Avalonia.UWP UWP Backend Development — Conversation Log (My dialog with WIndSurf ai system)

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USER: Try to implement actual rendering, follow the stubs and comments in UWPWindowImpl

ASSISTANT (ChatGpt 4.1):

• Checked for SkiaSharp/Direct2D references. None found.
• Recommended adding SkiaSharp.Views.UWP for UWP rendering.
• Offered to guide NuGet setup or generate Skia integration code.

USER: Generate the code for the actual Skia rendering integration (assuming the package is present)

ASSISTANT:

• Updated UWPWindowImpl to:
  • Create SKSwapChainPanel inside the SwapChainPanel.
  • Subscribe to PaintSurface and draw a red rectangle as a test.
• Added comments for Avalonia compositor integration.

USER: I want to proceed with full Avalonia compositor integration, need help with the Skia drawing bridge, or want to add more advanced rendering features. Integrate real Avalonia rendering, use the provided spot in SkiaPanel_PaintSurface to draw Avalonia’s visual tree onto the Skia canvas.

ASSISTANT:

• Integrated Avalonia rendering:
  • In SkiaPanel_PaintSurface, if Avalonia visual tree root is set, create a SkiaDrawingContext and use Avalonia’s immediate renderer to paint the UI.
  • If not, fallback to drawing the test red rectangle.
  • Updated SetInputRoot to store the root and trigger a redraw.

USER: Review Sample app. Scenario: when I run your UWP app. I should see a white canvas with a red rectangle and a green rectangle (below) rendered by SkiaSharp.

ASSISTANT:

• Updated SkiaPanel_PaintSurface to always draw both a red rectangle and a green rectangle (below it) as part of the sample scenario, before any Avalonia UI rendering.

USER: thank you. please generate out conversation as dialog.md

ASSISTANT:

• Generated this conversation log as md file, summarizing all major steps and code changes for your Avalonia UWP backend development.

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End of conversation log.

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ME: Hi again. I refactered our code a little. At now app runs normally but only shows surface backgrownd. Also, app reacts on left mouse button clicks. Heh, no text rendering, no avalonia controls parsing. I did some great errors... Help me, please. May be some enities and methods not realized yet in UWPWindowImpl.cs?... Please dream on our prototype improving... "Dream up" carefully once again to find and fix logic errors...

AI: Let's carefully analyze and "dream up" a robust fix for your prototype based on your symptoms and the current state of your code:

1. Symptoms Recap The app runs, but only shows the background color—no controls or text are visible. The app reacts to mouse clicks (your hit-test/counter logic works). You suspect issues with parsing, rendering, or the UWPWindowImpl backend.
2. Key Issues and Likely Causes A. AXAML Parsing and Control Tree If _parsedRoot is not a valid control tree (or is not being set at all), nothing will render. If your runtime loader or FindNamedControls is not finding the correct controls, rendering and hit-testing will silently fail. If you are not actually drawing the controls (e.g., text, shapes) in your Skia rendering loop, only the background appears. B. Skia Rendering

If your RenderControlRecursive

isn't walking the tree or the tree is empty, nothing will be drawn.

If your SkiaSharp paint event is not being triggered, or the canvas is cleared but not drawn on, only the background appears.

C. UWPWindowImpl Integration

If your UWPWindowImpl is not properly storing the visual tree or not triggering redraws, Avalonia controls won't appear. If your rendering surface is not initialized or not attached to the SwapChainPanel, nothing will be visible.

3. Step-by-Step Dream Fix Plan Step 1: Validate AXAML Parsing

Ensure your

AxamlRuntimeLoader

is actually parsing the AXAML file and returning a non-null, populated control tree.

Log or debug the output of AxamlRuntimeLoader.LoadMinimalWindowFromAxaml. If it returns null or an empty tree, fix the parsing logic.

Step 2: Ensure Control Tree is Walked Confirm that _parsedRoot is set to the root control (likely a Window or Grid).

In your

RenderControlRecursive

, add debug output to print the type and name of each control as you recurse. This will show if the tree is being walked.

Step 3: Fix Text and Shape Rendering

Make sure your drawing code for TextBlock, Button, Rectangle, etc., is being called with the correct coordinates and sizes.

For text, ensure you are using a valid font size and that the text is not empty or clipped.

For shapes, check that width/height are not zero.

Step 4: Hit-Testing and State

Ensure that the bounds for the button are being calculated and stored correctly for hit-testing.

Make sure the counter updates the text and triggers a redraw.

Step 5: UWPWindowImpl and Redraw

Confirm that

RequestRedraw()

triggers an actual repaint of the Skia surface.

Make sure your SwapChainPanel is visible and not covered by another control.

4. Dream Up: Concrete Fixes and Improvements

A. AXAML Loader

Add logging to the loader: Debug.WriteLine("Loaded root: " + root?.GetType().Name);

Ensure it returns a Grid or

Canvas

as the root, not just a

Window .

B. MainPage.xaml.cs After loading, check if _parsedRoot is not null and is of the expected type. In RenderControlRecursive , add Debug.WriteLine($"Rendering: {ctrl.GetType().Name}");

C. Rendering For text: Make sure to set paint.IsAntialias = true; and use a visible color. For controls: If width/height are zero, set reasonable defaults.

D. UWPWindowImpl

Ensure SetInputRoot stores the root as an IRenderRoot and calls RequestRedraw() . In RequestRedraw() , call Invalidate() on the Skia panel or SwapChainPanel.

E. General

Make sure your

MinimalWindow.axaml

file is present and readable at runtime.

Double-check that all controls are being created and initialized with the right properties.

5. Example: Improved Debugging and Safety

Add this to your

RenderControlRecursive :

csharp

Debug.WriteLine($"Rendering: {ctrl?.GetType().Name}, Bounds: {ctrl?.Bounds}");

Add this after AXAML load:

csharp if (_parsedRoot == null) Debug.WriteLine("AXAML parsing failed: _parsedRoot is null!"); else Debug.WriteLine("AXAML parsing OK: " + _parsedRoot.GetType().Name);

In

FindNamedControls

, make sure you are matching names exactly (not just type).

6. If You Want: I Can

Review your full

AxamlRuntimeLoader

code for bugs.

Provide a minimal working example of parsing, walking, and rendering a simple tree.

Suggest a robust fallback if parsing fails (e.g., draw a red error box).

7. Summary Table of What to Check

Area What to Check/Fix

AXAML Loader Returns valid, non-null populated tree

MainPage Logic _parsedRoot set and walked; debug output in recursion

Rendering Drawing code called, font/brushes set, width/height > 0

Hit-Testing Button bounds correct, click updates state and redraws

UWPWindowImpl Stores root, triggers redraw, panel visible

File Paths AXAML file present and readable at runtime

8. Next Steps

Add debug output everywhere in the control tree walk and rendering.

Fix any parsing or property bugs in your loader.

Ensure redraw logic is functional.

If you show me your current

AxamlRuntimeLoader

and the exact lines of your

MainPage.xaml.cs

where you load and walk the tree, I can give you a concrete patch.

Let me know if you want me to:

Review and patch your AXAML loader,

Provide a debug-enhanced rendering loop,

Or write a minimal working prototype for you to drop in!

Just say the word and paste the relevant code, and I’ll get you back to a working interactive prototype!