @@ 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,
         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, bool init_cs_toggle) {
+        const mcu_pin_obj_t* backlight_pin, bool init_cs_toggle, bool single_byte_bounds) {
     self->color_depth = color_depth;
     self->set_column_command = set_column_command;
     self->set_row_command = set_row_command;
@@ -55,6 +55,7 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     self->rowstart = rowstart;
     self->auto_brightness = false;
     self->init_cs_toggle = init_cs_toggle;
+    self->single_byte_bounds = single_byte_bounds;
 
     if (MP_OBJ_IS_TYPE(bus, &displayio_parallelbus_type)) {
         self->begin_transaction = common_hal_displayio_parallelbus_begin_transaction;
@@ -218,16 +219,25 @@ void displayio_display_end_transaction(displayio_display_obj_t* self) {
 }
 
 void displayio_display_set_region_to_update(displayio_display_obj_t* self, uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1) {
-    // TODO(tannewt): Handle displays with single byte bounds.
     uint16_t data[2];
     self->send(self->bus, true, &self->set_column_command, 1);
-    data[0] = __builtin_bswap16(x0 + self->colstart);
-    data[1] = __builtin_bswap16(x1 - 1 + self->colstart);
-    self->send(self->bus, false, (uint8_t*) data, 4);
+    if (self->single_byte_bounds) {
+        data[0] = __builtin_bswap16((x0 + self->colstart) << 8 | (x1 - 1 + self->colstart) && 0xFF);
+        self->send(self->bus, false, (uint8_t*) data, 2);
+    } else {
+        data[0] = __builtin_bswap16(x0 + self->colstart);
+        data[1] = __builtin_bswap16(x1 - 1 + self->colstart);
+        self->send(self->bus, false, (uint8_t*) data, 4);
+    }
     self->send(self->bus, true, &self->set_row_command, 1);
-    data[0] = __builtin_bswap16(y0  + self->rowstart);
-    data[1] = __builtin_bswap16(y1 - 1 + self->rowstart);
-    self->send(self->bus, false, (uint8_t*) data, 4);
+    if (self->single_byte_bounds) {
+        data[0] = __builtin_bswap16((y0 + self->rowstart) << 8 | (y1 - 1 + self->rowstart) && 0xFF);
+        self->send(self->bus, false, (uint8_t*) data, 2);
+    } else {
+        data[0] = __builtin_bswap16(y0  + self->rowstart);
+        data[1] = __builtin_bswap16(y1 - 1 + self->rowstart);
+        self->send(self->bus, false, (uint8_t*) data, 4);
+    }
     self->send(self->bus, true, &self->write_ram_command, 1);
 }
 
diff --git a/shared-module/displayio/Display.h b/shared-module/displayio/Display.h
index 250f44031..18118bc72 100644
--- a/shared-module/displayio/Display.h
+++ b/shared-module/displayio/Display.h
@@ -51,6 +51,7 @@ typedef struct {
     int16_t colstart;
     int16_t rowstart;
     bool init_cs_toggle;
+    bool single_byte_bounds;
     display_bus_begin_transaction begin_transaction;
     display_bus_send send;
     display_bus_end_transaction end_transaction;