ios - 在 xamarin iOS 中旋转 UIImage
<p><p>我想在 xamarin 中旋转 UIImage。我使用此代码但未成功获取旋转图像。</p>
<pre><code>public UIImage RotateImage(UIImage image)
{
CGImage imgRef = image.CGImage;
float width = imgRef.Width;
float height = imgRef.Height;
CGAffineTransform transform = CGAffineTransform.MakeIdentity();
RectangleF bounds = new RectangleF(0, 0, width, height);
transform = CGAffineTransform.MakeRotation((float)Math.PI / 4);
UIGraphics.BeginImageContext(bounds.Size);
CGContext context = UIGraphics.GetCurrentContext();
context.ConcatCTM(transform);
context.DrawImage(new RectangleF(0, 0, width, height), imgRef);
UIImage imageCopy = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return imageCopy;
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>试试这个，把Objective-C转成C#，引用<a href="https://stackoverflow.com/a/11667808/8187800" rel="noreferrer noopener nofollow">here</a> .</p>
<pre><code>public UIImage RotateImage(UIImage image, float degree)
{
float Radians = degree * (float)Math.PI / 180;
UIView view = new UIView(frame: new CGRect(0, 0, image.Size.Width, image.Size.Height));
CGAffineTransform t = CGAffineTransform.MakeRotation(Radians);
view.Transform = t;
CGSize size = view.Frame.Size;
UIGraphics.BeginImageContext(size);
CGContext context = UIGraphics.GetCurrentContext();
context.TranslateCTM(size.Width/2, size.Height/2);
context.RotateCTM(Radians);
context.ScaleCTM(1, -1);
context.DrawImage(new CGRect(-image.Size.Width/2, -image.Size.Height/2, image.Size.Width, image.Size.Height), image.CGImage);
UIImage imageCopy = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return imageCopy;
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - 在 xamarin iOS 中旋转 UIImage，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/49652589/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/49652589/
</a>
</p>
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