CoreGraphics - 在兩個四邊形之間形成可見的間隙形狀路徑

Question

我使用CoreGraphics繪製了兩個Quadrilaterals（4邊）形狀的路徑。共有6個點，path1使用前4個點，path2使用最後4個點，因此共享2個點。

的代碼如下

- (void)drawRect:(CGRect)rect { 

    CGPoint topLeft = CGPointMake(121, 116); 
    CGPoint topRight = CGPointMake(221, 216); 

    CGPoint middleLeft = CGPointMake(121, 180); 
    CGPoint middleRight = CGPointMake(221, 280); 

    CGPoint bottomLeft = CGPointMake(121, 244); 
    CGPoint bottomRight = CGPointMake(221, 344); 

    CGMutablePathRef subpath1 = CGPathCreateMutable(); 
    CGPathMoveToPoint(subpath1, NULL, topLeft.x, topLeft.y); 
    CGPathAddLineToPoint(subpath1, NULL, topRight.x, topRight.y); 
    CGPathAddLineToPoint(subpath1, NULL, middleRight.x, middleRight.y); 
    CGPathAddLineToPoint(subpath1, NULL, middleLeft.x, middleLeft.y); 
    CGPathAddLineToPoint(subpath1, NULL, topLeft.x, topLeft.y); 

    CGMutablePathRef subpath2 = CGPathCreateMutable(); 
    CGPathMoveToPoint(subpath2, NULL, middleLeft.x, middleLeft.y); 
    CGPathAddLineToPoint(subpath2, NULL, middleRight.x, middleRight.y); 
    CGPathAddLineToPoint(subpath2, NULL, bottomRight.x, bottomRight.y); 
    CGPathAddLineToPoint(subpath2, NULL, bottomLeft.x, bottomLeft.y); 
    CGPathAddLineToPoint(subpath2, NULL, middleLeft.x, middleLeft.y); 

    CGContextRef context = UIGraphicsGetCurrentContext(); 

    CGContextSetFillColorWithColor(context, [UIColor colorWithRed:0.19 green:0.42 blue:0.09 alpha:1.0].CGColor); 
    CGContextSetBlendMode(context, kCGBlendModeMultiply); 
    CGContextSetAlpha(context, 1.0); 

    CGContextAddPath(context, subpath1); 
    CGContextFillPath(context); 

    CGContextAddPath(context, subpath2); 
    CGContextFillPath(context); 
} 

輸出圖像是

但在屏幕有一個奇數白線出現在接合邊緣。我想刪除白線。

任何人都可以幫助如何避免這條白線？

Answer 1

首先添加兩個路徑到上下文，然後填充它。

- (void)drawRect:(CGRect)rect { 

    CGPoint topLeft = CGPointMake(121, 116); 
    CGPoint topRight = CGPointMake(221, 216); 

    CGPoint middleLeft = CGPointMake(121, 180); 
    CGPoint middleRight = CGPointMake(221, 280); 

    CGPoint bottomLeft = CGPointMake(121, 244); 
    CGPoint bottomRight = CGPointMake(221, 344); 

    CGMutablePathRef subpath1 = CGPathCreateMutable(); 
    CGPathMoveToPoint(subpath1, NULL, topLeft.x, topLeft.y); 
    CGPathAddLineToPoint(subpath1, NULL, topRight.x, topRight.y); 
    CGPathAddLineToPoint(subpath1, NULL, middleRight.x, middleRight.y); 
    CGPathAddLineToPoint(subpath1, NULL, middleLeft.x, middleLeft.y); 
    CGPathAddLineToPoint(subpath1, NULL, topLeft.x, topLeft.y); 

    CGMutablePathRef subpath2 = CGPathCreateMutable(); 
    CGPathMoveToPoint(subpath2, NULL, middleLeft.x, middleLeft.y); 
    CGPathAddLineToPoint(subpath2, NULL, middleRight.x, middleRight.y); 
    CGPathAddLineToPoint(subpath2, NULL, bottomRight.x, bottomRight.y); 
    CGPathAddLineToPoint(subpath2, NULL, bottomLeft.x, bottomLeft.y); 
    CGPathAddLineToPoint(subpath2, NULL, middleLeft.x, middleLeft.y); 

    CGContextRef context = UIGraphicsGetCurrentContext(); 

    CGContextSetFillColorWithColor(context, [UIColor colorWithRed:0.19 green:0.42 blue:0.09 alpha:1.0].CGColor); 
    CGContextSetBlendMode(context, kCGBlendModeMultiply); 
    CGContextSetAlpha(context, 1.0); 

    // Changes start here... 
    CGContextAddPath(context, subpath1); 
    CGContextAddPath(context, subpath2); 
    CGContextFillPath(context); 
}