iOS向后台发送图片，图片被翻转以及图片过大，发送缓慢问题的解决

聊天界面向后台发送图片时，发现选择相册图片会出现图片翻转的现象，调用相机拍照上传时，照片由于过大，导致界面交互缓慢，以下为解决方案

图片翻转解决方法

if (image.imageOrientation != UIImageOrientationUp)
    {
        UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
        [image drawInRect:(CGRect){0,0,image.size}];
        UIImage *normalImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        image = normalImage;
    }

图片发送缓慢解决方法

NSString *imageName = [NSString stringWithFormat:@"%lf.jpg", [NSDate date].timeIntervalSince1970];

NSString *imagePath =  [NSFileManager pathUserChatImage:imageName];

NSData  *saveData = (UIImageJPEGRepresentation(image, 1.0));

[[NSFileManager defaultManager] createFileAtPath:imagePath contents:saveData attributes:nil];

//UIImagePNGRepresentation(image) ? UIImagePNGRepresentation(image) :

NSData *imageData = [ZYSmartChatImageType reSizeImageData:image maxImageSize:320 maxSizeWithKB:1024];

在此处调用+ (NSData *)reSizeImageData:(UIImage *)sourceImage maxImageSize:(CGFloat)maxImageSize maxSizeWithKB:(CGFloat) maxSize方法，具体方法内容如下

+ (NSData *)reSizeImageData:(UIImage *)sourceImage maxImageSize:(CGFloat)maxImageSize maxSizeWithKB:(CGFloat) maxSize

{

if (maxSize <= 0.0) maxSize = 1024.0;

if (maxImageSize <= 0.0) maxImageSize = 1024.0;

//先调整分辨率

CGSize newSize = CGSizeMake(sourceImage.size.width, sourceImage.size.height);

CGFloat tempHeight = newSize.height / maxImageSize;

CGFloat tempWidth = newSize.width / maxImageSize;

if (tempWidth > 1.0 && tempWidth > tempHeight) {

newSize = CGSizeMake(sourceImage.size.width / tempWidth, sourceImage.size.height / tempWidth);

}

else if (tempHeight > 1.0 && tempWidth < tempHeight){

newSize = CGSizeMake(sourceImage.size.width / tempHeight, sourceImage.size.height / tempHeight);

}

UIGraphicsBeginImageContext(newSize);

[sourceImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

//调整大小

NSData *imageData = UIImageJPEGRepresentation(newImage,1.0);

CGFloat sizeOriginKB = imageData.length / 1024.0;

CGFloat resizeRate = 0.9;

while (sizeOriginKB > maxSize && resizeRate > 0.1) {

imageData = UIImageJPEGRepresentation(newImage,resizeRate);

sizeOriginKB = imageData.length / 1024.0;

resizeRate -= 0.1;

}

return imageData;

}

此模块中遇到的其它问题:

iOS聊天界面后台数据发送过快，导致展示cell的frame没有重新计算

聊天界面调用讯飞语音转换为文字，文字在cell上不显示

Xcode9.2运行iOS11系统时，下方键盘弹出导致statusBar颜色变化

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