这是我的代码。我想顺时针和逆时针旋转我的圆圈。如果有人知道如何使用核心图形绘制圆圈，请指导我如何操作。
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
mainSquare = CGRectMake(X_SPACE, Y_SPACE, 220, 200);
CGContextSaveGState(context);
// Create circle path and clip
CGContextAddEllipseInRect(context, mainSquare);
CGContextClip(context);
// Define rects
NSLog(@"helll %f",mainSquare.size.width);
CGRect topLeft = CGRectMake(mainSquare.origin.x, mainSquare.origin.y, (mainSquare.size.width / 2) , (mainSquare.size.height / 2) );
CGRect topRight = CGRectMake((mainSquare.size.width / 2) + X_SPACE, mainSquare.origin.y, mainSquare.size.width / 2, (mainSquare.size.height / 2) );
CGRect bottomLeft = CGRectMake(mainSquare.origin.x, (mainSquare.size.height / 2) + Y_SPACE, mainSquare.size.width / 2, (mainSquare.size.height / 2) );
CGRect bottomRight = CGRectMake((mainSquare.size.width / 2) + X_SPACE, (mainSquare.size.height / 2) + Y_SPACE, mainSquare.size.width / 2, mainSquare.size.height / 2);
// Define colors
CGColorRef topLeftColor = [[UIColor redColor] CGColor];
CGColorRef topRightColor = [[UIColor blueColor] CGColor];
CGColorRef bottomLeftColor = [[UIColor greenColor] CGColor];
CGColorRef bottomRightColor = [[UIColor yellowColor] CGColor];
// Fill rects with colors
CGContextSetFillColorWithColor(context, topLeftColor);
CGContextFillRect(context, topLeft);
CGContextSetFillColorWithColor(context, topRightColor);
CGContextFillRect(context, topRight);
CGContextSetFillColorWithColor(context, bottomLeftColor);
CGContextFillRect(context, bottomLeft);
CGContextSetFillColorWithColor(context, bottomRightColor);
CGContextFillRect(context, bottomRight);
CGContextRestoreGState(context);
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
UITouch *touch = [[event allTouches] anyObject];
swipeBackward = [touch locationInView: [touch view]];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesEnded:touches withEvent:event];
UITouch *touch = [[event allTouches] anyObject];
swipeForward = [touch locationInView: [touch view]];
double dx = swipeBackward.x - swipeForward.x;
// double dy = swipeBackward.y - swipeForward.y;
if( (swipeBackward.x < 160) && (swipeForward.x < 160) && (swipeBackward.y <= 151) && (swipeForward.y > 151) )
{
NSLog(@"Rotate Anticlockwise");
mainSquare.transform = CGAffineTransformMakeRotation(63.0*radianConst);
}
else if( (swipeBackward.x < 160) && (swipeForward.x < 160) && (swipeBackward.y >= 151) && (swipeForward.y < 151) )
{
NSLog(@"Rotate Clockwise");
}
else if( (swipeBackward.x > 160) && (swipeForward.x > 160) && (swipeBackward.y <= 151) && (swipeForward.y > 151) )
{
NSLog(@"Rotate Clockwise");
}
else if( (swipeBackward.x > 160) && (swipeForward.x > 160) && (swipeBackward.y >= 151) && (swipeForward.y < 151) )
{
NSLog(@"Rotate Anticlockwise");
}
else if( (swipeBackward.y > 151) && (swipeForward.y > 151) )
{
if (dx > 0 )
{
NSLog(@"Rotate Clockwise");
}
else
{
NSLog(@"Rotate Anticlockwise");
}
}
else
{
if (dx > 0 )
{
NSLog(@"Rotate Anticlockwise");
}
else
{
NSLog(@"Rotate Clockwise");
}
}
}