Question

喂我有一种情况我从相机中选择图像并尝试将其上传到服务器图像大小为1.6 MB

如何压缩此图片以将其上传到服务器？

-(UIImage*)resizedImage:(UIImage*)inImage  inRect:(CGRect)thumbRect { 

CGImageRef          imageRef = [inImage CGImage];
CGImageAlphaInfo    alphaInfo = CGImageGetAlphaInfo(imageRef);


if (alphaInfo == kCGImageAlphaNone)
    alphaInfo = kCGImageAlphaNoneSkipLast;

// Build a bitmap context that's the size of the thumbRect
CGFloat bytesPerRow;

if( thumbRect.size.width > thumbRect.size.height ) {
    bytesPerRow = 4 * thumbRect.size.width;
} else {
    bytesPerRow = 4 * thumbRect.size.height;
}

CGContextRef bitmap = CGBitmapContextCreate(    
                                            NULL,
                                            thumbRect.size.width,       // width
                                            thumbRect.size.height,      // height
                                            8, //CGImageGetBitsPerComponent(imageRef),  // really needs to always be 8
                                            bytesPerRow, //4 * thumbRect.size.width,    // rowbytes
                                            CGImageGetColorSpace(imageRef),
                                            alphaInfo
                                            );

// Draw into the context, this scales the image
CGContextDrawImage(bitmap, thumbRect, imageRef);

// Get an image from the context and a UIImage
CGImageRef  ref = CGBitmapContextCreateImage(bitmap);
UIImage*    result = [UIImage imageWithCGImage:ref];

CGContextRelease(bitmap);   // ok if NULL
CGImageRelease(ref);

return result;
}


- (void)uploadImage {
    /*
     turning the image into a NSData object
     getting the image back out of the UIImageView
     setting the quality to 90
     */
    [activityIndicator startAnimating];
    UIImage *compressedImge=[UIImage imageWithCGImage:itemImageView.image.CGImage   scale:0.15 orientation:UIImageOrientationUp];

    CGRect sz = CGRectMake(0.0f, 0.0f, 69.0f, 69.0f); 
    UIImage *smallImage = [self resizedImage:compressedImge inRect:sz];

    NSData *imageData = UIImageJPEGRepresentation(smallImage, 0.15);
    // setting up the URL to post to
    NSString *urlString = @"http://example.co/imageuploader.php";

    // setting up the request object now
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"POST"];

    /*
     add some header info now
     we always need a boundary when we post a file
     also we need to set the content type

     You might want to generate a random boundary.. this is just the same 
     as my output from wireshark on a valid html post
     */
    NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
    [request addValue:contentType forHTTPHeaderField: @"Content-Type"];

    /*
     now lets create the body of the post
     */
    NSMutableData *body = [NSMutableData data];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];    
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"ipodfile%@.jpeg\"\r\n",self.fileID] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[NSData dataWithData:imageData]];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    // setting the body of the post to the reqeust
    [request setHTTPBody:body];
    //[request did];

    // now lets make the connection to the web
    NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

    NSLog(returnString);
}

Answer 1

请参阅此问题：What's the easiest way to resize/optimize an image size with the iPhone SDK? 几个月前我有同样的问题，这可以让你将实际的图像数据调整到你想要的任何分辨率。

Answer 2

您已使用UIImageJPEGRepresentation(smallImage, 0.15);严重压缩它。

iphone：在UIImageView中压缩图像，以便将其上传到服务器

2 个答案: