I'm using AFAmazonS3Manager to upload and download images from my S3 instance. Is there any way to specify the image dimensions prior to download so that I don't need to download full-sized images if only a thumbnail is needed? Previously, I was storing images on my EC2 server, so that I was able to resize and even crop images before returning them to the iOS end, making it so I would only return the size I necessary for the given iPhone (e.g. 5 vs. 6) and context. However, I can't figure out how to do it when images are stored on S3.
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I'm loading images on a list from a server. The UIImageView size is very small (40 x 40), So ideally an image with a size of 40 x 40 or a little larger should be loaded in it. However, the server guy is sending an image of a much larger size (1920 x 1200).
When I diagnosed the view controller memory I noticed that it increases as the image is loading.
So my question is
Will the Kingfisher library download a smaller size version of the image?
Will it abort the image loading if the image size is too big?
Is there any way by which can I specifically achieve the above task.
Kingfisher: https://github.com/onevcat/Kingfisher
Will the Kingfisher library download a smaller size version of the
image?
Nor Kingfisher nor any other library will download a smaller version of an image. The server has to send you a smaller version of it. (different url, or same url with a parameter)
Will it abort the image loading if the image size is too big?
I don't know how the library implements the downloading but unless you are talking about unreasonably big files (way bigger than the resolution you expect (1920x1200)) it will not be aborted. And even then, it probably won't be aborted but instead the app might be killed by the system when displaying super high resolution images (again, way bigger than 1920 x 1200)
Is there any way by which can I specifically achieve the above task.
If you want to display many many images at once and are worried about their sizes, its better to create thumbnails of them.
You can use Kingfisher to
1) first download the image
2) then resize the image
3) then show and cache it if you need
Check this page to see a ton of code snippets for that library.
https://github.com/onevcat/Kingfisher/wiki/Cheat-Sheet
My application receives images inside a JSON file and stores them in a Core Data. For different resolutions it imports different images, like #2x and #3x. Is it possible to set an UIImage to get the data for different resolutions same way as application does automatically with #2x and #3x files? As an option I can take this data from the Core Data and write it as separate files with corresponding names, but I'm not sure that this is an optimal way.
Thank you for your advices in advance!
Depending on the device being used you can determine the scale. This will not change in the device.
UIScreen.main.scale
Based on the scale download only the images with the relevant resolution (example: 1x or 2x or 3x). Don't have to download them all and rename without #1x / #2x / #3x
Personally I prefer to store the downloaded images in the cached folder instead of core data so that if it is low on disk space it can be removed automatically.
Download images on demand (only when required to be displayed) asynchronously.
I am writing an app that relays an image saved on the iOS device to a larger screen. Since a fullRes image is too large and takes long to transfer (using an on-device CocoaHTTP server), I am trying to load thumbnail first.
In Windows, we have a thumbs.db, which means that if we access that, there is no image-resizing etc ... its a thumbnail version of the image pre-saved by the OS.
Does the [UIImage imageWithCGImage:asset.aspectRatioThumbnail] for the ALAsset class in iOS does the same action, or does it load the complete hi-res image and then scales it down before returning?
The documentation does not specify but from my experiments reading the thumbnail is 5 times faster than loading the image from disk (even without decoding or scaling it). I assume iOS stores the pre-made thumbnails somewhere for fast access.
I have to create a custom photolib like the default one, with animation etc. I had some doubts..
1. Doubt
Should I create 3 images (Thumbnail image, 320*480 image to display full image and original size image in case user share the image) (I am storing this all in app doc directory)
Or should I only store the original image and crop them wen required in 2 other images? In this case, if I use scroll view to display cropped images, how do I know what the user is seeing? And when do I crop next images to keep them ready to display?
(Can anything like reusable cells be created here like in tableview? If yes, can you give me some idea?)
Also, I am fetching images from doc directory. In this case should I load all images in Array or load in batches?
2. Problem Major:
Also need to compress original image and keep it of same size (I used uijpegrepresentation with compression ratio but with some jpegs after compression. It increases sizes even double the size).
You can use single image and for thumbnail you can Resize at run time else it increase size and performance issue. there is lots of open source library are there which do same what you needed. Please have a look below.
https://github.com/arturgrigor/AGImagePickerController
https://github.com/gdavis/FGallery-iPhone
Hi all
I have an app now showing photos from URL, not from my own database (file system).
For example, a photo from Facebook:
http://sphotos.ak.fbcdn.net/hphotos-ak-snc1/hs085.snc1/5041_98423808305_40796308305_1960517_6704612_n.jpg
I've added the crop function to get the cropping area (x,y,w,h) of the photo.
And now I'd like to save the cropped image from the URL (i.e. without downloading the original image to my database before cropping)
Is it even possible?
Or is there anyway to get the image into memory to process without saving it to database?
I've searched some questions here, but they all talk about how to save the crop of images which have been uploaded to the database by users.
Thank you very much in advance.
How do you imagine cropping works without access to the original image? The process would be like this:
Download the remote image to a /tmp as a temporary file (Tip: TempFile)
Crop the crap out of it
Save the cropped image with Paperclip to your DB
Remove the temporary file