int ok = IsImage(STRPTR filename, struct LoadImageCtrl *ctrl);

Width:

Must be set to the image width in pixels.

Height:

Must be set to the image height in pixels.

Depth:

Set this to the bit depth of the image. (V9.0)

AlphaChannel:

Must be set to True or False, depending on whether or not this image has an alpha channel.

Flags:

Your implementation may set the following flags:

HWIMGFLAGS_TRANSPARENCY:

Set this flag to tell Hollywood that the image has a monochrome transparency channel (e.g. a transparent pen in a palette-based image). (V6.0)

The following members of struct LoadImageCtrl are set by Hollywood before it calls your implementation of IsImage():

Adapter:

Starting with Hollywood 6.0 users can specify the file adapter that should be used to open certain files. If this member is non-NULL, Hollywood wants your plugin to use the file adapter specified in Adapter to open the file. This means that you have to use hw_FOpenExt() instead of hw_FOpen() to open the file. Make sure to check for Hollywood 6.0 before trying to access this member because it isn't there in previous versions. See hw_FOpenExt for details. (V6.0)

UserTags:

This member will be set to a list of user tags in case they were specified in the Hollywood script. User tags are a way of passing additional information from Hollywood scripts to plugin functions. Note that even if your plugin doesn't support any user tags, you should still look for this tag and pass the user tags to hw_FOpenExt because the user tags passed in UserTags could also be intended for another plugin, namely the file adapter plugin passed in Adapter. See User tags for details. Make sure to check for Hollywood 10.0 before trying to access this member because it isn't there in previous versions. (V10.0)

You must not touch any other members of the struct LoadImageCtrl pointer that is passed to this function. See LoadImage for details on this structure.

filename

filename to examine

ctrl

pointer to a struct LoadImageCtrl for storing information about the image

ok

True if the plugin wants to handle this file, False otherwise