android - 将 Saturation 和 ColorFilter 同时设置为图像

下面的函数成功地改变了图片的对比度和亮度。

Bitmap bmp;
ImageView alteredImageView;
...
public void drawAlteredImage(float contr,float bright) {
    Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());
    Canvas canvas = new Canvas(alteredBitmap);
    Paint paint = new Paint();
    ColorMatrix cm = new ColorMatrix();

    cm.set(new float[] {
            contr, 0, 0, 0, bright,
            0, contr, 0, 0, bright,
            0, 0, contr, 0, bright,
            0, 0, 0, 1, 0 });

    paint.setColorFilter(new ColorMatrixColorFilter(cm));
    Matrix matrix = new Matrix();
    canvas.drawBitmap(bmp, matrix, paint);
    alteredImageView.setImageBitmap(alteredBitmap);
}

但是当我将 setSaturation 方法添加到 ColorMatrix 时，对比度和亮度改变停止工作。编码:

public void drawAlteredImage(float contr,float bright,float satur) {
    Bitmap alteredBitmap = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());
    Canvas canvas = new Canvas(alteredBitmap);
    Paint paint = new Paint();
    ColorMatrix cm = new ColorMatrix();

    cm.set(new float[] {
            contr, 0, 0, 0, bright,
            0, contr, 0, 0, bright,
            0, 0, contr, 0, bright,
            0, 0, 0, 1, 0 });
    cm.setSaturation(satur);
    paint.setColorFilter(new ColorMatrixColorFilter(cm));
    Matrix matrix = new Matrix();
    canvas.drawBitmap(bmp, matrix, paint);
    alteredImageView.setImageBitmap(alteredBitmap);
}

在这种情况下，仅应用饱和效应。为什么会出现这个问题？我该如何解决？

最佳答案

setSaturation(...) 方法替换矩阵中的所有值。您可以创建一个组合了这两种操作的矩阵，也可以使用两个单独的 drawBitmap(...) 调用来执行这些操作。

尝试:

cm.setSaturation(satur);
final float m[] = cm.getArray();
final float c = contr;
cm.set(new float[] {
        m[ 0] * c, m[ 1] * c, m[ 2] * c, m[ 3] * c, m[ 4] * c + bright,
        m[ 5] * c, m[ 6] * c, m[ 7] * c, m[ 8] * c, m[ 9] * c + bright,
        m[10] * c, m[11] * c, m[12] * c, m[13] * c, m[14] * c + bright,
        m[15]    , m[16]    , m[17]    , m[18]    , m[19] });

关于android - 将 Saturation 和 ColorFilter 同时设置为图像，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7413867/