UIBezierPath充填颜色

Question

我要用UIBezierPath在一个图表中充填颜色。目前我已经完成的代码：

NSMutableArray *graphData=[[NSMutableArray alloc] initWithObjects:[NSArray arrayWithObjects:@"2013-06-26",@"46", nil],[NSArray arrayWithObjects:@"2013-06-27",@"37", nil],[NSArray arrayWithObjects:@"2013-06-28",@"96", nil],[NSArray arrayWithObjects:@"2013-06-29",@"29", nil],[NSArray arrayWithObjects:@"2013-06-30",@"29", nil],[NSArray arrayWithObjects:@"2013-07-01",@"24", nil], nil];
    UIBezierPath *aPath = [UIBezierPath bezierPath];
    [[UIColor blackColor] setStroke];
    [[UIColor redColor] setFill];    
    [aPath moveToPoint:CGPointMake(10, kGraphBottom-[[[graphData objectAtIndex:0] objectAtIndex:1]floatValue])];    
    for (int i = 1; i < graphData.count; i++)
    {
        [aPath addLineToPoint:CGPointMake(10+50* (i), kGraphBottom-[[[graphData objectAtIndex:i] objectAtIndex:1]floatValue])];    
    }
    [aPath moveToPoint:CGPointMake(10+50*graphData.count , kGraphBottom)];
    [aPath moveToPoint:CGPointMake(10 , kGraphBottom)];
    [aPath moveToPoint:CGPointMake(10 , kGraphBottom-[[[graphData objectAtIndex:0] objectAtIndex:1]floatValue])];
     [aPath closePath];
    [aPath fill];
    [aPath stroke];

得到的结果如下：

如何给图形和x,y坐标之间充填颜色？

Answer 1

你可以将aPath的所有边都设置为从y轴到数据点的垂直线，然后使用closePath方法来将路径闭合。这样就可以使用fill方法来填充路径内部的区域了。

---

下面是修改后的代码：

NSMutableArray *graphData = [[NSMutableArray alloc] initWithObjects:
    [NSArray arrayWithObjects:@"2013-06-26", @"46", nil],
    [NSArray arrayWithObjects:@"2013-06-27", @"37", nil],
    [NSArray arrayWithObjects:@"2013-06-28", @"96", nil],
    [NSArray arrayWithObjects:@"2013-06-29", @"29", nil],
    [NSArray arrayWithObjects:@"2013-06-30", @"29", nil],
    [NSArray arrayWithObjects:@"2013-07-01", @"24", nil],
    nil
];

UIBezierPath *aPath = [UIBezierPath bezierPath];
[[UIColor blackColor] setStroke];
[[UIColor redColor] setFill];

// 从x轴开始绘制
[aPath moveToPoint:CGPointMake(10, kGraphBottom)];

for (int i = 0; i < graphData.count; i++) {
    // 从y轴到数据点绘制垂直线
    [aPath addLineToPoint:CGPointMake(10 + 50 * i, kGraphBottom - [[[graphData objectAtIndex:i] objectAtIndex:1] floatValue])];
}

// 从最后一个数据点到x轴绘制垂直线
[aPath addLineToPoint:CGPointMake(10 + 50 * graphData.count, kGraphBottom)];

// 闭合路径
[aPath closePath];

// 填充路径内部的区域
[aPath fill];

// 绘制路径
[aPath stroke];

这样就可以在图形和x,y坐标之间充填颜色了。