iOS-生成颜色图片(纯色，渐变，模糊效果)

创建一张纯色图片

// 创建一张纯色图片
+ (UIImage *)createImageColor:(UIColor *)color size:(CGSize)size
{
    CGRect rect = CGRectMake(0, 0, size.width, size.height);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

创建一张渐变色图片

// 创建一张渐变色图片
- (UIImage *)createImageSize:(CGSize)imageSize gradientColors:(NSArray *)colors percentage:(NSArray *)percents gradientType:(GradientType)gradientType {
    
    NSAssert(percents.count <= 5, @"输入颜色数量过多，如果需求数量过大，请修改locations[]数组的个数");
    
    NSMutableArray *ar = [NSMutableArray array];
    for(UIColor *c in colors) {
        [ar addObject:(id)c.CGColor];
    }
    
    //    NSUInteger capacity = percents.count;
    //    CGFloat locations[capacity];
    CGFloat locations[5];
    for (int i = 0; i < percents.count; i++) {
        locations[i] = [percents[i] floatValue];
    }
    
    UIGraphicsBeginImageContextWithOptions(imageSize, YES, 1);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    CGColorSpaceRef colorSpace = CGColorGetColorSpace([[colors lastObject] CGColor]);
    CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (CFArrayRef)ar, locations);
    CGPoint start;
    CGPoint end;
    switch (gradientType) {
        case GradientFromTopToBottom:
            start = CGPointMake(imageSize.width/2, 0.0);
            end = CGPointMake(imageSize.width/2, imageSize.height);
            break;
        case GradientFromLeftToRight:
            start = CGPointMake(0.0, imageSize.height/2);
            end = CGPointMake(imageSize.width, imageSize.height/2);
            break;
        case GradientFromLeftTopToRightBottom:
            start = CGPointMake(0.0, 0.0);
            end = CGPointMake(imageSize.width, imageSize.height);
            break;
        case GradientFromLeftBottomToRightTop:
            start = CGPointMake(0.0, imageSize.height);
            end = CGPointMake(imageSize.width, 0.0);
            break;
        default:
            break;
    }
    CGContextDrawLinearGradient(context, gradient, start, end, kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    CGGradientRelease(gradient);
    CGContextRestoreGState(context);
    CGColorSpaceRelease(colorSpace);
    UIGraphicsEndImageContext();
    return image;
}

创建一张模糊效果图片

// 创建一张模糊效果图片
+ (UIImage *)createImageColor:(UIColor *)color size:(CGSize)size{
    
    CGRect rect = CGRectMake(0, 0, size.width, size.height);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}