displayio: Pass transparent_color to ColorConverter

Signed-off-by: Jensen <[email protected]>

Author: jensechu

shared-bindings/displayio/ColorConverter.c

@@ -43,24 +43,27 @@
 //|         """Create a ColorConverter object to convert color formats. Only supports RGB888 to RGB565
 //|         currently.
 //|         :param bool dither: Adds random noise to dither the output image"""
+//|         :param bool transparent_color: Sets one color in the colorset to transparent"""
 //|         ...
 //|
 
 // TODO(tannewt): Add support for other color formats.
 //|
 STATIC mp_obj_t displayio_colorconverter_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_dither};
+    enum { ARG_transparent_color };
 
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_dither, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
+        { MP_QSTR_transparent_color, MP_ARG_KW_ONLY | MP_ARG_INT, {.uint32_t = 0} },
     };
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
     displayio_colorconverter_t *self = m_new_obj(displayio_colorconverter_t);
     self->base.type = &displayio_colorconverter_type;
 
-    common_hal_displayio_colorconverter_construct(self, args[ARG_dither].u_bool);
+    common_hal_displayio_colorconverter_construct(self, args[ARG_dither].u_bool, args[ARG_transparent_color].uint32_t);
 
     return MP_OBJ_FROM_PTR(self);
 }

shared-bindings/displayio/ColorConverter.h

@@ -33,7 +33,7 @@
 
 extern const mp_obj_type_t displayio_colorconverter_type;
 
-void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self, bool dither);
+void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self, bool dither, uint32_t transparent_color);
 void 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_set_dither(displayio_colorconverter_t* self, bool dither);

shared-module/displayio/ColorConverter.c

@@ -39,8 +39,9 @@ uint32_t displayio_colorconverter_dither_noise_2(uint32_t x, uint32_t y) {
     return displayio_colorconverter_dither_noise_1(x + y * 0xFFFF);
 }
 
-void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self, bool dither) {
+void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self, bool dither, uint32_t transparent_color) {
     self->dither = dither;
+    self->transparent_color = transparent_color;
 }
 
 uint16_t displayio_colorconverter_compute_rgb565(uint32_t color_rgb888) {
@@ -161,6 +162,9 @@ void displayio_colorconverter_convert(displayio_colorconverter_t *self, const _d
         }
         output_color->pixel = packed;
         output_color->opaque = true;
+        if (self->transparent_color == pixel) {
+            output_color->opaque = false;
+        }
         return;
     } else if (colorspace->tricolor) {
         uint8_t luma = displayio_colorconverter_compute_luma(pixel);
@@ -170,6 +174,9 @@ void displayio_colorconverter_convert(displayio_colorconverter_t *self, const _d
                 output_color->pixel = 0;
             }
             output_color->opaque = true;
+            if (self->transparent_color == pixel) {
+                output_color->opaque = false;
+            }            
             return;
         }
         uint8_t pixel_hue = displayio_colorconverter_compute_hue(pixel);
@@ -179,6 +186,9 @@ void displayio_colorconverter_convert(displayio_colorconverter_t *self, const _d
         uint8_t luma = displayio_colorconverter_compute_luma(pixel);
         output_color->pixel = luma >> (8 - colorspace->depth);
         output_color->opaque = true;
+        if (self->transparent_color == pixel) {
+            output_color->opaque = false;
+        }
         return;
     }
     output_color->opaque = false;

shared-module/displayio/ColorConverter.h

@@ -36,6 +36,7 @@
 typedef struct {
     mp_obj_base_t base;
     bool dither;
+    uint32_t transparent_color;
 } displayio_colorconverter_t;
 
 bool displayio_colorconverter_needs_refresh(displayio_colorconverter_t *self);