UIImage 各种处理（分类）

@interface UIImage (conversion)
 
//压缩图片到宽度1024
+ (UIImage *)imageCompressSizeToMin1024Width:(UIImage *)image;
 
 
//修改图片size
+ (UIImage *)image:(UIImage *)image byScalingToSize:(CGSize)targetSize;
 
//UIColor 转UIImage
+ (UIImage *)imageWithColor: (UIColor*) color;
 
//图片转换成黑白(type1:灰 type2:橙 type3:蓝 other:不变)
+ (UIImage *)grayscale:(UIImage*)anImage type:(int)type;
 
//view转图片
+(UIImage *)getImageFromView:(UIView *)view;
 
//图片转化成png
+ (UIImage *)imageToPng:(UIImage *)image;
 
//图片转换成jpg格式
+ (UIImage *)imageToJpg:(UIImage *)image;
 
//图片正向处理，相册读出来的图片有时候头不朝上
+ (UIImage *)fixOrientation:(UIImage *)aImage;
 
@end

@implementation UIImage (conversion)

+ (UIImage *)imageCompressSizeToMin1024Width:(UIImage *)image {
    CGSize size = CGSizeZero;
    if (image.size.width>1024) {
        size.width = 1024;
        size.height = image.size.height*1024/image.size.width;
        image = [UIImage image:image byScalingToSize:size];
    }
    return image;
}

/**
 *  修改图片size
 *
 *  @param image      原图片
 *  @param targetSize 要修改的size
 *
 *  @return 修改后的图片
 */
+ (UIImage *)image:(UIImage*)image byScalingToSize:(CGSize)targetSize {
    UIImage *sourceImage = image;
    UIImage *newImage = nil;
    
    UIGraphicsBeginImageContext(targetSize);
    
    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = CGPointZero;
    thumbnailRect.size.width  = targetSize.width;
    thumbnailRect.size.height = targetSize.height;
    
    [sourceImage drawInRect:thumbnailRect];
    
    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return newImage ;
}

//UIColor 转UIImage
+ (UIImage *)imageWithColor: (UIColor*) color
{
    CGRect rect=CGRectMake(0,0, 1, 1);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return theImage;
}

//图片转换成黑白
+ (UIImage *)grayscale:(UIImage*)anImage type:(int)type {
    //先转换成png
    UIImage *pngImage = [UIImage imageToPng:anImage];
    
    CGImageRef imageRef = pngImage.CGImage;
    
    size_t width  = CGImageGetWidth(imageRef);
    size_t height = CGImageGetHeight(imageRef);
    
    size_t bitsPerComponent = CGImageGetBitsPerComponent(imageRef);
    size_t bitsPerPixel = CGImageGetBitsPerPixel(imageRef);
    
    size_t bytesPerRow = CGImageGetBytesPerRow(imageRef);
    
    CGColorSpaceRef colorSpace = CGImageGetColorSpace(imageRef);
    
    CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
    
    
    bool shouldInterpolate = CGImageGetShouldInterpolate(imageRef);
    
    CGColorRenderingIntent intent = CGImageGetRenderingIntent(imageRef);
    
    CGDataProviderRef dataProvider = CGImageGetDataProvider(imageRef);
    
    CFDataRef data = CGDataProviderCopyData(dataProvider);
    
    UInt8 *buffer = (UInt8*)CFDataGetBytePtr(data);
    
    NSUInteger  x, y;
    for (y = 0; y < height; y++) {
        for (x = 0; x < width; x++) {
            UInt8 *tmp;
            tmp = buffer + y * bytesPerRow + x * 4;
            
            UInt8 red,green,blue;
            red = *(tmp + 0);
            green = *(tmp + 1);
            blue = *(tmp + 2);
            
            UInt8 brightness;
            switch (type) {
                case 1:
                    brightness = (77 * red + 28 * green + 151 * blue) / 256;
                    *(tmp + 0) = brightness;
                    *(tmp + 1) = brightness;
                    *(tmp + 2) = brightness;
                    break;
                case 2:
                    *(tmp + 0) = red;
                    *(tmp + 1) = green * 0.7;
                    *(tmp + 2) = blue * 0.4;
                    break;
                case 3:
                    *(tmp + 0) = 255 - red;
                    *(tmp + 1) = 255 - green;
                    *(tmp + 2) = 255 - blue;
                    break;
                default:
                    *(tmp + 0) = red;
                    *(tmp + 1) = green;
                    *(tmp + 2) = blue;
                    break;
            }
        }
    }
    CFDataRef effectedData = CFDataCreate(NULL, buffer, CFDataGetLength(data));
    CGDataProviderRef effectedDataProvider = CGDataProviderCreateWithCFData(effectedData);
    CGImageRef effectedCgImage = CGImageCreate(width, height,
                                               bitsPerComponent, bitsPerPixel, bytesPerRow,
                                               colorSpace, bitmapInfo, effectedDataProvider,
                                               NULL, shouldInterpolate, intent);
    UIImage *effectedImage = [[UIImage alloc] initWithCGImage:effectedCgImage];
    CGImageRelease(effectedCgImage);
    CFRelease(effectedDataProvider);
    CFRelease(effectedData);
    CFRelease(data);
    
    return effectedImage;
    
}

//view转图片
+ (UIImage *)getImageFromView:(UIView *)view{
    
    UIGraphicsBeginImageContext(view.bounds.size);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

//图片转换成png格式
+ (UIImage *)imageToPng:(UIImage *)image {
    //我们需要将其转换成NSdata二进制存储，
    NSData *data;
    if (UIImagePNGRepresentation(image) == nil) {
        data = UIImageJPEGRepresentation(image, 1);
    } else {
        data = UIImagePNGRepresentation(image);
    }
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *sandPath = NSHomeDirectory();
    //文件路径
    NSString *path = [sandPath stringByAppendingPathComponent:@"tmp/image.png"];
    //    DLog(@"%@",path);
    [fileManager createFileAtPath:path contents:data attributes:nil];   // 将图片保存为PNG格式
    [data writeToFile:path atomically:YES];
    UIImage *pngImage = [UIImage imageWithContentsOfFile:path];
    return pngImage;
}

//图片转换成jpg格式
+ (UIImage *)imageToJpg:(UIImage *)image {
    //我们需要将其转换成NSdata二进制存储，
    NSData *data;
    if (UIImagePNGRepresentation(image) == nil) {
        data = UIImageJPEGRepresentation(image, 1);
    } else {
        data = UIImagePNGRepresentation(image);
    }
    
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *sandPath = NSHomeDirectory();
    //文件路径
    NSString *path = [sandPath stringByAppendingPathComponent:@"tmp/image.jpg"];
    [fileManager createFileAtPath:path contents:data attributes:nil];   // 将图片保存为JPG格式
    [data writeToFile:path atomically:YES];
    
    UIImage *jpgImage = [UIImage imageWithContentsOfFile:path];
    
    return jpgImage;
}

//正向处理
+ (UIImage *)fixOrientation:(UIImage *)aImage {
    
    // No-op if the orientation is already correct
    if (aImage.imageOrientation ==UIImageOrientationUp)
        return aImage;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform =CGAffineTransformIdentity;
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width,0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width,0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.height,0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx =CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
                                            CGImageGetBitsPerComponent(aImage.CGImage),0,
                                            CGImageGetColorSpace(aImage.CGImage),
                                            CGImageGetBitmapInfo(aImage.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (aImage.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx,CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx,CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg =CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

@end

mark -- 1. 对照片做处理的时候 先旋转方向   再改变格式

2.如果拍设的照片太大的话上传后台估计会出错

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {UIImage *originalImage = (UIImage *)[info objectForKey:UIImagePickerControllerEditedImage];if (!originalImage) {originalImage = (UIImage *)[info objectForKey:UIImagePickerControllerOriginalImage];}UIImage *imga = [UIImage fixOrientation:originalImage];//图片正向处理UIImage *img = [UIImage imageToJpg:imga];//转换成jpg
    NSData *imageData = UIImageJPEGRepresentation(img, 1);if  (imageData.length>300000){UIImage *image = [UIImage imageWithData:imageData];imageData = UIImageJPEGRepresentation(image, 0.005);}NSString *encodedImageStr = [imageData base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];[picker dismissViewControllerAnimated:YES completion:nil];
}