绘制对象=＆GT;灰阶 [英] Drawable => grayscale

问题描述

什么是正确的方式把一个色可绘制成灰度一（指示禁用状态）？

What would be the right way to turn a color Drawable into a grayscale one (to indicate disabled state)?

编辑：
B / W =>灰度

B/W => grayscale

推荐答案

显然，你可以使用嘉洛斯类做任何形式的色彩空间转换。它有一个 setSaturation（）的方法，可以轻松地为您创建一个颜色到灰度转换（零饱和度）。

Apparently you can use the ColorMatrix class to do any sort of color-space transformations. It has a setSaturation() method that easily creates a color-to-grayscale transformation (zeroes saturation) for you.

所以，你可以使用滤镜来绘制图像的新副本。我没有试过，但它应该工作：

So, you can use that filter to paint a new copy of the image. I haven't tried this, but it should work:

Bitmap grayscaleBitmap = Bitmap.createBitmap(
    colorBitmap.getWidth(), colorBitmap.getHeight(),
    Bitmap.Config.RGB_565);

Canvas c = new Canvas(grayscaleBitmap);
Paint p = new Paint();
ColorMatrix cm = new ColorMatrix();

cm.setSaturation(0);
ColorMatrixColorFilter filter = new ColorMatrixColorFilter(cm);
p.setColorFilter(filter); 
c.drawBitmap(colorBitmap, 0, 0, p);

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