使用 PDFBox 进行图像旋转 [英] Image rotation with PDFBox

问题描述

我对使用 PDFBox 很陌生.我需要的是在现有的 PDF 中添加带有旋转的图像！我知道如何添加图像，但我的问题是如何旋转图像！我见过一些关于 AffineTransform 和 Matrix 的东西，但我不知道那是什么以及它是如何工作的！

I am quit new to using PDFBox. What I need is to add an image with rotation to an exiting PDF! I know how to add the image, but my problem is how to rotate the image! I've seen somethign about AffineTransform and Matrix but I have no idea what is that and how it works!

非常感谢您传递一些示例代码，并提前感谢您！

I'd really appreciate passing some sample code, and thank you in advance!

最好的问候

推荐答案

帮忙看看简单"的图片展示方法的源码:

It helps to look at the source of the "simple" image display method:

 public void drawXObject(PDXObject xobject, float x, float y, float width, float height)
 {
     AffineTransform transform = new AffineTransform(width, 0, 0, height, x, y);
     drawXObject(xobject, transform);
 }

这就是您在 (200,200) 处以 45° 旋转显示图像的操作:

so this is what you do to display an image at (200,200) with a rotation of 45°:

 AffineTransform at = new AffineTransform(ximage.getWidth(), 0, 0, ximage.getHeight(), 200, 200);
 at.rotate(Math.toRadians(45));
 contentStream.drawXObject(ximage, at);

Re:AffineTransform:这是几何的一个子主题.要获得介绍，请阅读 java 描述 这里.

Re: AffineTransform: this is a subtopic of geometry. To get an introduction, read the java description here.

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