CGContextRef类画图形、文字、图片

- (void)drawRect:(CGRect)rect {

// Drawing code

//获取上下文(画笔)

CGContextRefcontext =UIGraphicsGetCurrentContext();

//设置线条宽度

CGContextSetLineWidth(context,5);

//设置线条的颜色

CGContextSetStrokeColorWithColor(context, [UIColorredColor].CGColor);

//1.画线

//[self addLine:context];

//2.一次画多条线

//[self addLines:context];

//3.画空心圆

//[self drawEllipse:context];

//4.画实心圆

//[self drawEllipse2:context];

//5.画矩形

//[self drawRect2:context];

//6.画文字

[selfdrawText:context];

//7.画图片

//[self drawImage];

}

1.画线

- (void)addLine:(CGContextRef)context

{

//从哪个点开始

CGContextMoveToPoint(context,100,100);

//添加另外一个点,连线

CGContextAddLineToPoint(context,50,200);

//添加一个线

CGContextAddLineToPoint(context,150,200);

CGContextAddLineToPoint(context,100,135);

//闭合

CGContextClosePath(context);

//绘画

CGContextStrokePath(context);

}

2.一次画多条线段

- (void)addLines:(CGContextRef)context

{

//从哪个点开始

CGContextMoveToPoint(context,100,100);

CGPointpoints[4] = {CGPointMake(130,100),CGPointMake(200,150),CGPointMake(200,200),CGPointMake(130,120)};

//画多条线

CGContextAddLines(context, points,sizeof(points)/sizeof(points[0]));

//闭合

CGContextClosePath(context);

//画线

CGContextStrokePath(context);

}

3.画空心圆

- (void)drawEllipse:(CGContextRef)context

{

//保存上下文

CGContextSaveGState(context);

//画椭圆

CGContextAddEllipseInRect(context,CGRectMake(10,10,self.bounds.size.width-20,self.bounds.size.height-20));

CGContextStrokePath(context);

//重新设置线条宽度

CGContextSetLineWidth(context,10);

//重新设置线条的颜色

CGContextSetStrokeColorWithColor(context, [UIColorgreenColor].CGColor);

//画椭圆

CGContextAddEllipseInRect(context,CGRectMake(20,20,self.bounds.size.width-40,self.bounds.size.height-40));

CGContextStrokePath(context);

//画椭圆

//恢复到上次保存的画布的状态

CGContextRestoreGState(context);

//画椭圆

CGContextAddEllipseInRect(context,CGRectMake(50,50,self.bounds.size.width-50,self.bounds.size.height-50));

CGContextStrokePath(context);

}

4.画实心圆

- (void)drawEllipse2:(CGContextRef)context

{

//设置填充的颜色

CGContextSetFillColorWithColor(context, [UIColororangeColor].CGColor);

//画填充的圆

CGContextFillEllipseInRect(context,CGRectMake(10,10,self.frame.size.width-20,self.frame.size.height-20));

}

5.画矩形

- (void)drawRect2:(CGContextRef)context

{

//画矩形

CGContextAddRect(context,CGRectMake(10,10,100,100));

//开始画

CGContextStrokePath(context);

//设置填充的颜色

CGContextSetFillColorWithColor(context, [UIColoryellowColor].CGColor);

//填充区域

CGContextFillRect(context,CGRectMake(200,200,90,30));

}

6.画文字

- (void)drawText:(CGContextRef)context

{

//文字属性

//NSDictionary *attributes = @{NSForegroundColorAttributeName:[]};

//

////画文字

[@"Hello ,xiaoming"drawAtPoint:CGPointMake(20,40)withAttributes:nil];

//设置文字居中显示

NSMutableParagraphStyle*style = [[NSMutableParagraphStylealloc]init];

style.alignment=NSTextAlignmentCenter;

[@"test "drawInRect:CGRectMake(100,100,90,50)withAttributes:@{NSFontAttributeName:[UIFontsystemFontOfSize:20],NSParagraphStyleAttributeName:style,NSForegroundColorAttributeName:[UIColoryellowColor]}];

}

7.画图片- (void)drawImage

{

//

[[UIImageimageNamed:@"2_27083_5beb4e628dd4d27"]drawAtPoint:CGPointMake(0,0)];

//[[UIImage imageNamed:@""] drawInRect:

}