Runtime detection for html versus canvaskit renderer

@yjbanov

There are a number of optimizations we'd like to make to the framework that will only work with the canvaskit renderer. For now, we can turn these off with kIsWeb, but ideally we could runtime detect canvaskit and apply those optimizations there as well.

Specifically:

Removal of opacity compositing
Route transitions with toGpuImage

@yjbanov

We also need this to unskip tests that can run in one of the renderers. Currently we skip tests for both renderers.

Would it make sense to have some kind of define like kAccelleratedGraphics?

Renderer	Value
Software	false
GL	true
Metal	true
Vulkan	true
WebGL/GPU	true
HTML	false

we'd still need to determine the difference between HTML and software, because some APIs just won't work in html

I mean I can implement this today as:

final bool isHtmlRenderer = () {
  try {
    ui.SceneBuilder().build().toGpuImage(1, 1);
   } catch {
     return false;
   }
   return true;
}();

But ideally we'd have something less hacky

This feels like we're trying to work around the lack of an API availability language feature...

yes :)

@mdebbar

@mdebbar
Is this issue still relevant?

We've had runtime detection for quite a while now:

flutter/packages/flutter/lib/src/foundation/capabilities.dart

Lines 9 to 22 in 57bc7aa

    
           /// Returns true if the application is using CanvasKit. 
        
           /// 
        
           /// Only to be used for web. 
        
           bool get isCanvasKit => capabilities.isCanvasKit; 
        
           /// Returns true if the application is using Skwasm. 
        
           /// 
        
           /// Only to be used for web. 
        
           bool get isSkwasm => capabilities.isSkwasm; 
        
           /// Returns true if the application is using CanvasKit or Skwasm. 
        
           /// 
        
           /// Only to be used for web. 
        
           bool get isSkiaWeb => isCanvasKit || isSkwasm;

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Runtime detection for html versus canvaskit renderer #106689

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	/// Returns true if the application is using CanvasKit.
	///
	/// Only to be used for web.
	bool get isCanvasKit => capabilities.isCanvasKit;

	/// Returns true if the application is using Skwasm.
	///
	/// Only to be used for web.
	bool get isSkwasm => capabilities.isSkwasm;

	/// Returns true if the application is using CanvasKit or Skwasm.
	///
	/// Only to be used for web.
	bool get isSkiaWeb => isCanvasKit \|\| isSkwasm;

Runtime detection for html versus canvaskit renderer #106689

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yjbanov commented on Jun 28, 2022

dnfield commented on Jun 28, 2022

jonahwilliams commented on Jun 28, 2022

jonahwilliams commented on Jun 28, 2022

dnfield commented on Jun 28, 2022

jonahwilliams commented on Jun 28, 2022

nshahan commented on Feb 13, 2026

mdebbar commented on Feb 13, 2026

github-actions commented on Feb 27, 2026

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