feat(draw): improve acceleration for LV_IMG_CF_ALPHA_8BIT (#3337)

* feat(draw): improve acceleration for LV_IMG_CF_ALPHA_8BIT

* fix format issue

* fix: use normal method when conditions are not fulfilled.

* fix a typo

* feat(demo): add Weighted FPS and Opa speed log output (#3326)

Signed-off-by: pengyiqiang <pengyiqiang@xiaomi.com>

Co-authored-by: pengyiqiang <pengyiqiang@xiaomi.com>

* perf(layer): cache the layer_type

fixes #3334

* fix partial redraw and setting color

Co-authored-by: _VIFEXTech <1290176185@qq.com>
Co-authored-by: pengyiqiang <pengyiqiang@xiaomi.com>
Co-authored-by: Gabor Kiss-Vamosi <kisvegabor@gmail.com>

src/draw/lv_draw_img.c

@@ -239,9 +239,18 @@ LV_ATTRIBUTE_FAST_MEM static lv_res_t decode_and_draw(lv_draw_ctx_t * draw_ctx,
 
     lv_img_cf_t cf;
     if(lv_img_cf_is_chroma_keyed(cdsc->dec_dsc.header.cf)) cf = LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED;
+    else if(LV_IMG_CF_ALPHA_8BIT == cdsc->dec_dsc.header.cf) cf = LV_IMG_CF_ALPHA_8BIT;
     else if(lv_img_cf_has_alpha(cdsc->dec_dsc.header.cf)) cf = LV_IMG_CF_TRUE_COLOR_ALPHA;
     else cf = LV_IMG_CF_TRUE_COLOR;
 
+    if(cf == LV_IMG_CF_ALPHA_8BIT) {
+        if(draw_dsc->angle || draw_dsc->zoom != LV_IMG_ZOOM_NONE) {
+            /* resume normal method */
+            cf = LV_IMG_CF_TRUE_COLOR_ALPHA;
+            cdsc->dec_dsc.img_data = NULL;
+        }
+    }
+
     if(cdsc->dec_dsc.error_msg != NULL) {
         LV_LOG_WARN("Image draw error");
 

src/draw/lv_img_decoder.c

@@ -361,7 +361,8 @@ lv_res_t lv_img_decoder_built_in_open(lv_img_decoder_t * decoder, lv_img_decoder
 
     lv_img_cf_t cf = dsc->header.cf;
     /*Process true color formats*/
-    if(cf == LV_IMG_CF_TRUE_COLOR || cf == LV_IMG_CF_TRUE_COLOR_ALPHA || cf == LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED) {
+    if(cf == LV_IMG_CF_TRUE_COLOR || cf == LV_IMG_CF_TRUE_COLOR_ALPHA || cf == LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED ||
+       cf == LV_IMG_CF_ALPHA_8BIT) {
         if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
             /*In case of uncompressed formats the image stored in the ROM/RAM.
              *So simply give its pointer*/
@@ -426,8 +427,7 @@ lv_res_t lv_img_decoder_built_in_open(lv_img_decoder_t * decoder, lv_img_decoder
         return LV_RES_OK;
     }
     /*Alpha indexed images.*/
-    else if(cf == LV_IMG_CF_ALPHA_1BIT || cf == LV_IMG_CF_ALPHA_2BIT || cf == LV_IMG_CF_ALPHA_4BIT ||
-            cf == LV_IMG_CF_ALPHA_8BIT) {
+    else if(cf == LV_IMG_CF_ALPHA_1BIT || cf == LV_IMG_CF_ALPHA_2BIT || cf == LV_IMG_CF_ALPHA_4BIT) {
         return LV_RES_OK; /*Nothing to process*/
     }
     /*Unknown format. Can't decode it.*/

src/draw/sw/lv_draw_sw_blend.c

@@ -142,7 +142,7 @@ LV_ATTRIBUTE_FAST_MEM void lv_draw_sw_blend_basic(lv_draw_ctx_t * draw_ctx, cons
     lv_coord_t mask_stride;
     if(mask) {
         mask_stride = lv_area_get_width(dsc->mask_area);
-        mask += mask_stride * (dsc->mask_area->y1 - blend_area.y1) + (dsc->mask_area->x1 - blend_area.x1);
+        mask += mask_stride * (blend_area.y1 - dsc->mask_area->y1) + (blend_area.x1 - dsc->mask_area->x1);
     }
     else {
         mask_stride = 0;

src/draw/sw/lv_draw_sw_img.c

@@ -67,6 +67,19 @@ LV_ATTRIBUTE_FAST_MEM void lv_draw_sw_img_decoded(struct _lv_draw_ctx_t * draw_c
         blend_dsc.blend_area = coords;
         lv_draw_sw_blend(draw_ctx, &blend_dsc);
     }
+    else if(!mask_any && !transform && cf == LV_IMG_CF_ALPHA_8BIT) {
+        lv_area_t clipped_coords;
+        if(!_lv_area_intersect(&clipped_coords, coords, draw_ctx->clip_area)) return;
+
+        blend_dsc.mask_buf = (lv_opa_t *)src_buf;
+        blend_dsc.mask_area = coords;
+        blend_dsc.src_buf = NULL;
+        blend_dsc.color = draw_dsc->recolor;
+        blend_dsc.mask_res = LV_DRAW_MASK_RES_CHANGED;
+
+        blend_dsc.blend_area = coords;
+        lv_draw_sw_blend(draw_ctx, &blend_dsc);
+    }
     /*In the other cases every pixel need to be checked one-by-one*/
     else {
         blend_area.x1 = draw_ctx->clip_area->x1;