Matt Gemmell的NSBezierPath + StrokeExtensions在剪辑矩形之外绘制

Question

我正在使用Matt Gemmell的NSBezierPath + StrokeExtensions类别在NSRect上绘制一个内部描边。这里是整个类别代码：

- (void)strokeInside 
{ 
    /* Stroke within path using no additional clipping rectangle. */ 
    [self strokeInsideWithinRect:NSZeroRect]; 
} 

- (void)strokeInsideWithinRect:(NSRect)clipRect 
{ 
    NSGraphicsContext *thisContext = [NSGraphicsContext currentContext]; 
    float lineWidth = [self lineWidth]; 

    /* Save the current graphics context. */ 
    [thisContext saveGraphicsState]; 

    /* Double the stroke width, since -stroke centers strokes on paths. */ 
    [self setLineWidth:(lineWidth * 2.0)]; 

    /* Clip drawing to this path; draw nothing outwith the path. */ 
    [self setClip]; 

    /* Further clip drawing to clipRect, usually the view's frame. */ 
    if (clipRect.size.width > 0.0 && clipRect.size.height > 0.0) { 
     [NSBezierPath clipRect:clipRect]; 
    } 

    /* Stroke the path. */ 
    [self stroke]; 

    /* Restore the previous graphics context. */ 
    [thisContext restoreGraphicsState]; 
    [self setLineWidth:lineWidth]; 
} 

这里是我的drawRect:方法：

- (void)drawRect:(NSRect)dirtyRect { 
    NSRect myRect = NSMakeRect(500, 0, 400, 100); 
    [[NSColor colorWithCalibratedRed:0 green:0 blue:1.0 alpha:0.5] set]; 
    NSRectFillUsingOperation(myRect, NSCompositeSourceOver); 

    [[NSColor blueColor] set]; 
    [[NSBezierPath bezierPathWithRect:myRect] strokeInside]; 
} 

然而，出现这种情况时，我向上滚动：

，你可以看，里面的笔画绘制到工具栏上。为什么会发生？我如何解决strokeInside方法？请注意，这不会发生在常规的stroke方法中。

Answer 1

好吧，我想通了。取而代之的这条线：

[self setClip];

使用此：

[self addClip];

工作正常，是有道理的。