Resizing an image before uploading to server on iOS - ios

Question

I'm trying to resize an image in a photo app and haven't been successful yet. I'm new to photo resizing on iOS, but I swear that I'm doing this right, but my logs show:
Error: <WUTModelImageUploadReq>
[photo]: <nil>
[extension]: <nil>
</WUTModelImageUploadReq>
I'm trying to set 'scaleImage' as the image in the AsyncPostFeed.m
Here is my code:
UIImage+Scaling.m
#implementation UIImage (Scaling)
- (UIImage *)scaleImageToSize:(CGSize)newSize {
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
CGFloat originX = 0.0;
CGFloat originY = 0.0;
CGRect destinationRect =
CGRectMake(originX, originY, newSize.width, newSize.height);
[self drawInRect:destinationRect];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
#end
WUTPostViewController.m:
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
...
}
WUTPostViewController.h:
#interface WUTPostViewController : WUTCommonViewController <UITextViewDelegate,UIAlertViewDelegate>
#property (strong, nonatomic) IBOutlet UILabel *lblUserName;
#property (strong, nonatomic) IBOutlet UIImageView *imageViewForPost;
#property (strong, nonatomic) IBOutlet UITextView *tvDesription;
#property (strong,nonatomic) UIImage *imageForPost;
#property (strong,nonatomic) UIImage *scaleImage;
- (void)wsPostLikeSuccessCallbackForPostId;
- (void)wsPostLikeFailCallbackWithMessage:(NSString *)errorMessage;
#end
AsyncPostFeed.m:
- (void)uploadPhoto {
WUTModelImageUploadReq *imageUploadReq = [[WUTModelImageUploadReq alloc]init];
// I'm trying to set scaleImage here
imageUploadReq.photo = [self encodeToBase64String:[UIImage imageWithData:UIImageJPEGRepresentation(self.viewControllerPost.scaleImage, 0.07f)]];
imageUploadReq.extension = #"jpg";
NSLog(#"Error: %#", imageUploadReq);
void (^wsSuccessHandler)(AFHTTPRequestOperation *operation, NSDictionary* responseObject) = ^(AFHTTPRequestOperation *operation, id responseObject){
NSLog(#"Pull Feed responseObject %#",responseObject);
NSError *error;
WUTModelPostImageResponse *wsResponse = [[WUTModelPostImageResponse alloc]initWithDictionary:(NSDictionary *)responseObject error:&error];
if (error) {
errorMessage = #"Failure to upload image.";
NSLog(#"Error: %#", error);
[self postExecuteFail];
}else{
if (wsResponse.success) {
WUTModelImage *imageTemp = [wsResponse.data firstObject];
[postItem setObject:imageTemp.photo forKey:#"photo"];
[self uploadPostFeed];
}else{
errorMessage = #"Failure to upload image.";
NSLog(#"Error: %#", error);
[self postExecuteFail];
}
}
};

Answer 1

Update
Looks like you forgot to set local variable scaleImage to scaleImage property of WUTPostViewController class.
Try this code (last line should make the trick):
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
self.scaleImage = scaleImage;
...
}
Original Answer
Your resizing algorithm is correct. I use the same in my project and it perfectly works.
Looks like you send scaleImageToSize: message to nil object. That's why the result of this message is nil.
You can verify this assumption by updating code in this way:
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
NSAssert(selectedImage != nil, #"Selected image is nil");
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
...
}
As you see I added NSAssert call, so your application will crash with provided message if selected image is nil.
If NSAssert is triggered, then you need look for root cause of the problem. Basically you need verify that _imageForPost variable is initialized before viewDidLoad method is called.

Answer 2

Please check first image are not null
CGSize size1=CGSizeMake(300,300);
UIGraphicsBeginImageContext(size1);
[selectgalleryimage drawInRect:CGRectMake(0, 0,size1.width, size1.height)];
UIImage *SELECTED_IMG1 = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();