iphone – 如何创建一个允许用户自由手绘的应用程序？

解决方法@H_301_24@

使用以下我之前使用过的.它肯定会起作用： –

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

    mouseSwiped = NO;
    UITouch *touch = [touches anyObject];

    if ([touch tapCount] == 2) {
        [drawImage setImage:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForresource:@"white" ofType:@"png"]]];
        return;
    }

    lastPoint = [touch LOCATIOnInView:self.view];
    lastPoint.y -= 20;

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    mouseSwiped = YES;

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

    NSLog(@"current Point is x: %d,y: %d",currentPoint.x,currentPoint.y);

    UIGraphicsBeginImageContext(self.drawImage.frame.sizE);
    [drawImage.image drawInRect:CGRectMake(0,self.drawImage.frame.size.width,self.drawImage.frame.size.height)];
    CGContextSetLineCap(UIGraphicsGetCurrentContext(),kCGLineCapRound);
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(),5.0);
    CGContextSetRGBstrokeColor(UIGraphicsGetCurrentContext(),0.0,0.5,0.6,1.0);
    CGContextBeginPath(UIGraphicsGetCurrentContext());
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(),lastPoint.x,lastPoint.y);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(),currentPoint.y);
    CGContextstrokePath(UIGraphicsGetCurrentContext());
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    lastPoint = currentPoint;

}