UI Frame Definition File (FDF)

FDF (Frame Definition File) is a plain-text declarative format used by Warcraft III to describe the UI frame hierarchy — positions, sizes, textures, fonts, and child frames. OpenWarcraft3 parses FDF files client-side in the Warcraft III UI runtime library (games/warcraft-3/ui/).

File Format

FDF files are hierarchical blocks enclosed in braces. The general form is:

FrameType "FrameName" {
    InheritsParts "BaseName"
    Width  0.025
    Height 0.025
    SetPoint TOPLEFT, TOPLEFT, 0.005, -0.005
    BackdropTileBackground false
    BackdropBackground "path\\to\\background.blp"
    ...
    ChildFrame {
        ...
    }
}

Frame Types

The following frame types are recognised by the Warcraft III UI parser (games/warcraft-3/ui/ui_fdf.c):

Type	Purpose
`BACKDROP`	Textured rectangle background
`BUTTON`	Clickable button with up/down/hover states
`CHATDISPLAY`	Scrolling chat log area
`CHECKBOX`	Toggleable checkbox
`DIALOG`	Modal dialog container
`EDITBOX`	Single-line text input
`FRAME`	Generic container
`GLUEBUTTON`	Menu/glue screen button
`GLUECHECKBOX`	Menu/glue screen checkbox
`GLUEEDITBOX`	Menu/glue screen text input
`GLUETEXTBUTTON`	Menu/glue screen text button
`HIGHLIGHT`	Highlight overlay
`LISTBOX`	Scrollable list
`MODEL`	Inline 3D model viewer
`POPUPMENU`	Drop-down menu
`SCROLLBAR`	Scroll bar control
`SIMPLEBUTTON`	Lightweight button
`SIMPLEFRAME`	Lightweight container
`SLIDER`	Numeric slider
`SPRITE`	Animated texture
`TEXT`	Static or dynamic text label
`TEXTAREA`	Multi-line text area
`TIMEDTEXTFRAME`	Timed-display text

Common Properties

Property	Description
`Width <float>`	Frame width as a fraction of the screen width
`Height <float>`	Frame height as a fraction of the screen height
`SetPoint <anchor>, <target>, <x>, <y>`	Attach a frame anchor to a parent anchor with an offset
`SetAllPoints`	Stretch to fill the parent
`InheritsParts "Name"`	Copy all properties from the named base template
`BackdropBackground "path"`	Texture path for the backdrop
`BackdropTileBackground <bool>`	Tile the texture instead of stretching
`BackdropEdgeFile "path"`	Texture for the nine-slice border edges
`BackdropEdgeSize <float>`	Width of the border region
`FontString <font>, <height>, <flags>`	Text font and size
`Text "<string>"`	Default text content
`Color <r> <g> <b> <a>`	RGBA vertex colour (0–255 each)

Anchor Points

SetPoint accepts one of nine named anchor points:

TOPLEFT, TOP, TOPRIGHT, LEFT, CENTER, RIGHT, BOTTOMLEFT, BOTTOM, BOTTOMRIGHT

The offset is specified in screen-width fractions:

SetPoint TOPLEFT, TOPLEFT, 0.02, -0.02

This aligns the frame's top-left corner 2% from the screen left edge and 2% from the top.

Frame Registry

UI_ParseFDF (games/warcraft-3/ui/ui_fdf.c) tokenises the FDF text, constructs frameDef_t structs, and stores them in the global frame registry keyed by name. Screen controllers query the registry, parent frames into the active tree, and draw through games/warcraft-3/ui/ui_render.c.

Programmatic API

Frames can also be created directly in C without any FDF text using the API described in ui_fdf.c:

FRAMEDEF f;
UI_InitFrame(&f, FT_TEXT);
UI_SetPoint(&f, FRAMEPOINT_TOPLEFT, NULL, FRAMEPOINT_TOPLEFT, 0.05, -0.30);
UI_SetText(&f, "Hello, world!");

Helper functions:

Function	Purpose
`UI_InitFrame(frame, type)`	Zero-initialise and set the frame type
`UI_SetPoint(frame, point, rel, targetPoint, x, y)`	Anchor a point to a relative frame
`UI_SetSize(frame, width, height)`	Set explicit dimensions
`UI_SetText(frame, fmt, ...)`	Printf-style text assignment
`UI_SetTexture(frame, name, decorate)`	Assign a texture by skin-entry name
`UI_SetParent(frame, parent)`	Attach to a parent frame
`UI_DrawFrame(frame)`	Draw a frame and its descendants

For draw-call inspection, use the stdout renderer:

make run-ui-text

Source	Purpose
`games/warcraft-3/ui/ui_fdf.c`	FDF text parser and programmatic frame API
`games/warcraft-3/ui/ui_main.c`	Loads FDF/theme assets and executes `ui_start_command`
`games/warcraft-3/ui/ui_render.c`	Layout solving and frame rendering
`games/warcraft-3/ui/ui_theme.c`	Warcraft theme file loading
`games/warcraft-3/ui/screens/*.c`	Screen controllers
`renderer/r_stdout.c`	Text renderer for draw-call diagnostics