Re: UTIs and type codes and extensions
Re: UTIs and type codes and extensions
- Subject: Re: UTIs and type codes and extensions
- From: "Julien Jalon" <email@hidden>
- Date: Wed, 14 Jan 2009 02:31:15 +0100
On Wed, Jan 14, 2009 at 2:14 AM, Randall Meadows <email@hidden>wrote:
> I'm just making sure I'm not missing something...
>
> There's no system-defined way to go from a UTI to an old-style file type
> code (which the UTI docs seem to refer to as a "tag") and back again, am I
> correct?
>
extern CFStringRef
UTTypeCopyPreferredTagWithClass(
CFStringRef inUTI,
CFStringRef inTagClass)
AVAILABLE_MAC_OS_X_VERSION_10_3_AND_LATER;
extern CFStringRef
UTTypeCreatePreferredIdentifierForTag(
CFStringRef inTagClass,
CFStringRef inTag,
CFStringRef inConformingToUTI) /* can be NULL */
AVAILABLE_MAC_OS_X_VERSION_10_3_AND_LATER;
extern CFArrayRef
UTTypeCreateAllIdentifiersForTag(
CFStringRef inTagClass,
CFStringRef inTag,
CFStringRef inConformingToUTI) /* can be NULL */
AVAILABLE_MAC_OS_X_VERSION_10_3_AND_LATER;
>
> For instance, my app can export files as TIFF, JPEG, or PNG. When the user
> makes the selection, I convert the selection popup menu to the appropriate
> UTI using the defined constants in UTCoreTypes.h (kUTTypeTIFF, et al). I'd
> like to generalize the subsequent code to take that UTI ("public.tiff" for
> example) and convert it to the appropriate type code ('TIFF'). The next
> logical step would be producing a file name extension based on that as well
> ("public.tiff" -> "tif").
>
> *All* this information is contained in the table at <
> http://developer.apple.com/documentation/Carbon/Conceptual/understanding_utis/utilist/chapter_4_section_1.html#//apple_ref/doc/uid/TP40001319-CH205-CHDIJFGJ>,
> but I could discern no way to actually do these types of conversions in a
> general manner.
>
> History: The reason I need to do this is, Photoshop is brain-dead when it
> comes to opening image files that happen to have no extension in the
> filename (and no file type code). Preview, QuickTime Player and
> GraphicConverter (and sometimes Safari) have NO problem identifying and
> opening the exact same files, sans extension, but PS simply says "Could not
> complete your request because Photoshop does not recognize this type of
> file." I am working around this by attaching type and creator codes to all
> the image files I export. (Yes, my client could avoid all this by simply
> including an extension to the image name, but old dogs, new tricks, and all
> that...)
>
You always can teach new tricks to old dogs... it's significantly more
difficult for human beings.
--
Julien
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