更新

Question

有没有办法获取在UIColor类别中设置backgroundColor的对象边界？

例如，我正在尝试从图像中应用UIColor，但我希望它能够相应地展开。相关的参考文献是否可以完成这或者最好在UIView类别中实现这样的方法吗？

更新

以下是设置backgroundColor的方法：

+ (UIColor *)colorWithGradientStyle:(GradientStyle)gradientStyle andColors:(NSArray *)colors {

//Create our background gradient layer
CAGradientLayer *backgroundGradientLayer = [CAGradientLayer layer];

//Set the frame to our object's bounds
backgroundGradientLayer.frame = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);

//To simplfy formatting, we'll iterate through our colors array and create a mutable array with their CG counterparts
NSMutableArray *cgColors = [[NSMutableArray alloc] init];
for (UIColor *color in colors) {
    [cgColors addObject:(id)[color CGColor]];
}

switch (gradientStyle) {
    case linearLeftToRight: {

        //Set out gradient's colors
        backgroundGradientLayer.colors = cgColors;

        //Specify the direction our gradient will take
        [backgroundGradientLayer setStartPoint:CGPointMake(0.0, 0.5)];
        [backgroundGradientLayer setEndPoint:CGPointMake(1.0, 0.5)];

        //Convert our CALayer to a UIImage object
        UIGraphicsBeginImageContext(backgroundGradientLayer.bounds.size);
        [backgroundGradientLayer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage * backgroundColorImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        return [UIColor colorWithPatternImage:backgroundColorImage];
    }

    case linearTopToBottom:
    default: {

        //Set out gradient's colors
        backgroundGradientLayer.colors = cgColors;

        //Convert our CALayer to a UIImage object
        UIGraphicsBeginImageContext(backgroundGradientLayer.bounds.size);
        [backgroundGradientLayer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage * backgroundColorImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        return [UIColor colorWithPatternImage:backgroundColorImage];
    }

}

}

Answer 1

无论您在何处放置此代码，都需要对视图的引用才能获得其边界。您可以将视图或边界作为参数传递，也可以将其作为UIView类或子类。

UIColor类仅用于创建颜色，它与渲染或定位颜色无关。这是UIView的工作。因此UIColor不是这个代码的地方。

我建议继承UIView并重写drawRect来绘制渐变。或者创建一个UIView方法，如：-(void)setBackgroundGradientWithStyle:(GradientStyle)gradientStyle colors:(NSArray *)colors并将此代码放在那里。

iOS：抓取-colorWithPatternImage的对象边界：在UIColor类别中？

更新

1 个答案: