带旋转的drawAtPoint

发布于 2024-11-08 02:32:31 字数 627 浏览 6 评论 0原文

我无法使用 drawAtPoint 将 imageView.image 绘制在正确的位置。在应用程序中，我使用 CGAffineTransformMakeRotation 来旋转图像视图，但是当我想使用 UIGraphicsGetImageFromCurrentImageContext 将 imageView 保存为与其他视图合并的一部分时，我不知道如何操作告诉它旋转..我所做的就是旋转 180 度。这是我用来将其与另一个图像合并的代码。

UIGraphicsBeginImageContext(imageView.bounds.size); 

[imageView.image drawAtPoint:CGPointMake(-40,0)];
[topView.image drawAtPoint:CGPointMake(0,160)];

UIImage *mergedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

所以我的问题是：如何以 180 度或 3.14159265 弧度旋转 drawAtPoint ？

提前致谢。

原文

I am having trouble drawing my imageView.image in the correct position using drawAtPoint. In the app I have used CGAffineTransformMakeRotation to rotate the image view, but when I want to save the imageView as part of a merge with others using UIGraphicsGetImageFromCurrentImageContext I don't know how to tell it to rotate.. all I am doing is rotating 180 degrees. here is the code I am using to merge it with another image.

UIGraphicsBeginImageContext(imageView.bounds.size); 

[imageView.image drawAtPoint:CGPointMake(-40,0)];
[topView.image drawAtPoint:CGPointMake(0,160)];

UIImage *mergedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

So my question is: How do I drawAtPoint with rotation of 180 degrees or 3.14159265 radians?

Thanks in advance.

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故乡的云 2024-11-15 02:32:31

您可以对图像内容应用变换，因此所有后续绘画操作都将使用该变换进行绘制，例如（未经测试）

UIGraphicsBeginImageContext(size);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextRotateCTM(c, M_PI/6);
[image drawAtPoint:CGPointZero];
...

You can apply a transform to the image content, so all subsequent painting operation will be drawn with that transform, e.g. (untested)

UIGraphicsBeginImageContext(size);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextRotateCTM(c, M_PI/6);
[image drawAtPoint:CGPointZero];
...

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