feat(img_cache): add support for alternate img cache algorithm (#3798)

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

docs/overview/image.md

@@ -316,6 +316,42 @@ Let's say you have loaded a PNG image into a `lv_img_dsc_t my_png` variable and
 
 To do this, use `lv_img_cache_invalidate_src(&my_png)`. If `NULL` is passed as a parameter, the whole cache will be cleaned.
 
+### Custom cache algorithm
+If you want to implement your own cache algorithm, you can refer to the following code to replace the LVGL built-in image cache manager:
+```c
+static _lv_img_cache_entry_t * my_img_cache_open(const void * src, lv_color_t color, int32_t frame_id)
+{
+  ...
+}
+
+static void my_img_cache_set_size(uint16_t new_entry_cnt)
+{
+  ...
+}
+
+static void my_img_cache_invalidate_src(const void * src)
+{
+  ...
+}
+
+void my_img_cache_init(void)
+{
+  /* Before replacing the image cache manager,
+   * you should ensure that all caches are cleared to prevent memory leaks.
+   */
+  lv_img_cache_invalidate_src(NULL);
+
+  /*Initialize image cache manager.*/
+  lv_img_cache_manager_t manager;
+  lv_img_cache_manager_init(&manager);
+  manager.open_cb = my_img_cache_open;
+  manager.set_size_cb = my_img_cache_set_size;
+  manager.invalidate_src_cb = my_img_cache_invalidate_src;
+
+  /*Apply image cache manager to LVGL.*/
+  lv_img_cache_manager_apply(&manager);
+}
+```
 
 ## API