ios涂料应用程序覆盖绘画描边

Question

我正在创建一个绘画应用程序，但是如果笔划一行一行，如果笔划另一行跨过前一笔划，则第一笔划将颜色更改为第二种颜色

以下是我用来绘画的代码：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];

    previousPoint1 = [touch previousLocationInView:self];
    previousPoint2 = [touch previousLocationInView:self];
    currentPoint = [touch locationInView:self];

    [self touchesMoved:touches withEvent:event];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView:self];

    /* check if the point is farther than min dist from previous */
    CGFloat dx = point.x - currentPoint.x;
    CGFloat dy = point.y - currentPoint.y;

    if ((dx * dx + dy * dy) < kPointMinDistanceSquared) {
        return;
    }

    previousPoint2 = previousPoint1;
    previousPoint1 = [touch previousLocationInView:self];
    currentPoint = [touch locationInView:self];

    CGPoint mid1 = midPoint(previousPoint1, previousPoint2);
    CGPoint mid2 = midPoint(currentPoint, previousPoint1);
    CGMutablePathRef subpath = CGPathCreateMutable();
    CGPathMoveToPoint(subpath, NULL, mid1.x, mid1.y);
    CGPathAddQuadCurveToPoint(subpath, NULL, previousPoint1.x, previousPoint1.y, mid2.x, mid2.y);
    CGRect bounds = CGPathGetBoundingBox(subpath);

    CGPathAddPath(path, NULL, subpath);
    CGPathRelease(subpath);

    CGRect drawBox = bounds;
    drawBox.origin.x -= self.lineWidth * 2.0;
    drawBox.origin.y -= self.lineWidth * 2.0;
    drawBox.size.width += self.lineWidth * 4.0;
    drawBox.size.height += self.lineWidth * 4.0;

    [self setNeedsDisplayInRect:drawBox];
}

- (void)drawRect:(CGRect)rect {

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextAddPath(context, path);
    CGContextSetLineCap(context, kCGLineCapRound);
    CGContextSetLineWidth(context, self.lineWidth);
    CGContextSetStrokeColorWithColor(context, self.lineColor.CGColor);

    CGContextStrokePath(context);


    self.empty = NO;
}

你们中的任何人都知道我做错了什么，或者我怎样才能让每个笔画彼此独立？

我真的很感谢你的帮助。

Answer 1

我认为您需要做的是在更改颜色时开始一条新路径。不要只是将新颜色的新子路径添加到具有旧颜色的相同路径中。

您需要为每个路径存储应呈现的颜色，然后在drawRect方法中遍历路径。