CGContext优化 [英] CGContext Optimization

问题描述

我的运行速度有一个小问题。在加载时，我生成一个CGMutablePath，它至少包含1000个点。我想在屏幕上滚动此路径，所以我使用这种代码：

I have a small run speed problem. On load, I generate a CGMutablePath containing at least 1000 points. I want to scroll this path on the screen, so I use this kind of code :

-(void) drawRect:(CGRect)rect {

    /*
    Here, I have a timer calling drawRect 60 times per second.
    There's also code for the scale and currentTime, based on
    an MP3 playback (AVAudioPlayer);
    */

    CGContextRef ref = UIGraphicsGetCurrentContext();   
    CGContextClearRect(ref, [self frame]);

    CGContextSaveGState(ref);
    CGContextTranslateCTM(ref, s.width/2+currentTime, 1);
    CGContextScaleCTM(ref, scale, 1);
    CGContextAddPath(ref, myGraphPath);
    CGContextSetRGBFillColor(ref, .1, .1, .1, .8);
    CGContextFillPath(ref);
    CGContextRestoreGState(ref);
}

问题是它有点慢，不是很慢，但正如我需要添加更多的图形代码...
我想知道设备是否正在绘制整个路径（一旦应用了比例，该路径大约为10.000像素宽），或者只是可见的部分屏幕 ？我可以做些什么来优化它？

The problem is that it's a bit slow, not very much, but as I need to add a whole lot more of graphic code... I was wondering if the device is drawing the whole path (once the scale is applied, the path is about 10.000 pixels wide), or just the part visible on the screen ? What can I do to optimize this ?

推荐答案

尝试了很多事情之后（例如将我的1000点积分路径分成较小的10点点路径等...），我已经使用简单的顶点数组将所有内容移植到了openGL。
我花了大约4个小时来移植所有内容（甚至缩放路径，滚动等等），现在，我一直都得到完整的60fps动画，当时我的平均峰值只有22fps使用CoreGraphics时为28。

After trying a lot of things (like dividing my huge 1000 points path into smaller 10 points paths etc...), I've ported everything to openGL, using simple vertex arrays. It took me about 4 hours to port everything (even scaling the path, scrolling it, etc...) and now, I get a full 60fps animation all the time, when I was having only 22fps average with peaks at 28 when using the CoreGraphics.

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