我有不同尺寸的文档图像,我希望能够以下列方式有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。在每次旋转时,面板的宽度和高度应交换,缩放的图像应旋转90度。在每次缩放时,图像应按因子“比例”缩放。
这是我迄今为止在BufferedImage img
上尝试过的... ...生成的BufferedImage缩放并旋转但不转换(在90度旋转后居中于面板上):
double scale = zoom * 600.0 / img.getWidth();
rotation = (rotation + degrees) % 360;
int scaledWidth = (int)(scale * img.getWidth());
int scaledHeight = (int)(scale * img.getHeight());
BufferedImage bufferedImage = new BufferedImage(scaledWidth, scaledHeight, img.getType());
if (rotation % 180 == 0)
bufferedImage = new BufferedImage(scaledWidth, scaledHeight, img.getType());
else
bufferedImage = new BufferedImage(scaledHeight, scaledWidth, img.getType());
AffineTransform transform = AffineTransform.getRotateInstance(Math.toRadians(rotation), scaledWidth/2, scaledHeight/2);
transform.scale(scale, scale);
AffineTransformOp operation = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR);
scaledImage = operation.filter(img, bufferedImage);
imagePanel.setPreferredSize(new Dimension(bufferedImage.getWidth(), bufferedImage.getHeight()));
答案 0 :(得分:1)
啊哈!密钥(JavaDoc令人困惑)意识到在AffineTransform
,rotate()
和其他方法转换矩阵,而不是图像!以下代码自动运行!
/**
* 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);
}