ios - 在 UIView 中的贝塞尔路径内绘制/绘制草图颜色
<p><p>我正在 UIView 上的 UIBezier 路径的帮助下绘制形状层:</p>
<pre><code> CAShapeLayer *pathLayer = ;
pathLayer.frame=CGRectMake(-view.frame.origin.x, -view.frame.origin.y, view.frame.size.width, view.frame.size.height);
pathLayer.path = path.CGPath;
pathLayer.strokeColor = [ CGColor];
pathLayer.fillColor = [ CGColor];
//pathLayer.fillColor = nil;
pathLayer.lineWidth = 6.0;
pathLayer.lineJoin = kCALineJoinBevel;
;
</code></pre>
<p>在我想在那个 UIView 上绘制的接触点上，我正在这样做:</p>
<pre><code>-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch=;
CGPoint touchBeganPoint;
touchBeganPoint=;
actionString=@"drawPencil";
previousPoint1 = ;
previousPoint2 = ;
currentPoint = ;
;
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = ;
previousPoint2= previousPoint1;
previousPoint1= currentPoint;
currentPoint = ;
;
}
CGPoint midPoint(CGPoint p1, CGPoint p2) //helper function
{
return CGPointMake((p1.x + p2.x) * 0.5, (p1.y + p2.y) * 0.5);
}
- (void)calculateMinImageArea:(CGPoint)pp1 :(CGPoint)pp2 :(CGPoint)cp
{
// calculate mid point
CGPoint mid1 = midPoint(pp1, pp2);
CGPoint mid2 = midPoint(cp, pp1);
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, mid1.x, mid1.y);
CGPathAddQuadCurveToPoint(path, NULL, pp1.x, pp1.y, mid2.x, mid2.y);
CGRect bounds = CGPathGetBoundingBox(path);
CGPathRelease(path);
CGRect drawBox = bounds;
//Pad our values so the bounding box respects our line width
drawBox.origin.x -= 20 * 1.5;
drawBox.origin.y -= 20 * 1.5;
drawBox.size.width += 20 * 2.5;
drawBox.size.height += 20 * 2.5;
UIGraphicsBeginImageContextWithOptions(drawBox.size, NO, 0);
;
curImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// generate the if conditionover here and than check and draw over paths
;
[ runMode:NSRunLoopCommonModes beforeDate: ];
}
-(void)drawRect:(CGRect)rect
{
CGPoint mid1 = midPoint(previousPoint1, previousPoint2);
CGPoint mid2 = midPoint(currentPoint, previousPoint1);
;
CGContextRef context = UIGraphicsGetCurrentContext();
CALayer *layer=;
;
CGContextMoveToPoint(context, mid1.x, mid1.y);
CGContextAddQuadCurveToPoint(context, previousPoint1.x, previousPoint1.y, mid2.x, mid2.y);
CGContextSetLineCap(context, kCGLineCapRound);
CGContextSetBlendMode(context, kCGBlendModeNormal);
CGContextSetLineJoin(context, kCGLineJoinRound);
CGContextSetLineWidth(context, 20);
CGContextSetStrokeColorWithColor(context,.CGColor);
CGContextSetShouldAntialias(context, YES);
CGContextSetAllowsAntialiasing(context, YES);
CGContextSetFlatness(context, 1.f);
CGContextSetAlpha(context,1.0);
CGContextStrokePath(context);
;
}
</code></pre>
<p>现在当我在 self.layer 上绘图时，它仍然会影响添加的子层(形状层)。我只想在这条路径内绘制，不能使用 ，如绘制矩形，我正在绘制的图像有一定的宽度，有时会穿过路径或干扰其笔画。</p>
<p>实现此目的的一种方法是使用其子层(CAShapelayer)剪辑 UIView，然后在 uiview 上再次绘制它(这将清除形状图层区域之外的背景)。但是找不到如何使用 CAShapeLayer 剪辑它。 </p>
<p>任何关于如何顺利实现这一目标的建议或见解都可能会有很大帮助。
谢谢!</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>拍摄另一张图像，该图像是具有所需路径的 View 快照，并填充了选定的颜色。
比触摸移动称为 drawrect 具有相同的代码，除了 作为上下文的颜色有一点异常(exception)。
<a href="https://stackoverflow.com/questions/30709045/drawing-in-uiview-with-drawrect-on-touch-points-gives-blurr-drawing-effect-on-bo" rel="noreferrer noopener nofollow">Drawing in UIView on touch points gives blurr drawing effect on boundaries</a> </p></p>
<p style="font-size: 20px;">关于ios - 在 UIView 中的贝塞尔路径内绘制/绘制草图颜色，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/30658974/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/30658974/
</a>
</p>
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