NSImage旋转 [英] NSImage rotation

问题描述

我有一个窗口，其中有NSView的子类。在视图中，我放了一个NSImage。

我想要将图片旋转90度，将图片的（新）左上角保留在视图的左上角。当然，我必须旋转图像，然后翻译它，把原点放回原处。

在Carbon中，我发现了CGContextRotateCTM，它做了我想要的。但是，我在ObjC中找不到正确的调用。 setFrameCenterRotation似乎没有做任何事情，在setFrameRotation，我似乎无法找出原点在哪里，所以我可以适当翻译。

似乎移动。当我调整窗口大小放置图像（或其中的一部分，我似乎有一个奇怪的剪辑问题），当我滚动，它跳转到一个不同的（而不总是saem）位置。

这对任何人都有意义吗？

感谢

我旋转文本在屏幕上我的工作的应用程序和Cocoa（我假设你的意思是Cocoa，而不是ObjC在你的问题）的方法是使用NSAffineTransform。

以下是一段您应该可以开始使用的代码段。

  double rotateDeg = 90; 
 NSAffineTransform * rotate = [[NSAffineTransform alloc] init]; 
 NSGraphicsContext * context = [NSGraphicsContext currentContext]; 
 
 [context saveGraphicsState]; 
 [rotate rotateByDegrees：rotateDeg]; 
 [rotate concat]; 
 
 / *你的绘图代码[NSImage drawAtPoint ....]的图像在这里
另外，如果你需要在绘制时锁定焦点，在这里。 * / 
 
 [rotate release]; 
 [context restoreGraphicsState]; 
  

旋转的数学可能会有点棘手，因为上面的是旋转坐标系统。我的旋转90度是逆时针旋转。

I have a window with an subclass of NSView in it. Inside the view, I put an NSImage.

I want to be able to rotate the image by 90 degrees, keeping the (new) upper left corner of the image in the upper left corner of the view. Of course, I will have to rotate the image, and then translate it to put the origin back into place.

In Carbon, I found CGContextRotateCTM which does what I want . However, I can't find the right call in ObjC. setFrameCenterRotation doesn't seem to do anything, and in setFrameRotation, I can't seem to figure out where the origin is, so I can approprately translate.

It seems to move. When I resize the window it puts the image (or part of it, I seem to have a strange clipping issue as wel) and when I scroll, it jumps to a different (and not always the saem) location.

Does this make sense to anyone?

thanks

解决方案

I rotate text on the screen for an app I work on and the Cocoa (I assume you mean Cocoa and not ObjC in your question) way of doing this is to use NSAffineTransform.

Here's a snippet that should get you started

double rotateDeg = 90;
NSAffineTransform *rotate = [[NSAffineTransform alloc] init];
NSGraphicsContext *context = [NSGraphicsContext currentContext];

[context saveGraphicsState];
[rotate rotateByDegrees:rotateDeg];
[rotate concat];

    /* Your drawing code [NSImage drawAtPoint....]for the image goes here 
       Also, if you need to lock focus when drawing, do it here.       */

[rotate release];
[context restoreGraphicsState];

The mathematics on the rotation can get a little tricky here because what the above does is to rotate the coordinate system that you are drawing into. My rotation of 90 degrees is a counter-clockwise rotation.

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