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使用AffineTransform进行Java图像旋转会输出黑色图像,但在调整大小时效果很好

更新时间:2023-10-30 18:47:58

将新的BufferedImage传递给filter()方法,而不是让它创建自己的作品(不是完全黑色)。

Passing a new BufferedImage into the filter() method rather than letting it create its own works (not completely black).

此外,转换似乎无法正常工作,图像最终在目标中偏移。我能够通过手动应用必要的翻译来修复它,按相反顺序记录这些工作,并在目标图像中宽度=旧高度,高度=旧宽度。

Also the transform did not appear to work correctly, the image ended up being offset in the destination. I was able to fix it by manually applying the necessary translations, note these work in reverse order, and in the destination image the width = the old height, and height = the old width.

AffineTransform tx = new AffineTransform();

// last, width = height and height = width :)
tx.translate(originalImage.getHeight() / 2,originalImage.getWidth() / 2);
tx.rotate(Math.PI / 2);
// first - center image at the origin so rotate works OK
tx.translate(-originalImage.getWidth() / 2,-originalImage.getHeight() / 2);

AffineTransformOp op = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);

// new destination image where height = width and width = height.
BufferedImage newImage =new BufferedImage(originalImage.getHeight(), originalImage.getWidth(), originalImage.getType());
op.filter(originalImage, newImage);

filter()的javadoc声明它会为你创建一个BufferedImage,我仍然不确定为什么这不起作用,这里一定有问题。

The javadoc for filter() states that it will create a BufferedImage for you, I'm still unsure why this does not work, there must be an issue here.

 If the destination image is null, a BufferedImage is created with the source ColorModel.