i am trying to load images from URL to UIIMageView.
it works fine, but i want to download the images at a lower resolution/size
because its taking too long to load.
i have tried to use AFNetworking+UIImage class but the performance are the same.
[iv setImageWithURL:[NSURL URLWithString:#"http://cegamers.com/wp-content/uploads/2011/06/automaton.jpg"] placeholderImage:[UIImage imageNamed:#"placeholder-avatar"]];
anyone know how a library or some kind of way for this?
Generally you can't do it without server-side help. Usually you'd rely on the server generating thumbnails for you. There are image conversion proxy servers that will download the full image server-side, and serve a resized version to you.
Without any sort of server-side resizing, the options are limited and not very good.
If the image is in progressive/interlaced format then you can download only part of the file, but that will be a low-quality approximation.
Unfortunately you can't know how much data you'll need in advance, so your best bet is to either request entire image and close the TCP/IP connection when you see you've got enough data (hopefully [NSURLConnection cancel] does that) .
Or you could download some arbitrary small amount of data using HTTP Range request and then estimate how much more you need to download (it might save some bandwidth, but it will cost you latency).
I'm not aware of anything in iOS SDK that would let you inspect how many progressive scans of a partially-downloaded JPEG file you've got, so you might need to get your hands dirty with libjpeg or your own JPEG parsing.
But really it'd be easier if you could download entire image server-side and generate a proper thumbnail for it.
Yes. If you simply add 's' to the end of the img_hash in any direct image link on imgur, then you get the small square version of it.
http://i.imgur.com/DkDdK.jpg <--- Direct link
http://i.imgur.com/DkDdKs.jpg <--- Small square version. Notice the extra s
Related
I've been playing around with making a draftjs plugin that lets the user paste in mixed text&image content from websites and have images auto-uploaded to the server. I've quickly come to the realization that it's not easy, simply because of how many different sites use different kinds of counter-measures for copy/pasting images. Standard image tags in page content are no problem - easily grab the src and handle the file upload from the url. However, many sites use all kinds of trickery to make this a pain. For example, some will only serve small thumbnails, requiring a GET request on the image with a hash key in order to retrieve a larger version. Others somehow seem to corrupt the image so that it's unreadable by the time it's been retrieved. Others still play with weird embed tags to mess with draftjs' image blocks.
But then I open up a Google Docs file, and find that when I copy any images into that from a website, there's never any troubles whatsoever. All the problematic websites that I'm finding myself having to write specific methods for retrieving from seem to be handled by Google Docs with ease.
Am I using completely the wrong approach by trying to retrieve images from a url? Does Google use a far superior approach (yes, I presume) - in which case, does anyone have any idea what that approach might be?
I need to download images from a website and display them on(?) multiple UIImageView.
Maybe I'll code a php to "read" the directory and search for images, write a XML file and use it as medium. But I'm not sure if it's the best way.
Let's see the options you have to fetch images from a website:
Fetching HTML and Parsing the HTML to find the images (on the iphone). Then downloading the images.
Writing a script (maybe PHP) that writes all image links to an XML file (or JSON), and then fetch the output of your script with all the links.
If you choose option (1) you'll need NSURLConnection to fetch data asynchronously (without blocking the UI). I would also use TFHpple to parse HTML using xpath queries, see this tutorial for help. Finally to fetch the images using their URLs you can use SDWebImage, SDWebimage also provides caching so your app will not download the same image multiple times.
The bad side of using option (1) is that any change in the Website you're getting the images from will break your app and you'll need to issue an update to the app store in order to fix it.
If you choose option (2), your app will be easier to fix if the website changes, you'll just need to modify your script.
If you go with option (2) you'll probably need NSURLConnection, NSXMLParser (or a third party XML parsing library) and to download the images I would recomend SDWebImage again. I would also advise using JSON (and NSJSONSerialization) instead of XML, just beacuse I find JSON easier to parse.
Yes, it will be very good if you write some php script to get image list (list of image urls).
After getting such urls you can asynchronously download and show them in image views. Look here for such async image view implementation
We're currently working with Filepicker.io to allow users the ability to upload both images and videos. It appears that if we specify image conversions in the Javascript API options, video uploads don't process and instead get stuck at 99.30%. If I remove the 'conversions' option, video uploads process without issue. Is it not possible to specify image conversion options and accept both type of uploads? If so, this should really be specified in the docs.
I attached a JSFiddle with the code in question. http://jsfiddle.net/BYkD4/
It might be an issue on our end, taking a look now. For large files (+1Mb) we split the file into chunks, upload them in parallel, and then reassemble them on the server side. We use browser progress up to the 90% mark, after which we have to "best guess" what the server-side progress looks like, for now at least. That's the reason why it's hanging at 99.30% - it may actually be able to complete if you give it enough time.
In any case, looking into it
Edit: looks like this was an issue on our end. Fix deployed, everything should be working fine. Sorry about the issue
Since the past few months, I've been noticing that they tend to some kind of pixelated image first which then gets replaced by a much better image.
Is this some kind of trick to reduce perceived latency by facebook?
Or is it Chrome doing it?
i think it's progressive image rendering. Quote from the linked blog
Images already render progressively in a web browser -- but you can do even better. Simply save your GIF or PNG images with the "interlaced" option, or your JPEG images with the "progressive" option.
This blog might answer your query - checkout following links -
Image Optimization Part 3: Four Steps to File Size Reduction
Image Optimization Part 4: Progressive JPEG…Hot or Not?
I am planning to cache the images from a server and use show it as a sort slide show in my App. I would be asynchronously loading the images.
I have two options:
Either to cache the images as a File and use it whenever necessary.
Cache the images objects in memory and use it when ever necessary and write it in to files when Application quits.
Which one would be better?
Please let me know if you you have any kind of suggestions regarding caching images.
Your second approach has 2 major flaws:
If there's too many images then your application will get low memory warning and you'll have to dispose your images from memory anyway
It's also not a good idea to save all images to file on application quit - it is not guaranteed that your saving code will finish on application exit (e.g. if it takes too long system may just terminate your app and your images will be lost)
I'd suggest saving images to files right after you download them and keep in memory reasonable number of images you need to show without visible delay (loading extra images when required and disposing of unnecessary ones)
I would recommend you the first option. Leaves you more flexibility, e.g. when the data size increases the memory size.
I'd do it like this: Have a NSMutableDictionary with the cached images (as UIImage objects). If the image is not in the cache, look whether it's available as a file. If it's not available as a file, load it, put it into your dictionary and also write it to a file.
As for where to write the files to: you can either use the NSTemporaryDirectory() or create a directory inside your NSLibraryDirectory (use NSSearchPathForDirectoriesInDomains to locate it). The later has the advantage/disadvantage that it will be in the iTunes backup (whether that's an advantage or not depends on the use case). Using the Library directory is Apple's recommended way of storing data that is backed up but does not appear in the iTune's file exchange thingy (Documents directory).
I have started using EGOImageView to handle my caching; it's very versatile and handles the intricacies of caching for you.
It works very well for pulling images via http, you can find it on the EGO developer website here
http://developers.enormego.com/
For image caching solution on iOS platform, you might want to consider SDWebImage framework available at: https://github.com/rs/SDWebImage. It is very easy to integrate and takes care of all your image caching worries.: read more about the working here: https://github.com/rs/SDWebImage#readme
We recently picked this up for our app and it works great.