If I use GetIconTagList() on any icon, then on AROS & OS4 it returns a nice object for me, but on MorphOS it always seems to fail (return NULL). I've tried changing various parameters, without luck.

Has anyone successfully used GetIconTagList()?

icon.library provided by ambient is merely a simple wrapper to accommodate for most needs of an application.

You can check the implementation here:
http://morphosambient.cvs.sourceforge.net/viewvc/morphosambient/ambient/iconlib/private.c?revision=1.13&view=markup

As you can see it's rather basic, just calling GetDiskObject for the name pretty much.

You can use following tags to get icon image with GetIconTagList():

ICONGETA_PNGBitMap 256
ICONGETA_PNGBitMap_Width 257
ICONGETA_PNGBitMap_Height 258

They are semi official (i.e. not found from the SDK) but since Ambient is open source they are public tags.

struct BitMap *bm;
ULONG w, h;

APTR diskobj = GetIconTags("foobargame", ICONGETA_PNGBitMap, &bm,
ICONGETA_PNGBitMap_Width, &w, ICONGETA_PNGBitMap_Height, &h, TAG_DONE);

Icon bitmap is valid until you destroy returned disk object. If retrieved icon is not a PNG icon then bitmap pointer is NULL and you can use old style planar bitmap from returned disk object.

Internally GetIconTagList() is calling GetDiskObject() and it should return something (if icon exists, that is)...

@itix Quote:
Would I have to somehow use the "do_Gadget" member to access this "old style bitmap"?

Yes you would have to. It is probably easier just provide some placeholder than start parsing GadgetRender data. Certainly I wouldnt.

@Itix (and Piru!)
Thanks for your hints. I've got PNG icons loading nicely (after handling the alpha mask).

I've also kind of got non-PNG (old style planar) icons loading, but anything above about 3 bitplanes looks horrible, presumably due to the lack of a proper palette. Any idea where that would be specified in the icon?

(I guess an alternative to reading the planar data would be to attach the gadget to a window, which should cause the gadget to render itself, then we can copy the result into a bitmap... but this means that a small window will temporarily open each time an icon is read. Not ideal.)

I wrote: Quote:
I tried this idea, and it actually worked on AmigaOS... but just crashes the whole machine on MorphOS, so I guess I'm trying to use some stuff which was never fully implemented on MorphOS?

So it seems I need to go back to my earlier method... and somehow extract the icon's palette (but I have no idea where it is stored).

I wrote:Quote:
I should add that this is for high-colour icons from OS4.

I just tested my code on OS4, and somehow it (usually) gives the right result on OS4. So perhaps this is something else which simply isn't implemented on MorphOS? Although somehow Ambient still manages to display high-colour icons from OS4!