Core Graphics Rotating a Path
This should be a simple one, basically I have a few paths drawn with core graphics, and I want to be able to rotate them (for convenience). I've tried using CGContextRotateCTM(context); but it's not rotating anything. Am I missing something?
Here's the source for drawRect
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 1.5);
CGContextSetStrokeColorWithC开发者_JAVA技巧olor(context, [UIColor whiteColor].CGColor);
CGContextSetShadow(context, CGSizeMake(0, 1), 0);
CGContextBeginPath(context);
CGContextMoveToPoint(context, 13.5, 13.5);
CGContextAddLineToPoint(context, 30.5, 13.5);
CGContextAddLineToPoint(context, 30.5, 30.5);
CGContextAddLineToPoint(context, 13.5, 30.5);
CGContextAddLineToPoint(context, 13.5, 13.5);
CGContextClosePath(context);
CGContextMoveToPoint(context, 26.2, 13.5);
CGContextAddLineToPoint(context, 26.2, 17.8);
CGContextAddLineToPoint(context, 30.5, 17.8);
CGContextMoveToPoint(context, 17.8, 13.5);
CGContextAddLineToPoint(context, 17.8, 17.8);
CGContextAddLineToPoint(context, 13.5, 17.8);
CGContextMoveToPoint(context, 13.5, 26.2);
CGContextAddLineToPoint(context, 17.8, 26.2);
CGContextAddLineToPoint(context, 17.8, 30.5);
CGContextStrokePath(context);
CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
CGContextSetShadowWithColor(context, CGSizeMake(0, 0), 0, [UIColor clearColor].CGColor);
CGContextFillRect(context, CGRectMake(26.2, 13.5, 4.3, 4.3));
CGContextFillRect(context, CGRectMake(13.5, 13.5, 4.3, 4.3));
CGContextFillRect(context, CGRectMake(13.5, 26.2, 4.3, 4.3));
CGContextRotateCTM(context, M_PI / 4);
}
Place this before drawing/filling your figure to translate to origin, rotate and then translate back to the point it should appear to rotate around:
static inline float radians(double degrees) { return degrees * M_PI / 180; }
CGContextTranslateCTM(c, midX, midY);
CGContextRotateCTM(c, radians(-73));
CGContextTranslateCTM(c, -midX, -midY);
Change the angle value passed to CGContextRotateCTM to make the figure point in another direction.
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