iOS绘制填充圆圈 [英] iOS draw filled Circles

问题描述

这里不是图形程序员，所以我试图绊倒这个。我正在尝试绘制9个实心圆圈，每个圆圈都有不同的颜色，每个圆圈都有一个白色边框。 UIView的框架是CGRectMake（0,0,60,60）。见附图。

Not a graphics programmer here, so I'm trying to stumble through this. I'm trying to draw 9 filled circles, each a different color, each with a white border. The UIView's frame is CGRectMake (0,0,60,60). See attached image.

问题是我在每边的边界上都有扁平斑点。以下是我的代码（来自UIView子类）：

The problem is I'm getting "flat spots" on the borders on each side. Following is my code (from the UIView subclass):

- (void)drawRect:(CGRect)rect
{
    CGRect borderRect = CGRectMake(0.0, 0.0, 60.0, 60.0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
    CGContextSetRGBFillColor(context, colorRed, colorGreen, colorBlue, 1.0);
    CGContextSetLineWidth(context, 2.0);
    CGContextFillEllipseInRect (context, borderRect);
    CGContextStrokeEllipseInRect(context, borderRect);
    CGContextFillPath(context);
}

如果我在drawRect中更改为CGRectMake（0,0,56,56） ，我只在顶部和左侧，底部和底部都有扁平斑点。右边看起来很好。

If I change to CGRectMake(0,0,56,56) in drawRect, I get flat spots only on the top and left sides, and the bottom & right sides look fine.

有谁能建议我如何解决这个问题？在我看来，UIView正在修剪边框，但对此并不了解，我真的不知道如何修复它。

Can anyone suggest how I might fix this? It seems to me the border is being clipped by the UIView, but not knowing much about this, I really don't know how to fix it.

谢谢，提前，对于任何图形专家的建议。

Thanks, in advance, for any of you graphics experts' suggestions.

推荐答案

我喜欢@AaronGolden的答案，只想添加：

I like the answer from @AaronGolden, just wanted to add:

CGRect borderRect = CGRectInset(rect, 2, 2);

或者更好：

CGFloat lineWidth = 2;
CGRect borderRect = CGRectInset(rect, lineWidth * 0.5, lineWidth * 0.5);

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