CALayer的反别名对角线边缘 [英] Anti-alias diagonal edges of CALayer

问题描述

当我使用CATransform3DRotate设置CALayer的transform属性时，图层被正确旋转。但是，该层的边缘是锯齿状的，没有消除锯齿。我已经阅读了几篇关于这个主题的帖子：

When I set the transform property of my CALayer with a CATransform3DRotate, the layer is properly rotated. However, the edges of the layer are jagged and not anti-aliased. I've read a couple posts on the subject:

iPhone：CALayer +旋转3D +抗锯齿？

iPhone - 将视角应用于CALayer时的锯齿状边缘

我是试图通过在我的对角线层设置以下属性来结合他们的建议

I've tried to incorporate their advice by setting the following properties on my diagonal layer

CALayer* layer = myView.layer;
layer.shadowOpacity = 0.01;
layer.edgeAntialiasingMask = kCALayerTopEdge | kCALayerBottomEdge | kCALayerRightEdge | kCALayerLeftEdge;
layer.borderWidth = 1.0;
layer.borderColor = [UIColor clearColor].CGColor;
layer.backgroundColor = [UIColor greenColor].CGColor;

我还覆盖了drawLayer：inContext：对角层的方法以确保消除锯齿：

I've also overridden the drawLayer:inContext: method of my diagonal layer to ensure anti-aliasing:

-(void)drawLayer:(CALayer*)layer inContext:(CGContextRef)context
{
    CGContextSetAllowsAntialiasing(context, true);
    CGContextSetShouldAntialias(context, true);
    CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);
    CGContextFillRect(context, self.bounds);
}

我缺少什么？

推荐答案

我刚刚对此图片发了一篇文章。也许它会有所帮助。

I just did a post on this for images. Maybe it will help.

我找到了一些帮助和设置边框的技巧没有按照我的想法做到。你可以做的是设置一些设置来帮助插值，栅格化和rasterisationScale。

I found a few tricks that help and setting just a border did not do what I thought it would. What you can do is set a few settings to help with interpolation, rasterizing, and the rasterisationScale.

查看此代码中的内容是否有帮助：

See if something from this code helps:

    UIImage * img =[UIImage imageWithData:[NSData dataWithContentsOfFile:[[[NSBundle mainBundle ] resourcePath ] stringByAppendingPathComponent:@"AliasImage.png" ] ] ];
CGRect imageRect = CGRectMake( 0 , 0 , img.size.width + 4 , img.size.height + 4 );
UIGraphicsBeginImageContext( imageRect.size );
[img drawInRect:CGRectMake( imageRect.origin.x + 2 , imageRect.origin.y + 2 , imageRect.size.width - 4 , imageRect.size.height - 4 ) ];
CGContextSetInterpolationQuality( UIGraphicsGetCurrentContext() , kCGInterpolationHigh );
img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[aliasImage setImage:img ];

aliasImage.transform = CGAffineTransformScale(aliasImage.transform , 0.45 , 0.45 );
aliasImage.layer.shouldRasterize = YES;
aliasImage.layer.rasterizationScale = 0.45;
aliasImage.layer.edgeAntialiasingMask = kCALayerLeftEdge | kCALayerRightEdge | kCALayerBottomEdge | kCALayerTopEdge;
aliasImage.clipsToBounds = NO;
aliasImage.layer.masksToBounds = NO;

我发布了一些例子这里

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