本文介绍了在绘制ios7时滞后的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在使用一个应用程序，我正在对视图进行一些草图绘制。
I am having an app in which I am doing some sketching on a view.
到目前为止，它工作正常，直到我安装 ios7 。
So far, it was working fine until I installed ios7.
我的应用程序使用触摸移动方法识别运动的变化。但是当我绘制一条线时，触摸方法会被调用但是直到我触摸 ios7 结束时才会更新。
My app uses touches moved method for recognizing the change of a movement. But when I draw a line, touches method gets called but line doesn't get updated until I touch ends in ios7.
所以绘画有一点滞后。
So there is a slight lag in drawing.
它适用于 ios6 和 ios7 模拟器但是当我在真正的 ios7 设备上进行测试时，绘图算法存在滞后现象。
It works fine on ios6 and on ios7 simulator but when i test it on a real ios7 device, there is a lag in drawing algorithm.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (!isImageSelection) {
mouseSwiped = NO;
UITouch *touch = [touches anyObject];
if ( [touch view] != baseview) {
lastPoint2 = [touch locationInView:self.viewDrawing2];
}
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if (!isImageSelection) {
// NSLog(@"in image selection==%d touch moved ",isImageSelection );
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
// if (([touch view] != btnInkColor) || ([touch view] != btnPenSize) || ([touch view] != baseview)) {
if ( [touch view] != baseview) {
CGPoint currentPoint = [touch locationInView:self.viewDrawing];
if(isEraser) {
// [[NSUserDefaults standardUserDefaults] floatForKey:@"strokeValue"];
UIGraphicsBeginImageContext(self.viewDrawing.frame.size);
[imgDrawing.image drawInRect:CGRectMake(0, 0, self.viewDrawing.frame.size.width, self.viewDrawing.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), stroke);
//uncommented by prerak
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeClear);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
imgDrawing.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
} else {
float strokeT= [[NSUserDefaults standardUserDefaults] floatForKey:@"strokeValue"];
// NSLog(@"strokeT=%f",strokeT);
UIGraphicsBeginImageContext(self.viewDrawing.frame.size);
[imgDrawing.image drawInRect:CGRectMake(0, 0, self.viewDrawing.frame.size.width, self.viewDrawing.frame.size.height)];
// NSLog(@"STROKE %f",stroke);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), strokeT);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
float redT=[[NSUserDefaults standardUserDefaults] floatForKey:@"redvalue"];
float greenT= [[NSUserDefaults standardUserDefaults] floatForKey:@"greenvalue"];
float blueT= [[NSUserDefaults standardUserDefaults] floatForKey:@"bluevalue"];
// NSLog(@"red=%f",redT);
// NSLog(@"green=%f",greenT);
// NSLog(@"blue=%f",blueT);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), redT, greenT, blueT, 1.0);
CGContextSetRGBFillColor(UIGraphicsGetCurrentContext(), redT, greenT, blueT, 1.0);
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineJoin(UIGraphicsGetCurrentContext(), kCGLineJoinRound);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
imgDrawing.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
lastPoint = currentPoint;
}
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
//if (([touch view] != btnInkColor) || ([touch view] != btnPenSize) || ([touch view] != baseview)) {
if ( [touch view] != baseview) {
if (!isImageSelection) {
if(!mouseSwiped) {
if (isEraser) {
UIGraphicsBeginImageContext(self.viewDrawing.frame.size);
[imgDrawing.image drawInRect:CGRectMake(0, 0, self.viewDrawing.frame.size.width, self.viewDrawing.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), stroke);
// CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeClear);
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFlush(UIGraphicsGetCurrentContext());
imgDrawing.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
} else {
UIGraphicsBeginImageContext(self.viewDrawing.frame.size);
[imgDrawing.image drawInRect:CGRectMake(0, 0, self.viewDrawing.frame.size.width, self.viewDrawing.frame.size.height)];
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), stroke);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextSetRGBFillColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineJoin(UIGraphicsGetCurrentContext(), kCGLineJoinRound);
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFlush(UIGraphicsGetCurrentContext());
imgDrawing.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
}
}
}
}
}
我该如何解决这个问题？
How can i solve this?
推荐答案
要找到即时解决方案，请替换此行
To find a instant solution, Replace this line
mainImage.image = UIGraphicsGetImageFromContext(UIGraphicsGetCurrentContext());
with
[mainImage performSelectorInBackground:@selector(setImage:) withObject:UIGraphicsGetImageFromCurrentImageContext()];
如果您需要精心准确的解决方案，请尝试使用CGMutablepath替换MoveTo。
希望这有帮助。
If you need an elaborate and accurate solution try to replace the MoveTo with CGMutablepath .Hope this helps.
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