It is possible for the plug-ins to use icons in their user interfaces (e.g. command panels). These icons are alpha-composited background icons and reside as *.bmp files in the \UI\Icons folder and are loaded during startup. It is also possible for the developers to integrate one or more resource based icons in their plug-in DLL file. In this case, those resource based icons will need to be converted to external icons and be stored as 24-bit image files with associated 24-bit alpha mask image files. The name of these files follow a fairly standard naming convention. As an example, the material editor icons and image files will be used for the following outline. The icon image files for this example can be found in the \UI\Icons folder as:

MeditImages_a.bmp//The 24-bit icon alpha mask

MeditImages_i.bmp//The 24-bit icon images

One difference with ordinary icon formats is that these use an alpha mask instead of an XOR mask. An XOR mask needs to be inverted in order to create a proper alpha mask out of it. The process for this is fairly straightforward; copy the images directly to a file (i.e. myicons_i.bmp), invert the mask file and storing that in the associated file (i.e. myicons_a.bmp). This process will result in icons which are identical to the XOR masked versions. Of course, you can also tweak the alpha mask to give it fuzzy edges and other effects you might like for your icons to help composite with the background color in a seamless and smooth way.

In the plugin code you will need to create image lists for the icons. Once again, taking the material editor as an example, you can create the image list in the following manner:

hMeditImages = ImageList_Create(BUTW, BUTH, ILC_COLOR24 | ILC_MASK, 5, 0);
LoadMAXFileIcon("MeditImages", hMeditImages, kBackground, FALSE);

The first thing we do is to create an image list with 24-bit images and a mask. Next, we need to call LoadMAXFileIcon()to load the images into the image list. See below for more information on this function.

If you want your icons to respond when the user customizes colors, you will need to implement a color change callback to reload the icons. This is not required, but it does enable your UI to integrate well with the color customization system. You need to create a callback as outlined below:

staticvoidColorChangeNotifyProc(void* param, NotifyInfo* pInfo)
{
   ImageList_RemoveAll(hMeditImages);
   LoadMAXFileIcon("MeditImages", hMeditImages, kBackground, FALSE);
}

Then you will need to register it after you load the icons for the first time:

RegisterNotification (ColorChangeNotifyProc, NULL, NOTIFY_COLOR_CHANGE);
	 

This way your buttons will always look correct when the user starts customizing colors.