I am working on an application where we are dealing with lots of images (Capturing , uploading, downloading from the server and displaying them).
If we are capturing images from iOS or any big resolution of Android devices, the captured images are coming properly without losing the quality.
But I am facing problem when images are getting captured from low end devices having low resolutions. (Android's lower end devices)
Is there any way to handle such scenario where irrespective of device resolution the image should not loose the quality.
You're pretty much stuck with the camera capabilities for that device. If the device has a camera that is 3.2MP, then it will only be able to create an image with a maximum resolution of 2048 × 1536, give or take.
Basically, you can downgrade an image's resolution, not upgrade whilst limited by the device's hardware.
Related
I have 2 iOS apps that have been in the market, 3 years on iPhone, 2 years on iPad HD version. The apps are a popular reference tool in the medical field. They are both comprised of 1100+ images. The current app size is roughly 52mb.
Approximately 400 images will be redone. They are currently jpg and low resolution. The replacements will be png, with higher resolution.
I'm uncertain on pixel size for these images. If they are in the 280x280 range, each file is about 100k, if in the 560x560 range, each file is almost 400k.
So I'd be looking at additional 40mb for the smaller images and 160mb for the larger.
There are plans for another 400+ images in the near future. So, I'm somewhat concerned with final app size.
If I went with the larger size for Retina devices, can I downsize for non-Retina devices?
If I supplied both sizes, image.png and image#2x.png, that would be 200mb just for these images.
I'm a little uncertain on how to manage these with regards to their individual size and, more importantly, their total size.
Any comments or suggestions are welcomed and would be helpful.
TIA,
jb
Here are a few options you have:
1. Downsizing Retina Images
I would not recommended downsizing retina images for the non-retina devices. This produces non-optimal performance and makes the images look bad. Your still loading in all the pixels of a retina image, but only displaying 1/4 of them.
2. Bundling All of the Images
Honestly for a medical reference app, I think it would be understandable if your app size would be quite large. I wouldn't imagine people would need to download this app over 3G or LTE. Your users understand this is a large database app which provides high resolution images, thus they should be okay with the large app size via this method.
3. Hosting the Images on a Web Service
Another alternative would be to host the images on a server, allowing them to be downloaded individually as needed, or in bundles. I think your users would prefer being able to fully use the app without internet connection rather than having a smaller app size.
4. Alternative Image Loading
This approach takes a bit of work and could be a little risky. You could bundle only 2x versions of your images into the app. Then on App launch you could force the user to wait until you resize all the images to their 1x counterparts and save them off to the disk. Then you could create an image loading convenience method which loads a UIImage from either disk or the app bundle based on whether or not it needs a retina image.
I definitely recommend option 2 for your purposes. I only mentioned the others to be thorough.
I have a multiplatform iOS/Android game that I programmed in Cocos2d-x. I have only one set of images to use (I'm only after high res devices) that get scaled according to the device's resolution. For example all images are for the iPad but if you are using a Galaxy S then the image locations and scaling are affected by GalaxyS_screenWidth/iPadscreenWidth.
This works fine for all Android devices and on iPad, iPad2 and old iPhones, but with Retina iPhone there is a problem. On the iPhone 4 all my images look extremely pixelated, a result from the images being scaled to iPhone non-retina resolution then scaled back up to fill the screen.
I tried enabling Retina Mode and the images are half of their intended size (maybe due to the usage of get winsize() which uses points) and scaling manually causes other sorts of problems. I tried playing with a lot of options and attributes but to no avail, so what should I do now?
EDIT:
This is not only a graphics issue, as text gets automatically scaled down then up and appears pixelated.
EDIT 2:
Fonts are bitmaps so my bad. But I don't want to use retina as all images are already retina by default. All of my images are set up for the iPad so for iPhone 4 I just scale them down a bit. This works with Android phones.
For example I have an image, depending on screen resolution obtained through getwinsize():
If current resolution width is 1024 then image stays the same.
If current resolution width is 900 then image gets scaled by 900/1024, no problem.
If device is iPhone 4 resolution width is 480, so image gets scaled by 480/1024, then cocos2d-x automatically scales the resulting image by 2 thus the pixelation. I tried using getwinsizeinpixels, I tried multiplying the screen size, I tried many things but nothing worked out of the box unless I am to redo many of my code.
So the question is, how can I just let the damn engine treat the iPhone 4 as an Android phone with resolution of 960x640?
If you want Retina resolution images to look like Retina resolution images, then those images need to be in Retina resolution (960x480).
If you first scale down the image to 480x320 and then upscale it on the device, it will of course look blurred. You can't magically make the Retina pixels appear from a lower resolution image by scaling it up.
SI couldn't get to the bottom of it so I employed a hack. I enabled Retina Display then I scaled everything x2 through code except for the text. Sounds stupid, but it worked, and pixelation is gone. Thanks everyone who spent time trying to help me.
I tried enabling Retina Mode and the images are half of their intended size
when you enable retina support, cocos2d gets images by appending #"-hd" to their provided filenames. Such images are meant to be double the "visual" size (in iOS terms, pixels vs. points), so that they can be sort of scaled down to make full use of device resolution.
If you have a look at the CCDirectorIOS class, you will find there a couple of methods dealing with this, especially those dealing with the scalingFactor. I don't know what kind of changes you should do to make it work, but if you step into those methods and look at the value of various objects, you might find a way to modify cocos2D default behavior for your specific case.
If this seems to complicated, one thing you could try is changing the CC_RETINA_DISPLAY_FILENAME_SUFFIX so that cocos2d will not look for specially-named files for the retina iPhone, but just use the normal ones.
For example all images are for the iPad but if you are using a Galaxy S then the image locations and scaling are affected by GalaxyS_screenWidth/iPadscreenWidth.
Another thing you might try is not using winSize, but winSizeInPixels, so that when you scale down, you down do it down to the point resolution, but just to the pixel resolution (which is double the point resolution).
Hope this helps.
I have a Universal photo type app in dev (iOS5+) and would like to offer the user the option to set the default image resolution, giving them some feedback as to image dimensions and the approximate file size per image. Since there are now so many devices with different camera capabilities, and different capabilities between front and back cameras on a device, this seems somewhat complicated.
Specifically:
Am I wrong in assuming that these presets vary by camera capability
per device (e.g. the sucky iPad 2 front camera "Photo" res is going
to yield an image of smaller dimensions than an iPhone 4G
How can I determine the image sizes of AVCaptureSessionPresetPhoto,
AVCaptureSessionPresetHigh, etc. per camera (by device, front +
back). If I know the size I can make a guess as to file size with a
given compression.
I'm using some animated gifs on our mobile-site. It's a clock-animation and since the iOS 5 update it sometimes happens that the clock gets blue instead of red, as planned. Happens on iPhone4 and iPhone5 with the new os.
Any ideas what could cause the problems? It's hard to reconstruct this failure but it happens from time to time.
Any help would be appreciated.
Sometimes ios devices may not be able to process all the images because of its relatively low graphics ability compared to that of a computer. Instead of using a GIF I would suggest using an animated PNG. This has been more popular among the ios devices as using GIFs has become obsolete when working with ios devices. I am not sure how fast this would be, but I would say it can apply less stress then that of a gif. Another idea, because it is a clock gif is to analyze the gif in a program and determine any problems. Also use imgoptim (for mac) or pngcrush for windows to reduce the size of the gif to reduce the stress on the processor.
use GIF 128 Dither and Please make sure that images size has to be base on the resolution it happen some time if your images size is not depend on retina or normal resolutions. And if I am not wrong you facing problem only in retina device, may be below details will help
iPhone Retina Display
~~~~~~~~~~~~~~~~~~~~~~~
Width - 640px
Height - 960px : including 40px status bar
DPI - 326
You can use Cocos2D framework, Cocos2d and UIKIT both work great with out any graphic related errors... Sprite sheets reduces the memory usage and also support all transparant images , you can run animation ,stop and repeat them. Good luck..
I have an app which display images in full Screen. Some of the images are 1952x3680 pixels and these images are raising memory warning level=1 and level=2.
How should i handle these image?
Scale your images down considerably. There is absolutely no reason you need images at that resolution in an iPhone app.
Don't use them. Either get your server to deliver a thumbnail version of the image (maybe using a thumb.php/jsp/asp/... file with GET params x=<width>&y=<height>), or scale the image down on the iPhone and discard the original data. The former method is vastly preferred as it saves on both bandwidth and large memory allocations client-side.
The largest images you should be working with are 480x320 (iPhone 3GS and earlier) and 960x640 (iPhone 4).
EDIT: The other situation I didn't think of is if you're bundling these images with the app. Please, please don't do that. If you have images that big, scale them down in Apple's Preview or any image editor to the sizes noted, and ideally have two copies, image.png and image#2x.png which are shown depending on the scale of the device's screen.
The screen itself is only 320x460 (not considering the clock bar on top), and 640x960 for retina display. There is no reason to have images this large to begin with. Scale them down. It'll both prevent the memory warnings and stymie unnecessary image size.
As said before, scale it down if you only want to show the image without zooming in fullscreen.
If you need to zoom and show it detailed, google for CATiledLayer. There are good examples around.