从 BufferedImage 到 SWT 图像的转换

Question

看了很多之后，我发现了一些将BufferedImage 转换为 SWT 图像的代码（暂时不要阅读它）：

public static ImageData convertToSWT(BufferedImage bufferedImage) {
    if (bufferedImage.getColorModel() instanceof DirectColorModel) {
        DirectColorModel colorModel = (DirectColorModel) bufferedImage.getColorModel();
        PaletteData palette = new PaletteData(
            colorModel.getRedMask(),
            colorModel.getGreenMask(),
            colorModel.getBlueMask()
        );
        ImageData data = new ImageData(
            bufferedImage.getWidth(),
            bufferedImage.getHeight(), colorModel.getPixelSize(),
            palette
        );
        WritableRaster raster = bufferedImage.getRaster();
        int[] pixelArray = new int[3];
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                raster.getPixel(x, y, pixelArray);
                int pixel = palette.getPixel(
                    new RGB(pixelArray[0], pixelArray[1], pixelArray[2])
                );
                data.setPixel(x, y, pixel);
            }
        }
        return data;
    } else if (bufferedImage.getColorModel() instanceof IndexColorModel) {
        IndexColorModel colorModel = (IndexColorModel) bufferedImage.getColorModel();
        int size = colorModel.getMapSize();
        byte[] reds = new byte[size];
        byte[] greens = new byte[size];
        byte[] blues = new byte[size];
        colorModel.getReds(reds);
        colorModel.getGreens(greens);
        colorModel.getBlues(blues);
        RGB[] rgbs = new RGB[size];
        for (int i = 0; i < rgbs.length; i++) {
            rgbs[i] = new RGB(reds[i] & 0xFF, greens[i] & 0xFF, blues[i] & 0xFF);
        }
        PaletteData palette = new PaletteData(rgbs);
        ImageData data = new ImageData(
            bufferedImage.getWidth(),
            bufferedImage.getHeight(),
            colorModel.getPixelSize(),
            palette
        );
        data.transparentPixel = colorModel.getTransparentPixel();
        WritableRaster raster = bufferedImage.getRaster();
        int[] pixelArray = new int[1];
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                raster.getPixel(x, y, pixelArray);
                data.setPixel(x, y, pixelArray[0]);
            }
        }
        return data;
    }
    return null;
}

（在这里找到：http://www.java2s.com/Code/Java/SWT-JFace-Eclipse/ConvertsabufferedimagetoSWTImageData.htm）。

我已经测试过了，它工作得很好。问题是我不理解它（我最好的猜测是它使用两者的原始数据接口进行传输）。我想到一个更简单的解决方案是将BufferedImage 写入ByteArrayOutputStream，然后用ByteArrayInputStream 将其读回SWT Image。这个解决方案有什么问题吗？速度呢？

这种转换是必要的，因为所有的图像大小调整库都适用于 AWT，但我正在使用 SWT 显示图像。

谢谢！

Answer 1

这是一个更完整的版本...问题中发布的版本对我不起作用。

/**
 * snippet 156: convert between SWT Image and AWT BufferedImage.
 * <p>
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
public static ImageData convertToSWT(BufferedImage bufferedImage) {
    if (bufferedImage.getColorModel() instanceof DirectColorModel) {
        /*
        DirectColorModel colorModel = (DirectColorModel)bufferedImage.getColorModel();
        PaletteData palette = new PaletteData(
                colorModel.getRedMask(),
                colorModel.getGreenMask(),
                colorModel.getBlueMask());
        ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(),
                colorModel.getPixelSize(), palette);
        WritableRaster raster = bufferedImage.getRaster();
        int[] pixelArray = new int[3];
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                raster.getPixel(x, y, pixelArray);
                int pixel = palette.getPixel(new RGB(pixelArray[0], pixelArray[1], pixelArray[2]));
                data.setPixel(x, y, pixel);
            }
        }
        */
        DirectColorModel colorModel = (DirectColorModel)bufferedImage.getColorModel();
        PaletteData palette = new PaletteData(
                colorModel.getRedMask(),
                colorModel.getGreenMask(),
                colorModel.getBlueMask());
        ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(),
                colorModel.getPixelSize(), palette);
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                int rgb = bufferedImage.getRGB(x, y);
                int pixel = palette.getPixel(new RGB((rgb >> 16) & 0xFF, (rgb >> 8) & 0xFF, rgb & 0xFF));
                data.setPixel(x, y, pixel);
                if (colorModel.hasAlpha()) {
                    data.setAlpha(x, y, (rgb >> 24) & 0xFF);
                }
            }
        }
        return data;
    }
    else if (bufferedImage.getColorModel() instanceof IndexColorModel) {
        IndexColorModel colorModel = (IndexColorModel)bufferedImage.getColorModel();
        int size = colorModel.getMapSize();
        byte[] reds = new byte[size];
        byte[] greens = new byte[size];
        byte[] blues = new byte[size];
        colorModel.getReds(reds);
        colorModel.getGreens(greens);
        colorModel.getBlues(blues);
        RGB[] rgbs = new RGB[size];
        for (int i = 0; i < rgbs.length; i++) {
            rgbs[i] = new RGB(reds[i] & 0xFF, greens[i] & 0xFF, blues[i] & 0xFF);
        }
        PaletteData palette = new PaletteData(rgbs);
        ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(),
                colorModel.getPixelSize(), palette);
        data.transparentPixel = colorModel.getTransparentPixel();
        WritableRaster raster = bufferedImage.getRaster();
        int[] pixelArray = new int[1];
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                raster.getPixel(x, y, pixelArray);
                data.setPixel(x, y, pixelArray[0]);
            }
        }
        return data;
    }
    else if (bufferedImage.getColorModel() instanceof ComponentColorModel) {
        ComponentColorModel colorModel = (ComponentColorModel)bufferedImage.getColorModel();
        //ASSUMES: 3 BYTE BGR IMAGE TYPE
        PaletteData palette = new PaletteData(0x0000FF, 0x00FF00,0xFF0000);
        ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(),
                colorModel.getPixelSize(), palette);
        //This is valid because we are using a 3-byte Data model with no transparent pixels
        data.transparentPixel = -1;
        WritableRaster raster = bufferedImage.getRaster();
        int[] pixelArray = new int[3];
        for (int y = 0; y < data.height; y++) {
            for (int x = 0; x < data.width; x++) {
                raster.getPixel(x, y, pixelArray);
                int pixel = palette.getPixel(new RGB(pixelArray[0], pixelArray[1], pixelArray[2]));
                data.setPixel(x, y, pixel);
            }
        }
        return data;
    }
    return null;
}

Answer 2

代码的复杂主要是由于BufferedImage这两种可能的颜色模型。我不认为你可以在这方面有很大的改进。首先，使用中间Stream 将要求两个图像系统具有共同的格式，并且与Stream 之间的转换肯定会比当前代码慢得多。