如何用BufferedImage中的另一种颜色替换颜色

Question

所以我有一个带有火山的图像文件。其他所有内容均为0xFFFF00FF（不透明的洋红色）。我想将包含该颜色的每个像素替换为0（透明）。到目前为止，我的方法如下所示：

public static BufferedImage replace(BufferedImage image, int target, int preferred) {
    int width = image.getWidth();
    int height = image.getHeight();
    BufferedImage newImage = new BufferedImage(width, height, image.getType());
    int color;

    for (int i = 0; i < width; i++) {
        for (int j = 0; j < height; j++) {
            color = image.getRGB(i, j);
            if (color == target) {
                newImage.setRGB(i, j, preferred);
            }
            else {
                newImage.setRGB(i, j, color);
            }
        }
    }

    return newImage;
}

这工作正常，但似乎很慢。我见过有人以其他方式执行此操作，但是我不知道发生了什么。如果有人知道更好的方法，我非常想听听。

Answer 1

为了避免遍历像素，请更改基础ColorModel。这是一个例子。以下是作者使用原始BufferedImage并应用新颜色模型的代码段。

 private static BufferedImage createImage() {
    int width = 200;
    int height = 200;
    // Generate the source pixels for our image
    // Lets just keep it to a simple blank image for now

    byte[] pixels = new byte[width * height];
    DataBuffer dataBuffer = new DataBufferByte(pixels, width*height, 0);
    SampleModel sampleModel = new SinglePixelPackedSampleModel(
    DataBuffer.TYPE_BYTE, width, height, new int[] {(byte)0xf});
    WritableRaster raster = Raster.createWritableRaster(
    sampleModel, dataBuffer, null);
    return new BufferedImage(createColorModel(0), raster, false, null);
}

private static ColorModel createColorModel(int n) {
    // Create a simple color model with all values mapping to
    // a single shade of gray
    // nb. this could be improved by reusing the byte arrays

    byte[] r = new byte[16];
    byte[] g = new byte[16];
    byte[] b = new byte[16];
    for (int i = 0; i < r.length; i++) {
        r[i] = (byte) n;
        g[i] = (byte) n;
        b[i] = (byte) n;
    }
    return new IndexColorModel(4, 16, r, g, b);
}

private BufferedImage image = createImage();
image = new BufferedImage(createColorModel(e.getX()), image.getRaster(), false, null);