Java文档图像缩放和旋转

我有不同尺寸的文档图像，我希望能够以以下方式高效地缩放和旋转它们（标准的“旋转”和“缩放”逻辑）。我该怎么做

图像高H像素，宽W像素。最初，它应该扩展到600像素宽。每次旋转时，面板的宽度和高度应交换，缩放图像应旋转90度。在每次缩放时，图像应按“比例”因子进行缩放

以下是我迄今为止在

BufferedImage img

上尝试的内容。。。生成的BuffereImage会缩放和旋转，但不会平移（旋转90度后在面板顶部居中）：

啊哈！关键（JavaDoc让人困惑）是意识到在

AffineTransform

上，

rotate（）

和其他方法变换矩阵，而不是图像！下面的代码自动工作

/**
 * Transforms the image efficiently without losing image quality.
 * Scales the image to a width of (600 * scale) pixels, rotates the image,
 * and translates (moves) the image to recenter it if rotated 90 or 270 degrees.
 */
protected BufferedImage transformImage(BufferedImage image)
{
    int scaledWidth = (int)(scale * image.getWidth());
    int scaledHeight = (int)(scale * image.getHeight());

    // Methods AffineTransform.rotate(), AffineTransform.scale() and AffineTransform.translate()
    // transform AffineTransform's transformation matrix to multiply with the buffered image.
    // Therefore those methods are called in a counterintuitive sequence.
    AffineTransform transform;
    if (rotation % 180 == 0)
    {
        // First scale and second rotate image
        transform = AffineTransform.getRotateInstance(Math.toRadians(rotation), scaledWidth/2, scaledHeight/2);
        transform.scale(scale, scale);
    }
    else
    {
        // First scale, second rotate, and third translate image
        transform = AffineTransform.getTranslateInstance((scaledHeight-scaledWidth)/2, (scaledWidth-scaledHeight)/2);
        transform.rotate(Math.toRadians(rotation), scaledWidth/2, scaledHeight/2);
        transform.scale(scale, scale);
    }
    AffineTransformOp operation = new AffineTransformOp(transform, AffineTransformOp.TYPE_BICUBIC);
    BufferedImage transformedImage = operation.createCompatibleDestImage(image, image.getColorModel());
    return operation.filter(image, transformedImage);
}

啊哈！关键（JavaDoc让人困惑）是意识到在

AffineTransform

上，

rotate（）

和其他方法变换矩阵，而不是图像！下面的代码自动工作

/**
 * Transforms the image efficiently without losing image quality.
 * Scales the image to a width of (600 * scale) pixels, rotates the image,
 * and translates (moves) the image to recenter it if rotated 90 or 270 degrees.
 */
protected BufferedImage transformImage(BufferedImage image)
{
    int scaledWidth = (int)(scale * image.getWidth());
    int scaledHeight = (int)(scale * image.getHeight());

    // Methods AffineTransform.rotate(), AffineTransform.scale() and AffineTransform.translate()
    // transform AffineTransform's transformation matrix to multiply with the buffered image.
    // Therefore those methods are called in a counterintuitive sequence.
    AffineTransform transform;
    if (rotation % 180 == 0)
    {
        // First scale and second rotate image
        transform = AffineTransform.getRotateInstance(Math.toRadians(rotation), scaledWidth/2, scaledHeight/2);
        transform.scale(scale, scale);
    }
    else
    {
        // First scale, second rotate, and third translate image
        transform = AffineTransform.getTranslateInstance((scaledHeight-scaledWidth)/2, (scaledWidth-scaledHeight)/2);
        transform.rotate(Math.toRadians(rotation), scaledWidth/2, scaledHeight/2);
        transform.scale(scale, scale);
    }
    AffineTransformOp operation = new AffineTransformOp(transform, AffineTransformOp.TYPE_BICUBIC);
    BufferedImage transformedImage = operation.createCompatibleDestImage(image, image.getColorModel());
    return operation.filter(image, transformedImage);
}

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您可以在保持图像和自由旋转图像的纵横比以及固定的90度旋转的同时查看缩放效果…感谢程序员，我想我需要自由旋转图像，然后将其平移一段距离。请记住，旋转很有趣…尤其是在凌晨2点；）我已经更新了我的解决方案，包括用于自动缩放、旋转和翻译图像的文档化代码。我可以进一步改进吗？您可以在保持图像和自由旋转图像的纵横比的同时查看缩放效果，并进行固定的90度旋转…感谢程序员，我想我需要自由旋转图像，然后将其平移一段距离。请记住，旋转很有趣…尤其是在凌晨2点；）我已经更新了我的解决方案，包括用于自动缩放、旋转和翻译图像的文档化代码。我可以进一步改进吗？请注意，您可能更喜欢在仿射变换之前使用Java本机图像缩放（并在此处删除scale（）调用），否则您将失去图像质量。请注意，您可能更喜欢在仿射变换之前使用Java本机图像缩放（并在此处删除scale（）调用），否则，您将失去图像质量。