快速上手IOS UIBezierPath（贝塞尔曲线）

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];

结语

关于uibezierpath的简单介绍就到这了,主要是用代码做了展示,属性跟方法,没详细去介绍,我觉得可以直接看苹果的api写的也蛮清楚的.或者自己试试不同的参数样式也能大概理解了.

核心动画跟贝赛尔曲线都有了简单的介绍了,接下来就可以动手做点简单的自定义动画了.

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持！