feat(bin_decoder): post process decoded image to fulfill decoder's args (#5082)

Signed-off-by: Xu Xingliang <xuxingliang@xiaomi.com>

src/draw/lv_draw_buf.c

@@ -166,7 +166,7 @@ lv_draw_buf_t * lv_draw_buf_create(uint32_t w, uint32_t h, lv_color_format_t cf,
     draw_buf->header.w = w;
     draw_buf->header.h = h;
     draw_buf->header.cf = cf;
-    draw_buf->header.flags = LV_IMAGE_FLAGS_MODIFIABLE;
+    draw_buf->header.flags = LV_IMAGE_FLAGS_MODIFIABLE | LV_IMAGE_FLAGS_ALLOCATED;
     draw_buf->header.stride = stride;
     draw_buf->data = lv_draw_buf_align(buf, cf);
     draw_buf->unaligned_data = buf;
@@ -174,14 +174,32 @@ lv_draw_buf_t * lv_draw_buf_create(uint32_t w, uint32_t h, lv_color_format_t cf,
     return draw_buf;
 }
 
+lv_draw_buf_t * lv_draw_buf_dup(const lv_draw_buf_t * draw_buf)
+{
+    const lv_image_header_t * header = &draw_buf->header;
+    lv_draw_buf_t * new_buf = lv_draw_buf_create(header->w, header->h, header->cf, header->stride);
+    if(new_buf == NULL) return NULL;
+
+    /*Choose the smaller size to copy*/
+    uint32_t size = LV_MIN(draw_buf->data_size, new_buf->data_size);
+
+    /*Copy image data*/
+    lv_memcpy(new_buf->data, draw_buf->data, size);
+    return new_buf;
+}
+
 void lv_draw_buf_destroy(lv_draw_buf_t * buf)
 {
     LV_ASSERT_NULL(buf);
     if(buf == NULL) return;
-    if(buf->header.flags & LV_IMAGE_FLAGS_MODIFIABLE)
-        lv_draw_buf_free(buf->unaligned_data);
 
-    lv_free(buf);
+    if(buf->header.flags & LV_IMAGE_FLAGS_ALLOCATED) {
+        lv_draw_buf_free(buf->unaligned_data);
+        lv_free(buf);
+    }
+    else {
+        LV_LOG_ERROR("draw buffer is not allocated, ignored");
+    }
 }
 
 void * lv_draw_buf_goto_xy(lv_draw_buf_t * buf, uint32_t x, uint32_t y)
@@ -230,6 +248,69 @@ lv_draw_buf_t * lv_draw_buf_adjust_stride(const lv_draw_buf_t * src, uint32_t st
     return dst;
 }
 
+lv_result_t lv_draw_buf_premultiply(lv_draw_buf_t * draw_buf)
+{
+    LV_ASSERT_NULL(draw_buf);
+    if(draw_buf == NULL) return LV_RESULT_INVALID;
+
+    if(draw_buf->header.flags & LV_IMAGE_FLAGS_PREMULTIPLIED) return LV_RESULT_INVALID;
+    if((draw_buf->header.flags & LV_IMAGE_FLAGS_MODIFIABLE) == 0) {
+        LV_LOG_WARN("draw buf is not modifiable: 0x%04x", draw_buf->header.flags);
+        return LV_RESULT_INVALID;
+    }
+
+    /*Premultiply color with alpha, do case by case by judging color format*/
+    lv_color_format_t cf = draw_buf->header.cf;
+    if(LV_COLOR_FORMAT_IS_INDEXED(cf)) {
+        int size = LV_COLOR_INDEXED_PALETTE_SIZE(cf);
+        lv_color32_t * palette = (lv_color32_t *)draw_buf->data;
+        for(int i = 0; i < size; i++) {
+            lv_color_premultiply(&palette[i]);
+        }
+    }
+    else if(cf == LV_COLOR_FORMAT_ARGB8888) {
+        uint32_t h = draw_buf->header.h;
+        uint32_t w = draw_buf->header.w;
+        uint32_t stride = draw_buf->header.stride;
+        uint8_t * line = (uint8_t *)draw_buf->data;
+        for(uint32_t y = 0; y < h; y++) {
+            lv_color32_t * pixel = (lv_color32_t *)line;
+            for(uint32_t x = 0; x < w; x++) {
+                lv_color_premultiply(pixel);
+                pixel++;
+            }
+            line += stride;
+        }
+    }
+    else if(cf == LV_COLOR_FORMAT_RGB565A8) {
+        uint32_t h = draw_buf->header.h;
+        uint32_t w = draw_buf->header.w;
+        uint32_t stride = draw_buf->header.stride;
+        uint32_t alpha_stride = stride / 2;
+        uint8_t * line = (uint8_t *)draw_buf->data;
+        lv_opa_t * alpha = (lv_opa_t *)(line + stride * h);
+        for(uint32_t y = 0; y < h; y++) {
+            lv_color16_t * pixel = (lv_color16_t *)line;
+            for(uint32_t x = 0; x < w; x++) {
+                lv_color16_premultiply(pixel, alpha[x]);
+                pixel++;
+            }
+            line += stride;
+            alpha += alpha_stride;
+        }
+    }
+    else if(LV_COLOR_FORMAT_IS_ALPHA_ONLY(cf)) {
+        /*Pass*/
+    }
+    else {
+        LV_LOG_WARN("draw buf has no alpha, cf: %d", cf);
+    }
+
+    draw_buf->header.flags |= LV_IMAGE_FLAGS_PREMULTIPLIED;
+
+    return LV_RESULT_OK;
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/draw/lv_draw_buf.h

@@ -181,6 +181,13 @@ void lv_draw_buf_copy(void * dest_buf, uint32_t dest_w, uint32_t dest_h, const l
  */
 lv_draw_buf_t * lv_draw_buf_create(uint32_t w, uint32_t h, lv_color_format_t cf, uint32_t stride);
 
+/**
+ * Duplicate a draw buf with same image size, stride and color format. Copy the image data too.
+ * @param draw_buf  the draw buf to duplicate
+ * @return          the duplicated draw buf on success, NULL if failed
+ */
+lv_draw_buf_t * lv_draw_buf_dup(const lv_draw_buf_t * draw_buf);
+
 /**
  * Destroy a draw buf by free the actual buffer if it's marked as LV_IMAGE_FLAGS_MODIFIABLE in header.
  * Then free the lv_draw_buf_t struct.
@@ -197,6 +204,20 @@ void * lv_draw_buf_goto_xy(lv_draw_buf_t * buf, uint32_t x, uint32_t y);
  */
 lv_draw_buf_t * lv_draw_buf_adjust_stride(const lv_draw_buf_t * src, uint32_t stride);
 
+/**
+ * Premultiply draw buffer color with alpha channel.
+ * If it's already premultiplied, return directly.
+ * Only color formats with alpha channel will be processed.
+ *
+ * @return LV_RESULT_OK: premultiply success
+ */
+lv_result_t lv_draw_buf_premultiply(lv_draw_buf_t * draw_buf);
+
+static inline bool lv_draw_buf_has_flag(lv_draw_buf_t * draw_buf, lv_image_flags_t flag)
+{
+    return draw_buf->header.flags & flag;
+}
+
 /**
  * As of now, draw buf share same definition as `lv_image_dsc_t`.
  * And is interchangeable with `lv_image_dsc_t`.

src/draw/lv_image_buf.h

@@ -75,6 +75,11 @@ typedef enum _lv_image_flags_t {
      */
     LV_IMAGE_FLAGS_COMPRESSED       = (1 << 3),
 
+    /**
+     * The image is alloced from heap, thus should be freed after use.
+     */
+    LV_IMAGE_FLAGS_ALLOCATED        = (1 << 4),
+
     /**
      * Flags reserved for user, lvgl won't use these bits.
      */

src/draw/lv_image_decoder.c

@@ -115,17 +115,14 @@ lv_result_t lv_image_decoder_open(lv_image_decoder_dsc_t * dsc, const void * src
     lv_image_decoder_t * decoder;
     lv_image_decoder_args_t * args_copy = NULL;
 
+    static const lv_image_decoder_args_t def_args = {
+        .stride_align = LV_DRAW_BUF_STRIDE_ALIGN != 1,
+        .premultiply = false,
+        .no_cache = false,
+    };
+
     /*Make a copy of args */
-    if(args) {
-        args_copy = lv_malloc(sizeof(lv_image_decoder_args_t));
-        LV_ASSERT_MALLOC(args_copy);
-        if(args_copy == NULL) {
-            LV_LOG_WARN("Out of memory");
-            return LV_RESULT_INVALID;
-        }
-        lv_memcpy(args_copy, args, sizeof(lv_image_decoder_args_t));
-        dsc->args = args_copy;
-    }
+    dsc->args = args ? *args : def_args;
 
     _LV_LL_READ(img_decoder_ll_p, decoder) {
         /*Info and Open callbacks are required*/
@@ -174,7 +171,6 @@ void lv_image_decoder_close(lv_image_decoder_dsc_t * dsc)
 {
     if(dsc->decoder) {
         if(dsc->decoder->close_cb) dsc->decoder->close_cb(dsc->decoder, dsc);
-        if(dsc->args) lv_free(dsc->args);
 
         if(dsc->src_type == LV_IMAGE_SRC_FILE) {
             lv_free((void *)dsc->src);
@@ -233,6 +229,48 @@ void lv_image_decoder_set_close_cb(lv_image_decoder_t * decoder, lv_image_decode
     decoder->close_cb = close_cb;
 }
 
+lv_draw_buf_t * lv_image_decoder_post_process(lv_image_decoder_dsc_t * dsc, lv_draw_buf_t * decoded)
+{
+    if(decoded == NULL) return NULL; /*No need to adjust*/
+
+    lv_image_decoder_args_t * args = &dsc->args;
+    if(args->stride_align && decoded->header.cf != LV_COLOR_FORMAT_RGB565A8) {
+        uint32_t stride_expect = lv_draw_buf_width_to_stride(decoded->header.w, decoded->header.cf);
+        if(decoded->header.stride != stride_expect) {
+            LV_LOG_WARN("Stride mismatch");
+            lv_draw_buf_t * aligned = lv_draw_buf_adjust_stride(decoded, stride_expect);
+            if(aligned == NULL) {
+                LV_LOG_ERROR("No memory for Stride adjust.");
+                return NULL;
+            }
+
+            decoded = aligned;
+        }
+    }
+
+    /*Premultiply alpha channel*/
+    if(args->premultiply
+       && !lv_draw_buf_has_flag(decoded, LV_IMAGE_FLAGS_PREMULTIPLIED) /*Hasn't done yet*/
+      ) {
+        LV_LOG_WARN("Alpha premultiply.");
+        if(lv_draw_buf_has_flag(decoded, LV_IMAGE_FLAGS_MODIFIABLE)) {
+            /*Do it directly*/
+            lv_draw_buf_premultiply(decoded);
+        }
+        else {
+            decoded = lv_draw_buf_dup(decoded);
+            if(decoded == NULL) {
+                LV_LOG_ERROR("No memory for premulitplying.");
+                return NULL;
+            }
+
+            lv_draw_buf_premultiply(decoded);
+        }
+    }
+
+    return decoded;
+}
+
 static uint32_t img_width_to_stride(lv_image_header_t * header)
 {
     if(header->cf == LV_COLOR_FORMAT_RGB565A8) {
@@ -242,4 +280,3 @@ static uint32_t img_width_to_stride(lv_image_header_t * header)
         return ((uint32_t)header->w * lv_color_format_get_bpp(header->cf) + 7) >> 3;
     }
 }
-

src/draw/lv_image_decoder.h

@@ -121,7 +121,7 @@ typedef struct _lv_image_decoder_dsc_t {
     lv_image_decoder_t * decoder;
 
     /*A copy of parameters of how this image is decoded*/
-    lv_image_decoder_args_t * args;
+    lv_image_decoder_args_t args;
 
     /**The image source. A file path like "S:my_img.png" or pointer to an `lv_image_dsc_t` variable*/
     const void * src;
@@ -268,6 +268,15 @@ void lv_image_decoder_set_get_area_cb(lv_image_decoder_t * decoder, lv_image_dec
  */
 void lv_image_decoder_set_close_cb(lv_image_decoder_t * decoder, lv_image_decoder_close_f_t close_cb);
 
+/**
+ * Check the decoded image, make any modification if decoder `args` requires.
+ * @note A new draw buf will be allocated if provided `decoded` is not modifiable or stride mismatch etc.
+ * @param dsc       pointer to a decoder descriptor
+ * @param decoded   pointer to a decoded image to post process to meet dsc->args requirement.
+ * @return          post processed draw buffer, when it differs with `decoded`, it's newly allocated.
+ */
+lv_draw_buf_t * lv_image_decoder_post_process(lv_image_decoder_dsc_t * dsc, lv_draw_buf_t * decoded);
+
 /**********************
  *      MACROS
  **********************/

src/draw/sw/lv_draw_sw_arc.c

@@ -132,8 +132,8 @@ void lv_draw_sw_arc(lv_draw_unit_t * draw_unit, const lv_draw_arc_dsc_t * dsc, c
         lv_area_move(&img_area, dsc->center.x - ofs, dsc->center.y - ofs);
         blend_dsc.src_area = &img_area;
         blend_dsc.src_buf = _lv_image_decoder_get_data(&decoder_dsc);
-        blend_dsc.src_color_format = decoder_dsc.header.cf;
-        blend_dsc.src_stride = decoder_dsc.header.stride;
+        blend_dsc.src_color_format = decoder_dsc.decoded->header.cf;
+        blend_dsc.src_stride = decoder_dsc.decoded->header.stride;
     }
 
     lv_opa_t * circle_mask = NULL;

src/draw/sw/lv_draw_sw_vector.c

@@ -291,7 +291,8 @@ static void _set_paint_fill_pattern(Tvg_Paint * obj, Tvg_Canvas * canvas, const
                                     const lv_matrix_t * m)
 {
     lv_image_decoder_dsc_t decoder_dsc;
-    lv_result_t res = lv_image_decoder_open(&decoder_dsc, p->src, NULL);
+    lv_image_decoder_args_t args = { 0 };
+    lv_result_t res = lv_image_decoder_open(&decoder_dsc, p->src, &args);
     if(res != LV_RESULT_OK) {
         LV_LOG_ERROR("Failed to open image");
         return;

src/libs/bin_decoder/lv_bin_decoder.c

@@ -160,7 +160,9 @@ lv_result_t lv_bin_decoder_info(lv_image_decoder_t * decoder, const void * src,
     }
 
     /*For backward compatibility, all images are not premultiplied for now.*/
-    header->flags &= ~LV_IMAGE_FLAGS_PREMULTIPLIED;
+    if(header->magic != LV_IMAGE_HEADER_MAGIC) {
+        header->flags &= ~LV_IMAGE_FLAGS_PREMULTIPLIED;
+    }
 
     return LV_RESULT_OK;
 }
@@ -276,24 +278,6 @@ lv_result_t lv_bin_decoder_open(lv_image_decoder_t * decoder, lv_image_decoder_d
                 decoded->header.stride = dsc->header.stride;
             }
 
-            /**
-             * @todo need to convert c-array image stride if not match
-             *
-             * lv_draw_buf_create(); //create new draw buf that meets requirement
-             * lv_draw_buf_copy(); //copy from c-array image to new draw buf
-             */
-            uint32_t stride_expect = lv_draw_buf_width_to_stride(dsc->header.w, dsc->header.cf);
-            if(dsc->header.stride != stride_expect) {
-                LV_LOG_WARN("Stride mismatch");
-#if 0
-                /**
-                 * @fixme ignore for now
-                 */
-                free_decoder_data(dsc);
-                return LV_RESULT_INVALID;
-#endif
-            }
-
             res = LV_RESULT_OK;
         }
     }
@@ -305,6 +289,22 @@ lv_result_t lv_bin_decoder_open(lv_image_decoder_t * decoder, lv_image_decoder_d
 
     if(dsc->decoded == NULL) return LV_RESULT_OK; /*Need to read via get_area_cb*/
 
+    lv_draw_buf_t * decoded = (lv_draw_buf_t *)dsc->decoded;
+    lv_draw_buf_t * adjusted = lv_image_decoder_post_process(dsc, decoded);
+    if(adjusted == NULL) {
+        free_decoder_data(dsc);
+        return LV_RESULT_INVALID;
+    }
+
+    /*The adjusted draw buffer is newly allocated.*/
+    if(adjusted != decoded) {
+        free_decoder_data(dsc);
+        decoder_data_t * decoder_data = get_decoder_data(dsc);
+        decoder_data->decoded = adjusted; /*Now this new buffer need to be free'd on decoder close*/
+    }
+
+    dsc->decoded = adjusted;
+
     /*Add it to cache*/
     t = lv_tick_elaps(t);
     lv_cache_lock();

src/misc/lv_color.h

@@ -407,6 +407,20 @@ static inline lv_color_t lv_color_black(void)
     return lv_color_make(0x00, 0x00, 0x00);
 }
 
+static inline void lv_color_premultiply(lv_color32_t * c)
+{
+    c->red = LV_OPA_MIX2(c->red, c->alpha);
+    c->green = LV_OPA_MIX2(c->green, c->alpha);
+    c->blue = LV_OPA_MIX2(c->blue, c->alpha);
+}
+
+static inline void lv_color16_premultiply(lv_color16_t * c, lv_opa_t a)
+{
+    c->red = LV_OPA_MIX2(c->red, a);
+    c->green = LV_OPA_MIX2(c->green, a);
+    c->blue = LV_OPA_MIX2(c->blue, a);
+}
+
 /**********************
  *      MACROS
  **********************/

src/others/snapshot/lv_snapshot.c

@@ -100,13 +100,13 @@ lv_result_t lv_snapshot_take_to_buf(lv_obj_t * obj, lv_color_format_t cf, lv_ima
     lv_area_increase(&snapshot_area, ext_size, ext_size);
 
     lv_memzero(buf, buf_size);
-    lv_memzero(dsc, sizeof(lv_image_dsc_t));
     dsc->data = buf;
     dsc->data_size = buf_size_needed;
+    /*Keep header flags unchanged, because we don't know if it's allocated or not.*/
     dsc->header.w = w;
     dsc->header.h = h;
     dsc->header.cf = cf;
-    dsc->header.flags = LV_IMAGE_FLAGS_MODIFIABLE;
+    dsc->header.magic = LV_IMAGE_HEADER_MAGIC;
 
     lv_layer_t layer;
     lv_memzero(&layer, sizeof(layer));