icon.library — Workbench Icons (.info Files)

Overview

Every Workbench-visible file has a companion .info file containing its icon imagery, tool types (key=value metadata), default tool, stack size, and position. icon.library provides reading, writing, and manipulating these structures.

The .info file format is binary, not text. icon.library handles all serialization.

flowchart LR
    subgraph "Disk"
        FILE["myapp"]
        INFO["myapp.info"]
    end

    subgraph "icon.library"
        GET["GetDiskObject"] --> DO["struct DiskObject"]
        DO --> IMG["Icon imagery<br/>(selected + unselected)"]
        DO --> TT["ToolTypes<br/>(key=value strings)"]
        DO --> DT["DefaultTool<br/>(path to handler)"]
        DO --> POS["Position<br/>(x, y on Workbench)"]
    end

    INFO --> GET
    style DO fill:#e8f4fd,stroke:#2196f3,color:#333

struct DiskObject

/* workbench/workbench.h — NDK39 */
struct DiskObject {
    UWORD           do_Magic;      /* $E310 = WB_DISKMAGIC */
    UWORD           do_Version;    /* WB_DISKVERSION (1) */
    struct Gadget   do_Gadget;     /* the icon gadget (contains imagery) */
    UBYTE           do_Type;       /* icon type: WBDISK, WBTOOL, etc. */
    char           *do_DefaultTool; /* default tool path */
    char          **do_ToolTypes;   /* NULL-terminated string array */
    LONG            do_CurrentX;   /* icon X position on Workbench */
    LONG            do_CurrentY;   /* icon Y position */
    BPTR            do_DrawerData;  /* drawer window position (BPTR) */
    char           *do_ToolWindow;  /* tool window spec (CON: string) */
    LONG            do_StackSize;   /* stack size for tool launch */
};

Icon Types

Constant	Value	Description	Workbench Behavior
`WBDISK`	1	Disk/volume icon	Opens drawer showing disk contents
`WBDRAWER`	2	Drawer (directory)	Opens drawer window
`WBTOOL`	3	Executable tool	Launches the program
`WBPROJECT`	4	Project (document)	Launches `do_DefaultTool` with this file as argument
`WBGARBAGE`	5	Trashcan	Special drawer for deleted files
`WBDEVICE`	6	Device	Shown in Workbench root
`WBKICK`	7	Kickstart disk	ROM update disk
`WBAPPICON`	8	AppIcon (OS 2.0+)	Application-registered dynamic icon

Reading Icons

struct Library *IconBase = OpenLibrary("icon.library", 0);

/* Load a DiskObject from disk: */
struct DiskObject *dobj = GetDiskObject("SYS:Utilities/MultiView");
if (dobj)
{
    Printf("Type: %ld\n", dobj->do_Type);
    Printf("Default tool: %s\n", dobj->do_DefaultTool ?
           dobj->do_DefaultTool : "(none)");
    Printf("Stack: %ld bytes\n", dobj->do_StackSize);

    FreeDiskObject(dobj);
}

/* Get the default icon for a file type: */
struct DiskObject *defIcon = GetDefDiskObject(WBPROJECT);
/* ... use defIcon ... */
FreeDiskObject(defIcon);

ToolTypes — Key/Value Metadata

ToolTypes are the Amiga's equivalent of application-specific metadata. They're stored as a NULL-terminated array of strings in the .info file.

/* Example .info file ToolTypes:
   PUBSCREEN=Workbench
   NOBLITTER=YES
   DONOTWAIT
   CX_PRIORITY=0
   (DISABLED_OPTION)
*/

struct DiskObject *dobj = GetDiskObject("myapp");
if (dobj)
{
    /* Find a specific ToolType: */
    char *screen = FindToolType(dobj->do_ToolTypes, "PUBSCREEN");
    if (screen)
        Printf("Public screen: %s\n", screen);  /* "Workbench" */

    /* Check if a ToolType exists (no value): */
    if (FindToolType(dobj->do_ToolTypes, "DONOTWAIT"))
        Printf("DONOTWAIT is set\n");

    /* Check for a specific value within a multi-value ToolType: */
    char *flags = FindToolType(dobj->do_ToolTypes, "FLAGS");
    if (MatchToolValue(flags, "DEBUG"))
        Printf("Debug mode enabled\n");

    /* Enumerate all ToolTypes: */
    char **tt = dobj->do_ToolTypes;
    while (*tt)
    {
        Printf("  ToolType: %s\n", *tt);
        tt++;
    }

    FreeDiskObject(dobj);
}

ToolType Conventions

Convention	Meaning	Example
`KEY=VALUE`	Named setting with value	`PUBSCREEN=Workbench`
`KEY` (no value)	Boolean flag — presence = true	`DONOTWAIT`
`(KEY)`	Disabled/commented out	`(CX_POPUP=NO)`
`KEY=val1	val2`	Multi-value (check with `MatchToolValue`)

Writing / Modifying Icons

/* Write a DiskObject to disk: */
PutDiskObject("myfile", dobj);

/* Create a new icon programmatically: */
struct DiskObject *newIcon = GetDefDiskObject(WBPROJECT);
newIcon->do_DefaultTool = "SYS:Utilities/MultiView";
newIcon->do_StackSize = 8192;

char *toolTypes[] = {
    "PUBSCREEN=Workbench",
    "DONOTWAIT",
    NULL
};
newIcon->do_ToolTypes = toolTypes;

PutDiskObject("myfile", newIcon);
FreeDiskObject(newIcon);

OS 3.5+ New-Style Icons

AmigaOS 3.5 introduced true-color icons (PNG-based) alongside the legacy planar format. The icon.library v46+ handles both transparently — GetDiskObject returns the best available format.

Feature	Legacy (OS 1.x–3.1)	New-Style (OS 3.5+)
Format	Planar bitplane imagery	PNG/true-color embedded
Colors	4–16 (Workbench palette)	24-bit true color
Size	Fixed (standard sizes)	Scalable
Transparency	1-bit mask	8-bit alpha channel
Storage	`do_Gadget.GadgetRender`	Extended chunks in `.info`

References

NDK39: workbench/workbench.h, workbench/icon.h
ADCD 2.1: icon.library autodocs
See also: workbench.md — Workbench integration (AppIcon, AppWindow)

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