Question

I’m working on a touch draw app, everything is working fine in portrait, but when i rotate my iPad the line i draw when touching is 5 cm above my finger.

iv been googling a lot to try and find out how x & y changes when rotating.

can any of you help me ?

my code for drawing it this:

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

mouseSwiped = YES;

UITouch *touch = [touches anyObject];   
CGPoint currentPoint = [touch locationInView:self.view];
currentPoint.y -= -20;


UIGraphicsBeginImageContext(self.view.frame.size);

[drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
CGContextSaveGState(UIGraphicsGetCurrentContext());
CGContextSetShouldAntialias(UIGraphicsGetCurrentContext(), YES);
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), f5);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), f1, f2, f3, f4);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
CGContextRestoreGState(UIGraphicsGetCurrentContext());
UIGraphicsEndImageContext();

lastPoint = currentPoint;


mouseMoved++;

if (mouseMoved == 10) {
    mouseMoved = 0;}}

Answer 1

I was using bounds in my appDelegate and frame in my draw code …
i changed it to:

 UIGraphicsBeginImageContext(self.view.bounds.size);

[drawImage.image drawInRect:CGRectMake(0, 0, self.view.bounds.size.width,self.view.bounds.size.height)];