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New AppIcon functionality

Responding to menu commands

As of Workbench V44, it is possible to invoke menu actions for AppIcons just like they were normal icons. You have to tell Workbench which menu items your icon responds to using the tag item list you provide to AddAppIconA(). When one of the supported menu items is invoked, you will receive an AppMessage with the am_Class entry set to a value out of AMCLASSICON_Open..AMCLASSICON_EmptyTrash, corresponding to the menu item used.

The following BOOL tags are provided by AddAppIconA() to control which menu commands are supported by an AppIcon:

WBAPPICONA_SupportsOpen
WBAPPICONA_SupportsCopy
WBAPPICONA_SupportsRename
WBAPPICONA_SupportsInformation
WBAPPICONA_SupportsSnapshot
WBAPPICONA_SupportsUnSnapshot
WBAPPICONA_SupportsLeaveOut
WBAPPICONA_SupportsPutAway
WBAPPICONA_SupportsDelete
WBAPPICONA_SupportsFormatDisk
WBAPPICONA_SupportsEmptyTrash

Custom AppIcon rendering hook

The new tag WBAPPICONA_RenderHook takes a pointer to a struct Hook that will be invoked when rendering your AppIcon. With this hook and WorkbenchControlA() you can create dynamic or animated AppIcons. Your hook will be called with the following parameters and has to return a result value:


result = hookFunc(hook, reserved, arm)
  D0               A0     A2      A1

LONG hookFunc(struct Hook *hook, APTR reserved,
              struct AppIconRenderMsg *arm);

struct AppIconRenderMsg
{
    struct RastPort *   arm_RastPort;
    struct DiskObject * arm_Icon;
    STRPTR              arm_Label;
    struct TagItem *    arm_Tags;
    WORD  arm_Left;
    WORD  arm_Top;
    WORD  arm_Width;
    WORD  arm_Height;
    ULONG  arm_State;
};

The reserved parameter will be set to NULL. The render message contents are as follows:

arm_RastPort
A pointer to the RastPort to render into.
arm_Icon
A pointer to the Icon to be rendered.
arm_Label
A pointer to the label text to be printed below the icon.
arm_Tags
Further control tags which you should pass on to icon.library/DrawIconStateA(), should you call this routine.
arm_Left
arm_Top
Rendering origin; note that these coordinates DO NOT take the embossing border sizes into account.
arm_Width
arm_Height
Size of the Icon's image area; you should limit your drawing to this area.
arm_State
An icon drawing state, such as used by icon.library/DrawIconStateA().

Note that all the data in the render message is read-only.

If your hook code returns TRUE, the AppIcon's regular image will be drawn. If your code returns FALSE, the regular image will not be drawn; this allows you to do all the icon's on-screen rendering with the exception of the icon image used when dragging the icon on the screen.

AppIcon positioning

The new WBAPPICONA_PropagatePosition tag allows the AppIcon's position to be propagated back to the original DiskObject you passed to AddAppIconA(). By default, Workbench will make a copy of that DiskObject's icon imagery, allowing the application to free the it. But if you specify WBAPPICONA_PropagatePosition,TRUE, Workbench will assume that you will not free the DiskObject and that the AppIcon's current position should be stored in its do_CurrentX/do_CurrentY members.

AppIcon selection

The new tag WBAPPICONA_NotifySelectState causes the application to be be notified whenever the AppIcon becomes selected or unselected. You will hear only state transitions, i.e. changes from selected to unselected state and the other way round. On a state transition you will receive AppMessages with the AppMessage->am_Class member set to AMCLASSICON_Selected or AMCLASSICON_Unselected, respectively.


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