1. // Only override drawRect: if you perform custom drawing.  
2. // An empty implementation adversely affects performance during animation.  
3. - (void)drawRect:(CGRect)rect  
4. {  
5.     UIColor *color = [UIColor redColor];  
6.     [color set]; //设置线条颜色  
7.       
8.     UIBezierPath* aPath = [UIBezierPath bezierPath];  
9.     aPath.lineWidth = 5.0;  
10.       
11.     aPath.lineCapStyle = kCGLineCapRound; //线条拐角  
12.     aPath.lineJoinStyle = kCGLineCapRound; //终点处理  
13.       
14.     // Set the starting point of the shape.  
15.     [aPath moveToPoint:CGPointMake(100.0, 0.0)];  
16.       
17.     // Draw the lines  
18.     [aPath addLineToPoint:CGPointMake(200.0, 40.0)];  
19.     [aPath addLineToPoint:CGPointMake(160, 140)];  
20.     [aPath addLineToPoint:CGPointMake(40.0, 140)];  
21.     [aPath addLineToPoint:CGPointMake(0.0, 40.0)];  
22.     [aPath closePath];//第五条线通过调用closePath方法得到的  
23.       
24.     [aPath stroke];//Draws line 根据坐标点连线  
25. }  

1. Creates and returns a new UIBezierPath object initialized with a rectangular path.  
2.   
3. + (UIBezierPath *)bezierPathWithRect:(CGRect)rect  

1. - (void)drawRect:(CGRect)rect  
2. {  
3.     UIColor *color = [UIColor redColor];  
4.     [color set]; //设置线条颜色  
5.       
6.     UIBezierPath* aPath = [UIBezierPath bezierPathWithRect:CGRectMake(20, 20, 100, 50)];  
7.       
8.     aPath.lineWidth = 5.0;  
9.     aPath.lineCapStyle = kCGLineCapRound; //线条拐角  
10.     aPath.lineJoinStyle = kCGLineCapRound; //终点处理  
11.       
12.     [aPath stroke];  
13. }  

1. Creates and returns a new UIBezierPath object initialized with an oval path inscribed in the specified rectangle  
2.   
3. + (UIBezierPath *)bezierPathWithOvalInRect:(CGRect)rect  

1. Creates and returns a new UIBezierPath object initialized with an arc of a circle.  
2.   
3. + (UIBezierPath *)bezierPathWithArcCenter:(CGPoint)center radius:(CGFloat)radius startAngle:(CGFloat)startAngle endAngle:(CGFloat)endAngle clockwise:(BOOL)clockwise  
4. Parameters  
5. center  
6. Specifies the center point of the circle (in the current coordinate system) used to define the arc.  
7. radius  
8. Specifies the radius of the circle used to define the arc.  
9. startAngle  
10. Specifies the starting angle of the arc (measured in radians).  
11. endAngle  
12. Specifies the end angle of the arc (measured in radians).  
13. clockwise  
14. The direction in which to draw the arc.  
15. Return Value  
16. A new path object with the specified arc.  

1. #define pi 3.14159265359  
2. #define   DEGREES_TO_RADIANS(degrees)  ((pi * degrees)/ 180)  

1. - (void)drawRect:(CGRect)rect  
2. {  
3.     UIColor *color = [UIColor redColor];  
4.     [color set]; //设置线条颜色  
5.       
6.     UIBezierPath* aPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150)  
7.                                                          radius:75  
8.                                                      startAngle:0  
9.                                                        endAngle:DEGREES_TO_RADIANS(135)  
10.                                                       clockwise:YES];  
11.       
12.     aPath.lineWidth = 5.0;  
13.     aPath.lineCapStyle = kCGLineCapRound; //线条拐角  
14.     aPath.lineJoinStyle = kCGLineCapRound; //终点处理  
15.       
16.     [aPath stroke];  
17. }  

1. Appends a quadratic Bézier curve to the receiver’s path.  
2.   
3. - (void)addQuadCurveToPoint:(CGPoint)endPoint controlPoint:(CGPoint)controlPoint  
4. Parameters  
5. endPoint  
6. The end point of the curve.  
7. controlPoint  
8. The control point of the curve.  

1. - (void)drawRect:(CGRect)rect  
2. {  
3.     UIColor *color = [UIColor redColor];  
4.     [color set]; //设置线条颜色  
5.       
6.     UIBezierPath* aPath = [UIBezierPath bezierPath];  
7.       
8.     aPath.lineWidth = 5.0;  
9.     aPath.lineCapStyle = kCGLineCapRound; //线条拐角  
10.     aPath.lineJoinStyle = kCGLineCapRound; //终点处理  
11.       
12.     [aPath moveToPoint:CGPointMake(20, 100)];  
13.       
14.     [aPath addQuadCurveToPoint:CGPointMake(120, 100) controlPoint:CGPointMake(70, 0)];  
15.       
16.     [aPath stroke];  
17. }  

1. Appends a cubic Bézier curve to the receiver’s path.  
2.   
3. - (void)addCurveToPoint:(CGPoint)endPoint controlPoint1:(CGPoint)controlPoint1 controlPoint2:(CGPoint)controlPoint2  
4. Parameters  
5. endPoint  
6. The end point of the curve.  
7. controlPoint1  
8. The first control point to use when computing the curve.  
9. controlPoint2  
10. The second control point to use when computing the curve.  

1. - (void)drawRect:(CGRect)rect  
2. {  
3.     UIColor *color = [UIColor redColor];  
4.     [color set]; //设置线条颜色  
5.       
6.     UIBezierPath* aPath = [UIBezierPath bezierPath];  
7.       
8.     aPath.lineWidth = 5.0;  
9.     aPath.lineCapStyle = kCGLineCapRound; //线条拐角  
10.     aPath.lineJoinStyle = kCGLineCapRound; //终点处理  
11.       
12.     [aPath moveToPoint:CGPointMake(20, 50)];  
13.       
14.     [aPath addCurveToPoint:CGPointMake(200, 50) controlPoint1:CGPointMake(110, 0) controlPoint2:CGPointMake(110, 100)];  
15.       
16.     [aPath stroke];  
17. }  

 Mixing Core Graphics and UIBezierPath calls

UIBezierPath*    aPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 300, 300)];

// Get the CGPathRef and create a mutable version.

CGPathRef cgPath = aPath.CGPath;

CGMutablePathRef  mutablePath = CGPathCreateMutableCopy(cgPath);

// Modify the path and assign it back to the UIBezierPath object

CGPathAddEllipseInRect(mutablePath, NULL, CGRectMake(50, 50, 200, 200));

aPath.CGPath = mutablePath;

// Release both the mutable copy of the path.

CGPathRelease(mutablePath);

  Drawing a path in a view

- (void)drawRect:(CGRect)rect

{

    // Create an oval shape to draw.

    UIBezierPath* aPath = [UIBezierPath bezierPathWithOvalInRect:

                                CGRectMake(0, 0, 200, 100)];

    // Set the render colors

    [[UIColor blackColor] setStroke];

    [[UIColor redColor] setFill];

    CGContextRef aRef = UIGraphicsGetCurrentContext();

    // If you have content to draw after the shape,

    // save the current state before changing the transform

    //CGContextSaveGState(aRef);

    // Adjust the view‘s origin temporarily. The oval is

    // now drawn relative to the new origin point.

    CGContextTranslateCTM(aRef, 50, 50);

    // Adjust the drawing options as needed.

    aPath.lineWidth = 5;

    // Fill the path before stroking it so that the fill

    // color does not obscure the stroked line.

    [aPath fill];

    [aPath stroke];

    // Restore the graphics state before drawing any other content.

    //CGContextRestoreGState(aRef);

}