adding skip_self_index argument to bitmap.blit()

shared-bindings/displayio/Bitmap.c

@@ -196,7 +196,8 @@ STATIC mp_obj_t bitmap_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t val
 //|         y1: int,
 //|         x2: int,
 //|         y2: int,
-//|         skip_index: int
+//|         skip_index: int,
+//|         skip_self_index: int
 //|     ) -> None:
 //|         """Inserts the source_bitmap region defined by rectangular boundaries
 //|                     (x1,y1) and (x2,y2) into the bitmap at the specified (x,y) location.
@@ -211,10 +212,12 @@ STATIC mp_obj_t bitmap_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t val
 //|         :param int x2: Maximum x-value (exclusive) for rectangular bounding box to be copied from the source bitmap
 //|         :param int y2: Maximum y-value (exclusive) for rectangular bounding box to be copied from the source bitmap
 //|         :param int skip_index: bitmap palette index in the source that will not be copied,
-//|                                set to None to copy all pixels"""
+//|                                set to None to copy all pixels
+//|         :param int skip_self_index: bitmap palette index in the self bitmap that will not get overwritten
+//|                                 by the pixels from the source"""
 //|         ...
 STATIC mp_obj_t displayio_bitmap_obj_blit(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum {ARG_x, ARG_y, ARG_source, ARG_x1, ARG_y1, ARG_x2, ARG_y2, ARG_skip_index};
+    enum {ARG_x, ARG_y, ARG_source, ARG_x1, ARG_y1, ARG_x2, ARG_y2, ARG_skip_index, ARG_skip_self_index};
     static const mp_arg_t allowed_args[] = {
         {MP_QSTR_x, MP_ARG_REQUIRED | MP_ARG_INT, {.u_obj = MP_OBJ_NULL} },
         {MP_QSTR_y, MP_ARG_REQUIRED | MP_ARG_INT, {.u_obj = MP_OBJ_NULL} },
@@ -224,6 +227,7 @@ STATIC mp_obj_t displayio_bitmap_obj_blit(size_t n_args, const mp_obj_t *pos_arg
         {MP_QSTR_x2, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} }, // None convert to source->width
         {MP_QSTR_y2, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} }, // None convert to source->height
         {MP_QSTR_skip_index, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
+        {MP_QSTR_skip_self_index, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
     };
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
@@ -283,7 +287,19 @@ STATIC mp_obj_t displayio_bitmap_obj_blit(size_t n_args, const mp_obj_t *pos_arg
         skip_index_none = false;
     }
 
-    common_hal_displayio_bitmap_blit(self, x, y, source, x1, y1, x2, y2, skip_index, skip_index_none);
+    uint32_t skip_self_index;
+    bool skip_self_index_none; // flag whether skip_self_value was None
+
+    if (args[ARG_skip_self_index].u_obj == mp_const_none) {
+        skip_self_index = 0;
+        skip_self_index_none = true;
+    } else {
+        skip_self_index = mp_obj_get_int(args[ARG_skip_self_index].u_obj);
+        skip_self_index_none = false;
+    }
+
+    common_hal_displayio_bitmap_blit(self, x, y, source, x1, y1, x2, y2, skip_index, skip_index_none, skip_self_index,
+        skip_self_index_none);
 
     return mp_const_none;
 }

shared-bindings/displayio/Bitmap.h

@@ -44,7 +44,7 @@ uint32_t common_hal_displayio_bitmap_get_bits_per_value(displayio_bitmap_t *self
 void common_hal_displayio_bitmap_set_pixel(displayio_bitmap_t *bitmap, int16_t x, int16_t y, uint32_t value);
 void common_hal_displayio_bitmap_blit(displayio_bitmap_t *self, int16_t x, int16_t y, displayio_bitmap_t *source,
     int16_t x1, int16_t y1, int16_t x2, int16_t y2,
-    uint32_t skip_index, bool skip_index_none);
+    uint32_t skip_index, bool skip_index_none, uint32_t skip_self_index, bool skip_self_index_none);
 uint32_t common_hal_displayio_bitmap_get_pixel(displayio_bitmap_t *bitmap, int16_t x, int16_t y);
 void common_hal_displayio_bitmap_fill(displayio_bitmap_t *bitmap, uint32_t value);
 int common_hal_displayio_bitmap_get_buffer(displayio_bitmap_t *self, mp_buffer_info_t *bufinfo, mp_uint_t flags);

shared-module/displayio/Bitmap.c

@@ -175,7 +175,8 @@ void displayio_bitmap_write_pixel(displayio_bitmap_t *self, int16_t x, int16_t y
 }
 
 void common_hal_displayio_bitmap_blit(displayio_bitmap_t *self, int16_t x, int16_t y, displayio_bitmap_t *source,
-    int16_t x1, int16_t y1, int16_t x2, int16_t y2, uint32_t skip_index, bool skip_index_none) {
+    int16_t x1, int16_t y1, int16_t x2, int16_t y2, uint32_t skip_index, bool skip_index_none, uint32_t skip_self_index,
+    bool skip_self_index_none) {
     if (self->read_only) {
         mp_raise_RuntimeError(translate("Read-only"));
     }
@@ -222,8 +223,17 @@ void common_hal_displayio_bitmap_blit(displayio_bitmap_t *self, int16_t x, int16
 
                 if ((yd_index >= 0) && (yd_index < self->height)) {
                     uint32_t value = common_hal_displayio_bitmap_get_pixel(source, xs_index, ys_index);
-                    if ((skip_index_none) || (value != skip_index)) {   // write if skip_value_none is True
+                    if (skip_self_index_none) { // if skip_self_index is none, then only check source skip
-                        displayio_bitmap_write_pixel(self, xd_index, yd_index, value);
+                        if ((skip_index_none) || (value != skip_index)) {   // write if skip_value_none is True
+                            displayio_bitmap_write_pixel(self, xd_index, yd_index, value);
+                        }
+                    } else { // check dest_value index against skip_self_index and skip if they match
+                        uint32_t dest_value = common_hal_displayio_bitmap_get_pixel(self, xd_index, yd_index);
+                        if (dest_value != skip_self_index) {
+                            if ((skip_index_none) || (value != skip_index)) {   // write if skip_value_none is True
+                                displayio_bitmap_write_pixel(self, xd_index, yd_index, value);
+                            }
+                        }
                     }
                 }
             }