Question

我创建了一个示例SWT应用程序。我正在将几张图片上传到应用程序中。我必须调整所有高于16x16（宽*高）分辨率的图像，并将它们保存在不同的位置。

出于这个原因，我正在缩放图像并将缩放后的图像保存到目标位置。下面是我用来做的那段代码。

使用getImageData()获取图片数据并保存我正在使用ImageLoader save()方法。

final Image mySampleImage = ImageResizer.scaleImage(img, 16, 16);
final ImageLoader imageLoader = new ImageLoader();
imageLoader.data = new ImageData[] { mySampleImage.getImageData() };
final String fileExtension = inputImagePath.substring(inputImagePath.lastIndexOf(".") + 1);
if ("GIF".equalsIgnoreCase(fileExtension)) {
    imageLoader.save(outputImagePath, SWT.IMAGE_GIF);
} else if ("PNG".equalsIgnoreCase(fileExtension)) {
    imageLoader.save(outputImagePath, SWT.IMAGE_PNG);
}

当我尝试保存少量特定图像（GIF或PNG格式）时，ImageLoader imageLoader.save(outputImagePath, SWT.IMAGE_GIF);抛出以下异常。

org.eclipse.swt.SWTException: Unsupported color depth
    at org.eclipse.swt.SWT.error(SWT.java:4533)
    at org.eclipse.swt.SWT.error(SWT.java:4448)
    at org.eclipse.swt.SWT.error(SWT.java:4419)
    at org.eclipse.swt.internal.image.GIFFileFormat.unloadIntoByteStream(GIFFileFormat.java:427)
    at org.eclipse.swt.internal.image.FileFormat.unloadIntoStream(FileFormat.java:124)
    at org.eclipse.swt.internal.image.FileFormat.save(FileFormat.java:112)
    at org.eclipse.swt.graphics.ImageLoader.save(ImageLoader.java:218)
    at org.eclipse.swt.graphics.ImageLoader.save(ImageLoader.java:259)
    at mainpackage.ImageResizer.resize(ImageResizer.java:55)
    at mainpackage.ImageResizer.main(ImageResizer.java:110)

让我知道如果有任何其他方法可以做同样的（或）有任何方法来解决这个问题。

Answer 1

最后，通过参考现有的日食错误Unsupported color depth eclipse bug，我得到了一个解决方案。在下面的代码中，我创建了一个带有RGB值的PaletteData并更新了我的图像数据。

我的updateImagedata（）方法将采用缩放图像，如果图像深度为32或更大，将返回正确更新的imageData。

private static ImageData updateImagedata(Image image) {
        ImageData data = image.getImageData();
        if (!data.palette.isDirect && data.depth <= 8)
            return data;

        // compute a histogram of color frequencies
        HashMap<RGB, ColorCounter> freq = new HashMap<>();
        int width = data.width;
        int[] pixels = new int[width];
        int[] maskPixels = new int[width];
        for (int y = 0, height = data.height; y < height; ++y) {
            data.getPixels(0, y, width, pixels, 0);
            for (int x = 0; x < width; ++x) {
                RGB rgb = data.palette.getRGB(pixels[x]);
                ColorCounter counter = (ColorCounter) freq.get(rgb);
                if (counter == null) {
                    counter = new ColorCounter();
                    counter.rgb = rgb;
                    freq.put(rgb, counter);
                }
                counter.count++;
            }
        }

        // sort colors by most frequently used
        ColorCounter[] counters = new ColorCounter[freq.size()];
        freq.values().toArray(counters);
        Arrays.sort(counters);

        // pick the most frequently used 256 (or fewer), and make a palette
        ImageData mask = null;
        if (data.transparentPixel != -1 || data.maskData != null) {
            mask = data.getTransparencyMask();
        }
        int n = Math.min(256, freq.size());
        RGB[] rgbs = new RGB[n + (mask != null ? 1 : 0)];
        for (int i = 0; i < n; ++i)
            rgbs[i] = counters[i].rgb;
        if (mask != null) {
            rgbs[rgbs.length - 1] = data.transparentPixel != -1 ? data.palette.getRGB(data.transparentPixel)
                    : new RGB(255, 255, 255);
        }
        PaletteData palette = new PaletteData(rgbs);

        ImageData newData = new ImageData(width, data.height, 8, palette);
        if (mask != null)
            newData.transparentPixel = rgbs.length - 1;
        for (int y = 0, height = data.height; y < height; ++y) {
            data.getPixels(0, y, width, pixels, 0);
            if (mask != null)
                mask.getPixels(0, y, width, maskPixels, 0);
            for (int x = 0; x < width; ++x) {
                if (mask != null && maskPixels[x] == 0) {
                    pixels[x] = rgbs.length - 1;
                } else {
                    RGB rgb = data.palette.getRGB(pixels[x]);
                    pixels[x] = closest(rgbs, n, rgb);
                }
            }
            newData.setPixels(0, y, width, pixels, 0);
        }
        return newData;
    }

查找最低指数：

static int closest(RGB[] rgbs, int n, RGB rgb) {
        int minDist = 256*256*3;
        int minIndex = 0;
        for (int i = 0; i < n; ++i) {
            RGB rgb2 = rgbs[i];
            int da = rgb2.red - rgb.red;
            int dg = rgb2.green - rgb.green;
            int db = rgb2.blue - rgb.blue;
            int dist = da*da + dg*dg + db*db;
            if (dist < minDist) {
                minDist = dist;
                minIndex = i;
            }
        }
        return minIndex;
    }

ColourCounter课程：

class ColorCounter implements Comparable<ColorCounter> {
    RGB rgb;
    int count;

    public int compareTo(ColorCounter o) {
        return o.count - count;
    }
}

org.eclipse.swt.SWTException：不支持的颜色深度

1 个答案: