在Java中更改png的不透明部分的颜色 [英] Change color of non-transparent parts of png in Java

问题描述

我尝试自动更改一组图标的颜色。
每个图标都有一个白色填充层，其他部分是透明的。
下面是一个例子：（在这种情况下它是绿色的，只是为了使它可见）

I am trying to automatically change the color for a set of icons. Every icon has a white filled layer and the other part is transparent. Here is an example: (in this case it's green, just to make it visible)

我尝试过以下操作：

private static BufferedImage colorImage(BufferedImage image) {
        int width = image.getWidth();
        int height = image.getHeight();

        for (int xx = 0; xx < width; xx++) {
            for (int yy = 0; yy < height; yy++) {
                Color originalColor = new Color(image.getRGB(xx, yy));
                System.out.println(xx + "|" + yy + " color: " + originalColor.toString() + "alpha: "
                        + originalColor.getAlpha());
                if (originalColor.equals(Color.WHITE) && originalColor.getAlpha() == 255) {
                    image.setRGB(xx, yy, Color.BLUE.getRGB());
                }
            }
        }
        return image;
    }

我遇到的问题是每个像素都有相同的值： / p>

The problem I have is that every pixel I get has the same value:

32|18 color: java.awt.Color[r=255,g=255,b=255]alpha: 255

所以我的结果只是一个彩色的正方形。
如何实现仅改变不透明部分的颜色？为什么呢，所有的像素都有相同的alpha值？我想我的主要问题：alpha值不能正确读取。

So my result is just a colored square. How can I achieve to change the color of the non-transparent parts only? And why is it, that all pixels have even the same alpha value? I guess that#s my main problem: That the alpha value isn't read correctly.

推荐答案

问题是， / p>

The problem is, that

Color originalColor = new Color(image.getRGB(xx, yy));

丢弃所有的alpha值。您必须使用

discards all the alpha values. Instead you have to use

 Color originalColor = new Color(image.getRGB(xx, yy), true);

以保持Alpha值可用。

to keep alpha values available.

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