Ios 使用渐变图像在UILabel上绘制文本

我有一个UILabel子类，它使用模式图像在drawinRect方法中绘制一些文本。这个图案图像是我正在创建的渐变图像

-(void)drawRect:(CGRect)rect
{
      UIColor *color = [UIColor colorWithPatternImage:[self gradientImage]];
      [color set];

      [someText drawInRect:rec withFont:font lineBreakMode:UILineBreakModeWordWrap alignment:someAlignment];
}

梯度图像法

-(UIImage *)gradientImage
{
    NSData *colorData = [[NSUserDefaults standardUserDefaults] objectForKey:@"myColor"];
    UIColor *co = [NSKeyedUnarchiver unarchiveObjectWithData:colorData];

    colors = [NSArray arrayWithObjects:co,co,[UIColor whiteColor],co,co,co,co,nil];

    NSArray *gradientColors=colors;

    CGFloat width;         
    CGFloat height;      

    CGSize textSize = [someText sizeWithFont:font];

    width=textSize.width; height=textSize.height;

    UIGraphicsBeginImageContext(CGSizeMake(width, height));

    // get context
    CGContextRef context = UIGraphicsGetCurrentContext();

    // push context to make it current (need to do this manually because we are not drawing in a UIView)
    UIGraphicsPushContext(context);

    //draw gradient
    CGGradientRef gradient;
    CGColorSpaceRef rgbColorspace;

    //set uniform distribution of color locations
    size_t num_locations = [gradientColors count];

    CGFloat locations[num_locations];
    for (int k=0; k<num_locations; k++)
    {
        locations[k] = k / (CGFloat)(num_locations - 1); //we need the locations to start at 0.0 and end at 1.0, equaly filling the domain
    }

    //create c array from color array
    CGFloat components[num_locations * 4];
    for (int i=0; i<num_locations; i++)
    {
        UIColor *color = [gradientColors objectAtIndex:i];
        NSAssert(color.canProvideRGBComponents, @"Color components could not be extracted from StyleLabel gradient colors.");
        components[4*i+0] = color.red;
        components[4*i+1] = color.green;
        components[4*i+2] = color.blue;
        components[4*i+3] = color.alpha;
    }

    rgbColorspace = CGColorSpaceCreateDeviceRGB();
    gradient = CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations);

    CGRect currentBounds = self.bounds;

    CGPoint topCenter = CGPointMake(CGRectGetMidX(currentBounds), 0.0f);
    CGPoint midCenter = CGPointMake(CGRectGetMidX(currentBounds), CGRectGetMidY(currentBounds));
    CGContextDrawLinearGradient(context, gradient, topCenter, midCenter, 0);


    CGGradientRelease(gradient);
    CGColorSpaceRelease(rgbColorspace);

    // pop context
    UIGraphicsPopContext();

    // get a UIImage from the image context
    UIImage *gradientImage = UIGraphicsGetImageFromCurrentImageContext();

    // clean up drawing environment
    UIGraphicsEndImageContext();

    return  gradientImage;
}

-（UIImage*）梯度图像
{
NSData*colorData=[[NSUserDefaults standardUserDefaults]objectForKey:@“myColor”]；
UIColor*co=[NSKeyedUnarchiver unarchiveObjectWithData:colorData]；
colors=[NSArray arrayWithObjects:co，co，[UIColor whiteColor]，co，co，co，co，nil]；
NSArray*渐变颜色=颜色；
CGFloat宽度；
浮子高度；
CGSize textSize=[someText sizeWithFont:font]；
宽度=textSize.width；高度=textSize.height；
UIGraphicsBeginImageContext（CGSizeMake（宽度、高度））；
//获取上下文
CGContextRef context=UIGraphicsGetCurrentContext（）；
//推送上下文使其成为当前上下文（需要手动执行此操作，因为我们不是在UIView中绘制）
UIGraphicsPushContext（context）；
//绘制坡度
梯度梯度；
CGColorSpaceRef rgbColorspace；
//设置颜色位置的均匀分布
大小\u t数量\u位置=[GradientColor计数]；
CGFloat位置[num_位置]；
对于（int k=0；k，您可能希望使用现有的第三方解决方案，如