Question

我看到了许多如何使用iPhone SDK绘制圆角矩形的示例。我真正需要的是修剪过的角落矩形，其外观如下：

alt text

谢谢，约什

Answer 1

（这是根据Jonathan Grynspan的建议编辑的，只需使用辅助函数来创建路径。现在它也允许修剪角的高度与宽度不同。）

这是一个帮助C函数来创建这样的路径：

// Note: caller is responsible for releasing the returned path
CGPathRef createAngledCornerRectPath(CGRect rect,
                                     CGSize cornerSize,
                                     CGFloat strokeWidth)
{
    CGMutablePathRef p = CGPathCreateMutable();

    // Make points for the corners
    CGFloat inset = strokeWidth/2; // because the stroke is centered on the path.
    CGPoint tlc = CGPointMake(CGRectGetMinX(rect) + inset,
                              CGRectGetMinY(rect) + inset);
    CGPoint trc = CGPointMake(CGRectGetMaxX(rect) - inset,
                              CGRectGetMinY(rect) + inset);
    CGPoint blc = CGPointMake(CGRectGetMinX(rect) + inset,
                              CGRectGetMaxY(rect) - inset);
    CGPoint brc = CGPointMake(CGRectGetMaxX(rect) - inset,
                              CGRectGetMaxY(rect) - inset);

    // Start in top left and move around counter-clockwise.
    CGPathMoveToPoint(p, NULL, tlc.x, tlc.y+cornerSize.height);
    CGPathAddLineToPoint(p, NULL, blc.x, blc.y-cornerSize.height);
    CGPathAddLineToPoint(p, NULL, blc.x+cornerSize.width, blc.y);
    CGPathAddLineToPoint(p, NULL, brc.x-cornerSize.width, brc.y);
    CGPathAddLineToPoint(p, NULL, brc.x, brc.y-cornerSize.height);
    CGPathAddLineToPoint(p, NULL, trc.x, trc.y+cornerSize.height);
    CGPathAddLineToPoint(p, NULL, trc.x-cornerSize.width, trc.y);
    CGPathAddLineToPoint(p, NULL, tlc.x+cornerSize.width, trc.y);
    CGPathCloseSubpath(p);

    return p;
}

以下是您在自定义视图中使用它的方法-drawRect：method：

- (void)drawRect:(CGRect)rect
{
    // Define a few parameters
    CGSize cornerSize = CGSizeMake(30.f, 30.f);
    CGFloat strokeWidth = 3.f;
    CGColorRef strokeColor = [UIColor redColor].CGColor;

    CGContextRef c = UIGraphicsGetCurrentContext();
    CGContextSetStrokeColorWithColor(c, strokeColor);
    CGContextSetLineWidth(c, strokeWidth);

    // Create the path, add it to the context, and stroke it.
    CGPathRef path = createAngledCornerRectPath(rect,
                                                cornerSize,
                                                strokeWidth);
    CGContextAddPath(c, path);
    CGContextStrokePath(c);

    // we are responsible for releasing the path
    CGPathRelease(path);
}

Answer 2

我只使用8个线段（起始路径，添加到路径的行，结束路径，笔划路径）。您只需要在每个x或y角坐标中添加或减去一些常量，即可得到所有8个点。您可以使用与CGStrokeRect相同的api编写一个简单函数来封装上述所有内容。

如何在iPhone上绘制带有剪裁而非圆角的矩形？

2 个答案: