iOS development using custom curves to draw complex graphics (Bezier curves) on UIView

Sometimes we need to draw a graph of irregular paths, which may contain lines or curves, and can be implemented using Uibezierpath.

The Uibezierpath class can represent any shape that can be defined with Bézier curves, and we can create our own custom curves. When you are done, you can use the resulting Uibezierpath object to fill and stroke like any other path.

1, the following demonstrates drawing an irregular graphic using Uibezierpath:

(1) The brush moves to the upper-left corner of the rectangular area

(2) Draw a straight line from the point of the pen's current position to the top right corner

(3) Draw a straight line from the point of the pen's current position to the lower-left corner

(4) Draw a curve from the pen's current position to the lower right corner, and the two control points of the curve bending degree are the midpoint of the rectangular region

(5) Draw a straight line from the point to the top left of the pen's current position, closing the path

2, the effect chart is as follows:

3, the code is as follows:

The code is as follows

Copy Code

Import Uikit Class Viewcontroller:uiviewcontroller { Override Func Viewdidload () { Super.viewdidload () Let Viewrect = CGRect (x:50, y:50, width:100, height:100) Let View1 = MyCanvas (frame:viewrect) Self.view.addSubview (View1) } Override Func didreceivememorywarning () { Super.didreceivememorywarning () } } Class Mycanvas:uiview { Override Init (Frame:cgrect) { Super.init (Frame:frame) Set the background color to transparent Self.backgroundcolor = Uicolor.clearcolor () } Required init? (Coder Adecoder:nscoder) { FatalError ("Init (coder:) has not been implemented") } Override func DrawRect (rect:cgrect) { Let Bezierpath = Uibezierpath () Creates a rectangle with all of its edges indented 5% Let Drawingrect = Cgrectinset (Self.bounds, Self.bounds.size.width * 0.05, Self.bounds.size.height * 0.05) Identify the points that make up the painting Let TopLeft = Cgpointmake (Cgrectgetminx (Drawingrect), Cgrectgetminy (Drawingrect)) Let TopRight = Cgpointmake (Cgrectgetmaxx (Drawingrect), Cgrectgetminy (Drawingrect)) Let BottomRight = Cgpointmake (Cgrectgetmaxx (Drawingrect), Cgrectgetmaxy (Drawingrect)) Let Bottomleft = Cgpointmake (Cgrectgetminx (Drawingrect), Cgrectgetmaxy (Drawingrect)) Let center = cgpointmake (Cgrectgetmidx (Drawingrect), Cgrectgetmidy (Drawingrect)) Start drawing Bezierpath.movetopoint (TopLeft) Bezierpath.addlinetopoint (TopRight) Bezierpath.addlinetopoint (Bottomleft) Bezierpath.addcurvetopoint (BottomRight, Controlpoint1:center, Controlpoint2:center) Closes the path and ends the drawing Bezierpath.closepath () Set colors, and draw them Uicolor.greencolor (). Setfill () Uicolor.blackcolor (). Setstroke () Bezierpath.fill () Bezierpath.stroke () } }