很难理解NSBezierPath的curveToPoint:方法

Question

很难理解NSBezierPath的curveToPoint:方法

d11*_*wtq 7 macos cocoa objective-c quartz-graphics

我正试图在Cocoa中掌握绘制(相当基本的)形状.我理解如何创建具有直边的路径(呃!),但是当涉及到做曲线时,我无法理解哪些输入会产生什么形状的曲线.具体而言,我不知道该怎么controlPoint1:和controlPoint2:参数的方法影响的形状.

我正在尝试近似Google Chrome中标签的形状:

Google Chrome标签

我正在使用的代码是:

-(void)drawRect:(NSRect)dirtyRect {
    NSSize size = [self bounds].size;

    CGFloat height = size.height;
    CGFloat width = size.width;

    NSBezierPath *path = [NSBezierPath bezierPath];
    [path setLineWidth:1];

    [path moveToPoint:NSMakePoint(0, 0)];

    [path curveToPoint:NSMakePoint(width * 0.1, height)
         controlPoint1:NSMakePoint(width * 0.05, height)
         controlPoint2:NSMakePoint(width * 0.03, height * 0.05)];

    [path lineToPoint:NSMakePoint(width * 0.9, height)];

    [path curveToPoint:NSMakePoint(width, 0)
         controlPoint1:NSMakePoint(width * 0.95, height)
         controlPoint2:NSMakePoint(width * 0.97, height * 0.05)];

    [path closePath];

    [[NSColor colorWithCalibratedWhite:0.98 alpha:1] set];
    [path fill];

    [[NSColor colorWithCalibratedWhite:0.6 alpha:1] set];
    [path stroke];
}

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我失败的可怕.

看,这就是为什么我们不能有好东西:(

我的尝试