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androidgradientdithering

How to draw a smooth/dithered gradient on a canvas in Android


Several answers mention to use GradientDrawable.setDither(true) to draw smooth gradients in Android. That has no effect in my code. Any idea what I have to change to get a well looking gradient in my live wallpaper?

GradientDrawable gradient = new GradientDrawable(Orientation.TL_BR, colors);
gradient.setGradientType(GradientDrawable.RADIAL_GRADIENT);
gradient.setGradientRadius(canvas.getWidth() * 2);
gradient.setDither(true);
gradient.setGradientCenter(-0.1f, -0.1f);
gradient.setBounds(cb);
gradient.draw(canvas);

Solution

  • Seeing as you have a Canvas to work with. Here is one option.

    private Bitmap makeRadGrad() {
        RadialGradient gradient = new RadialGradient(200, 200, 200, 0xFFFFFFFF,
                0xFF000000, android.graphics.Shader.TileMode.CLAMP);
        Paint p = new Paint();
        p.setDither(true);
        p.setShader(gradient);
    
        Bitmap bitmap = Bitmap.createBitmap(400, 400, Config.ARGB_8888);
        Canvas c = new Canvas(bitmap);
        c.drawCircle(200, 200, 200, p);
    
        return bitmap;
    }
    

    Result:

    Result