在 Java 中更改 png 非透明部分的颜色
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Change color of non-transparent parts of png in Java
提问by 4ndro1d
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)
我正在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，另一部分是透明的。这是一个例子：（在这种情况下它是绿色的，只是为了让它可见）
I tried to do the following:
我尝试执行以下操作：
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;
}
The problem I have is that every pixel I get has the same value:
我的问题是我得到的每个像素都具有相同的值：
32|18 color: java.awt.Color[r=255,g=255,b=255]alpha: 255
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.
所以我的结果只是一个彩色方块。我怎样才能实现只改变非透明部分的颜色？为什么所有像素都具有相同的 alpha 值？我想这是我的主要问题：无法正确读取 alpha 值。
采纳答案by 4ndro1d
The problem is, that
问题是，那
Color originalColor = new Color(image.getRGB(xx, yy));
discards all the alpha values. Instead you have to use
丢弃所有的 alpha 值。相反，你必须使用
Color originalColor = new Color(image.getRGB(xx, yy), true);
to keep alpha values available.
保持 alpha 值可用。
回答by MadProgrammer
Why it doesn't work, I don't know, this will.
为什么它不起作用，我不知道，这会。
This changes all the pixles to blue, maintaining their alpha values...
这会将所有像素更改为蓝色，保持它们的 alpha 值......
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
public class TestColorReplace {
public static void main(String[] args) {
try {
BufferedImage img = colorImage(ImageIO.read(new File("NWvnS.png")));
ImageIO.write(img, "png", new File("Test.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
private static BufferedImage colorImage(BufferedImage image) {
int width = image.getWidth();
int height = image.getHeight();
WritableRaster raster = image.getRaster();
for (int xx = 0; xx < width; xx++) {
for (int yy = 0; yy < height; yy++) {
int[] pixels = raster.getPixel(xx, yy, (int[]) null);
pixels[0] = 0;
pixels[1] = 0;
pixels[2] = 255;
raster.setPixel(xx, yy, pixels);
}
}
return image;
}
}
