UIImage+Exension.h

#import <UIKit/UIKit.h>

@interface UIImage (Exension)

/**

 生成一张高斯模糊的图片

 @param image 原图
 @param blur 模糊程度
 @return 高斯模糊的图片
 */
+ (UIImage *)blurImage:(UIImage *)image blur:(CGFloat)blur;

/**
 根据颜色生成一张图片

 @param color 颜色
 @param size 要生成图片的尺寸
 @return 图片
 */
+ (UIImage *)imageWithColor:(UIColor *)color size:(CGSize)size;

/**
 生成一张圆形图片

 @param originImage 原始图片
 @param borderColor 边框颜色
 @param borderWidth 边框宽度
 @return 圆形图片
 */
+ (UIImage *)circleImage:(UIImage *)originImage borderColor:(UIColor *)borderColor borderWidth:(CGFloat)borderWidth;

/**
 生成一张不被渲染的图片

 @param imageName 图片名称
 @return 不会被渲染的原始图片
 */
+ (UIImage *)imageRenderingModeAlowsOriginal:(NSString *)imageName;

@end

UIImage+Exension.m

#import "UIImage+Exension.h"
#import <Accelerate/Accelerate.h>

@implementation UIImage (Exension)

/**
 生成一张高斯模糊的图片
*/
+ (UIImage *)blurImage:(UIImage *)image blur:(CGFloat)blur
{
    // 模糊度越界
    if (blur < 0.f || blur > 1.f) {
        blur = 0.5f;
    }
    int boxSize = (int)(blur * 40);
    boxSize = boxSize - (boxSize % 2) + 1;
    CGImageRef img = image.CGImage;
    vImage_Buffer inBuffer, outBuffer;
    vImage_Error error;
    void *pixelBuffer;
    //从CGImage中获取数据
    CGDataProviderRef inProvider = CGImageGetDataProvider(img);
    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);
    //设置从CGImage获取对象的属性
    inBuffer.width = CGImageGetWidth(img);
    inBuffer.height = CGImageGetHeight(img);
    inBuffer.rowBytes = CGImageGetBytesPerRow(img);
    
    if (inBitmapData) {
        inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);
    }

    pixelBuffer = malloc(CGImageGetBytesPerRow(img) *
                         CGImageGetHeight(img));
    
    if(pixelBuffer == NULL)
        NSLog(@"No pixelbuffer");

    outBuffer.data = pixelBuffer;
    outBuffer.width = CGImageGetWidth(img);
    outBuffer.height = CGImageGetHeight(img);
    outBuffer.rowBytes = CGImageGetBytesPerRow(img);

    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);

    if (error) {
        NSLog(@"error from convolution %ld", error);
    }

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef ctx = CGBitmapContextCreate(
                                             outBuffer.data,
                                             outBuffer.width,
                                             outBuffer.height,
                                             8,
                                             outBuffer.rowBytes,
                                             colorSpace,
                                             kCGImageAlphaNoneSkipLast);
    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

    CGContextRelease(ctx);
    CGColorSpaceRelease(colorSpace);

    free(pixelBuffer);
    CFRelease(inBitmapData);

    CGColorSpaceRelease(colorSpace);
    CGImageRelease(imageRef);

    return returnImage;
}


/**
 根据颜色生成一张图片
*/
+ (UIImage *)imageWithColor:(UIColor *)color size:(CGSize)size
{
    if (color) {
        CGRect rect = CGRectMake(0, 0, size.width, size.height);
        // 开启图形上下文
        UIGraphicsBeginImageContext(rect.size);
        // 获取当前的上下文
        CGContextRef context = UIGraphicsGetCurrentContext();
        // 将颜色填充到上下文
        CGContextSetFillColorWithColor(context, color.CGColor);
        // 将内容填满指定的尺寸
        CGContextFillRect(context, rect);
        // 从上下文获取图片
        UIImage *image =UIGraphicsGetImageFromCurrentImageContext();
        // 关闭上下文
        UIGraphicsEndImageContext();
        
        return image;
    }
    return nil;
}


/**
 生成一张圆形图片
*/
+ (UIImage *)circleImage:(UIImage *)originImage borderColor:(UIColor *)borderColor borderWidth:(CGFloat)borderWidth
{
    // 设置圆形图片的直径
    CGFloat imageDia = originImage.size.width;
    // 计算外圆的直径(边框是在图片外额外添加的区域)
    CGFloat borderDia = imageDia + 2 * borderWidth;

    // 开启图形上下文
    UIGraphicsBeginImageContext(originImage.size);
    // 画一个包含边框的圆形
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, borderDia, borderDia)];
    // 设置颜色
    [borderColor set];
    [path fill];

    // 设置裁剪区域
    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(borderWidth, borderWidth, imageDia, imageDia)];
    // 裁剪图片
    [clipPath addClip];
    
    // 绘制图片
    [originImage drawAtPoint:CGPointMake(borderWidth, borderWidth)];
    // 从上下文中获取图片
    UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
    // 关闭上下文
    UIGraphicsEndImageContext();
    
    return resultImage;
}


/**
 生成一张不被渲染的图片
*/
+ (UIImage *)imageRenderingModeAlowsOriginal:(NSString *)imageName
{
    UIImage *image = [UIImage imageNamed:imageName];
    return [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
}

@end