ReFix bug: PremultipliedAlpha is not working for png (cocos2d#19138)

Author: sense-zzz-time

cocos/platform/CCImage.cpp

@@ -1145,9 +1145,18 @@ bool Image::initWithPngData(const unsigned char * data, ssize_t dataLen)
         png_read_end(png_ptr, nullptr);
 
         // premultiplied alpha for RGBA8888
-        if (PNG_PREMULTIPLIED_ALPHA_ENABLED && color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
         {
-            premultipliedAlpha();
+            if (PNG_PREMULTIPLIED_ALPHA_ENABLED)
+            {
+                premultipliedAlpha();
+            }
+            else
+            {
+#if CC_ENABLE_PREMULTIPLIED_ALPHA != 0
+                _hasPremultipliedAlpha = true;
+#endif
+            }
         }
 
         if (row_pointers != nullptr)