快速上手IOS UIBezierPath（贝塞尔曲线）

2020-07-26 02:53:30

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UIBezierPath主要用来绘制矢量图形，它是基于Core Graphics对CGPathRef数据类型和path绘图属性的一个封装，所以是需要图形上下文的（CGContextRef），所以一般UIBezierPath在drawRect中使用。

使用方法

UIBezierPath 是对 CGPathRef 的封装。创建矢量图形时，拆解成一或多条线段，拼接起来，每条线段的终点都是下一条线段的起点。

具体地：

1.创建一个 UIBezierPath 对象

2.用 moveToPoint: 设置初始线段的起点

3.添加线段，定义一或多个子路径

4.修改 UIBezierPath 的绘图相关的属性，比如stroke path的属性 lineWidth 和 lineJoinStyle ，filled path的属性 usesEvenOddFillRule

注意:如果是矩形或者圆之类的特殊图形，可以不用第2步。

代码案例

画直线

UIBezierPath *path = [UIBezierPath bezierPath];[path moveToPoint:CGPointMake(50, 50)];[path addLineToPoint:CGPointMake(100, 50)];path.lineWidth = 5.0f;path.lineJoinStyle = kCGLineJoinRound;[path stroke];

创建三角形

UIBezierPath *path = [UIBezierPath bezierPath];[path moveToPoint:CGPointMake(50, 50)];[path addLineToPoint:CGPointMake(300, 50)];[path addLineToPoint:CGPointMake(200, 150)];// 最后的闭合线是可以通过调用closePath方法来自动生成的，也可以调用-addLineToPoint:方法来添加// [path addLineToPoint:CGPointMake(50, 50)];[path closePath];path.lineWidth = 5.0f;[path stroke];

创建矩形

UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(50, 100, 50, 50)];path.lineWidth = 5.0f;[path stroke];

创建内切曲线

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 200, 50, 50)];path.lineWidth = 5.0f;[path stroke];

 UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 200, 50, 100)]; path.lineWidth = 5.0f; [path stroke];

创建带有圆角的矩形，当矩形变成正圆的时候，Radius就不再起作用

UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(50, 300, 50, 50) cornerRadius:15.0f];path.lineWidth = 5.0f;[path stroke];

设定特定的角为圆角的矩形

UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(50, 400, 50, 50) byRoundingCorners:UIRectCornerBottomLeft cornerRadii:CGSizeMake(5,5)];path.lineWidth = 5.0f;[path stroke];

创建圆弧

UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(100, 550) radius:25 startAngle:0 endAngle:1.5*M_PI clockwise:YES];path.lineWidth = 5.0f;[path stroke];

通过路径A创建路径B

UIBezierPath *path_A = [UIBezierPath bezierPath];[path_A moveToPoint:CGPointMake(200, 50)];[path_A addLineToPoint:CGPointMake(250, 100)];path_A.lineWidth = 5.0f;UIBezierPath *path_B = [UIBezierPath bezierPathWithCGPath:path_A.CGPath];[path_B stroke];

创建三次贝塞尔曲线

UIBezierPath *path = [UIBezierPath bezierPath];[path moveToPoint:CGPointMake(100, 200)];[path addCurveToPoint:CGPointMake(300, 200) controlPoint1:CGPointMake(150, 150) controlPoint2:CGPointMake(250, 250)];[path stroke];

创建二次贝塞尔曲线

UIBezierPath *path = [UIBezierPath bezierPath];[path moveToPoint:CGPointMake(100, 200)];[path addQuadCurveToPoint:CGPointMake(300, 200) controlPoint:CGPointMake(150, 150)];[path stroke];

添加圆弧

 UIBezierPath *path = [UIBezierPath bezierPath]; [path moveToPoint:CGPointMake(200, 400)]; [path addLineToPoint:CGPointMake(225, 410)]; [path addArcWithCenter:CGPointMake(200, 400) radius:25 startAngle:0 endAngle:1.5*M_PI clockwise:YES];// [path closePath];// [path removeAllPoints]; [path stroke];

追加路径

UIBezierPath *path_A = [UIBezierPath bezierPath];[path_A moveToPoint:CGPointMake(200, 500)];[path_A addLineToPoint:CGPointMake(225, 410)];UIBezierPath *path_B = [UIBezierPath bezierPath];[path_B moveToPoint:CGPointMake(200, 600)];[path_B addLineToPoint:CGPointMake(225, 500)];[path_A appendPath:path_B];[path_A stroke];

创建翻转路径，即起点变成终点，终点变成起点

 UIBezierPath *path = [UIBezierPath bezierPath]; [path moveToPoint:CGPointMake(50, 50)]; [path addLineToPoint:CGPointMake(100, 50)]; path.lineWidth = 5.0f; NSLog(@"%@",NSStringFromCGPoint(path.currentPoint)); UIBezierPath *path_b = [path bezierPathByReversingPath]; CGAffineTransform transform = CGAffineTransformMakeTranslation(200, 0); [path_b applyTransform: transform]; // 两条路径分别添加一条直接到 self.center [path addLineToPoint: CGPointMake(self.frame.size.width*0.5, self.frame.size.height*0.5)]; [path_b addLineToPoint: CGPointMake(self.frame.size.width*0.5, self.frame.size.height*0.5)]; NSLog(@"%@",NSStringFromCGPoint(path_b.currentPoint)); [[UIColor redColor] set]; [path stroke]; [[UIColor blueColor] set]; [path_b stroke];

路径进行仿射变换

 UIBezierPath *path = [UIBezierPath bezierPath]; [path moveToPoint:CGPointMake(100, 50)]; [path addLineToPoint:CGPointMake(200, 50)]; CGAffineTransform transform = CGAffineTransformRotate(self.transform, M_PI_4); [path applyTransform:transform]; path.lineWidth = 5.0f; [path stroke];

创建虚线

CGFloat dashStyle[] = {1.0f, 2.0f};UIBezierPath *path = [UIBezierPath bezierPath];[path moveToPoint:CGPointMake(50, 50)];[path addLineToPoint:CGPointMake(100, 50)];[path setLineDash:dashStyle count:2 phase:0.0];[path stroke];

设置颜色

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(100, 100, 100, 100)];[[UIColor greenColor] setStroke];[[UIColor redColor] setFill];[path stroke];[path fill];

设置描边混合模式

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(100, 100, 100, 100)];[[UIColor greenColor] setStroke];path.lineWidth = 10.0f;[path strokeWithBlendMode:kCGBlendModeSaturation alpha:1.0];[path stroke];

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(100, 100, 100, 100)]; [[UIColor redColor] setFill]; [path fillWithBlendMode:kCGBlendModeSaturation alpha:0.6]; [path fill];

修改当前图形上下文的绘图区域可见,随后的绘图操作导致呈现内容只有发生在指定路径的填充区域

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(100, 100, 100, 100)];[[UIColor greenColor] setStroke];[path addClip];[path stroke];