ios 如何使用 CGAffineTransformMakeRotation？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/5725099/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
提示：将鼠标放在中文语句上可以显示对应的英文。显示中英文
时间：2020-08-30 19:38:25 来源:igfitidea点击:
How to use CGAffineTransformMakeRotation?
提问by Krishnabhadra
I want to draw text use Quartz 2D. The "menu" direction is wrong. I want "Menu" still readable and have 45 degree with X-axis. Below is my code:
我想使用 Quartz 2D 绘制文本。“菜单”方向错误。我希望“菜单”仍然可读并且与 X 轴成 45 度。下面是我的代码：
CGContextSelectFont(context, "Arial", 12, kCGEncodingMacRoman);
CGContextSetTextDrawingMode(context, kCGTextFill);
CGContextSetRGBFillColor(context, 0, 0, 0, 1); // 6
CGContextSetRGBStrokeColor(context, 0, 0, 0, 1);
CGContextSetTextMatrix(context, CGAffineTransformMake(1.0,0.0, 0.0, -1.0, 0.0, 0.0));
CGContextSetTextMatrix(context, CGAffineTransformMakeRotation(45));
CGContextShowTextAtPoint(context,10, 10, "Menu", 4);
回答by Krishnabhadra
CGAffineTransformMakeRotation expects angle in radians, not in degrees.
CGAffineTransformMakeRotation 期望以弧度为单位的角度，而不是以度为单位。
#define DEGREES_TO_RADIANS(x) (M_PI * (x) / 180.0)
...
CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(45));
回答by Sandeep Saurabh
[view setTransform:CGAffineTransformMakeRotation(M_PI / 2)];
