Android BlurMaskFilter has no effect in canvas.drawOval while text is blurred

Question

I\'ve been trying to create a custom view which has blurred shapes under text. The problem is that the BlurMaskFilter has no effect on any shape that I draw on the canvas. H

Answer 1

Looks like a bug to me. I reported it to the Android team; we'll see what they say.

It renders correctly if you set android:hardwareAccelerated="false" on your Activity in AndroidManifest.xml.

Here is the official word from the Android graphics team: "BlurMaskFilter is not supported with hardware acceleration." (As of July 10, 2012)

Answer 2

If you can not disable hardware acceleration in your activity (for example it uses TextureView which require hardware acceleration) you can just call setLayerType with first parameter LAYER_TYPE_SOFTWARE and the second parameter null for your view.

Like this

public class BlurTestView extends View {

    public BlurTestView(Context context) {
        this(context, null, 0);
    }

    public BlurTestView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public BlurTestView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        // Disable hardware acceleration for this view
        setLayerType(View.LAYER_TYPE_SOFTWARE, null); 

        // Perform other initialisation 
    }

    // Other methods and so on...
}

More info about mask filters, effects and shaders you can find here.

Answer 3

I had the same issue while adding a filter to a path. I noticed that setting the target to 13 or below allows the filters to work. 14 and up they didn't.

android:targetSdkVersion="13"