这是我用来改变图像对比度和亮度的代码。我可以用它来增加和减少图像的亮度,因为它需要 -255 到 255 的亮度值,我可以用 0 到 10 的值增加对比度,但我不能降低对比度,因为在这段代码中它不需要 -ve 值为了对比。那么如何降低对比度呢?
/**
*
* @param bmp input bitmap
* @param contrast 0..10 1 is default
* @param brightness -255..255 0 is default
* @return new bitmap
*/
public static Bitmap changeBitmapContrastBrightness(Bitmap bmp, float contrast, float brightness)
{
ColorMatrix cm = new ColorMatrix(new float[]
{
contrast, 0, 0, 0, brightness,
0, contrast, 0, 0, brightness,
0, 0, contrast, 0, brightness,
0, 0, 0, 1, 0
});
Bitmap ret = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());
Canvas canvas = new Canvas(ret);
Paint paint = new Paint();
paint.setColorFilter(new ColorMatrixColorFilter(cm));
canvas.drawBitmap(bmp, 0, 0, paint);
return ret;
}