我的 touchesMoved 上有这段代码,但与其他代码一样,它在 UIScrollView 上不起作用
在我的 touchesMoved 上:
touchSwiped = YES;
currentTouch = [touch locationInView:self.view];
currentTouch.y -= 5;
UIGraphicsBeginImageContext(self.view.frame.size);
[writeView.image drawInRect:CGRectMake(0, 0, 768, 1024)];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineCap(context, kCGLineCapRound);
CGContextSetLineWidth(context, 15);
CGContextSetRGBStrokeColor(context, 0, 0, 0, 1);
CGContextSetBlendMode(context, kCGBlendModeNormal);
CGContextMoveToPoint(context, endPoint.x, endPoint.y);
CGContextAddLineToPoint(context, currentTouch.x, currentTouch.y);
CGContextStrokePath(context);
writeView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
endPoint = currentTouch;
touchMoved++;
if (touchMoved == 10) {
touchMoved = 0;
}
因此,我使用手势识别器传输了它,但它仍然无法正常工作。
我使用了 PanGestureRecognizer
这里:
- (void) writePan:(UIPanGestureRecognizer *)writingRecognizerP {
switch (writingRecognizerP.state)
{
case UIGestureRecognizerStateChanged:
[scrollView setScrollEnabled:NO];
[scrollView setUserInteractionEnabled:NO];
touchSwiped = YES;
currentTouch = [writingRecognizerP locationInView:scrollView];
currentTouch.y -= 5;
UIGraphicsBeginImageContext(self.view.frame.size);
[writeView.image drawInRect:CGRectMake(0, 0, 768, 1024)];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineCap(context, kCGLineCapRound);
CGContextSetLineWidth(context, 15);
CGContextSetRGBStrokeColor(context, 0, 0, 0, 1);
CGContextSetBlendMode(context, kCGBlendModeNormal);
CGContextMoveToPoint(context, endPoint.x, endPoint.y);
CGContextAddLineToPoint(context, currentTouch.x, currentTouch.y);
CGContextStrokePath(context);
writeView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
endPoint = currentTouch;
touchMoved++;
if (touchMoved == 10) {
touchMoved = 0;
}
break;
case UIGestureRecognizerStateEnded:
[scrollView setScrollEnabled:YES];
[scrollView setUserInteractionEnabled:YES];
break;
}
}
有人知道我怎样才能用触摸写字吗??
我们将不胜感激! :)
最佳答案
您应该在 -drawRect:
中完成所有绘图,当某些内容发生变化时,请发送您的 View -setNeedsDisplay
或 setNeedsDisplay InRect:
消息。
关于objective-c - Objective-C : Draw(Write) on Touch in a UIScrollView,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8999027/