iPhone 4 has 960-by-640 resolution while iPhone 3G only 480-by-320. Do I have to design 2 different res. versions on of each on screen image when building app and targeting both devices? I'm building simple game with UIKit, and currently, most of my app on screen items are designed with interface builder. If separate version for each item is required than how to implement that?
No, you don't have to do double the work.
Lay out all of your screens assuming 320x480.
Create your graphics (typically PNG files) assuming a 640x960 display. Then create copies of each of the files at 50% of the original size. Use Apple's naming convention (below) and you'll be good to go -- high res graphics on retina displays and lower res graphics on non-retina displays.
Name a typical image file:
"myImage#2x.png" // for the retina image
"myImage.png" // for the non-retina image
If you load the graphic programmatically, use:
UIImage *theImage = [UIImage imageNamed:#"myImage"];
Or you can just specify "myImage" in Interface Builder - it will load the right one automatically.
Related
I have icons inside my application for uibutton & on uitable cell. Lets say I have image named "sampleImage.png". Can my app use the image named "sampleImage#2x.png iphone with retina display automatically provide it is in my app bundle ?
If yes how can write code for it because I have code like
cell.imageview.image = [UIImage named:#"sampleImage.png"];
Does it work even if I hardcoded the image name?
Any kind of help is appreciated.Thanks
Yes, UIImage will automatically use the #2x version of an image on a retina display.
Searching for an answer of your question I came across this: what is the code to detect whether ios app running in iPhone, iPhone Retina display, or iPad?
One of the answers mentions this:
There's often no need to determine directly whether you're on a retina display because UIImage handles that automatically when you use imageNamed and append "#2x" to your high resolution image file names (see Supporting High-Resolution Screens in the Drawing and Printing Guide for iOS).
I have an iPhone Xcode project that currently only contains images for retina display (twice the size as normal and with a #2x.png suffix). When I run the app on the iPhone Simulator (non retina) the images are still being displayed. Does this mean I don't need to worry about including two sets of images: retina and non-retina?
This all seems a bit odd. I would assume that no images would appear on a non retina device if there are no non-#2x files included.
Note: I have not tested my app on a non retina device. Just the simulator.
I'm pretty sure that iOS will just use the #2x and scale it down if you don't have a non-retina graphic. Although that's sub-optimal since you're letting iOS do the scaling at runtime which will be slower than including the non-retina graphic and also iOS might not do as good a job as scaling as your graphics editor of choice.
Even if it works, it's not good practice, and if you have a media heavy app definitely it would impact performance and battery life and memory foot print and ....
By the way, is it just that you don't have the 1x graphics available to you or you are concerned about your apps (download size) or ...
If you are assigning the images in Interface Builder, and you set the image property on a UIImageView to image#2x.png, for example, iOS will not know that it's a high resolution "2x" image. In fact, on a retina display, iOS will look for an image named image#2x#2x.png. Since it won't find it, it will set the scale factor of the image to 1.0.
The contentMode property (just "mode" in XCode) will decide if any scaling of the image occurs to fit the constraints of the UIImageView. You may wish to set the mode to "Aspect Fit" to get the high resolution image to scale as needed for both retina and non-retina displays. In general, the image will display as seen in Interface Builder.
If you are using UIImage's imageNamed or similar function to load the image, and just specify image (where "image.png" doesn't exist, but "image#2x.png" does), then iOS will actually find the image on a non-retina display, though the scale factor will be 1.0. As previously, you'll need to scale it to fit your view. The image will work normally on a retina device, and the scale factor will be set to 2.0, since iOS looks for a "2x" image first, and it doesn't matter if the other file exists or not.
This is from Apple's documentation on imageNamed:
On a device running iOS 4 or later, the behavior is identical if the
device’s screen has a scale of 1.0. If the screen has a scale of 2.0,
this method first searches for an image file with the same filename
with an #2x suffix appended to it. For example, if the file’s name is
button, it first searches for button#2x. If it finds a 2x, it loads
that image and sets the scale property of the returned UIImage object
to 2.0. Otherwise, it loads the unmodified filename and sets the scale
property to 1.0. See iOS App Programming Guide for more information on
supporting images with different scale factors.
If at all possible, you really should include both retina and non-retina images. Using higher-resolution images than necessary negatively affects memory and performance.
I have a few questions about screen resolution, that I'm not clear on. These questions assume they my app will be running on iOS 4.0 and up, and on either iPhone 3GS or iPhone 4.
Should the size of the splash image (default.png) be (960x640) or (480x320)?
Should the size of the app icon (Icon.png) be (57x57) or (114x114)?
What about other graphics that I may use in my app, such a graphic that represents a button? Should I always create these images for the higher resolution, and have the app scale them down? In other words, if I want a button image to be displayed on the 3GS that is 200x40 - should I create the image at 400x80, so that iPhone 4 can take advantage of it?
Thanks!
A good guide to this can be found here: http://mobile.tutsplus.com/tutorials/iphone/preparing-your-iphone-app-for-higher-resolutions/
In general you just create 2 sets of images. Your original and then a new one twice as big with #2x in the name. So for image.png at size 32x32 you would have one that is twice the resolution called image#2x.png at size 64x64. In your app just always use the image.png in Interface Builder and when loading in code.
There is no need to detect the device. These images will automatically be picked up by the OS and subbed in as necessary.
Provide both sizes (960x640 & 480x320) for the splash image using the #2x method described above
Provide both icons (57x57 & 114x114) using the #2x method
For our apps we use a combination of the #2x images and just Scaling the large images. (More information on this can be found in the above article) We use the #2x images for bar buttons, icons, etc. But for UIImageViews we often just use the Scaling. There can be a performance hit for doing this, but for most apps I'd say this is negligible. The savings in file size sometimes make scaling the only option.
Related Questions:
Retina/non-retina images in UIImageView
Making an app Retina Display friendly
You need to provide both if you want them to look nice. For example,
Default.png -> (480x320)
Amd
Default#2x.png -> (960x640)
I'm developing my software, all the ui is drawn based on 480x320 size screen, can my software run on iphone4 without any modification?
Yes it can run with no modification.
If you'd like to create "retina" assets you can create all of your images at the double resolution and include copies with '#2x' appended to the filename in your Application bundle. The iPhone will automatically load the correct images.
Example:
existing image - myImage.png
new up-sampled image - myImage#2x.png
Yes, but any images sized for the earlier iPhone models will look chunky compared to custom-designed iPhone 4 images.
Both the iPhone 4 and older devices are 320x480 points in size, which is the coordinate system that Core Graphics and UIKit uses. So your software will run the same.
Only the automatic scaling between your bitmaps and the display will be different. If you have bitmapped content or images, you can optionally provide #2x sized versions that will look somewhat smoother without the 2X scaling on iPhone 4 devices. This is nice, but optional.
I'd like to design a background image for my app. The image should fill the iPhone screen.
What image size that will work for 3G and 4G?
A) 320 x 480.
B) 640 x 960.
I prefer to use B as it will have more quality, will 3G resize the image to fit?
Thanks for any help.
Simply author both sizes and save the hi-res with a #2x suffix in the filename (like background.png and background#2x.png). iPhone 4 will use the hi-res image, older devices will stick to the ordinary one. See the docs for +[UIImage imageNamed::
This method looks in the system caches
for an image object with the specified
name and returns that object if it
exists. If a matching image object is
not already in the cache, this method
loads the image data from the
specified file, caches it, and then
returns the resulting object.
On a device running iOS 4 or later,
the behavior is identical if the
device’s screen has a scale of 1.0. If
the screen has a scale of 2.0, this
method first searches for an image
file with the same filename with an
#2x suffix appended to it. For
example, if the file’s name is button,
it first searches for button#2x. If it
finds a 2x, it loads that image and
sets the scale property of the
returned UIImage object to 2.0.
Otherwise, it loads the unmodified
filename and sets the scale property
to 1.0. See iOS Application
Programming Guide for more information
on supporting images with different
scale factors.
Also read the appropriate part of iOS Application Programming Guide.
Although it is trivial to resize the image to the proper size, you should prepare both 320×480 and 640×960 (and probably you need a 1024×768 for iPad too). In this way the system can choose the best image for that model.
Basically, you create a 320×480 background.png for the older models, and a 640×960 background#2x.png for retina display. Then load the image with
UIImage* backgroundImage = [UIImage imageNamed:#"background.png"];
in this way, the system will choose the best resolution automatically.