Circular sector shaped clipping mask with Path.addArc?

android, android-canvas, clipping, drawing, graphics

Solution

Ok, it seems there is no proper way doing this using a clipping mask.

However there is an alternate way using `PorterDuffXfermode`. See Xfermodes in ApiDemos.

I simply draw a sector using `drawArc` over my image with the `DST_OUT` operator. This makes the part of the image covered by the sector invisible (not drawn).

paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(0xFFFFFFFF);
paint.setStyle(Style.FILL);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));

canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
drawable.draw(canvas);
canvas.drawArc(oval, 30, 90, true, paint);

Problem

I need to create a clipping mask with a shape of a circular sector. I am able to draw one using the following: ``` paint.setColor(0x88FF0000); paint.setStyle(Style.FILL); canvas.drawArc(oval, 0, 30, true, paint); ``` I want to use it as a clipping path, so I've tried: ``` Path path = new Path(); path.addArc(oval, 0, 30); canvas.clipPath(path, Op.REPLACE); ``` However addArc doesn't have the useCenter parameter so what I get is not a sector but a segment.

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