在NSBezierPath上剥离的笔划

我想绘制一个简单的图。我有用线连接的正方形。这些线条用NSBezierPath's绘制。我使用随机颜色的线条，所以我可以跟着他们。我的问题是线条改变颜色。在NSBezierPath上剥离的笔划

输出 -

enter image description here

代码 - 我删除画正方形的线，所以它只能绘制线：

- (void)drawRect:(NSRect)dirtyRect 
{ 
    // Drawing code here. 
    [[NSColor whiteColor] setFill]; 
    NSRectFill(dirtyRect); 

    CGFloat height = 70.0f; 
    CGFloat yOffset = 20.0f; 

    NSRect rect = NSMakeRect(50.0f, 50.0f, 200.0f, height); 

    NSEnumerator *reverseEnumerator = [steps reverseObjectEnumerator]; 

    NSMutableDictionary *rectsByStep = [NSMutableDictionary dictionaryWithCapacity:10]; 

    for(WFGJobStep *step in reverseEnumerator) 
    { 
     [[NSColor redColor] setFill]; 


     [rectsByStep setObject:[NSValue valueWithRect:rect] forKey:[NSNumber numberWithInteger:step.step]]; 

     rect.origin.y += height + yOffset; 

    } 

    reverseEnumerator = [steps reverseObjectEnumerator]; 
    for(WFGJobStep *step in reverseEnumerator) 
    { 
     NSRect stepRect = [[rectsByStep objectForKey:[NSNumber numberWithInteger:step.step]] rectValue]; 
     NSPoint startPoint = NSMakePoint(stepRect.origin.x + stepRect.size.width, stepRect.origin.y); 

     // draw lines 
     for(NSNumber *stepNumber in step.nextSteps) 
     { 

     // 
     // 
     // Line drawing code here 
     // 
     // 

      NSBezierPath * path = [NSBezierPath bezierPath]; 
      [path setLineWidth: 4]; 

      NSRect targetStepRect = [[rectsByStep objectForKey:stepNumber] rectValue]; 
      NSPoint endPoint = NSMakePoint(targetStepRect.origin.x + targetStepRect.size.width, targetStepRect.origin.y + targetStepRect.size.height); 

      [path moveToPoint:startPoint]; 

      CGFloat controlX = (startPoint.y - endPoint.y) * .2 + stepRect.origin.x + stepRect.size.width + 20; 

      [path curveToPoint:endPoint controlPoint1:NSMakePoint(controlX, startPoint.y) controlPoint2:NSMakePoint(controlX, endPoint.y)]; 

      NSRect square = NSMakeRect(endPoint.x, endPoint.y, 9, 9); 
      [path appendBezierPathWithOvalInRect: square]; 

      [[self randomColor] set]; 
      [path stroke]; 
     } 
    } 
} 

- (NSColor *)randomColor { 
    float c[4]; 

    c[0] = (arc4random()/RAND_MAX) * 1; 
    c[1] = (arc4random()/RAND_MAX) * 1; 
    c[2] = (arc4random()/RAND_MAX) * 1; 
    c[3] = 1.0f; 

    return [NSColor colorWithDeviceRed:c[0] green:c[1] blue:c[2] alpha:c[3]]; 
}

来源

2012-10-29 Brian

该死的 - 很确定在基本的WWDC可可图形会话中有类似的东西，但是无法追踪相关的会话..你是否将'NSView'标记为不透明？ – Jay

我试着重写方法isOpaque并返回YES。同样的结果。 – Brian

我的问题是，这是一个scoll视图这是我的第一个NSScrollView。我没有意识到，当视图滚动它重绘其子视图。问题在于我为我的笔画使用了随机颜色，因此当我滚动它时，会随机更改线条的颜色。

来源

2012-10-29 15:04:27 Brian

在NSBezierPath上剥离的笔划

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