摘要 : CGContextRef 功能强大，我们借助它可以画各种图形。这里所举例子只是简单内容绘制，冰山一角，对此感兴趣的朋友可以举一反三，实现各种酷炫效果。
效果如下：
KMDrawView.h
#import <UIKit/UIKit.h> @interface KMDrawView : UIView @end
KMDrawView.m
#import "KMDrawView.h" @interface KMDrawView ()
- (void)drawFont;
- (void)drawLine;
- (void)drawCircle;
- (void)drawRectangle; @end @implementation KMDrawView - (instancetype)initWithFrame:(CGRect)frame{
if (self=[super initWithFrame:frame]) {
self.backgroundColor = [UIColor colorWithWhite:0.7 alpha:1.0];
}
return self;
} - (void)drawRect:(CGRect)rect {
[self drawFont];
[self drawLine];
[self drawCircle];
[self drawRectangle]; [super drawRect:rect];
} #pragma mark - 绘制『文字』、『线条』、『圆形』、『矩形』
- (void)drawFont {
NSDictionary *dicAttribute = @{
NSForegroundColorAttributeName : [UIColor brownColor],
NSFontAttributeName : [UIFont systemFontOfSize:18.0]
}; [@"我是文字" drawInRect:CGRectMake(20.0, 20.0, 100.0, 30.0) withAttributes:dicAttribute];
} - (void)drawLine {
CGContextRef contextRef = UIGraphicsGetCurrentContext(); //获取绘制上下文对象实例
CGContextSetRGBStrokeColor(contextRef, 0.5, 0.5, 0.5, 1.0); //设置笔画颜色
CGContextSetLineWidth(contextRef, 2.0); //设置线条粗细大小 CGContextMoveToPoint(contextRef, 20.0, 100.0); //设置直线的首端
CGContextAddLineToPoint(contextRef, 320.0, 100.0); //设置直线的末端
CGContextStrokePath(contextRef); //沿着要求的路径，开始绘制
} - (void)drawCircle {
CGContextRef contextRef = UIGraphicsGetCurrentContext(); //获取绘制上下文对象实例
CGContextSetRGBStrokeColor(contextRef, 1.0, 1.0, 1.0, 1.0); //设置笔画颜色
CGContextSetLineWidth(contextRef, 2.0); //设置线条粗细大小 //voidCGContextAddArc(CGContextRef c,CGFloat x,CGFloat y,CGFloat radius,CGFloat startAngle,CGFloat endAngle,int clockwise)
//1弧度＝180°/π（≈57.3°）度
//360°＝360 * π/180＝2π弧度
//x,y为圆点坐标，radius半径，startAngle为开始的弧度，endAngle为结束的弧度，clockwise0为顺时针，1为逆时针。
CGContextAddArc(contextRef, 70.0, 200.0, 50.0, , *M_PI, ); //添加一个圆；M_PI为180度
CGContextDrawPath(contextRef, kCGPathStroke); //绘制路径
} - (void)drawRectangle {
CGContextRef contextRef = UIGraphicsGetCurrentContext(); //获取绘制上下文对象实例
CGContextSetRGBStrokeColor(contextRef, 0.0, 0.0, 0.0, 1.0); //设置笔画颜色
CGContextSetLineWidth(contextRef, 2.0); //设置线条粗细大小 CGContextAddRect(contextRef, CGRectMake(20.0, 300.0, 200.0, 100.0)); //设置矩形位置和宽高
CGContextStrokePath(contextRef); //沿着要求的路径，开始绘制
} @end
ViewController.h
#import <UIKit/UIKit.h> @interface ViewController : UIViewController @end
ViewController.m
#import "ViewController.h"
#import "KMDrawView.h" @interface ViewController ()
- (void)layoutUI;
@end @implementation ViewController - (void)viewDidLoad {
[super viewDidLoad]; [self layoutUI];
} - (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
} - (void)layoutUI {
KMDrawView *drawView = [[KMDrawView alloc] initWithFrame:self.view.frame];
[self.view addSubview:drawView];
} @end