如何从local url获取UIImage并将图片发布到服务器？
我的url位于以下位置：
file:///Users/macmini/Library/Developer/CoreSimulator/Devices/89104EAC-5BE1-4BEC-BE8E-7B8FFBF9CBD2/data/Media/DCIM/100APPLE/IMG_0005.JPG
以及如何减少此图片的尺寸
< UIImage: 0x7b8d6170>, {3000, 2002}
提前谢谢..
答案 0 :(得分：2)
从local url获取图片：
NSURL *localurl = [NSURL URLWithString:path];
NSData *data = [NSData dataWithContentsOfURL:localurl];
UIImage *img = [[UIImage alloc] initWithData:data];
将图片发布到server：
- (void)sendImageToServer {
UIImage *img= [UIImage imageNamed:@"image.png"];
NSData *imageData = UIImagePNGRepresentation(img);
NSString *postLength = [NSString stringWithFormat:@"%d", [imageData length]];
// Init the URLRequest
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setHTTPMethod:@"POST"];
[request setURL:[NSURL URLWithString:[NSString stringWithString:@"http://yoururl.domain"]]];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setHTTPBody:imageData];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (connection) {
// response data of the request
}
}
答案 1 :(得分：1)
使用此代码挑选图片....
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
{
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
imagePicker.delegate = self;
imagePicker.allowsEditing = NO;
[self presentViewController:imagePicker animated:YES completion:nil];
}
else
{
[self showMessage:@"This device doesn't support photo libraries."
withTitle:@"Error"];
}
使用以下代码合并压缩
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
NSURL *refURL = [info valueForKey:UIImagePickerControllerReferenceURL];
[picker.presentingViewController dismissViewControllerAnimated:YES completion:nil];
// to get the image image name use the following code
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *imageAsset)
{
ALAssetRepresentation *imageRep = [imageAsset defaultRepresentation];
NSLog(@"[imageRep filename] : %@", [imageRep filename]);
[_imageNameArray addObject:[imageRep filename]];
};
[_uploadTbleView reloadData];
ALAssetsLibrary* assetslibrary = [[ALAssetsLibrary alloc] init];
[assetslibrary assetForURL:refURL resultBlock:resultblock failureBlock:nil];
UIImage* selectedImage = [info objectForKey:UIImagePickerControllerOriginalImage];
NSData *imgData = UIImageJPEGRepresentation(selectedImage, 1.0);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// [self.baseArray addObject:[self encodeToBase64String: selectedImage]];
[self.baseArray addObject:[self base64forData:imgData]];
// NSLog(@"%@",[self encodeToBase64String: selectedImage]);
});
[self.imageSizeArray addObject: [NSNumber numberWithInteger:[imgData length]]];
NSLog(@"Size of Image(bytes):%ld",[imgData length]);
}
以下是在上传之前将图像压缩为base64的代码
- (NSString*)base64forData:(NSData*) theData
{
const uint8_t* input = (const uint8_t*)[theData bytes];
NSInteger length = [theData length];
static char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];
uint8_t* output = (uint8_t*)data.mutableBytes;
NSInteger i;
for (i=0; i < length; i += 3) {
NSInteger value = 0;
NSInteger j;
for (j = i; j < (i + 3); j++) {
value <<= 8;
if (j < length) {
value |= (0xFF & input[j]);
}
}
NSInteger theIndex = (i / 3) * 4;
output[theIndex + 0] = table[(value >> 18) & 0x3F];
output[theIndex + 1] = table[(value >> 12) & 0x3F];
output[theIndex + 2] = (i + 1) < length ? table[(value >> 6) & 0x3F] : '=';
output[theIndex + 3] = (i + 2) < length ? table[(value >> 0) & 0x3F] : '=';
}
return [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
}
注意：
你的后端反过来必须解码这个base64数据以获取图像内容。如果有任何问题，请再次回复我，我会帮助您
答案 2 :(得分：0)
要从网址获取图片，您可以执行以下操作。
NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageURL]];
UIImage *image = [UIImage imageWithData:imageData];
要压缩它，您必须再次将其转换为NSData。
NSData *lowResImgData= UIImageJPEGRepresentation(highResImage,0.1 /*compressionQuality*/);
UIImage *lowResImage = [UIImage imageWithData:lowResImgData];
答案 3 :(得分：0)
要缩小图像的大小，请使用以下方法
-(UIImage *)resizeImage:(UIImage *)image scaledToSize:(CGSize)targetSize
{
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = targetSize.height;
float maxWidth = targetSize.width;
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.50;//50 percent compression
if (actualHeight > maxHeight || actualWidth > maxWidth)
{
if(imgRatio < maxRatio)
{
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio)
{
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else
{
actualHeight = maxHeight;
actualWidth = maxWidth;
}
}
CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();
return [UIImage imageWithData:imageData];
}
请查看以下网址以在您的服务器中重置图片。
答案 4 :(得分：0)
要压缩UIImage，它取决于你的需求。根据压缩的质量或根据大小的压缩。
第一种方式（质量），使用API如下：
UIImageJPEGRepresentation(UIImage * __nonnull image, CGFloat compressionQuality)
第二种方式，使用代码如下：
+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
// Create a graphics image context
UIGraphicsBeginImageContext(newSize);
// Tell the old image to draw in this new context, with the desired
// new size
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
// Get the new image from the context
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
// End the context
UIGraphicsEndImageContext();
// Return the new image.
return newImage;
}
要将本地图像文件上传到服务器，如果您使用AFNetWorking 3.x，可以使用此类代码：
AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc] initWithBaseURL:[NSURL URLWithString:host]];
[manager POST:path parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> _Nonnull formData) {
//local file url,for you is /Users/macmini/Library/Developer/CoreSimulator/Devices/89104EAC-5BE1-4BEC-BE8E-7B8FFBF9CBD2/data/Media/DCIM/100APPLE/IMG_0005.JPG
NSURL *url = [NSURL fileURLWithPath:fileUrl];
[formData appendPartWithFileURL:url name:name fileName:fileName mimeType:mimeType error:nil];
} progress:^(NSProgress * _Nonnull uploadProgress) {
} success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
if (successBlock) {
if (responseObject) {
successBlock(responseObject);
}
}
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
if (failureBlock) {
HttpFailResponse *failResponse = [self _kep_configureFailResponseWithError:error];
failureBlock(failResponse);
}
}];