如何创建UIBezierPath渐变填充？ [英] How to create UIBezierPath gradient fill?

问题描述

我想用10px圆角和渐变填充创建 UIBezierPath 。我怎样才能实现这种效果？

I would like to create a UIBezierPath with 10px rounded corners and with gradient fill. How can I acheive this effect?

这是我想要做的图像：

如您所见，此广场有：

• 2px黑色边框


• 10px圆角


• 红色到绿色线性渐变填充

如何以编程方式不使用图案图像颜色？

以下是我创建路径的方法：

Here's how I create the path:

UIBezierPath *border = [UIBezierPath bezierPathWithRoundedRect:self.bounds cornerRadius:10.0f];
[border setLineWidth:2];
[[UIColor blackColor] setStroke];
[border stroke];
[[UIColor redColor] setFill]; <-- what should I put here?
[border fill];

推荐答案

我能想到的3种方式。

1. 创建一个CAGradientLayer并将其作为View.layer的子层插入。您甚至可以在图层上放置圆角半径。当然你必须导入QuartzCore框架。

1. Create a CAGradientLayer and insert it as a sublayer of theView.layer. You can even put a rounded corner radius on the layer. Of course you'll have to import QuartzCore framework.

使用CoreGraphics这样做：

Do it with CoreGraphics, like so:

CGGradientRef gradient;
CGColorSpaceRef colorspace;
size_t num_locations = 2;
CGFloat locations[2] = { 0.0, 1.0 };
CGFloat components[8] = { 1.0, 0.0, 0.0, 1.0,  // Start color
        0.0, 1.0, 0.0, 1.0 }; // End color

colorspace = CGColorSpaceCreateDeviceRGB();
gradient = CGGradientCreateWithColorComponents (colorspace, components, locations, num_locations);
CGContextDrawLinearGradient (ctx, gradient, gradientStartPoint, gradientEndPoint, 0);
CGGradientRelease(gradient);

创建一个像素宽且具有渐变的屏幕外图像上下文，生成然后使用colorWithPatternImage设置背景颜色。

Create an off-screen image context that's one pixel wide and has a gradient, generate the image, then set the background color with colorWithPatternImage.

这些是最容易的，最难的。

These are in order of easiest to hardest.

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