/**
 *  壓縮圖片到指定檔案大小
 *
 *  @param image 目標圖片
 *  @param size  目標大小（最大值）
 *
 *  @return 返回的圖片檔案
 */
- (NSData *)zh_compressOriginalImage:(UIImage *)image toMaxDataSizeKBytes:(CGFloat)size
{
    NSData *data = UIImageJPEGRepresentation(image, 1.f);
    
    CGFloat dataKBytes = data.length / 1000.f;
    
    CGFloat maxQuality = .9f;
    
    CGFloat lastData = dataKBytes;
    
    while (dataKBytes > size && maxQuality > .01f)
    {
        maxQuality -= .01f;
        
        data = UIImageJPEGRepresentation(image, maxQuality);
        
        dataKBytes = data.length / 1000.f;
        
        NSLog(@"當前圖片大小：%fKB", dataKBytes);
        
        if (lastData == dataKBytes)
        {
            break;
        }
        else
        {
            lastData = dataKBytes;
        }
    }
    return data;
}

//圖片base64編碼後的處理，// 由於字串中會有“+”，“+”上傳到伺服器會變空格，此處用了支付寶支付時帶的編碼方法

- (NSString *)encode:(NSString *)str
{
    return (__bridge_transfer  NSString*)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)str, NULL, (__bridge CFStringRef)@"!*'();:@&=+$,/?%#[]", kCFStringEncodingUTF8 );
}
 

呼叫方法並進行base64編碼

NSData *imageData = [ShowTool zh_compressOriginalImage:image toMaxDataSizeKBytes:80.f];
    CGFloat len = [imageData length] / 1000.f;
    if (len > 100.f){
        [ShowTool showHud:@"圖片過大請手動輸入" view:self.view];
        return;
    }
    // base64編碼
    NSString *imageBase64Str = [imageData base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength]; 
    imageBase64Str = [ShowTool encode:imageBase64Str];