有比-drawInRect:withFont:lineBreakMode:alignment:更快的东西吗? [英] Is there something faster than -drawInRect:withFont:lineBreakMode:alignment:?

问题描述

Shark向我展示了此方法带来了巨大的性能损失.就像我的表格视图中的80％.我要做的就是在每个单元格上绘制两个标签(每页总共8个标签).在滚动过程中.我用了drawInRect:.

Shark shows me that this method takes a HUGE performance hit. Like 80% in my table view. All I do is draw two labels per cell (about 8 in total per page). During scrolling. I drawInRect: with that.

有更好的方法吗?像直接绘制到某个图层一样?

Are there some better methods? Like drawing directly to some layer?

推荐答案

您可以使用以下代码来更快地进行绘制:

You can do faster drawing using code like the following:

CGContextSetStrokeColorWithColor(context, strokeColor); 
CGContextSetFillColorWithColor(context, strokeColor);

CGContextSelectFont(context, "Helvetica", fontSize, kCGEncodingMacRoman);
CGContextSetTextDrawingMode(context, kCGTextFill);
CGContextSetTextPosition(context, 0.0f, round(fontSize / 4.0f));
CGContextShowText(context, [text cStringUsingEncoding:NSMacOSRomanStringEncoding], strlen([text cStringUsingEncoding:NSMacOSRomanStringEncoding]));     

但是，iPhone上的Helvetica字体的Mac Roman编码缺少许多非英语字符的符号，因此，除非您想在iPhone OS中升级到Core Text，否则我认为您会迷上NSString绘制方法. 3.2.

However, the Mac Roman encoding for the Helvetica font on the iPhone is missing symbols for many non-English characters, so I think you're stuck with the NSString drawing methods unless you want to step up to Core Text in iPhone OS 3.2.

要检查您的字符串是否可以使用Mac Roman字符集表示，请使用类似以下的内容:

To check and see if your string can be represented using the Mac Roman character set, use something like the following:

if ([text canBeConvertedToEncoding:NSMacOSRomanStringEncoding])

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