android - 灰度图片Drawable

Question

要对可绘制对象进行灰度化，我会这样做:

ColorMatrix matrix = new ColorMatrix();
matrix.setSaturation(200);
ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrix);
drawable.setColorFilter(filter);

如 Justin said 。效果很好。

我正在使用 svg-android 库。所以我正在尝试:

PictureDrawable pictureDrawable = svg.createPictureDrawable();
ColorMatrix matrix = new ColorMatrix();
matrix.setSaturation(200);
ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrix);
pictureDrawable.setColorFilter(filter);
imageView.setImageDrawable(pictureDrawable);

但是什么也没发生...出了什么问题？

Answer 1

恐怕我在 Android 源代码中找到了原因:

Drawable.java

public abstract void setColorFilter(ColorFilter cf);

PictureDrawable.java

@Override
public void setColorFilter(ColorFilter colorFilter) {}

简单地说，任何对 setColorFilter 的调用对于 PictureDrawable 来说都是无用的。