我正在尝试使用CGContextSetLineDash
绘制虚线。
这是我的代码:
float dashPhase = 0.0;
float dashLengths[] = {30, 30};
CGContextSetLineDash(context, dashPhase, dashLengths, 20.0);
self.previousPoint2 = self.previousPoint1;
self.previousPoint1 = previous;
self.currentPoint = current;
self.mid1 = [self pointBetween:self.previousPoint1 andPoint:self.previousPoint2];
self.mid2 = [self pointBetween:self.currentPoint andPoint:self.previousPoint1];
UIBezierPath* newPath = [UIBezierPath bezierPath];
[newPath moveToPoint:self.mid1];
[newPath addLineToPoint:self.mid2];
[newPath setLineWidth:self.brushSize];
然而,如果我画得慢一些,那些虚线就不会出现(参见下图的顶部),但是如果我画得快一些,它们就会出现(参见下图的底部)。为什么会这样呢?