iOS-UIImage图片绘制颜色、UIColor渐变色

图片绘制颜色

- (UIImage *)dtk_setImageColor:(UIColor *)imageColor{
    //获取画布
    UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);
    //画笔沾取颜色
    [imageColor setFill];
    CGRect bounds = CGRectMake(0, 0, self.size.width, self.size.height);
    //绘制一次
    UIRectFill(bounds);
    //再绘制一次
    [self drawInRect:bounds blendMode:kCGBlendModeOverlay alpha:1.0f];
    //获取图片
    [self drawInRect:bounds blendMode:kCGBlendModeDestinationIn alpha:1.0f];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

 渐变色

.h

/**
 渐变方式
 
 - GradientChangeDirectionLevel:              水平渐变
 - GradientChangeDirectionVertical:           竖直渐变
 - GradientChangeDirectionUpwardDiagonalLine: 向下对角线渐变
 - GradientChangeDirectionDownDiagonalLine:   向上对角线渐变
 */
typedef NS_ENUM(NSInteger, DUEGradientChangeDirection) {
    DUEGradientChangeDirectionLevel,
    DUEGradientChangeDirectionVertical,
    DUEGradientChangeDirectionUpwardDiagonalLine,
    DUEGradientChangeDirectionDownDiagonalLine,
};

/**
 创建渐变颜色
 
 @param size       渐变的size
 @param direction  渐变方式
 @param startcolor 开始颜色
 @param endColor   结束颜色
 
 @return 创建的渐变颜色
 */
+ (instancetype)due_colorGradientChangeWithSize:(CGSize)size
                                     direction:(DUEGradientChangeDirection)direction
                                    startColor:(UIColor *)startcolor
                                      endColor:(UIColor *)endColor;

.m

+ (instancetype)due_colorGradientChangeWithSize:(CGSize)size
                                     direction:(DUEGradientChangeDirection)direction
                                    startColor:(UIColor *)startcolor
                                      endColor:(UIColor *)endColor {
    if (CGSizeEqualToSize(size, CGSizeZero) || !startcolor || !endColor) {
        return nil;
    }
    CAGradientLayer *gradientLayer = [CAGradientLayer layer];
    gradientLayer.frame = CGRectMake(0, 0, size.width, size.height);
    
    CGPoint startPoint = CGPointZero;
    if (direction == DUEGradientChangeDirectionDownDiagonalLine) {
        startPoint = CGPointMake(0.0, 1.0);
    }
    gradientLayer.startPoint = startPoint;
    
    CGPoint endPoint = CGPointZero;
    switch (direction) {
        case DUEGradientChangeDirectionLevel:
            endPoint = CGPointMake(1.0, 0.0);
            break;
        case DUEGradientChangeDirectionVertical:
            endPoint = CGPointMake(0.0, 1.0);
            break;
        case DUEGradientChangeDirectionUpwardDiagonalLine:
            endPoint = CGPointMake(1.0, 1.0);
            break;
        case DUEGradientChangeDirectionDownDiagonalLine:
            endPoint = CGPointMake(1.0, 0.0);
            break;
        default:
            break;
    }
    gradientLayer.endPoint = endPoint;
    
    gradientLayer.colors = @[(__bridge id)startcolor.CGColor, (__bridge id)endColor.CGColor];
    UIGraphicsBeginImageContext(size);
    [gradientLayer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage*image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return [UIColor colorWithPatternImage:image];
}