How do you cut (remove) a section from a bitmap??? I want that section/shape to be removed.. leave transparent in place of section.. Say shape is cercle or square..
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问题:
回答1:
You should be able do this with a Porter-Duff color filter and a Canvas
:
public void punchHole(Bitmap bitmap, float cx, float cy, float radius) {
Canvas c = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColorFilter(new PorderDuffColorFilter(0, PorderDuff.Mode.CLEAR));
c.drawCircle(cx, cy, radius, paint);
}
Well, that was wrong. However, using a Porter-Duff transfer mode does work:
public void punchHole(Bitmap bitmap, float cx, float cy, float radius) {
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
canvas.drawCircle(cx, cy, radius, paint);
}
(The bitmap passed as an arg needs to be modifiable, of course.)
回答2:
Use Bitmap.setPixel(x,y,Color) function to set the desired pixels to transparent
for example:
Bitmap bmp = ...;
bmp.setPixel (100,100,Color.TRANSPARENT);
for the pixel at x/y offset 100,100. Though you'll find this potentially slow to do this on many pixels...
回答3:
Did you try drawing a circle with a transparent color, ARGB = 0,0,0,0 ?