java缓冲图像导致空白图像

Question

我试图从 gif 中提取所有帧并将它们放入一列中，下一帧位于最后一帧下方。因此，人们只需向下滚动一张高图像即可看到 gif。我可以提取所有框架，但当我尝试将其写出来时，我只得到一个黑色 Canvas 。宽度和高度是正确的，并且它说它读取图像是正确的。这里出了什么问题？

    String img = "test.gif"; //original gif
    String[] temp = img.split(".gif");
    String base = temp[0];

    try {
        ImageReader reader = ImageIO.getImageReadersBySuffix("GIF").next();
        ImageInputStream in = ImageIO.createImageInputStream(new File(img));
        reader.setInput(in);

        int rows = reader.getNumImages(true);  // How many images there will be 
        int cols = 1;
        int chunks = rows;
        int chunkWidth, chunkHeight;
        int type;

        type = reader.read(0).getType(); //Get single frame file type
        chunkWidth = reader.read(0).getWidth(); //Get single frame width
        chunkHeight = reader.read(0).getHeight();  //Get single frame height

        //Initializing the final image
        BufferedImage finalImg = new BufferedImage(chunkWidth, chunkHeight * rows, type);

        for (int i = 0, count = reader.getNumImages(true); i < count; i++) {
            BufferedImage image = reader.read(i); //read next frame from gif
            finalImg.createGraphics().drawImage(image, chunkWidth, chunkHeight * i, null); //append new image to new file
        }

        System.out.println("Image concatenated.....");
        ImageIO.write(finalImg, "png", new File("finalImg1234555.png")); //final png with all gif images in it

    } catch (IOException ex) {
        Logger.getLogger(Gifextract.class.getName()).log(Level.SEVERE, null, ex);
    }

Answer 1

finalImg.createGraphics().drawImage(image, chunkWidth, chunkHeight * i, null);

x 坐标为 chunkWidth，这意味着图像的左边缘从 chunkWidth 开始。由于 finalImg 的宽度仅为 chunkWidth，因此您的绘制完全超出了 finalImg 的边界。我怀疑 x 坐标应该是 0。