Merge remote-tracking branch 'adafruit/master' into choose-usb-devices-xac

14 files changed, 520 insertions, 157 deletions

diff --git a/shared-module/_stage/__init__.c b/shared-module/_stage/__init__.c
index 2c525be87..d5da74272 100644
--- a/shared-module/_stage/__init__.c
+++ b/shared-module/_stage/__init__.c
@@ -36,6 +36,22 @@ void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
         uint16_t *buffer, size_t buffer_size,
         displayio_display_obj_t *display, uint8_t scale) {
 
+
+    displayio_area_t area;
+    area.x1 = x0;
+    area.y1 = y0;
+    area.x2 = x1;
+    area.y2 = y1;
+    displayio_display_core_set_region_to_update(
+        &display->core, display->set_column_command, display->set_row_command,
+        NO_COMMAND, NO_COMMAND, display->data_as_commands, false, &area);
+
+    while (!displayio_display_core_begin_transaction(&display->core)) {
+        RUN_BACKGROUND_TASKS;
+    }
+    display->core.send(display->core.bus, DISPLAY_COMMAND,
+                      CHIP_SELECT_TOGGLE_EVERY_BYTE,
+                      &display->write_ram_command, 1);
     size_t index = 0;
     for (uint16_t y = y0; y < y1; ++y) {
         for (uint8_t yscale = 0; yscale < scale; ++yscale) {
@@ -57,8 +73,9 @@ void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
                     index += 1;
                     // The buffer is full, send it.
                     if (index >= buffer_size) {
-                        display->core.send(display->core.bus, DISPLAY_DATA, CHIP_SELECT_UNTOUCHED, ((uint8_t*)buffer),
-                                      buffer_size * 2);
+                        display->core.send(display->core.bus, DISPLAY_DATA,
+                                           CHIP_SELECT_UNTOUCHED,
+                                           ((uint8_t*)buffer), buffer_size * 2);
                         index = 0;
                     }
                 }
@@ -67,6 +84,10 @@ void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
     }
     // Send the remaining data.
     if (index) {
-        display->core.send(display->core.bus, DISPLAY_DATA, CHIP_SELECT_UNTOUCHED, ((uint8_t*)buffer), index * 2);
+        display->core.send(display->core.bus, DISPLAY_DATA,
+                           CHIP_SELECT_UNTOUCHED,
+                           ((uint8_t*)buffer), index * 2);
     }
+
+    displayio_display_core_end_transaction(&display->core);
 }
diff --git a/shared-module/audiocore/__init__.c b/shared-module/audiocore/__init__.c
index 067cae5dd..f9762676f 100644
--- a/shared-module/audiocore/__init__.c
+++ b/shared-module/audiocore/__init__.c
@@ -27,13 +27,14 @@
 #include "shared-module/audioio/__init__.h"
 
 #include "py/obj.h"
-#include "shared-bindings/audiocore/Mixer.h"
 #include "shared-bindings/audiocore/RawSample.h"
 #include "shared-bindings/audiocore/WaveFile.h"
-#include "shared-module/audiocore/Mixer.h"
 #include "shared-module/audiocore/RawSample.h"
 #include "shared-module/audiocore/WaveFile.h"
 
+#include "shared-bindings/audiomixer/Mixer.h"
+#include "shared-module/audiomixer/Mixer.h"
+
 uint32_t audiosample_sample_rate(mp_obj_t sample_obj) {
     if (MP_OBJ_IS_TYPE(sample_obj, &audioio_rawsample_type)) {
         audioio_rawsample_obj_t* sample = MP_OBJ_TO_PTR(sample_obj);
@@ -41,9 +42,11 @@ uint32_t audiosample_sample_rate(mp_obj_t sample_obj) {
     } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_wavefile_type)) {
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         return file->sample_rate;
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
         return mixer->sample_rate;
+    #endif
     }
     return 16000;
 }
@@ -55,9 +58,11 @@ uint8_t audiosample_bits_per_sample(mp_obj_t sample_obj) {
     } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_wavefile_type)) {
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         return file->bits_per_sample;
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
         return mixer->bits_per_sample;
+    #endif
     }
     return 8;
 }
@@ -69,9 +74,11 @@ uint8_t audiosample_channel_count(mp_obj_t sample_obj) {
     } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_wavefile_type)) {
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         return file->channel_count;
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* mixer = MP_OBJ_TO_PTR(sample_obj);
         return mixer->channel_count;
+    #endif
     }
     return 1;
 }
@@ -83,9 +90,11 @@ void audiosample_reset_buffer(mp_obj_t sample_obj, bool single_channel, uint8_t
     } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_wavefile_type)) {
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         audioio_wavefile_reset_buffer(file, single_channel, audio_channel);
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
-        audioio_mixer_reset_buffer(file, single_channel, audio_channel);
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
+        audiomixer_mixer_reset_buffer(file, single_channel, audio_channel);
+    #endif
     }
 }
 
@@ -99,9 +108,11 @@ audioio_get_buffer_result_t audiosample_get_buffer(mp_obj_t sample_obj,
     } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_wavefile_type)) {
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         return audioio_wavefile_get_buffer(file, single_channel, channel, buffer, buffer_length);
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
-        return audioio_mixer_get_buffer(file, single_channel, channel, buffer, buffer_length);
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
+        return audiomixer_mixer_get_buffer(file, single_channel, channel, buffer, buffer_length);
+    #endif
     }
     return GET_BUFFER_DONE;
 }
@@ -117,9 +128,11 @@ void audiosample_get_buffer_structure(mp_obj_t sample_obj, bool single_channel,
         audioio_wavefile_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
         audioio_wavefile_get_buffer_structure(file, single_channel, single_buffer, samples_signed,
                                               max_buffer_length, spacing);
-    } else if (MP_OBJ_IS_TYPE(sample_obj, &audioio_mixer_type)) {
-        audioio_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
-        audioio_mixer_get_buffer_structure(file, single_channel, single_buffer, samples_signed,
+    #if CIRCUITPY_AUDIOMIXER
+    } else if (MP_OBJ_IS_TYPE(sample_obj, &audiomixer_mixer_type)) {
+        audiomixer_mixer_obj_t* file = MP_OBJ_TO_PTR(sample_obj);
+        audiomixer_mixer_get_buffer_structure(file, single_channel, single_buffer, samples_signed,
                                               max_buffer_length, spacing);
+    #endif
     }
 }
diff --git a/shared-module/audiocore/Mixer.c b/shared-module/audiomixer/Mixer.c
index da66bb36e..e0fb4fab8 100644
--- a/shared-module/audiocore/Mixer.c
+++ b/shared-module/audiomixer/Mixer.c
@@ -4,6 +4,8 @@
  * The MIT License (MIT)
  *
  * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *               2018 DeanM for Adafruit Industries
+ *               2019 Michael Schroeder
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -24,7 +26,8 @@
  * THE SOFTWARE.
  */
 
-#include "shared-bindings/audiocore/Mixer.h"
+#include "shared-bindings/audiomixer/Mixer.h"
+#include "shared-bindings/audiomixer/MixerVoice.h"
 
 #include <stdint.h>
 
@@ -32,24 +35,24 @@
 #include "shared-module/audiocore/__init__.h"
 #include "shared-module/audiocore/RawSample.h"
 
-void common_hal_audioio_mixer_construct(audioio_mixer_obj_t* self,
-                                        uint8_t voice_count,
-                                        uint32_t buffer_size,
-                                        uint8_t bits_per_sample,
-                                        bool samples_signed,
-                                        uint8_t channel_count,
-                                        uint32_t sample_rate) {
+void common_hal_audiomixer_mixer_construct(audiomixer_mixer_obj_t* self,
+                                           uint8_t voice_count,
+                                           uint32_t buffer_size,
+                                           uint8_t bits_per_sample,
+                                           bool samples_signed,
+                                           uint8_t channel_count,
+                                           uint32_t sample_rate) {
     self->len = buffer_size / 2 / sizeof(uint32_t) * sizeof(uint32_t);
 
     self->first_buffer = m_malloc(self->len, false);
     if (self->first_buffer == NULL) {
-        common_hal_audioio_mixer_deinit(self);
+        common_hal_audiomixer_mixer_deinit(self);
         mp_raise_msg(&mp_type_MemoryError, translate("Couldn't allocate first buffer"));
     }
 
     self->second_buffer = m_malloc(self->len, false);
     if (self->second_buffer == NULL) {
-        common_hal_audioio_mixer_deinit(self);
+        common_hal_audiomixer_mixer_deinit(self);
         mp_raise_msg(&mp_type_MemoryError, translate("Couldn't allocate second buffer"));
     }
 
@@ -58,130 +61,85 @@ void common_hal_audioio_mixer_construct(audioio_mixer_obj_t* self,
     self->channel_count = channel_count;
     self->sample_rate = sample_rate;
     self->voice_count = voice_count;
-
-    for (uint8_t i = 0; i < self->voice_count; i++) {
-        self->voice[i].sample = NULL;
-    }
 }
 
-void common_hal_audioio_mixer_deinit(audioio_mixer_obj_t* self) {
+void common_hal_audiomixer_mixer_deinit(audiomixer_mixer_obj_t* self) {
     self->first_buffer = NULL;
     self->second_buffer = NULL;
 }
 
-bool common_hal_audioio_mixer_deinited(audioio_mixer_obj_t* self) {
+bool common_hal_audiomixer_mixer_deinited(audiomixer_mixer_obj_t* self) {
     return self->first_buffer == NULL;
 }
 
-uint32_t common_hal_audioio_mixer_get_sample_rate(audioio_mixer_obj_t* self) {
+uint32_t common_hal_audiomixer_mixer_get_sample_rate(audiomixer_mixer_obj_t* self) {
     return self->sample_rate;
 }
 
-void common_hal_audioio_mixer_play(audioio_mixer_obj_t* self, mp_obj_t sample, uint8_t v, bool loop) {
-    if (v >= self->voice_count) {
-        mp_raise_ValueError(translate("Voice index too high"));
-    }
-    if (audiosample_sample_rate(sample) != self->sample_rate) {
-        mp_raise_ValueError(translate("The sample's sample rate does not match the mixer's"));
-    }
-    if (audiosample_channel_count(sample) != self->channel_count) {
-        mp_raise_ValueError(translate("The sample's channel count does not match the mixer's"));
-    }
-    if (audiosample_bits_per_sample(sample) != self->bits_per_sample) {
-        mp_raise_ValueError(translate("The sample's bits_per_sample does not match the mixer's"));
-    }
-    bool single_buffer;
-    bool samples_signed;
-    uint32_t max_buffer_length;
-    uint8_t spacing;
-    audiosample_get_buffer_structure(sample, false, &single_buffer, &samples_signed,
-                                     &max_buffer_length, &spacing);
-    if (samples_signed != self->samples_signed) {
-        mp_raise_ValueError(translate("The sample's signedness does not match the mixer's"));
-    }
-    audioio_mixer_voice_t* voice = &self->voice[v];
-    voice->sample = sample;
-    voice->loop = loop;
-
-    audiosample_reset_buffer(sample, false, 0);
-    audioio_get_buffer_result_t result = audiosample_get_buffer(sample, false, 0, (uint8_t**) &voice->remaining_buffer, &voice->buffer_length);
-    // Track length in terms of words.
-    voice->buffer_length /= sizeof(uint32_t);
-    voice->more_data = result == GET_BUFFER_MORE_DATA;
-}
-
-void common_hal_audioio_mixer_stop_voice(audioio_mixer_obj_t* self, uint8_t voice) {
-    self->voice[voice].sample = NULL;
-}
-
-bool common_hal_audioio_mixer_get_playing(audioio_mixer_obj_t* self) {
-    for (int32_t v = 0; v < self->voice_count; v++) {
-        if (self->voice[v].sample != NULL) {
+bool common_hal_audiomixer_mixer_get_playing(audiomixer_mixer_obj_t* self) {
+    for (uint8_t v = 0; v < self->voice_count; v++) {
+        if (common_hal_audiomixer_mixervoice_get_playing(MP_OBJ_TO_PTR(self->voice[v]))) {
             return true;
         }
     }
     return false;
 }
 
-void audioio_mixer_reset_buffer(audioio_mixer_obj_t* self,
-                                bool single_channel,
-                                uint8_t channel) {
-    for (int32_t i = 0; i < self->voice_count; i++) {
-        self->voice[i].sample = NULL;
+void audiomixer_mixer_reset_buffer(audiomixer_mixer_obj_t* self,
+                                   bool single_channel,
+                                   uint8_t channel) {
+    for (uint8_t i = 0; i < self->voice_count; i++) {
+        common_hal_audiomixer_mixervoice_stop(self->voice[i]);
     }
 }
 
 uint32_t add8signed(uint32_t a, uint32_t b) {
-    #if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
-    return __QADD8(a, b);
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return __SHADD8(a, b);
     #else
     uint32_t result = 0;
     for (int8_t i = 0; i < 4; i++) {
         int8_t ai = a >> (sizeof(int8_t) * 8 * i);
         int8_t bi = b >> (sizeof(int8_t) * 8 * i);
-        int32_t intermediate = (int32_t) ai + bi;
+        int32_t intermediate = (int32_t) ai + bi / 2;
         if (intermediate > CHAR_MAX) {
             intermediate = CHAR_MAX;
         } else if (intermediate < CHAR_MIN) {
-            //intermediate = CHAR_MIN;
+            intermediate = CHAR_MIN;
         }
-        result |= (((uint32_t) intermediate) & 0xff) << (sizeof(int8_t) * 8 * i);
+        result |= ((uint32_t) intermediate & 0xff) << (sizeof(int8_t) * 8 * i);
     }
     return result;
     #endif
 }
 
 uint32_t add8unsigned(uint32_t a, uint32_t b) {
-    #if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
-    // Subtract out the DC offset, add and then shift back.
-    a = __USUB8(a, 0x80808080);
-    b = __USUB8(b, 0x80808080);
-    uint32_t sum = __QADD8(a, b);
-    return __UADD8(sum, 0x80808080);
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return __UHADD8(a, b);
     #else
     uint32_t result = 0;
     for (int8_t i = 0; i < 4; i++) {
-        int8_t ai = (a >> (sizeof(uint8_t) * 8 * i)) - 128;
-        int8_t bi = (b >> (sizeof(uint8_t) * 8 * i)) - 128;
-        int32_t intermediate = (int32_t) ai + bi;
+        uint8_t ai = (a >> (sizeof(uint8_t) * 8 * i));
+        uint8_t bi = (b >> (sizeof(uint8_t) * 8 * i));
+        int32_t intermediate = (int32_t) (ai + bi) / 2;
         if (intermediate > UCHAR_MAX) {
             intermediate = UCHAR_MAX;
         }
-        result |= ((uint8_t) intermediate + 128) << (sizeof(uint8_t) * 8 * i);
+        result |= ((uint32_t) intermediate & 0xff) << (sizeof(uint8_t) * 8 * i);
     }
     return result;
     #endif
 }
 
 uint32_t add16signed(uint32_t a, uint32_t b) {
-    #if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
-    return __QADD16(a, b);
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return __SHADD16(a, b);
     #else
     uint32_t result = 0;
     for (int8_t i = 0; i < 2; i++) {
         int16_t ai = a >> (sizeof(int16_t) * 8 * i);
         int16_t bi = b >> (sizeof(int16_t) * 8 * i);
-        int32_t intermediate = (int32_t) ai + bi;
+        int32_t intermediate = (int32_t) ai + bi / 2;
         if (intermediate > SHRT_MAX) {
             intermediate = SHRT_MAX;
         } else if (intermediate < SHRT_MIN) {
@@ -194,32 +152,146 @@ uint32_t add16signed(uint32_t a, uint32_t b) {
 }
 
 uint32_t add16unsigned(uint32_t a, uint32_t b) {
-    #if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
-    // Subtract out the DC offset, add and then shift back.
-    a = __USUB16(a, 0x80008000);
-    b = __USUB16(b, 0x80008000);
-    uint32_t sum = __QADD16(a, b);
-    return __UADD16(sum, 0x80008000);
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return __UHADD16(a, b);
     #else
     uint32_t result = 0;
     for (int8_t i = 0; i < 2; i++) {
         int16_t ai = (a >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
         int16_t bi = (b >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
-        int32_t intermediate = (int32_t) ai + bi;
+        int32_t intermediate = (int32_t) ai + bi / 2;
         if (intermediate > USHRT_MAX) {
             intermediate = USHRT_MAX;
         }
-        result |= ((uint16_t) intermediate + 0x8000) << (sizeof(int16_t) * 8 * i);
+        result |= ((uint32_t) intermediate & 0xffff) << (sizeof(int16_t) * 8 * i);
     }
     return result;
     #endif
 }
 
-audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
-                                                     bool single_channel,
-                                                     uint8_t channel,
-                                                     uint8_t** buffer,
-                                                     uint32_t* buffer_length) {
+static inline uint32_t mult8unsigned(uint32_t val, int32_t mul) {
+    // if mul == 0, no need in wasting cycles
+    if (mul == 0) {
+        return 0;
+    }
+    /* TODO: workout ARMv7 instructions
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return val;
+    #else*/
+    uint32_t result = 0;
+    float mod_mul = (float) mul / (float) ((1<<15)-1);
+    for (int8_t i = 0; i < 4; i++) {
+        uint8_t ai = val >> (sizeof(uint8_t) * 8 * i);
+        int32_t intermediate = ai * mod_mul;
+        if (intermediate > SHRT_MAX) {
+            intermediate = SHRT_MAX;
+        }
+        result |= ((uint32_t) intermediate & 0xff) << (sizeof(uint8_t) * 8 * i);
+    }
+
+    return result;
+    //#endif
+}
+
+static inline uint32_t mult8signed(uint32_t val, int32_t mul) {
+    // if mul == 0, no need in wasting cycles
+    if (mul == 0) {
+        return 0;
+    }
+    /* TODO: workout ARMv7 instructions
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    return val;
+    #else
+    */
+    uint32_t result = 0;
+    float mod_mul = (float)mul / (float)((1<<15)-1);
+    for (int8_t i = 0; i < 4; i++) {
+        int16_t ai = val >> (sizeof(int8_t) * 8 * i);
+        int32_t intermediate = ai * mod_mul;
+        if (intermediate > CHAR_MAX) {
+            intermediate = CHAR_MAX;
+        } else if (intermediate < CHAR_MIN) {
+            intermediate = CHAR_MIN;
+        }
+        result |= (((uint32_t) intermediate) & 0xff) << (sizeof(int16_t) * 8 * i);
+    }
+    return result;
+    //#endif
+}
+
+//TODO:
+static inline uint32_t mult16unsigned(uint32_t val, int32_t mul) {
+    // if mul == 0, no need in wasting cycles
+    if (mul == 0) {
+        return 0;
+    }
+    /* TODO: the below ARMv7m instructions "work", but the amplitude is much higher/louder
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    // there is no unsigned equivalent to the 'SMULWx' ARMv7 Thumb function,
+    // so we have to do it by hand.
+    uint32_t lo = val & 0xffff;
+    uint32_t hi = val >> 16;
+    //mp_printf(&mp_plat_print, "pre-asm: (mul: %d)\n\tval: %x\tlo: %x\thi: %x\n", mul, val, lo, hi);
+    uint32_t val_lo;
+    asm volatile("mul %0, %1, %2" : "=r" (val_lo) : "r" (mul), "r" (lo));
+    asm volatile("mla %0, %1, %2, %3" : "=r" (val) : "r" (mul), "r" (hi), "r" (val_lo));
+    //mp_printf(&mp_plat_print, "post-asm:\n\tval: %x\tlo: %x\n\n", val, val_lo);
+    return val;
+    #else
+    */
+    uint32_t result = 0;
+    float mod_mul = (float)mul / (float)((1<<15)-1);
+    for (int8_t i = 0; i < 2; i++) {
+        int16_t ai = (val >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
+        int32_t intermediate = ai * mod_mul;
+        if (intermediate > SHRT_MAX) {
+            intermediate = SHRT_MAX;
+        } else if (intermediate < SHRT_MIN) {
+            intermediate = SHRT_MIN;
+        }
+        result |= (((uint32_t) intermediate) + 0x8000) << (sizeof(int16_t) * 8 * i);
+    }
+    return result;
+    //#endif
+}
+
+static inline uint32_t mult16signed(uint32_t val, int32_t mul) {
+    // if mul == 0, no need in wasting cycles
+    if (mul == 0) {
+        return 0;
+    }
+    #if (defined (__ARM_ARCH_7EM__) && (__ARM_ARCH_7EM__ == 1)) //Cortex-M4 w/FPU
+    int32_t hi, lo;
+    int32_t bits = 16; // saturate to 16 bits
+    int32_t shift = 0; // shift is done automatically
+    asm volatile("smulwb %0, %1, %2" : "=r" (lo) : "r" (mul), "r" (val));
+    asm volatile("smulwt %0, %1, %2" : "=r" (hi) : "r" (mul), "r" (val));
+    asm volatile("ssat %0, %1, %2, asr %3" : "=r" (lo) : "I" (bits), "r" (lo), "I" (shift));
+    asm volatile("ssat %0, %1, %2, asr %3" : "=r" (hi) : "I" (bits), "r" (hi), "I" (shift));
+    asm volatile("pkhbt %0, %1, %2, lsl #16" : "=r" (val) : "r" (lo), "r" (hi)); // pack
+    return val;
+    #else
+    uint32_t result = 0;
+    float mod_mul = (float)mul / (float)((1<<15)-1);
+    for (int8_t i = 0; i < 2; i++) {
+        int16_t ai = val >> (sizeof(int16_t) * 8 * i);
+        int32_t intermediate = ai * mod_mul;
+        if (intermediate > SHRT_MAX) {
+            intermediate = SHRT_MAX;
+        } else if (intermediate < SHRT_MIN) {
+            intermediate = SHRT_MIN;
+        }
+        result |= (((uint32_t) intermediate) & 0xffff) << (sizeof(int16_t) * 8 * i);
+    }
+    return result;
+    #endif
+}
+
+audioio_get_buffer_result_t audiomixer_mixer_get_buffer(audiomixer_mixer_obj_t* self,
+                                                        bool single_channel,
+                                                        uint8_t channel,
+                                                        uint8_t** buffer,
+                                                        uint32_t* buffer_length) {
     if (!single_channel) {
         channel = 0;
     }
@@ -243,7 +315,7 @@ audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
         self->use_first_buffer = !self->use_first_buffer;
         bool voices_active = false;
         for (int32_t v = 0; v < self->voice_count; v++) {
-            audioio_mixer_voice_t* voice = &self->voice[v];
+            audiomixer_mixervoice_obj_t* voice = MP_OBJ_TO_PTR(self->voice[v]);
 
             uint32_t j = 0;
             bool voice_done = voice->sample == NULL;
@@ -285,6 +357,21 @@ audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
                     sample_value = voice->remaining_buffer[j];
                 }
 
+                // apply the mixer level
+            	if (!self->samples_signed) {
+                    if (self->bits_per_sample == 8) {
+                        sample_value = mult8unsigned(sample_value, voice->level);
+                    } else {
+                        sample_value = mult16unsigned(sample_value, voice->level);
+                    }
+                } else {
+                    if (self->bits_per_sample == 8) {
+                        sample_value = mult8signed(sample_value, voice->level);
+                    } else {
+                        sample_value = mult16signed(sample_value, voice->level);
+                    }
+                }
+
                 if (!voices_active) {
                     word_buffer[i] = sample_value;
                 } else {
@@ -327,7 +414,7 @@ audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
     return GET_BUFFER_MORE_DATA;
 }
 
-void audioio_mixer_get_buffer_structure(audioio_mixer_obj_t* self, bool single_channel,
+void audiomixer_mixer_get_buffer_structure(audiomixer_mixer_obj_t* self, bool single_channel,
                                         bool* single_buffer, bool* samples_signed,
                                         uint32_t* max_buffer_length, uint8_t* spacing) {
     *single_buffer = false;
diff --git a/shared-module/audiocore/Mixer.h b/shared-module/audiomixer/Mixer.h
index 22eb6a37f..ab4780efc 100644
--- a/shared-module/audiocore/Mixer.h
+++ b/shared-module/audiomixer/Mixer.h
@@ -24,22 +24,15 @@
  * THE SOFTWARE.
  */
 
-#ifndef MICROPY_INCLUDED_SHARED_MODULE_AUDIOIO_MIXER_H
-#define MICROPY_INCLUDED_SHARED_MODULE_AUDIOIO_MIXER_H
+#ifndef MICROPY_INCLUDED_SHARED_MODULE_AUDIOMIXER_MIXER_H
+#define MICROPY_INCLUDED_SHARED_MODULE_AUDIOMIXER_MIXER_H
 
 #include "py/obj.h"
+#include "py/objtuple.h"
 
 #include "shared-module/audiocore/__init__.h"
 
 typedef struct {
-    mp_obj_t sample;
-    bool loop;
-    bool more_data;
-    uint32_t* remaining_buffer;
-    uint32_t buffer_length;
-} audioio_mixer_voice_t;
-
-typedef struct {
     mp_obj_base_t base;
     uint32_t* first_buffer;
     uint32_t* second_buffer;
@@ -55,21 +48,22 @@ typedef struct {
     uint32_t right_read_count;
 
     uint8_t voice_count;
-    audioio_mixer_voice_t voice[];
-} audioio_mixer_obj_t;
+    mp_obj_tuple_t *voice_tuple;
+    mp_obj_t voice[];
+} audiomixer_mixer_obj_t;
 
 
 // These are not available from Python because it may be called in an interrupt.
-void audioio_mixer_reset_buffer(audioio_mixer_obj_t* self,
+void audiomixer_mixer_reset_buffer(audiomixer_mixer_obj_t* self,
                                     bool single_channel,
                                     uint8_t channel);
-audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
+audioio_get_buffer_result_t audiomixer_mixer_get_buffer(audiomixer_mixer_obj_t* self,
                                                          bool single_channel,
                                                          uint8_t channel,
                                                          uint8_t** buffer,
                                                          uint32_t* buffer_length); // length in bytes
-void audioio_mixer_get_buffer_structure(audioio_mixer_obj_t* self, bool single_channel,
+void audiomixer_mixer_get_buffer_structure(audiomixer_mixer_obj_t* self, bool single_channel,
                                             bool* single_buffer, bool* samples_signed,
                                             uint32_t* max_buffer_length, uint8_t* spacing);
 
-#endif // MICROPY_INCLUDED_SHARED_MODULE_AUDIOIO_MIXER_H
+#endif // MICROPY_INCLUDED_SHARED_MODULE_AUDIOMIXER_MIXER_H
diff --git a/shared-module/audiomixer/MixerVoice.c b/shared-module/audiomixer/MixerVoice.c
new file mode 100644
index 000000000..ff05dc93e
--- /dev/null
+++ b/shared-module/audiomixer/MixerVoice.c
@@ -0,0 +1,87 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 DeanM 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/audiomixer/Mixer.h"
+#include "shared-module/audiomixer/MixerVoice.h"
+
+#include <stdint.h>
+
+#include "py/runtime.h"
+#include "shared-module/audiomixer/__init__.h"
+#include "shared-module/audiocore/RawSample.h"
+
+void common_hal_audiomixer_mixervoice_construct(audiomixer_mixervoice_obj_t *self) {
+    self->sample = NULL;
+    self->level = ((1 << 15) - 1);
+}
+
+void common_hal_audiomixer_mixervoice_set_parent(audiomixer_mixervoice_obj_t* self, audiomixer_mixer_obj_t *parent) {
+	self->parent = parent;
+}
+
+float common_hal_audiomixer_mixervoice_get_level(audiomixer_mixervoice_obj_t* self) {
+	return ((float) self->level / ((1 << 15) - 1));
+}
+
+void common_hal_audiomixer_mixervoice_set_level(audiomixer_mixervoice_obj_t* self, float level) {
+	self->level = level * ((1 << 15)-1);
+}
+
+void common_hal_audiomixer_mixervoice_play(audiomixer_mixervoice_obj_t* self, mp_obj_t sample, bool loop) {
+    if (audiosample_sample_rate(sample) != self->parent->sample_rate) {
+        mp_raise_ValueError(translate("The sample's sample rate does not match the mixer's"));
+    }
+    if (audiosample_channel_count(sample) != self->parent->channel_count) {
+        mp_raise_ValueError(translate("The sample's channel count does not match the mixer's"));
+    }
+    if (audiosample_bits_per_sample(sample) != self->parent->bits_per_sample) {
+        mp_raise_ValueError(translate("The sample's bits_per_sample does not match the mixer's"));
+    }
+    bool single_buffer;
+    bool samples_signed;
+    uint32_t max_buffer_length;
+    uint8_t spacing;
+    audiosample_get_buffer_structure(sample, false, &single_buffer, &samples_signed,
+                                     &max_buffer_length, &spacing);
+    if (samples_signed != self->parent->samples_signed) {
+        mp_raise_ValueError(translate("The sample's signedness does not match the mixer's"));
+    }
+    self->sample = sample;
+    self->loop = loop;
+
+    audiosample_reset_buffer(sample, false, 0);
+    audioio_get_buffer_result_t result = audiosample_get_buffer(sample, false, 0, (uint8_t**) &self->remaining_buffer, &self->buffer_length);
+    // Track length in terms of words.
+    self->buffer_length /= sizeof(uint32_t);
+    self->more_data = result == GET_BUFFER_MORE_DATA;
+}
+
+bool common_hal_audiomixer_mixervoice_get_playing(audiomixer_mixervoice_obj_t* self) {
+	return self->sample != NULL;
+}
+
+void common_hal_audiomixer_mixervoice_stop(audiomixer_mixervoice_obj_t* self) {
+    self->sample = NULL;
+}
diff --git a/shared-module/audiomixer/MixerVoice.h b/shared-module/audiomixer/MixerVoice.h
new file mode 100644
index 000000000..efac19156
--- /dev/null
+++ b/shared-module/audiomixer/MixerVoice.h
@@ -0,0 +1,46 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 DeanM 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 SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_
+#define SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_
+
+#include "py/obj.h"
+
+#include "shared-module/audiomixer/__init__.h"
+#include "shared-module/audiomixer/Mixer.h"
+
+typedef struct {
+	mp_obj_base_t base;
+	audiomixer_mixer_obj_t *parent;
+    mp_obj_t sample;
+    bool loop;
+    bool more_data;
+    uint32_t* remaining_buffer;
+    uint32_t buffer_length;
+    int16_t level;
+} audiomixer_mixervoice_obj_t;
+
+
+#endif /* SHARED_MODULE_AUDIOMIXER_MIXERVOICE_H_ */
diff --git a/shared-module/audiomixer/__init__.c b/shared-module/audiomixer/__init__.c
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/shared-module/audiomixer/__init__.c
diff --git a/shared-module/audiomixer/__init__.h b/shared-module/audiomixer/__init__.h
new file mode 100644
index 000000000..35b731558
--- /dev/null
+++ b/shared-module/audiomixer/__init__.h
@@ -0,0 +1,32 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Dan Halbert 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_AUDIOMIXER__INIT__H
+#define MICROPY_INCLUDED_SHARED_MODULE_AUDIOMIXER__INIT__H
+
+#include "shared-module/audiocore/__init__.h"
+
+#endif  // MICROPY_INCLUDED_SHARED_MODULE_AUDIOMIXER__INIT__H
diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index 212ee8c7b..06b81f2f8 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -50,6 +50,8 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
         uint8_t* init_sequence, uint16_t init_sequence_len, 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, bool auto_refresh, uint16_t native_frames_per_second) {
+    // Turn off auto-refresh as we init.
+    self->auto_refresh = false;
     uint16_t ram_width = 0x100;
     uint16_t ram_height = 0x100;
     if (single_byte_bounds) {
@@ -64,7 +66,6 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     self->write_ram_command = write_ram_command;
     self->brightness_command = brightness_command;
     self->auto_brightness = auto_brightness;
-    self->auto_refresh = auto_refresh;
     self->first_manual_refresh = !auto_refresh;
     self->data_as_commands = data_as_commands;
 
@@ -128,6 +129,7 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     // Set the group after initialization otherwise we may send pixels while we delay in
     // initialization.
     common_hal_displayio_display_show(self, &circuitpython_splash);
+    self->auto_refresh = auto_refresh;
 }
 
 bool common_hal_displayio_display_show(displayio_display_obj_t* self, displayio_group_t* root_group) {
diff --git a/shared-module/displayio/Group.c b/shared-module/displayio/Group.c
index 38418a029..d69e9f585 100644
--- a/shared-module/displayio/Group.c
+++ b/shared-module/displayio/Group.c
@@ -34,6 +34,47 @@ void common_hal_displayio_group_construct(displayio_group_t* self, uint32_t max_
     displayio_group_construct(self, children, max_size, scale, x, y);
 }
 
+bool common_hal_displayio_group_get_hidden(displayio_group_t* self) {
+    return self->hidden;
+}
+
+void common_hal_displayio_group_set_hidden(displayio_group_t* self, bool hidden) {
+    if (self->hidden == hidden) {
+        return;
+    }
+    self->hidden = hidden;
+    if (self->hidden_by_parent) {
+        return;
+    }
+    for (size_t i = 0; i < self->size; i++) {
+        mp_obj_t layer = self->children[i].native;
+        if (MP_OBJ_IS_TYPE(layer, &displayio_tilegrid_type)) {
+            displayio_tilegrid_set_hidden_by_parent(layer, hidden);
+        } else if (MP_OBJ_IS_TYPE(layer, &displayio_group_type)) {
+            displayio_group_set_hidden_by_parent(layer, hidden);
+        }
+    }
+}
+
+void displayio_group_set_hidden_by_parent(displayio_group_t *self, bool hidden) {
+    if (self->hidden_by_parent == hidden) {
+        return;
+    }
+    self->hidden_by_parent = hidden;
+    // If we're already hidden, then we're done.
+    if (self->hidden) {
+        return;
+    }
+    for (size_t i = 0; i < self->size; i++) {
+        mp_obj_t layer = self->children[i].native;
+        if (MP_OBJ_IS_TYPE(layer, &displayio_tilegrid_type)) {
+            displayio_tilegrid_set_hidden_by_parent(layer, hidden);
+        } else if (MP_OBJ_IS_TYPE(layer, &displayio_group_type)) {
+            displayio_group_set_hidden_by_parent(layer, hidden);
+        }
+    }
+}
+
 uint32_t common_hal_displayio_group_get_scale(displayio_group_t* self) {
     return self->scale;
 }
diff --git a/shared-module/displayio/Group.h b/shared-module/displayio/Group.h
index 4e2308e56..5afaac1ba 100644
--- a/shared-module/displayio/Group.h
+++ b/shared-module/displayio/Group.h
@@ -42,18 +42,22 @@ typedef struct {
 typedef struct {
     mp_obj_base_t base;
     displayio_group_child_t* children;
+    displayio_buffer_transform_t absolute_transform;
+    displayio_area_t dirty_area; // Catch all for changed area
     int16_t x;
     int16_t y;
     uint16_t scale;
     uint16_t size;
     uint16_t max_size;
-    bool item_removed;
-    bool in_group;
-    displayio_buffer_transform_t absolute_transform;
-    displayio_area_t dirty_area; // Catch all for changed area
+    bool item_removed :1;
+    bool in_group :1;
+    bool hidden :1;
+    bool hidden_by_parent :1;
+    uint8_t padding :4;
 } displayio_group_t;
 
 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);
+void displayio_group_set_hidden_by_parent(displayio_group_t *self, bool hidden);
 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_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);
diff --git a/shared-module/displayio/I2CDisplay.c b/shared-module/displayio/I2CDisplay.c
index a3b167a33..d9452dc50 100644
--- a/shared-module/displayio/I2CDisplay.c
+++ b/shared-module/displayio/I2CDisplay.c
@@ -97,7 +97,7 @@ bool common_hal_displayio_i2cdisplay_bus_free(mp_obj_t obj) {
 
 bool common_hal_displayio_i2cdisplay_begin_transaction(mp_obj_t obj) {
     displayio_i2cdisplay_obj_t* self = MP_OBJ_TO_PTR(obj);
-    return !common_hal_busio_i2c_try_lock(self->bus);
+    return common_hal_busio_i2c_try_lock(self->bus);
 }
 
 void common_hal_displayio_i2cdisplay_send(mp_obj_t obj, display_byte_type_t data_type, display_chip_select_behavior_t chip_select, uint8_t *data, uint32_t data_length) {
diff --git a/shared-module/displayio/TileGrid.c b/shared-module/displayio/TileGrid.c
index f34d2fc52..45b05110f 100644
--- a/shared-module/displayio/TileGrid.c
+++ b/shared-module/displayio/TileGrid.c
@@ -67,14 +67,30 @@ void common_hal_displayio_tilegrid_construct(displayio_tilegrid_t *self, mp_obj_
     self->bitmap = bitmap;
     self->pixel_shader = pixel_shader;
     self->in_group = false;
-    self->first_draw = true;
+    self->hidden = false;
+    self->hidden_by_parent = false;
+    self->previous_area.x1 = 0xffff;
+    self->previous_area.x2 = self->previous_area.x1;
     self->flip_x = false;
     self->flip_y = false;
     self->transpose_xy = false;
 }
 
+
+bool common_hal_displayio_tilegrid_get_hidden(displayio_tilegrid_t* self) {
+    return self->hidden;
+}
+
+void common_hal_displayio_tilegrid_set_hidden(displayio_tilegrid_t* self, bool hidden) {
+    self->hidden = hidden;
+}
+
+void displayio_tilegrid_set_hidden_by_parent(displayio_tilegrid_t *self, bool hidden) {
+    self->hidden_by_parent = hidden;
+}
+
 bool displayio_tilegrid_get_previous_area(displayio_tilegrid_t *self, displayio_area_t* area) {
-    if (self->first_draw) {
+    if (self->previous_area.x1 == self->previous_area.x2) {
         return false;
     }
     displayio_area_copy(&self->previous_area, area);
@@ -138,12 +154,10 @@ void displayio_tilegrid_update_transform(displayio_tilegrid_t *self,
     self->in_group = absolute_transform != NULL;
     self->absolute_transform = absolute_transform;
     if (absolute_transform != NULL) {
-        self->moved = !self->first_draw;
+        self->moved = true;
 
         _update_current_x(self);
         _update_current_y(self);
-    } else {
-        self->first_draw = true;
     }
 }
 
@@ -155,7 +169,7 @@ void common_hal_displayio_tilegrid_set_x(displayio_tilegrid_t *self, mp_int_t x)
         return;
     }
 
-    self->moved = !self->first_draw;
+    self->moved = true;
 
     self->x = x;
     if (self->absolute_transform != NULL) {
@@ -170,7 +184,7 @@ void common_hal_displayio_tilegrid_set_y(displayio_tilegrid_t *self, mp_int_t y)
     if (self->y == y) {
         return;
     }
-    self->moved = !self->first_draw;
+    self->moved = true;
     self->y = y;
     if (self->absolute_transform != NULL) {
         _update_current_y(self);
@@ -306,6 +320,11 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_c
         return false;
     }
 
+    bool hidden = self->hidden || self->hidden_by_parent;
+    if (hidden) {
+        return false;
+    }
+
     displayio_area_t overlap;
     if (!displayio_area_compute_overlap(area, &self->current_area, &overlap)) {
         return false;
@@ -455,14 +474,17 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_c
 }
 
 void displayio_tilegrid_finish_refresh(displayio_tilegrid_t *self) {
-    if (self->moved || self->first_draw) {
+    bool first_draw = self->previous_area.x1 == self->previous_area.x2;
+    bool hidden = self->hidden || self->hidden_by_parent;
+    if (!first_draw && hidden) {
+        self->previous_area.x2 = self->previous_area.x1;
+    } else if (self->moved || first_draw) {
         displayio_area_copy(&self->current_area, &self->previous_area);
     }
 
     self->moved = false;
     self->full_change = false;
     self->partial_change = false;
-    self->first_draw = false;
     if (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_palette_type)) {
         displayio_palette_finish_refresh(self->pixel_shader);
     } else if (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_colorconverter_type)) {
@@ -481,7 +503,17 @@ void displayio_tilegrid_finish_refresh(displayio_tilegrid_t *self) {
 }
 
 displayio_area_t* displayio_tilegrid_get_refresh_areas(displayio_tilegrid_t *self, displayio_area_t* tail) {
-    if (self->moved && !self->first_draw) {
+    bool first_draw = self->previous_area.x1 == self->previous_area.x2;
+    bool hidden = self->hidden || self->hidden_by_parent;
+    // Check hidden first because it trumps all other changes.
+    if (hidden) {
+        if (!first_draw) {
+            self->previous_area.next = tail;
+            return &self->previous_area;
+        } else {
+            return tail;
+        }
+    } else if (self->moved && !first_draw) {
         displayio_area_union(&self->previous_area, &self->current_area, &self->dirty_area);
         if (displayio_area_size(&self->dirty_area) <= 2U * self->pixel_width * self->pixel_height) {
             self->dirty_area.next = tail;
@@ -512,7 +544,7 @@ displayio_area_t* displayio_tilegrid_get_refresh_areas(displayio_tilegrid_t *sel
          displayio_palette_needs_refresh(self->pixel_shader)) ||
         (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_colorconverter_type) &&
          displayio_colorconverter_needs_refresh(self->pixel_shader));
-    if (self->full_change || self->first_draw) {
+    if (self->full_change || first_draw) {
         self->current_area.next = tail;
         return &self->current_area;
     }
diff --git a/shared-module/displayio/TileGrid.h b/shared-module/displayio/TileGrid.h
index 0a414b062..e97d3dfd4 100644
--- a/shared-module/displayio/TileGrid.h
+++ b/shared-module/displayio/TileGrid.h
@@ -55,17 +55,21 @@ typedef struct {
     displayio_area_t dirty_area; // Stored as a relative area until the refresh area is fetched.
     displayio_area_t previous_area; // Stored as an absolute area.
     displayio_area_t current_area; // Stored as an absolute area so it applies across frames.
-    bool partial_change;
-    bool full_change;
-    bool first_draw;
-    bool moved;
-    bool inline_tiles;
-    bool in_group;
-    bool flip_x;
-    bool flip_y;
-    bool transpose_xy;
+    bool partial_change :1;
+    bool full_change :1;
+    bool moved :1;
+    bool inline_tiles :1;
+    bool in_group :1;
+    bool flip_x :1;
+    bool flip_y :1;
+    bool transpose_xy  :1;
+    bool hidden :1;
+    bool hidden_by_parent :1;
+    uint8_t padding :6;
 } displayio_tilegrid_t;
 
+void displayio_tilegrid_set_hidden_by_parent(displayio_tilegrid_t *self, bool hidden);
+
 // Updating the screen is a three stage process.
 
 // The first stage is used to determine i