Method tone

src/com/cloudream/ishow/algorithm/Effect.java:98–132

Tone is a color term commonly used by painters. tone a bitmap with specified color, it's like mixing the color pixel by pixel, the color resulting in layering a color dst RGB with a src color RGB is: new_R = dst_R + (src_R - dst_R) amount new_G = dst_G + (src_G - dst_G) amount new_B = dst_B +

(Bitmap bitmap, int color, float amount)

	 * @return
	 */
	public static Bitmap tone(Bitmap bitmap, int color, float amount)
	{
		if(BuildConfig.DEBUG && (amount < 0.0f || amount > 1.0f))
			throw new IllegalArgumentException("amount is out of range [0, 1]");

		if(NATIVE)
		{
			// FIXME work not as expected
			Bitmap result = bitmap.copy(Bitmap.Config.ARGB_8888, true);
			nativeTone(result, color, amount);
			return result;
		}
		else
		{
			final float c = 1.0f - amount;
			matrix.setScale(c, c, c, 1.0f);
			
			final float array[] = matrix.getArray();
			array[ 4] = Color.red(color)   * amount;
			array[ 9] = Color.green(color) * amount;
			array[14] = Color.blue(color)  * amount;
//			array[19] = Color.alpha(color) * amount;
			
			ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrix);
			Paint paint = new Paint();  // (Paint.ANTI_ALIAS_FLAG);
			paint.setColorFilter(filter);
			
			Bitmap result = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
//			result.eraseColor(color & 0x00ffffff);
			Canvas canvas = new Canvas(result);
			canvas.drawBitmap(bitmap, 0, 0, paint);
			
			return result;
		}
	}
	
	public static Bitmap tone(Bitmap bitmap, int color)
	{