How to lighten a bitmap in Android?

Asked Dec 28 '15 at 06:24

Active Dec 28 '15 at 06:24

Viewed 267 times

I'm using a set of bitmaps to draw my SurfaceView and developing a night mode. To turn on night mode I just darken all bitmaps and redraw the SurfaceView:

    Bitmap newBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(newBitmap);
    Paint paint = new Paint();
    paint.setColorFilter(new LightingColorFilter(0x808080, 0));
    c.drawBitmap(bitmap, 0, 0, paint);
    bitmap = newBitmap;

But how can I lighten these bitmaps when I need to turn off night mode?

asked Dec 28 '15 at 06:24

auntyellow

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tried `add` param in `LightingColorFilter`? – pskink Dec 28 '15 at 06:34
"Add" does not match my requirement. I need to *Darken* by (r, g, b) -> (r / 2, g / 2, b / 2) and *Lighten* by (r, g, b) -> (r * 2, g * 2, b * 2), but LightingColorFilter seems unable to do multiplication :-( – auntyellow Dec 28 '15 at 06:52
so you want to darken or lighten? – pskink Dec 28 '15 at 06:54
darken is ok. need a solution to lighten bitmaps – auntyellow Dec 28 '15 at 06:57
so did you try `add` parameter? – pskink Dec 28 '15 at 06:58
not yet. how much to add? – auntyellow Dec 28 '15 at 07:03
i have no idea, you have to try – pskink Dec 28 '15 at 07:05
I tried `new LightingColorFilter(0xFFFFFF, 0x808080)` and bitmaps become greyish white :-( – auntyellow Dec 28 '15 at 10:17
the same for 0x606060, 0x404040, 0x202020 ? – pskink Dec 28 '15 at 10:40
a bit white, less than 0x808080 – auntyellow Dec 28 '15 at 11:09
found a solution :-) `new ColorMatrixColorFilter(new float[] { 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, }));` – auntyellow Dec 28 '15 at 11:09

How to lighten a bitmap in Android?

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