Here are few notes about the current "MultiEffect" implementation which should be considered before adding it as part of Qt (6.5).

1) Name: Currently the componnt is called "MultiEffect". Alternatives could be e.g. "ItemEffect", "EffectItem", "PostEffect". Can't be just "Effect" as Quick3D has taken that.

2) Effects: Currenly effects are same as with QuickMultiEffect: blur, shadow, brightness, contrast, saturation, colorize, mask. Should we add/remove/adjust some?

3) Source: Currently ShaderEffectSource own is always created. This is easier for user as any Items can be used as source without "effect.layer: enabled" or own ShaderEffectSource. But it wastes memory / performance if item could be used directly, for example images. Remove internal ShaderEffectSource or add API to enable/disable it? Could isTextureProvider() be used to automatically create when needed? https://doc.qt.io/qt-6/qquickitem.html#isTextureProvider

4) Color effect enable properties: Currently all effects contain matching *Enabled property. Also color effects which are actually always enabled to have less shader versions (brightnessEnabled, contrastEnabled, saturationEnabled, colorizeEnabled). Either remove these properties if they are not needed or make them work in shader (which has some performance penalty).

5) Autotests: Some set of autotests are needed to make sure effect works correctly and continues to work. Lancelot tests or also API?

6) blurSrc6: Currently blur creates 6 blurred & scaled sources, but only 5 biggest ones are used in shader. Either remove blurSrc6 or take it into use if more blurring is required?

7) Disabling blur sources: Currently blur sources are always created. Instead they should be only created when blur or shadow are enabled. And the amount of blur sources (or which ones have "source" connected) should be based on blurLevel for better performance when only slight blur is needed.

8) Shadow blurring with padding: When increasing padding left/right/top/bottom item size doesn't change, as expected. But shadow blur amount increases, which probably shouldn't happen? (Note 9 would fix also this).

9) Separate shadow item: Currently shadow is baked into same shader, which can be good for performance. But making shadow own item which would be rendered below the main item would have benefits also. Like the shadow blending would work properly, shadow (and related blur sources) could be updated only when needed, shadow could use less pixels for higher performance etc. Consider this.

10) Shadow update options: Currently shadow (and blurred items) are regeneraged when ever the source item changes. Say the source is e.g. Rectangle with Text inside, when the text changes shadow needs to be regeneraged even thought the outcome remains unchanged (shadow comes from rectange not the stuff inside it). Consider ways to make shadow "static" so it is updated only on request. Consider also mode where shadow/blur sources are updated 1/frame so updating all takes 6 frames. (Similar to screen space reflections).

11) Performance testing: Proper performance testing should be done on couple mobile HW to make sure performance is optimal vs. Graphical Effects. Test also how it behaves in ListView delegate. This information can be used also in the blog post.

12) Document examples: Examples don't contain doc directory with documentation. Write those and make sure examples open OK from Qt Creator.