fix(draw_sw): in ARGB8888_PREMULTIPLIED fix rounding error and add RGB888 image blending support (#8264)

src/draw/sw/blend/lv_draw_sw_blend_to_argb8888_premultiplied.c

@@ -41,6 +41,11 @@ typedef struct {
     static void /* LV_ATTRIBUTE_FAST_MEM */ argb8888_image_blend(lv_draw_sw_blend_image_dsc_t * dsc);
 #endif
 
+#if LV_DRAW_SW_SUPPORT_RGB888 || LV_DRAW_SW_SUPPORT_XRGB8888
+static void /* LV_ATTRIBUTE_FAST_MEM */ rgb888_image_blend(lv_draw_sw_blend_image_dsc_t * dsc,
+                                                           const uint8_t src_px_size);
+#endif
+
 static void /* LV_ATTRIBUTE_FAST_MEM */ argb8888_premultiplied_image_blend(lv_draw_sw_blend_image_dsc_t * dsc);
 
 static inline void /* LV_ATTRIBUTE_FAST_MEM */ blend_non_normal_pixel_premultiplied(
@@ -77,6 +82,23 @@ static inline void * /* LV_ATTRIBUTE_FAST_MEM */ drawbuf_next_row(const void * b
     #define   LV_DRAW_SW_ARGB8888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_MIX_MASK_OPA(...)             LV_RESULT_INVALID
 #endif
 
+#ifndef LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED
+    #define   LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED(...)             LV_RESULT_INVALID
+#endif
+
+#ifndef LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_OPA
+    #define   LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_OPA(...)             LV_RESULT_INVALID
+#endif
+
+#ifndef LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_MASK
+    #define   LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_MASK(...)             LV_RESULT_INVALID
+#endif
+
+#ifndef LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_MIX_MASK_OPA
+    #define   LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_MIX_MASK_OPA(...)             LV_RESULT_INVALID
+#endif
+
+
 #ifndef LV_DRAW_SW_ARGB8888_PREMULTIPLIED_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED
     #define   LV_DRAW_SW_ARGB8888_PREMULTIPLIED_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED(...)             LV_RESULT_INVALID
 #endif
@@ -121,11 +143,18 @@ void LV_ATTRIBUTE_FAST_MEM lv_draw_sw_blend_color_to_argb8888_premultiplied(lv_d
     int32_t y;
 
     /* Convert source color to premultiplied */
+    if(opa >= LV_OPA_MAX) opa = 0xff;
     lv_color32_t color_argb = lv_color_to_32(dsc->color, opa);
-    color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
-    color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
-    color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
-
+    lv_color32_t color_argb_premul;
+    if(opa == 0xff) {
+        color_argb_premul = color_argb;
+    }
+    else {
+        color_argb_premul.alpha = opa;
+        color_argb_premul.red   = (color_argb.red   * opa) >> 8;
+        color_argb_premul.green = (color_argb.green * opa) >> 8;
+        color_argb_premul.blue  = (color_argb.blue  * opa) >> 8;
+    }
 
     /* Simple fill */
     if(mask == NULL && opa >= LV_OPA_MAX) {
@@ -144,7 +173,7 @@ void LV_ATTRIBUTE_FAST_MEM lv_draw_sw_blend_color_to_argb8888_premultiplied(lv_d
         lv_color32_t * dest_buf = dsc->dest_buf;
         for(y = 0; y < h; y++) {
             for(x = 0; x < w; x++) {
-                dest_buf[x] = lv_color_32_32_mix_premul(color_argb, dest_buf[x], &cache);
+                dest_buf[x] = lv_color_32_32_mix_premul(color_argb_premul, dest_buf[x], &cache);
             }
             dest_buf = drawbuf_next_row(dest_buf, dest_stride);
         }
@@ -155,11 +184,16 @@ void LV_ATTRIBUTE_FAST_MEM lv_draw_sw_blend_color_to_argb8888_premultiplied(lv_d
         for(y = 0; y < h; y++) {
             for(x = 0; x < w; x++) {
                 lv_color32_t color_premul = color_argb;
-                color_premul.alpha = mask[x];
-                color_premul.red   = (color_premul.red   * color_premul.alpha) >> 8;
-                color_premul.green = (color_premul.green * color_premul.alpha) >> 8;
-                color_premul.blue  = (color_premul.blue  * color_premul.alpha) >> 8;
-                dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                if(mask[x] >= LV_OPA_MAX) {
+                    dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                }
+                else if(mask[x] > LV_OPA_MIN) {
+                    color_premul.alpha = mask[x];
+                    color_premul.red   = (color_premul.red   * color_premul.alpha) >> 8;
+                    color_premul.green = (color_premul.green * color_premul.alpha) >> 8;
+                    color_premul.blue  = (color_premul.blue  * color_premul.alpha) >> 8;
+                    dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                }
             }
             dest_buf = drawbuf_next_row(dest_buf, dest_stride);
             mask += mask_stride;
@@ -171,11 +205,17 @@ void LV_ATTRIBUTE_FAST_MEM lv_draw_sw_blend_color_to_argb8888_premultiplied(lv_d
         for(y = 0; y < h; y++) {
             for(x = 0; x < w; x++) {
                 lv_color32_t color_premul = color_argb;
-                color_premul.alpha = LV_OPA_MIX2(mask[x], opa);
-                color_premul.red   = (color_premul.red   * color_premul.alpha) >> 8;
-                color_premul.green = (color_premul.green * color_premul.alpha) >> 8;
-                color_premul.blue  = (color_premul.blue  * color_premul.alpha) >> 8;
-                dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                lv_opa_t alpha = LV_OPA_MIX2(mask[x], opa);
+                if(alpha >= LV_OPA_MAX) {
+                    dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                }
+                else if(mask[x] > LV_OPA_MIN) {
+                    color_premul.alpha = alpha;
+                    color_premul.red   = (color_premul.red   * color_premul.alpha) >> 8;
+                    color_premul.green = (color_premul.green * color_premul.alpha) >> 8;
+                    color_premul.blue  = (color_premul.blue  * color_premul.alpha) >> 8;
+                    dest_buf[x] = lv_color_32_32_mix_premul(color_premul, dest_buf[x], &cache);
+                }
             }
             dest_buf = drawbuf_next_row(dest_buf, dest_stride);
             mask += mask_stride;
@@ -199,6 +239,19 @@ void LV_ATTRIBUTE_FAST_MEM lv_draw_sw_blend_image_to_argb8888_premultiplied(lv_d
             argb8888_image_blend(dsc);
             break;
 #endif
+
+#if LV_DRAW_SW_SUPPORT_RGB888
+        case LV_COLOR_FORMAT_RGB888:
+            rgb888_image_blend(dsc, 3);
+            break;
+#endif
+
+#if LV_DRAW_SW_SUPPORT_XRGB8888
+        case LV_COLOR_FORMAT_XRGB8888:
+            rgb888_image_blend(dsc, 4);
+            break;
+#endif
+
         case LV_COLOR_FORMAT_ARGB8888_PREMULTIPLIED:
             argb8888_premultiplied_image_blend(dsc);
             break;
@@ -240,12 +293,23 @@ static void LV_ATTRIBUTE_FAST_MEM argb8888_image_blend(lv_draw_sw_blend_image_ds
                     for(x = 0; x < w; x++) {
                         color_argb = src_buf_c32[x];
 
-                        /* Premultiply alpha */
-                        color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
-                        color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
-                        color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
+                        if(color_argb.alpha >= LV_OPA_MAX) {
+                            color_argb.alpha = 0xff;
+                            dest_buf_c32[x] = color_argb;
+                        }
+                        else if(color_argb.alpha > LV_OPA_MIN) {
+                            /*Premultiplication can cause loss of precision which can result slightly
+                             *darker color when blending the same color to the background.*/
+                            if(dest_buf_c32[x].red != color_argb.red ||
+                               dest_buf_c32[x].green != color_argb.green ||
+                               dest_buf_c32[x].blue != color_argb.blue) {
 
-                        dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                                color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
+                                color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
+                                color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
+                                dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                            }
+                        }
                     }
                     dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
                     src_buf_c32 = drawbuf_next_row(src_buf_c32, src_stride);
@@ -259,14 +323,25 @@ static void LV_ATTRIBUTE_FAST_MEM argb8888_image_blend(lv_draw_sw_blend_image_ds
                         color_argb = src_buf_c32[x];
 
                         /* Apply global opacity */
-                        color_argb.alpha = LV_OPA_MIX2(color_argb.alpha, opa);
+                        lv_opa_t alpha = LV_OPA_MIX2(color_argb.alpha, opa);
 
-                        /* Premultiply alpha */
-                        color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
-                        color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
-                        color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
-
-                        dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                        if(alpha >= LV_OPA_MAX) {
+                            color_argb.alpha = 0xff;
+                            dest_buf_c32[x] = color_argb;
+                        }
+                        else if(alpha > LV_OPA_MIN) {
+                            /*Premultiplication can cause loss of precision which can result slightly
+                             *darker color when blending the same color to the background.*/
+                            if(dest_buf_c32[x].red != color_argb.red ||
+                               dest_buf_c32[x].green != color_argb.green ||
+                               dest_buf_c32[x].blue != color_argb.blue) {
+                                color_argb.alpha = alpha;
+                                color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
+                                color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
+                                color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
+                                dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                            }
+                        }
                     }
                     dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
                     src_buf_c32 = drawbuf_next_row(src_buf_c32, src_stride);
@@ -280,14 +355,25 @@ static void LV_ATTRIBUTE_FAST_MEM argb8888_image_blend(lv_draw_sw_blend_image_ds
                         color_argb = src_buf_c32[x];
 
                         /* Apply mask opacity */
-                        color_argb.alpha = LV_OPA_MIX2(color_argb.alpha, mask_buf[x]);
+                        lv_opa_t alpha = LV_OPA_MIX2(color_argb.alpha, mask_buf[x]);
 
-                        /* Premultiply alpha */
-                        color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
-                        color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
-                        color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
-
-                        dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                        if(alpha >= LV_OPA_MAX) {
+                            color_argb.alpha = 0xff;
+                            dest_buf_c32[x] = color_argb;
+                        }
+                        else if(alpha > LV_OPA_MIN) {
+                            /*Premultiplication can cause loss of precision which can result slightly
+                             *darker color when blending the same color to the background.*/
+                            if(dest_buf_c32[x].red != color_argb.red ||
+                               dest_buf_c32[x].green != color_argb.green ||
+                               dest_buf_c32[x].blue != color_argb.blue) {
+                                color_argb.alpha = alpha;
+                                color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
+                                color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
+                                color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
+                                dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                            }
+                        }
                     }
                     dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
                     src_buf_c32 = drawbuf_next_row(src_buf_c32, src_stride);
@@ -302,14 +388,25 @@ static void LV_ATTRIBUTE_FAST_MEM argb8888_image_blend(lv_draw_sw_blend_image_ds
                         color_argb = src_buf_c32[x];
 
                         /* Apply both mask and global opacity */
-                        color_argb.alpha = LV_OPA_MIX3(color_argb.alpha, opa, mask_buf[x]);
+                        lv_opa_t alpha = LV_OPA_MIX3(color_argb.alpha, opa, mask_buf[x]);
 
-                        /* Premultiply alpha */
-                        color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
-                        color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
-                        color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
-
-                        dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                        if(alpha >= LV_OPA_MAX) {
+                            color_argb.alpha = 0xff;
+                            dest_buf_c32[x] = color_argb;
+                        }
+                        else if(alpha > LV_OPA_MIN) {
+                            /*Premultiplication can cause loss of precision which can result slightly
+                             *darker color when blending the same color to the background.*/
+                            if(dest_buf_c32[x].red != color_argb.red ||
+                               dest_buf_c32[x].green != color_argb.green ||
+                               dest_buf_c32[x].blue != color_argb.blue) {
+                                color_argb.alpha = alpha;
+                                color_argb.red   = (color_argb.red   * color_argb.alpha) >> 8;
+                                color_argb.green = (color_argb.green * color_argb.alpha) >> 8;
+                                color_argb.blue  = (color_argb.blue  * color_argb.alpha) >> 8;
+                                dest_buf_c32[x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[x], &cache);
+                            }
+                        }
                     }
                     dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
                     src_buf_c32 = drawbuf_next_row(src_buf_c32, src_stride);
@@ -345,6 +442,128 @@ static void LV_ATTRIBUTE_FAST_MEM argb8888_image_blend(lv_draw_sw_blend_image_ds
 
 #endif
 
+#if LV_DRAW_SW_SUPPORT_RGB888 || LV_DRAW_SW_SUPPORT_XRGB8888
+
+static void LV_ATTRIBUTE_FAST_MEM rgb888_image_blend(lv_draw_sw_blend_image_dsc_t * dsc, const uint8_t src_px_size)
+{
+
+    int32_t w = dsc->dest_w;
+    int32_t h = dsc->dest_h;
+    lv_opa_t opa = dsc->opa;
+    lv_color32_t * dest_buf_c32 = dsc->dest_buf;
+    int32_t dest_stride = dsc->dest_stride;
+    const uint8_t * src_buf = dsc->src_buf;
+    int32_t src_stride = dsc->src_stride;
+    const lv_opa_t * mask_buf = dsc->mask_buf;
+    int32_t mask_stride = dsc->mask_stride;
+
+    lv_color32_t color_argb;
+    lv_color_mix_alpha_cache_t cache;
+    lv_color_mix_with_alpha_cache_init(&cache);
+
+    int32_t dest_x;
+    int32_t src_x;
+    int32_t y;
+
+    LV_UNUSED(color_argb);
+
+    if(dsc->blend_mode == LV_BLEND_MODE_NORMAL) {
+        /*Special case*/
+        if(mask_buf == NULL && opa >= LV_OPA_MAX) {
+            if(LV_RESULT_INVALID == LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED(dsc, src_px_size)) {
+                if(src_px_size == 4) {
+                    uint32_t line_in_bytes = w * 4;
+                    for(y = 0; y < h; y++) {
+                        lv_memcpy(dest_buf_c32, src_buf, line_in_bytes);
+                        dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+                        src_buf = drawbuf_next_row(src_buf, src_stride);
+                    }
+                }
+                else if(src_px_size == 3) {
+                    for(y = 0; y < h; y++) {
+                        for(dest_x = 0, src_x = 0; dest_x < w; dest_x++, src_x += 3) {
+                            dest_buf_c32[dest_x].red = src_buf[src_x + 2];
+                            dest_buf_c32[dest_x].green = src_buf[src_x + 1];
+                            dest_buf_c32[dest_x].blue = src_buf[src_x + 0];
+                            dest_buf_c32[dest_x].alpha = 0xff;
+                        }
+                        dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+                        src_buf = drawbuf_next_row(src_buf, src_stride);
+                    }
+                }
+            }
+        }
+        if(mask_buf == NULL && opa < LV_OPA_MAX) {
+            if(LV_RESULT_INVALID == LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_OPA(dsc, src_px_size)) {
+                color_argb.alpha = opa;
+                for(y = 0; y < h; y++) {
+                    for(dest_x = 0, src_x = 0; dest_x < w; dest_x++, src_x += src_px_size) {
+                        color_argb.red = (src_buf[src_x + 2] * color_argb.alpha) >> 8;
+                        color_argb.green = (src_buf[src_x + 1] * color_argb.alpha) >> 8;
+                        color_argb.blue = (src_buf[src_x + 0] * color_argb.alpha) >> 8;
+                        dest_buf_c32[dest_x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[dest_x], &cache);
+                    }
+                    dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+                    src_buf = drawbuf_next_row(src_buf, src_stride);
+                }
+            }
+        }
+        if(mask_buf && opa >= LV_OPA_MAX) {
+            if(LV_RESULT_INVALID == LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_WITH_MASK(dsc, src_px_size)) {
+                for(y = 0; y < h; y++) {
+                    for(dest_x = 0, src_x = 0; dest_x < w; dest_x++, src_x += src_px_size) {
+                        color_argb.alpha = mask_buf[dest_x];
+                        color_argb.red = (src_buf[src_x + 2] * color_argb.alpha) >> 8;
+                        color_argb.green = (src_buf[src_x + 1] * color_argb.alpha) >> 8;
+                        color_argb.blue = (src_buf[src_x + 0] * color_argb.alpha) >> 8;
+                        dest_buf_c32[dest_x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[dest_x], &cache);
+                    }
+                    dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+                    src_buf = drawbuf_next_row(src_buf, src_stride);
+                    mask_buf += mask_stride;
+                }
+            }
+        }
+        if(mask_buf && opa < LV_OPA_MAX) {
+            if(LV_RESULT_INVALID == LV_DRAW_SW_RGB888_BLEND_NORMAL_TO_ARGB8888_PREMULTIPLIED_MIX_MASK_OPA(dsc, src_px_size)) {
+                for(y = 0; y < h; y++) {
+                    for(dest_x = 0, src_x = 0; dest_x < w; dest_x++, src_x += src_px_size) {
+                        color_argb.alpha = (opa * mask_buf[dest_x]) >> 8;
+                        color_argb.red = (src_buf[src_x + 2] * color_argb.alpha) >> 8;;
+                        color_argb.green = (src_buf[src_x + 1] * color_argb.alpha) >> 8;;
+                        color_argb.blue = (src_buf[src_x + 0] * color_argb.alpha) >> 8;;
+                        dest_buf_c32[dest_x] = lv_color_32_32_mix_premul(color_argb, dest_buf_c32[dest_x], &cache);
+                    }
+                    dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+                    src_buf = drawbuf_next_row(src_buf, src_stride);
+                    mask_buf += mask_stride;
+                }
+            }
+        }
+    }
+    else {
+        lv_color32_t src_argb;
+        for(y = 0; y < h; y++) {
+            for(dest_x = 0, src_x = 0; dest_x < w; dest_x++, src_x += src_px_size) {
+                src_argb.red = src_buf[src_x + 2];
+                src_argb.green = src_buf[src_x + 1];
+                src_argb.blue = src_buf[src_x + 0];
+                if(mask_buf == NULL) src_argb.alpha = opa;
+                else src_argb.alpha = LV_OPA_MIX2(mask_buf[dest_x], opa);
+
+                blend_non_normal_pixel_premultiplied(&dest_buf_c32[dest_x], src_argb, dsc->blend_mode, &cache);
+            }
+
+            if(mask_buf) mask_buf += mask_stride;
+            dest_buf_c32 = drawbuf_next_row(dest_buf_c32, dest_stride);
+            src_buf = drawbuf_next_row(src_buf, src_stride);
+        }
+    }
+}
+
+#endif
+
+
 static void LV_ATTRIBUTE_FAST_MEM argb8888_premultiplied_image_blend(lv_draw_sw_blend_image_dsc_t * dsc)
 {
     int32_t w = dsc->dest_w;

src/misc/lv_color_op.c

@@ -73,7 +73,6 @@ lv_color32_t lv_color_mix32_premultiplied(lv_color32_t fg, lv_color32_t bg)
     bg.red   = fg.red   + ((bg.red   * inv_fg_alpha) >> 8);
     bg.green = fg.green + ((bg.green * inv_fg_alpha) >> 8);
     bg.blue  = fg.blue  + ((bg.blue  * inv_fg_alpha) >> 8);
-    bg.alpha = fg.alpha + ((bg.alpha * inv_fg_alpha) >> 8);
 
     return bg;
 }