- (void)drawRect:(CGRect)rect{    //获取图像上下文对象    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextSetRGBStrokeColor(context, 250/255.0, 250/255.0, 250/255.0, 1);    CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);    CGContextSetShadowWithColor(context, CGSizeMake(1, 1), 3, [UIColor yellowColor].CGColor);    CGContextSetLineWidth(context, 2);        //添加直线（方式1）    //1，2点组成第一条线段，2，3点组成第二条线段，3，4点组成第3条线段，以此类推    CGPoint points[] = {CGPointMake(50, 15),CGPointMake(150, 15),CGPointMake(50, 25),CGPointMake(100, 25),CGPointMake(200, 25)};    CGContextAddLines(context, points, 5);    CGContextDrawPath(context, kCGPathStroke);            //添加直线（方式2）    CGContextMoveToPoint(context, 0, 40);    CGContextAddLineToPoint(context, 100, 40);    CGContextAddLineToPoint(context, 100, 50);    //闭合路径，连接终点和起点    CGContextClosePath(context);    CGContextDrawPath(context, kCGPathStroke);            //添加矩形    CGContextAddRect(context, CGRectMake(150, 50, 100, 30));    CGContextDrawPath(context, kCGPathFill);            //添加椭圆    CGContextAddEllipseInRect(context, CGRectMake(0, 50, 100, 30));    CGContextDrawPath(context, kCGPathStroke);            //添加弧    //最后一个参数代表方向，0表示顺时针，1表示逆时针    CGContextAddArc(context, 100, 150, 30, -90*M_PI/180, 90*M_PI/180, 1);    CGContextDrawPath(context, kCGPathStroke);        //添加二次函数曲线    CGContextMoveToPoint(context, 300, 200);    CGContextAddQuadCurveToPoint(context, 160, 300, 320, 300);    CGContextDrawPath(context, kCGPathStroke);        //添加贝塞尔曲线    CGContextMoveToPoint(context, 10, 200);    CGContextAddCurveToPoint(context, 160, 230, 0, 300, 50, 400);    CGContextDrawPath(context, kCGPathStroke);        }

//绘制圆角矩形//rect表示矩形区域，radius表示圆角半径void drawRoundrect(CGContextRef context,CGRect rect,CGFloat radius) {    CGPoint origin = rect.origin;    CGSize size = rect.size;    CGContextMoveToPoint(context, origin.x + radius, origin.y);    //添加上边    CGContextAddLineToPoint(context, origin.x + size.width - radius, origin.y);    //添加右上角弧    CGContextAddArcToPoint(context, origin.x + size.width, origin.y, origin.x + size.width, origin.y + radius, radius);    //添加右边    CGContextAddLineToPoint(context, origin.x + size.width, origin.y + size.height - radius);    //添加右下角弧    CGContextAddArcToPoint(context, origin.x + size.width, origin.y + size.height, origin.x + size.width - radius, origin.y + size.height, radius);    //添加底边    CGContextAddLineToPoint(context, origin.x + radius, origin.y + size.height);    //添加左下角弧    CGContextAddArcToPoint(context, origin.x, origin.y + size.height, origin.x, origin.y + size.height - radius, radius);    //添加左边    CGContextAddLineToPoint(context, origin.x, origin.y + radius);    //添加左上角弧    CGContextAddArcToPoint(context, origin.x, origin.y, origin.x + radius, origin.y, radius);    }- (void)drawRect:(CGRect)rect{    //获取图像上下文对象    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextSetRGBStrokeColor(context, 1,1,1, 0.7);    CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);    CGContextSetLineWidth(context, 2);        drawRoundrect(context,CGRectMake(20, 20, 200, 150), 20);    CGContextDrawPath(context, kCGPathStroke);}

//绘制多角形//centerPoint代表中心点，size代表边的长度，count代表角的个数void drawMulAngle(CGContextRef context,CGPoint centerPoint,CGFloat size,int count) {    CGFloat dig = 4 * M_PI / count;        CGContextMoveToPoint(context, centerPoint.x, centerPoint.y + size);    for (int i = 1; i <= count; i++) {        CGFloat x = sin(i*dig) * size + centerPoint.x;        CGFloat y = cos(i*dig) * size + centerPoint.y;                CGContextAddLineToPoint(context, x, y);    }}- (void)drawRect:(CGRect)rect{    //获取图像上下文对象    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextSetRGBStrokeColor(context, 1,1,1, 0.7);    CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);    CGContextSetLineWidth(context, 2);    CGContextBeginPath(context);    drawMulAngle(context,CGPointMake(160, 200), 50,5);    CGContextClosePath(context);    CGContextDrawPath(context, kCGPathFillStroke);}