Question

我目前有以下代码来获取一个Bitmap对象，剥离颜色，然后将其变为红色，但是我需要将图像的较暗元素变暗，此时它就像是有人放了一部红色电影在图像上，这几乎是我想要的，但需要黑色更暗：

Bitmap sourceBitmap = BitmapFactory.decodeFile(imgPath);
        float[] colorTransform = {
                0, 1f, 0, 0, 0, 
                0, 0, 0f, 0, 0,
                0, 0, 0, 0f, 0, 
                0, 0, 0, 1f, 0};
        ColorMatrix colorMatrix = new ColorMatrix();
        colorMatrix.setSaturation(0f); //Remove Colour 
        colorMatrix.set(colorTransform); //Apply the Red

        ColorMatrixColorFilter colorFilter = new ColorMatrixColorFilter(colorMatrix);
        Paint paint = new Paint();
        paint.setColorFilter(colorFilter);   

        Display display = getWindowManager().getDefaultDisplay(); 

        Bitmap resultBitmap = Bitmap.createBitmap(sourceBitmap, 0, (int)(display.getHeight() * 0.15), display.getWidth(), (int)(display.getHeight() * 0.75));            

        image.setImageBitmap(resultBitmap);

        Canvas canvas = new Canvas(resultBitmap);
        canvas.drawBitmap(resultBitmap, 0, 0, paint);

Answer 1

c = 2;//this will boost your contrast by 2x thus deepening the black (and lightning the white). I'm not sure why at 0 you have anything but black... maybe I don't understand the matrix as well as I think I do... I thought 1 (in place of my c) gets you the original colors.

Anyway... give that a whirl. 


float[] colorTransform = {
                c, 1f, 0, 0, 0, 
                0, c, 0f, 0, 0,
                0, 0, c, 0f, 0, 
                0, 0, 0, 1f, 0};

Answer 2

彩色矩阵中前三个原始的最后一列改变图像的亮度。它在[-255 ... 255]之间变化。 -255将为您提供黑色图像，255将使其为白色。这种方法可以改变你的对比度。比明亮的物体会变得更加明亮，黑暗更暗。比你可以设置你的亮度，以满足你的需求。对比度在[-1 ... 1]之间变化。

private static void setContrast(ColorMatrix cm, float contrast) {
                float scale = contrast + 1.f;
                   float translate = (-.5f * scale + .5f) * 255.f;
                cm.set(new float[] {
                       scale, 0, 0, 0, translate,
                       0, scale, 0, 0, translate,
                       0, 0, scale, 0, translate,
                       0, 0, 0, 1, 0 });
        }

在Android中使用colorMatrix使黑色更暗

2 个答案: