Assets naming for iPhone and iPad - iphone

Question

Is it possible to have an image asset named architecture.png and rename it as architecture~ipad.png for the iPad version? And still use it in code as:
[UIImage imageWithName:#"architecture.png"];
will this then look for architecture~ipad for the iPad version?

Answer 1

If you have two image resources in your app:
"architecture.png" (iPhone version)
"architecture~ipad.png" (iPad version)
then
[UIImage imageWithName:#"architecture.png"]
will automatically load the correct one on iPhone/iPad devices.
(As DOOManiac correctly noticed, this works on iOS 4 and later.)
For more information, see "iOS Supports Device-Specific Resources" in the Resource Programming Guide.

Answer 2

Update:
From the link iOS Supports Device-Specific Resources, It looks like this is possible from iOS 4.0 onwards.
In iOS 4.0 and later, it is possible to mark individual resource files
as usable only on a specific type of device. This capability
simplifies the code you have to write for Universal applications.
Rather than creating separate code paths to load one version of a
resource file for iPhone and a different version of the file for iPad,
you can let the bundle-loading routines choose the correct file. All
you have to do is name your resource files appropriately.
To associate a resource file with a particular device, you add a
custom modifier string to its filename. The inclusion of this modifier
string yields filenames with the following format:
<basename><device>.<filename_extension>
The <basename> string represents the original name of the resource
file. It also represents the name you use when accessing the file from
your code. Similarly, the <filename_extension> string is the standard
filename extension used to identify the type of the file. The <device>
string is a case-sensitive string that can be one of the following
values:
~ipad - The resource should be loaded on iPad devices only.
~iphone - The resource should be loaded on iPhone or iPod touch
devices only.
You can apply device modifiers to any type of resource file. For
example, suppose you have an image named MyImage.png. To specify
different versions of the image for iPad and iPhone, you would create
resource files with the names MyImage~ipad.png and MyImage~iphone.png
and include them both in your bundle. To load the image, you would
continue to refer to the resource as MyImage.png in your code and let
the system choose the appropriate version, as shown here:
UIImage* anImage = [UIImage imageNamed:#"MyImage.png"]; On an iPhone
or iPod touch device, the system loads the MyImage~iphone.png resource
file, while on iPad, it loads the MyImage~ipad.png resource file. If a
device-specific version of a resource is not found, the system falls
back to looking for a resource with the original filename, which in
the preceding example would be an image named MyImage.png.
For devices which supports iOS < 4.0, you can follow the below approach. But I dont think it is needed any more. Still keeping it as it is.
One solution I can think of is, by defining a macro for iPad to append ~ipad.png for every image files. Then always call this macro while using this method as [UIImage imageWithName:imageName(#"architecture")]; which will convert it as [UIImage imageWithName:#"architecture.png"]; for iPhone and [UIImage imageWithName:#"architecture~ipad.png"]; for iPad.
For eg:-
#define IMAGENAME(Name) (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)?[(Name) stringByAppendingString:(#"~ipad.png")]:[(Name) stringByAppendingString:(#".png")]
and then use it as [UIImage imageWithName:IMAGENAME(#"architecture")];
it can also be defined as,
#define IMAGENAME(Name) (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)?[(Name) stringByReplacingOccurrencesOfString:#".png" withString:#"~ipad.png"]:(Name)
and then use it as [UIImage imageWithName:IMAGENAME(#"architecture.png")];
Another solution is to subclass UIImage class and override imageWithName method to have this logic implemented here. You need to search for .png in the name param and replace it with a ~ipad.png for iPad. After that you can directly use it as [UIImage imageWithName:#"architecture.png"] for both iPad and iPhone. This can also be achieved by creating a category on NSObject or UIImage. I dont think there are any other ways to achieve this.