I'm taking images from the camera or the camera roll and I'm saving them to core data using an ImageToDataTransformer class. I need to use these saved images in two different places in my app: 250x250 imageview and 50x50 imageview.
First, should I use png format for both imageviews?
Second, can I compress the image before I save it to core data, and what's the best way?
Third, should I save two different images, one for the big image and another for the thumbnail in a different view?
When Xcode builds your project, it automatically optimizes PNG files included in your project. So, I guess you should use PNG.
I don't know about runtime.
That would be a good idea if you have a table view and you want to show thumbnails. You wouldn't want to be loading the huge files, that would be excruciatingly slow.
Related
I currently working on a project that i need to display large images on a UITableView,this is very common problem for a lot of developers and learning with they threads i reached to the following procedure:
NOTE:The large images i refer,they all have 300x300px(600x600px,retina) and about 200kb,JPEG
Create a NSOperationQueue;
Download images asynchronously(Each image has 600x600px,corresponding to the #2x image);
Resize and create the non retina image(300x300px image);
Decompress both images;
Store all images on a NSCache;
After all that procedures have finished i update my UITableView on the main thread.I'am using a UITableViewCell subclass to draw all my needed content(As seen on Apple's sample codes).The main problem is that i'm confused about step 4(decompress images),my doubts:
NOTE:I'm currently storing my decompressed images on a NSCache.
Should i decompress the images and store then as UIImage's or NSData's?
How can i store the decompressed images?(NSCache,NSMutableArray...)
What is the best way to pass the decompressed image to my UITableViewCell subclass?
NOTE:I'm using the decompression code presented here:link
You can't really store an UIImage object to disk, but you can turn it to NSData using UIImagePNGRepresentation
Using UIImage will give you cache out of the box, I bet it's the most efficient you can get
Just put the image into UIImageView, Apple spent a lot of time on making image rendering fast.
That said, your images are not particularly big, especially for retina devices, I would advice looking at something like AFNetworking library that has a complete and tested solution for this problem.
Plus, you can look up the code of AFImageRequestOperation which does exactly what you need: download, store, cache, reuse.
I am new with cocs2d. I have created an app using Cocos2d. The app is working fine but problem is that application size is too large 350MB. There are many images in this app. I have used png and where possible jpeg images. There are many png images that have larger than 1 mb.
Is there any way to reduce the application size. I've reduced the size whereever possible. Is there any other format that can be used in place of png? There are no many animations. The png are used only purpose of transparency.
Your images are way out of size. Even if you put them on server, and then download it will take time to download.
The best option is to reduce the image size. A couple of sites that can help you do that are:-
Reduce image size
Compress image size
You can keep the image content on your server and then download the image content asynchronously (which is more imp download it first). If there are levels then download initial levels first and download remaining on the background thread. You can always display a loader on launch and display some help kinda stuff meanwhile the data gets download and cached.
You can make use of SDWebImage and other libraries to get your images stuff async.
Hope it helps.
While your pictures are fairly large and you should try to reduce the number and size, you can make gains through packaging the .png into pvr.ccz files. There are multiple different programs available to do this. I like to use Texture Packer which is available here: http://www.codeandweb.com/texturepacker
You can find some tips in my post on reducing memory usage & bundle size.
Most importantly use texture atlases in .pvr.ccz format and where possible reduce image color depth to 16 bit. Avoid JPGs altogether because they're terribly slow to load in cocos2d.
There is no issue in using png files although your images are too large, You can reduce their size by 70 - 80% by using tinypng and it will not going to hurt your graphics.
https://tinypng.com/
I usually edit the image size now https://resizeimage.io , you try!
I am facing a problem, hope some one will help me to sort it out. I am working on an application that saves png files in the documents folder of the iPhone application, and also user can view the files that were saved.
So, i want to know is there any way to find out the dimension of the file being displayed? so that, if image dimension is bigger than my imageView then i can make them scroll, currently image is shrink.
this may help...
ImageIO framework (CGImageSource...)
similar Q to accessing UIImage properties without loading in memory the image
Create a UIImage from the file, using imageWithContentsOfFile:. The size of the image is held in the size property of your new UIImage object.
I need to create a very short background animation for the entire iPhone screen. I am trying to figure out whether I should use a video or animate a series of PNG files.
Does anybody know the advantage of using video as an app background instead of the series of PNG files being animated inside UIImageView? I heard that video can be compressed to really small size and will look better that animated PNGs.
Thanks in advance.
I really don't think using a video rather than a series of PNG is a good idea. You'll make your life more complicated for a few kilobytes saved, if you even save any.
It is of course highly dependent on what exactly you are trying to animate, and where you try to save space. For example, if you try to save memory in the binary and if you have your PNGs (already well compressed format) in a zip that you unzip on the fly, most similarities will be factored out by the zip algorithm. If you're trying to save space in memory during the game itself (not in the binary), then this doesn't count. However, loading up the video library binaries has a serious chance to clutter your memory more than the few PNGs will.
This project does the job with JPG, it should be very easy to change that with PNG ;)
I have an iPhone application that downloads images from the internet and saves them for display later.
The user can select the images to view from a UITableView, the table view has custom cells which display thumbnails of the original images in varying sizes.
When the large image is first downloaded it is scaled to thumbnail size and the thumbnail is saved using UIImagePNGRepresentation.
What I would like to do is save the thumbnail in the optimized iPhone PNG format. How can I do that? does it happen magically just by loading the original large image into memory and saving it? Do I have to do any further processing on the thumbnail before saving?
Chances are the UIImagePNGRepresentation does not create the images, as they are non-comformant PNGs, and can't be read by anything else. If they API generated PNGs that could not be read I think it would document that, and anyone who uploads PNGs from the phone would notice that they did not work.
The optimization is useful, but most of the optimized PNGs are part of the UI where the optimization is done as part of the build process. Chances are the cost of performing the optimization will offset any gains you get from it.
So it turns out that the RGB565 colorspace used in the optimized format is simply not available in a CGGraphicsContext, which is the rendering class used by all the UIwhatever components.
So if I DID write some code to change the color space of the image before saving it, I couldn't get the texture back into a UI class. The only way to use it is to load it directly into the OpenGL innards and use OpenGL in my app.
Don't worry about the "optimized PNG" format, as it isn't making any significant difference.
It does not affect rendering speed at all, and loading speed is dictated by file size more than file format.
So simply save it in a format that will give you smallest files. If you're not using transparency, then it might be JPEG.
If you need transparency, and can spend more CPU time when saving images, then include pngquant in your program (it's under BSD-like license) and shrink those PNGs to 8-bit palette.