画笔程序代码

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

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

    if ([touch tapCount] == 2) {  
        drawImage.image = nil;  
        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.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)];  
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);  
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 20.0);  
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0.0, 0.0, 1.0, 1.0);  
    CGContextBeginPath(UIGraphicsGetCurrentContext());  
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);  
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);  
    CGContextStrokePath(UIGraphicsGetCurrentContext());  
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext();  
    UIGraphicsEndImageContext();  

    lastPoint = currentPoint;  

    mouseMoved++;  

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

}  

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

    UITouch *touch = [touches anyObject];  

    if ([touch tapCount] == 2) {  
        drawImage.image = nil;  
        return;  
    }  


    if(!mouseSwiped) {  
        UIGraphicsBeginImageContext(self.view.frame.size);  
        [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];  
        CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);  
        CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 20.0);  
        CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0.0, 0.0, 1.0, 1.0);  
        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);  
        CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);  
        CGContextStrokePath(UIGraphicsGetCurrentContext());  
        CGContextFlush(UIGraphicsGetCurrentContext());  
        drawImage.image = UIGraphicsGetImageFromCurrentImageContext();  
        UIGraphicsEndImageContext();  
    }  
}