[Bugfix] UIFrame: Child appearance changes don't invalidate parent's cached texture #225

New issue

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opened 2026-01-22 15:48:56 +00:00 by john · 0 comments

john commented

2026-01-22 15:48:56 +00:00

Owner

Summary

When a Frame uses clip_children=True or cache_subtree=True, children are rendered to a RenderTexture. However, changes to child properties (color, text, sprite index, etc.) don't reliably invalidate the parent's cached texture.

Root Cause

The dirty propagation in UIDrawable::markContentDirty() (lines 909-919) has issues:

void UIDrawable::markContentDirty() {
    if (render_dirty) return;  // ← Early return if already dirty
    
    render_dirty = true;
    composite_dirty = true;
    
    auto p = parent.lock();
    if (p) {
        p->markContentDirty();  // ← Propagate up
    }
}

Issues

Early return: If render_dirty is already true, propagation stops. Parent may not be notified.
Weak pointer expiration: If parent.lock() returns nullptr (weak_ptr expired), propagation fails silently.
No propagation for some setters: Not all property setters call markDirty(). Some call markCompositeDirty() which only propagates position changes, not content changes.

Symptoms

Change child Caption's text → parent texture not updated
Change child Frame's fill_color → parent texture not updated
Change child Sprite's sprite_index → parent texture not updated

Until something else triggers a full redraw.

Proposed Fix

Remove or rethink the early return in markContentDirty()
Audit all property setters to ensure they call appropriate dirty method
Consider adding debug logging when parent.lock() fails

## Summary When a Frame uses `clip_children=True` or `cache_subtree=True`, children are rendered to a RenderTexture. However, changes to child properties (color, text, sprite index, etc.) don't reliably invalidate the parent's cached texture. ## Root Cause The dirty propagation in `UIDrawable::markContentDirty()` (lines 909-919) has issues: ```cpp void UIDrawable::markContentDirty() { if (render_dirty) return; // ← Early return if already dirty render_dirty = true; composite_dirty = true; auto p = parent.lock(); if (p) { p->markContentDirty(); // ← Propagate up } } ``` ### Issues 1. **Early return**: If `render_dirty` is already true, propagation stops. Parent may not be notified. 2. **Weak pointer expiration**: If `parent.lock()` returns nullptr (weak_ptr expired), propagation fails silently. 3. **No propagation for some setters**: Not all property setters call `markDirty()`. Some call `markCompositeDirty()` which only propagates position changes, not content changes. ## Symptoms - Change child Caption's text → parent texture not updated - Change child Frame's fill_color → parent texture not updated - Change child Sprite's sprite_index → parent texture not updated Until something else triggers a full redraw. ## Proposed Fix 1. Remove or rethink the early return in `markContentDirty()` 2. Audit all property setters to ensure they call appropriate dirty method 3. Consider adding debug logging when parent.lock() fails