Added bitmap.blit function for bitmap slice copy

Author: Margaret Matocha

shared-bindings/displayio/Bitmap.c

@@ -172,42 +172,82 @@ STATIC mp_obj_t bitmap_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t val
     return mp_const_none;
 }
 
-//|     def blit(self, x: int, y: int, source_bitmap: bitmap, x1: int, y1: int, x2: int, y2:int) -> Any:
+//|     def blit(self, x: int, y: int, source_bitmap: bitmap, x1: int, y1: int, x2: int, y2: int, skip_index: int) -> Any:
 //|         """Inserts the source_bitmap region defined by rectangular boundaries
 //|         (x1,y1) and (x2,y2) into the bitmap at the specified (x,y) location.
 //|         :param int x: Horizontal pixel location in bitmap where source_bitmap upper-left
 //|             corner will be placed
 //|         :param int y: Vertical pixel location in bitmap where source_bitmap upper-left
 //|             corner will be placed
 //|         :param bitmap source_bitmap: Source bitmap that contains the graphical region to be copied
-//|         : param x1: Minimum x-value for rectangular bounding box to be copied from the source bitmap
-//|         : param y1: Minimum y-value for rectangular bounding box to be copied from the source bitmap
-//|         : param x2: Maximum x-value for rectangular bounding box to be copied from the source bitmap
-//|         : param y2: Maximum y-value for rectangular bounding box to be copied from the source bitmap
-//|         
+//|         : param int x1: Minimum x-value for rectangular bounding box to be copied from the source bitmap
+//|         : param int y1: Minimum y-value for rectangular bounding box to be copied from the source bitmap
+//|         : param int x2: Maximum x-value for rectangular bounding box to be copied from the source bitmap
+//|         : param int y2: Maximum y-value 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 `None` to copy all pixels
 //|         ...
 //|
 
 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};
+    static const mp_arg_t allowed_args[] = {
+        {MP_QSTR_x, MP_ARG_REQUIRED | MP_ARG_INT},
+        {MP_QSTR_y, MP_ARG_REQUIRED | MP_ARG_INT},
+        {MP_QSTR_source, MP_ARG_REQUIRED | MP_ARG_OBJ},
+        {MP_QSTR_x1, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        {MP_QSTR_y1, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        {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_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);
+
+    displayio_bitmap_t *self = MP_OBJ_TO_PTR(pos_args[0]); //*******
+
+    int16_t x = args[ARG_x].u_int;
+    int16_t y = args[ARG_y].u_int;
+
+    displayio_bitmap_t *source = MP_OBJ_TO_PTR(args[ARG_source].u_obj);
+
+    int16_t x1, y1;
+    // if x1 or y1 is None, then set as the zero-point of the bitmap
+    if ( args[ARG_x1].u_obj == mp_const_none ) {
+        x1 = 0;
+    } else {
+        x1 = mp_obj_get_int(args[ARG_x1].u_obj);
+    }
+    //int16_t y1;
+    if ( args[ARG_y1].u_obj == mp_const_none ) {
+        y1 = 0;
+    } else {
+        y1 = mp_obj_get_int(args[ARG_y1].u_obj);
+    }
+   
+    int16_t x2, y2;
+    // if x2 or y2 is None, then set as the maximum size of the source bitmap
+    if ( args[ARG_x2].u_obj == mp_const_none ) {
+        x2 = source->width-1;
+    } else {
+        x2 = mp_obj_get_int(args[ARG_x2].u_obj);
+    }
+    //int16_t y2;
+    if ( args[ARG_y2].u_obj == mp_const_none ) {
+        y2 = source->height-1;
+    } else {
+        y2 = mp_obj_get_int(args[ARG_y2].u_obj);
+    }
 
-    // Consider improving the input checking.
-
-    displayio_bitmap_t *self = MP_OBJ_TO_PTR(pos_args[0]);
-    int16_t x = mp_obj_get_int(pos_args[1]);
-    int16_t y = mp_obj_get_int(pos_args[2]);
-    displayio_bitmap_t *source = MP_OBJ_TO_PTR(pos_args[3]);    
-    int16_t x1 = mp_obj_get_int(pos_args[4]);
-    int16_t y1 = mp_obj_get_int(pos_args[5]);
-    int16_t x2 = mp_obj_get_int(pos_args[6]);
-    int16_t y2 = mp_obj_get_int(pos_args[7]);
 
-    if ( (x<0) || (y<0) || (x > self-> width) || (y > self->height) ) {
+    // Check x,y are within self (target) bitmap boundary
+    if ( (x < 0) || (y < 0) || (x >= self->width) || (y >= self->height) ) {
             mp_raise_ValueError(translate("(x,y): out of range of target bitmap"));
     }
-    if ( (x1 < 0) || (x1 > source->width)  || 
-        (y1 < 0) || (y1 > source->height) || 
-        (x2 < 0) || (x2 > source->width)  ||
-        (y2 < 0) || (y2 > source->height) ) {
+    // Check x1,y1,x2,y2 are within source bitmap boundary
+    if ( (x1 < 0) || (x1 >= source->width)  || 
+        (y1 < 0) || (y1 >= source->height) || 
+        (x2 < 0) || (x2 >= source->width)  ||
+        (y2 < 0) || (y2 >= source->height) ) {
             mp_raise_ValueError(translate("(x1,y1) or (x2,y2): out of range of source bitmap"));
     }
 
@@ -223,13 +263,23 @@ STATIC mp_obj_t displayio_bitmap_obj_blit(size_t n_args, const mp_obj_t *pos_arg
         y1=temp;
     }
 
-    common_hal_displayio_bitmap_blit(self, x, y, source, x1, y1, x2, y2);
+    uint32_t skip_index; 
+    bool skip_index_none; // flag whether skip_value was None
+
+    if (args[ARG_skip_index].u_obj == mp_const_none ) {
+        skip_index = 0;
+        skip_index_none = true;
+    } else {
+        skip_index = mp_obj_get_int(args[ARG_skip_index].u_obj);
+        skip_index_none = false;
+    }
+
+    common_hal_displayio_bitmap_blit(self, x, y, source, x1, y1, x2, y2, skip_index, skip_index_none);
 
     return mp_const_none;
 }
-
-MP_DEFINE_CONST_FUN_OBJ_KW(displayio_bitmap_blit_obj, 8, displayio_bitmap_obj_blit);
-// requires 8 parameters
+MP_DEFINE_CONST_FUN_OBJ_KW(displayio_bitmap_blit_obj, 4, displayio_bitmap_obj_blit);
+// `displayio_bitmap_obj_blit` requires at least 4 arguments
 
 //|     def fill(self, value: Any) -> Any:
 //|         """Fills the bitmap with the supplied palette index value."""

shared-bindings/displayio/Bitmap.h

@@ -41,7 +41,8 @@ uint16_t common_hal_displayio_bitmap_get_width(displayio_bitmap_t *self);
 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);
+                                        int16_t x1, int16_t y1, int16_t x2, int16_t y2, 
+                                        uint32_t skip_index, bool skip_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);
 

shared-module/displayio/Bitmap.c

@@ -106,26 +106,24 @@ uint32_t common_hal_displayio_bitmap_get_pixel(displayio_bitmap_t *self, int16_t
 }
 
 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) {
+                                        int16_t x1, int16_t y1, int16_t x2, int16_t y2, uint32_t skip_index, bool skip_index_none) {
     // Copy complete "source" bitmap into "self" bitmap at location x,y in the "self"
     // Add a boolean to determine if all values are copied, or only if non-zero
-    // Default is copy all values, but for text glyphs this should copy only non-zero values
+    // 
+    // If skip_value is encountered in the source bitmap, it will not be copied.  
+    // If skip_value is `None`, then all pixels are copied.
 
     if (self->read_only) {
         mp_raise_RuntimeError(translate("Read-only object"));
     }
 
-    // If this value is encountered in the source bitmap, it will not be copied (for text glyphs)
-    // This should be added as an optional parameter, and if it is `None`, then all pixels are copied
-    uint32_t skip_value=0;
-
     // simplest version - use internal functions for get/set pixels
-    for (uint16_t i=0; i<= (x2-x1) ; i++) {
+    for (int16_t i=0; i<= (x2-x1) ; i++) {
         if ( (x+i >= 0) && (x+i < self->width) ) {
-            for (uint16_t j=0; j<= (y2-y1) ; j++){
+            for (int16_t j=0; j<= (y2-y1) ; j++){
                 if ((y+j >= 0) && (y+j < self->height) ) {
                     uint32_t value = common_hal_displayio_bitmap_get_pixel(source, x1+i, y1+j);
-                    if ( (value != skip_value) ) { 
+                    if ( (skip_index_none) || (value != skip_index) ) { // write if skip_value_none is True
                             common_hal_displayio_bitmap_set_pixel(self, x+i, y+j, value);
                     }
                 }