# Keyboard Geometry

The Xkb description of a keyboard includes an optional keyboard geometry that describes the physical appearance of the keyboard. Keyboard geometry describes the shape, location, and color of all keyboard keys or other visible keyboard components such as indicators. The information contained in a keyboard geometry is sufficient to allow a client program to draw an accurate two-dimensional image of the keyboard.

You can retrieve a keyboard geometry from an X server that supports Xkb, or you can allocate it from scratch and initialize it in a client program. The keyboard geometry need not have any correspondence with the physical keyboard that is connected to the X server.

Geometry measurements are specified in mm/10 units. The origin (0,0) is in the top left corner of the keyboard image. A component’s own origin is also its upper left corner. In some cases a component needs to be drawn rotated. For example, a special keyboard may have a section of keys arranged in rows in a rectangular area, but the entire rectangle may not be in alignment with the rest of the keyboard, and instead, it is rotated from horizontal by 30 o . Rotation for a geometry object is specified in 1/10 o increments about its origin. An example of a keyboard with rotated sections is shown in Figure 13.1.

Rotated Keyboard Sections

Some geometry components include a priority , which indicates the order in which overlapping objects should be drawn. Objects should be drawn in order from highest priority (0) to lowest (255).

The keyboard geometry’s top-level description is stored in a XkbGeometryRec structure. This structure contains three types of information:

1. Lists of items, not used to draw the basic keyboard, but indexed by the geometry descriptions that comprise the entire keyboard geometry (colors, geometry properties, key aliases, shapes)

2. A number of singleton items that describe the keyboard as a whole (keyboard name, width and height, a color for the keyboard as a whole, and a color for keyboard key labels)

3. A list of the keyboard’s sections and nonkey doodads

The top-level geometry is described in more detail in the following.

The lists of items used by components of the keyboard geometry description is as follows:

- The top-level keyboard geometry description includes a list of up to MaxColors (32) color names . A color name is a string whose interpretation is not specified by Xkb. The XkbColorRec structure provides a field for this name as well as a pixel field. The pixel field is a convenient place for an application to store a pixel value or color definition, if it needs to. All other geometry data structures refer to colors using their indices in this global list.

- The top-level keyboard geometry description includes a list of geometry properties . A geometry property associates an arbitrary string with an equally arbitrary name. Geometry properties can be used to provide hints to programs that display images of keyboards, but they are not interpreted by Xkb. No other geometry structures refer to geometry properties. As an example of a possible use of properties , consider the pause/break key on most PC keyboards: the "break" symbol is usually on the front of the key and is often a different color. A program might set a property to:

  LBL_PAUS = "{Pause/top/black,Break/front/red}"

  and use the property information to draw the key with a front label as well as a top label.

- The top-level keyboard geometry description includes a list of key aliases (see Chapter 18). Key aliases allow the keyboard layout designer to assign multiple key names to a single key.

  Key aliases defined in the geometry component of a keyboard mapping override those defined in the keycodes component of the server database, which are stored in the XkbNamesRec ( xkb->names ). Therefore, consider the key aliases defined by the geometry before considering key aliases supplied by the keycodes.

- The top-level keyboard geometry description includes a list of shapes ; other keyboard components refer to shapes by their index in this list. A shape consists of an arbitrary name of type Atom and one or more closed-polygon outlines . All points in an outline are specified relative to the origin of its enclosing shape, that is, whichever shape that contains this outline in its list of outlines. One outline is the primary outline. The primary outline is by default the first outline, or it can be optionally specified by the primary field in the XkbShapeRec structure. A keyboard display application can generate a simpler but still accurate keyboard image by displaying only the primary outlines for each shape. Nonrectangular keys must include a rectangular approximation as one of the outlines associated with the shape. The approximation is not normally displayed but can be used by very simple keyboard display applications to generate a recognizable but degraded image of the keyboard.

The XkbGeometryRec top-level geometry description contains the following information that pertains to the keyboard as a whole:

- A keyboard symbolic name of type Atom to help users identify the keyboard.

- The width and height of the keyboard, in mm/10. For nonrectangular keyboards, the width and height describe the smallest bounding box that encloses the outline of the keyboard.

- The base color of the keyboard is the predominant color on the keyboard and is used as the default color for any components whose color is not explicitly specified.

- The label color is the color used to draw the labels on most of the keyboard keys.

- The label font is a string that describes the font used to draw labels on most keys; label fonts are arbitrary strings, because Xkb does not specify the format or name space for font names.

The keyboard is subdivided into named sections of related keys and doodads. The sections and doodads on the keyboard are listed in the XkbGeometryRec top-level keyboard geometry description. A section is composed of keys that are physically together and logically related. Figure 13.2 shows a keyboard that is divided into four sections. A doodad describes some visible aspect of the keyboard that is not a key and is not a section.

Keyboard with Four Sections

## Shapes and Outlines

A shape , used to draw keyboard components and stored in a XkbShapeRec structure, has:

- An arbitrary name of type Atom.

- Bounds (two x and y coordinates) that describe the corners of a rectangle containing the shape’s top surface outline.

- A list of one or more outlines (described below).

- Optional pointers to a primary and an approximation outline (described below). If either of these pointers is NULL , the default primary/approximation outline is the first one in the list of outlines for the shape.

An outline , stored in a XkbOutlineRec structure, is a list of one or more points that describes a single closed-polygon, as follows:

- A list with a single point describes a rectangle with one corner at the origin of the shape (0,0) and the opposite corner at the specified point.

- A list of two points describes a rectangle with one corner at the position specified by the first point and the opposite corner at the position specified by the second point.

- A list of three or more points describes an arbitrary polygon. If necessary, the polygon is automatically closed by connecting the last point in the list with the first.

- A nonzero value for the corner_radius field specifies that the corners of the polygon should be drawn as circles with the specified radius.

All points in an outline are specified relative to the origin of the enclosing shape. Points in an outline may have negative values for the X and Y coordinate.

One outline is the primary outline; a keyboard display application can generate a simple but still accurate keyboard image by displaying only the primary outlines for each shape. The default primary outline is the first in a shape’s list of outlines. If the primary field of the XkbShapeRec structure is not NULL , it points to the primary outline. A rectangular approximation must be included for nonrectangular keys as one of the outlines associated with the shape; the approximation is not normally displayed but can be used by very simple keyboard display applications to generate a recognizable but degraded image of the keyboard.

## Sections

As previously noted, a keyboard is subdivided into sections of related keys. Each section has its own coordinate system — if a section is rotated, the coordinates of any components within the section are interpreted relative to the edges that were on the top and left before rotation. The components that make up a section, stored in a XkbSectionRec , include:

- An arbitrary name of type Atom.

- A priority, to indicate drawing order. 0 is the highest priority, 255 the lowest.

- Origin of the section, relative to the origin of the keyboard.

- The width and height and the angle of rotation.

- A list of rows . A row is a list of horizontally or vertically adjacent keys. Horizontal rows parallel the (prerotation) top of the section, and vertical rows parallel the (prerotation) left of the section. All keys in a horizontal row share a common top coordinate; all keys in a vertical row share a left coordinate. Figure 13.3 shows the alpha section from the keyboard shown in Figure 13.2, divided into rows. Rows and keys are defined below.

Rows in a Section

- An optional list of doodads ; any type of doodad can be enclosed within a section. Position and angle of rotation are relative to the origin and angle of rotation of the sections that contain them. Priority for doodads in a section is relative to the other components of the section, not to the keyboard as a whole.

- An optional overlay with a name of type Atom and a list of overlay rows (described below).

- Bounds (two x and y coordinates) that describe the corners of a rectangle containing the entire section.

## Rows and Keys

A row description ( XkbRowRec ) consists of the coordinates of its origin relative to its enclosing section, a flag indicating whether the row is horizontal or vertical, and a list of keys in the row.

A key description ( XkbKeyRec ) consists of a key name, a shape, a key color, and a gap. The key name should correspond to one of the keys named in the keyboard names description, the shape specifies the appearance of the key, and the key color specifies the color of the key (not the label on the key; the label color is stored in the XkbGeometryRec ). Keys are normally drawn immediately adjacent to one another from left to right (or top to bottom) within a row. The gap field specifies the distance between a key and its predecessor.

## Doodads

Doodads can be global to the keyboard or part of a section. Doodads have symbolic names of arbitrary length. The only doodad name whose interpretation is specified by Xkb is "Edges", which, if present, describes the outline of the entire keyboard.

Each doodad’s origin is stored in fields named left and top , which are the coordinates of the doodad’s origin relative to its enclosing object, whether it be a section or the top-level keyboard. The priority for doodads that are listed in the top-level geometry is relative to the other doodads listed in the top-level geometry and the sections listed in the top-level geometry. The priority for doodads listed in a section are relative to the other components of the section. Each doodad is stored in a structure with a type field, which specifies the type of doodad.

Xkb supports five types of doodads:

- An indicator doodad describes one of the physical keyboard indicators. Indicator doodads specify the shape of the indicator, the indicator color when it is lit ( on_color ) and the indicator color when it is dark ( off_color ).

- An outline doodad describes some aspect of the keyboard to be drawn as one or more hollow, closed polygons. Outline doodads specify the shape, color, and angle of rotation about the doodad origin at which they should be drawn.

- A solid doodad describes some aspect of the keyboard to be drawn as one or more filled polygons. Solid doodads specify the shape, color, and angle of rotation about the doodad origin at which they should be drawn.

- A text doodad describes a text label somewhere on the keyboard. Text doodads specify the label string, the font and color to use when drawing the label, and the angle of rotation of the doodad about its origin.

- A logo doodad is a catch-all, which describes some other visible element of the keyboard. A logo doodad is essentially an outline doodad with an additional symbolic name that describes the element to be drawn. If a keyboard display program recognizes the symbolic name, it can draw something appropriate within the bounding region of the shape specified in the doodad. If the symbolic name does not describe a recognizable image, it should draw an outline using the specified shape, outline, and angle of rotation. The Xkb extension does not specify the interpretation of logo names.

The structures these doodads are stored in and the values of the type fields are shown in Table 13.1.

### Doodad Types

Doodad | Structure | Type
--- | --- | ---
indicator doodad | XkbIndicatorDoodadRec | XkbIndicatorDoodad
outline doodad | XkbShapeDoodadRec | XkbOutlineDoodad
solid doodad | XkbShapeDoodadRec | XkbSolidDoodad
text doodad | XkbTextDoodadRec | XkbTextDoodad
logo doodad | XkbLogoDoodadRec | XkbLogoDoodad

## Overlay Rows and Overlay Keys

An overlay row ( XkbOverlayRowRec ) contains a pointer to the row it overlays and a list of overlay keys .

Each overlay key definition ( XkbOverlayKeyRec ) indicates a key that can yield multiple keycodes and consists of a field named under , which specifies the primary name of the key and a field named over , which specifies the name for the key when the overlay keycode is selected. The key specified in under must be a member of the section that contains the overlay key definition, while the key specified in over must not be.

## Drawing a Keyboard Representation

To draw a representation of the keyboard, draw in the following order:

         Draw the top-level keyboard as a rectangle, using its width and height.
         For each component (section or doodad) of the top-level geometry, in priority order:
            If component is a section
               For each row, in the order it appears in the section
                  Draw keys in the order they appear in the row
               Draw doodads within the section in priority order.
            Else draw doodad

## Geometry Data Structures

In the following figures, a solid arrow denotes a pointer to an array of structures or a singleton structure. A dotted arrow denotes an index or a pointer into the array.

Xkb Geometry Data Structures
Xkb Geometry Data Structures (Doodads)
Xkb Geometry Data Structures (Overlays)

    typedef struct _XkbGeometry {              /* top-level keyboard geometry structure */
          Atom                name;            /* keyboard name */
          unsigned short      width_mm;        /* keyboard width in  mm / 10 */
          unsigned short      height_mm;       /* keyboard height in  mm / 10 */
          char *              label_font;      /* font for key labels */
          XkbColorPtr         label_color;     /* color for key labels - pointer into colors array */
          XkbColorPtr         base_color;      /* color for basic keyboard - pointer into colors array */
          unsigned short      sz_properties;   /* size of properties array */
          unsigned short      sz_colors;       /* size of colors array */
          unsigned short      sz_shapes;       /* size of shapes array */
          unsigned short      sz_sections;     /* size of sections array */
          unsigned short      sz_doodads;      /* size of doodads array */
          unsigned short      sz_key_aliases;  /* size of key aliases array */
          unsigned short      num_properties;  /* number of properties in the properties array */
          unsigned short      num_colors;      /* number of colors in the colors array */
          unsigned short      num_shapes;      /* number of shapes in the shapes array */
          unsigned short      num_sections;    /* number of sections in the sections array */
          unsigned short      num_doodads;     /* number of doodads in the doodads array */
          unsigned short      num_key_aliases; /* number of key aliases in the key */
          XkbPropertyPtr      properties;      /* properties array */
          XkbColorPtr         colors;          /* colors array */
          XkbShapePtr         shapes;          /* shapes array */
          XkbSectionPtr       sections;        /* sections array */
          XkbDoodadPtr        doodads;         /* doodads array */
          XkbKeyAliasPtr      key_aliases;     /* key aliases array */
    } XkbGeometryRec*XkbGeometryPtr;

The doodads array is only for doodads not contained in any of the sections that has its own doodads . The key aliases contained in the key_aliases array take precedence over any defined in the keycodes component of the keyboard description.

    typedef struct _XkbProperty {
          char *      name;            /* property name */
          char *      value;           /* property value */
    } XkbPropertyRec,*XkbPropertyPtr;

    typedef struct _XkbColor {
          unsigned int      pixel;     /* color */
          char *            spec;      /* color name */
    } XkbColorRec,*XkbColorPtr;

    typedef struct _XkbKeyAliasRec {
          char      real[XkbKeyNameLength];   /* real name of the key */
          char      alias[XkbKeyNameLength];  /* alias for the key */
    } XkbKeyAliasRec,*XkbKeyAliasPtr;

    typedef struct _XkbPoint {                /* x,y coordinates */
          short      x;
          short      y;
    } XkbPointRec, *XkbPointPtr;

    typedef struct _XkbOutline {
          unsigned short      num_points;     /* number of points in the outline */
          unsigned short      sz_points;      /* size of the points array */
          unsigned short      corner_radius;  /* draw corners as circles with this radius */
          XkbPointPtr         points;         /* array of points defining the outline */
    } XkbOutlineRec, *XkbOutlinePtr;

    typedef struct _XkbBounds {
          short      x1,y1;            /* upper left corner of the bounds,
                                          in mm/10 */
           short      x2,y2;            /* lower right corner of the bounds, in
                                          mm/10 */
    } XkbBoundsRec, *XkbBoundsPtr;

    typedef struct _XkbShape {
          Atom              name;           /* shape’s name */
          unsigned short    num_outlines;   /* number of outlines for the shape */
          unsigned short    sz_outlines;    /* size of the outlines array */
          XkbOutlinePtr     outlines;       /* array of outlines for the shape */
          XkbOutlinePtr     approx;         /* pointer into the array to the approximating outline */
          XkbOutlinePtr     primary;        /* pointer into the array to the primary outline */
          XkbBoundsRec      bounds;         /* bounding box for the shape; encompasses all outlines */
    } XkbShapeRec, *XkbShapePtr;

If approx and/or primary is NULL , the default value is used. The default primary outline is the first element in the outlines array, as is the default approximating outline.

    typedef struct _XkbKey {         /* key in a row */
          XkbKeyNameRec    name;     /* key name */
          short            gap;      /* gap in mm/10 from previous key in row */
          unsigned char    shape_ndx;      /* index of shape for key */
          unsigned char    color_ndx;      /* index of color for key body */
    } XkbKeyRec, *XkbKeyPtr;

    typedef struct _XkbRow {             /* row in a section */
          short               top;       /* top coordinate of row origin, relative to section’s origin */
          short               left;      /* left coordinate of row origin, relative to section’s origin */
          unsigned short      num_keys;  /* number of keys in the keys array */
          unsigned short      sz_keys;   /* size of the keys array */
          int                 vertical;  /* True =>vertical row,
                                             False =>horizontal row */
          XkbKeyPtr           keys;      /* array of keys in the row*/
          XkbBoundsRec        bounds;    /* bounding box for the row */
    } XkbRowRec, *XkbRowPtr;

top and left are in mm / 10 .

    typedef struct _XkbOverlayRec {
          Atom              name;           /* overlay name */
          XkbSectionPtr     section_under;  /* the section under this overlay */
          unsigned short    num_rows;       /* number of rows in the rows array */
          unsigned short    sz_rows;        /* size of the rows array */
          XkbOverlayRowPtr  rows;           /* array of rows in the overlay */
          XkbBoundsPtr      bounds;         /* bounding box for the overlay */
    } XkbOverlayRec,*XkbOverlayPtr;

    typedef struct _XkbOverlayRow {
          unsigned short      row_under;     /* index into the row under this overlay row */
          unsigned short      num_keys;      /* number of keys in the keys array */
          unsigned short      sz_keys;       /* size of the keys array */
          XkbOverlayKeyPtr    keys;          /* array of keys in the overlay row */
    } XkbOverlayRowRec,*XkbOverlayRowPtr;

row_under is an index into the array of rows in the section under this overlay. The section under this overlay row is the one pointed to by section_under in this overlay row’s XkbOverlayRec .

    typedef struct _XkbOverlayKey {
          XkbKeyNameRec      over;      /* name of this overlay key */
          XkbKeyNameRec      under;     /* name of the key under this overlay key */
    } XkbOverlayKeyRec,*XkbOverlayKeyPtr;

    typedef struct _XkbSection {
          Atom            name;          /* section name */
          unsigned char   priority;      /* drawing priority, 0=>highest, 255=>lowest */
          short           top;           /* top coordinate of section origin */
          short           left;          /* left coordinate of row origin */
          unsigned short  width;         /* section width, in mm/10 */
          unsigned short  height;        /* section height, in mm/10 */
          short           angle;         /* angle of section rotation, counterclockwise */
          unsigned short  num_rows;      /* number of rows in the rows array */
          unsigned short  num_doodads;   /* number of doodads in the doodads array */
          unsigned short  num_overlays;  /* number of overlays in the overlays array */
          unsigned short  sz_rows;       /* size of the rows array */
          unsigned short  sz_doodads;    /* size of the doodads array */
          unsigned short  sz_overlays;   /* size of the overlays array */
          XkbRowPtr       rows;          /* section rows array */
          XkbDoodadPtr    doodads;       /* section doodads array */
          XkbBoundsRec    bounds;        /* bounding box for the section, before rotation*/
          XkbOverlayPtr   overlays;      /* section overlays array */
    } XkbSectionRec, *XkbSectionPtr;

top and left are the origin of the section, relative to the origin of the keyboard, in mm / 10 . angle is in 1 / 10 degrees.

### DoodadRec Structures

The doodad arrays in the XkbGeometryRec and the XkbSectionRec may contain any of the doodad structures and types shown in Table 13.1.

The doodad structures form a union:

    typedef union _XkbDoodad {
            XkbAnyDoodadRec        any;
            XkbShapeDoodadRec      shape;
            XkbTextDoodadRec       text;
            XkbIndicatorDoodadRec  indicator;
            XkbLogoDoodadRec       logo;
    } XkbDoodadRec, *XkbDoodadPtr;

The top and left coordinates of each doodad are the coordinates of the origin of the doodad relative to the keyboard’s origin if the doodad is in the XkbGeometryRec doodad array, and with respect to the section’s origin if the doodad is in a XkbSectionRec doodad array. The color_ndx or on_color_ndx and off_color_ndx fields are color indices into the XkbGeometryRec ’s color array and are the colors to draw the doodads with. Similarly, the shape_ndx fields are indices into the XkbGeometryRec ’s shape array.

    typedef struct _XkbShapeDoodad {
          Atom       name;                /* doodad name */
          unsigned char      type;        /* XkbOutlineDoodad
                                             or XkbSolidDoodad */
          unsigned char      priority;    /* drawing priority,
                                             0=>highest, 255=>lowest */
          short      top;                 /* top coordinate, in mm/10 */
          short      left;                /* left coordinate, in mm/10 */
          short      angle;               /* angle of rotation, clockwise, in 1/10 degrees */
          unsigned short      color_ndx;  /* doodad color */
          unsigned short      shape_ndx;  /* doodad shape */
    } XkbShapeDoodadRec, *XkbShapeDoodadPtr;

    typedef struct _XkbTextDoodad {
          Atom            name;         /* doodad name */
          unsigned char   type;         /*  XkbTextDoodad */
          unsigned char   priority;     /* drawing priority,
                                           0=>highest, 255=>lowest */
          short           top;          /* top coordinate, in mm/10 */
          short           left;         /* left coordinate, in mm/10 */
          short           angle;        /* angle of rotation, clockwise, in 1/10 degrees */
          short           width;        /* width in mm/10 */
          short           height;       /* height in mm/10 */
          unsigned short  color_ndx;    /* doodad color */
          char *           text;        /* doodad text */
          char *           font;        /* arbitrary font name for doodad text */
    } XkbTextDoodadRec, *XkbTextDoodadPtr;

    typedef struct _XkbIndicatorDoodad {
          Atom           name;          /* doodad name */
          unsigned char  type;          /* XkbIndicatorDoodad */
          unsigned char  priority;      /* drawing priority, 0=>highest, 255=>lowest */
          short          top;           /* top coordinate, in mm/10 */
          short          left;          /* left coordinate, in mm/10 */
          short          angle;         /* angle of rotation, clockwise, in 1/10 degrees */
          unsigned short shape_ndx;     /* doodad shape */
          unsigned short on_color_ndx;  /* color for doodad if indicator is on */
          unsigned short off_color_ndx; /* color for doodad if indicator is off */
    } XkbIndicatorDoodadRec, *XkbIndicatorDoodadPtr;

    typedef struct _XkbLogoDoodad {
          Atom               name;        /* doodad name */
          unsigned char      type;        /*  XkbLogoDoodad */
          unsigned char      priority;    /* drawing priority, 0=>highest, 255=>lowest */
          short              top;         /* top coordinate, in mm/10 */
          short              left;        /* left coordinate, in mm/10 */
          short              angle;       /* angle of rotation, clockwise, in 1/10 degrees */
          unsigned short      color_ndx;  /* doodad color */
          unsigned short      shape_ndx;  /* doodad shape */
          char *      logo_name;          /* text for logo */
    } XkbLogoDoodadRec, *XkbLogoDoodadPtr

## Getting Keyboard Geometry From the Server

You can load a keyboard geometry as part of the keyboard description returned by XkbGetKeyboard . However, if a keyboard description has been previously loaded, you can instead obtain the geometry by calling the XkbGetGeometry . In this case, the geometry returned is the one associated with the keyboard whose device ID is contained in the keyboard description.

To load a keyboard geometry if you already have the keyboard description, use XkbGetGeometry.

Status XkbGetGeometry ( dpy , xkb )
Display * dpy ; /* connection to the X server */
XkbDescPtr xkb ; /* keyboard description that contains the ID for the keyboard and into which the geometry should be loaded */

XkbGetGeometry can return BadValue , BadImplementation , BadName , BadAlloc, or BadLength errors or Success if it succeeds.

It is also possible to load a keyboard geometry by name. The X server maintains a database of keyboard components (see Chapter 20). To load a keyboard geometry description from this database by name, use XkbGetNamedGeometry.

Status XkbGetNamedGeometry ( dpy , xkb , name )
Display * dpy ; /* connection to the X server */
XkbDescPtr xkb ; /* keyboard description into which the geometry should be loaded */
Atom name ; /* name of the geometry to be loaded */

XkbGetNamedGeometry can return BadName if the name cannot be found.

## Using Keyboard Geometry

Xkb provides a number of convenience functions to help use a keyboard geometry. These include functions to return the bounding box of a shape’s top surface and to update the bounding box of a shape row or section.

A shape is made up of a number of outlines. Each outline is a polygon made up of a number of points. The bounding box of a shape is a rectangle that contains all the outlines of that shape.

Key Surface, Shape Outlines, and Bounding Box

To determine the bounding box of the top surface of a shape, use XkbComputeShapeTop.

Bool XkbComputeShapeTop ( shape , bounds_rtrn )
XkbShapePtr shape ; /* shape to be examined */
XkbBoundsPtr bounds_rtrn /* backfilled with the bounding box for the shape */

XkbComputeShapeTop returns a BoundsRec that contains two x and y coordinates. These coordinates describe the corners of a rectangle that contains the outline that describes the top surface of the shape. The top surface is defined to be the approximating outline if the approx field of shape is not NULL . If approx is NULL , the top surface is defined as the last outline in the shape ’s array of outlines. XkbComputeShapeTop returns False if shape is NULL or if there are no outlines for the shape; otherwise, it returns True.

A ShapeRec contains a BoundsRec that describes the bounds of the shape. If you add or delete an outline to or from a shape, the bounding box must be updated. To update the bounding box of a shape, use XkbComputeShapeBounds.

Bool XkbComputeShapeBounds ( shape )
XkbShapePtr shape ; /* shape to be examined */

XkbComputeShapeBounds updates the BoundsRec contained in the shape by examining all the outlines of the shape and setting the BoundsRec to the minimum x and minimum y, and maximum x and maximum y values found in those outlines. XkbComputeShapeBounds returns False if shape is NULL or if there are no outlines for the shape; otherwise, it returns True .

If you add or delete a key to or from a row, or if you update the shape of one of the keys in that row, you may need to update the bounding box of that row. To update the bounding box of a row, use XkbComputeRowBounds.

Bool XkbComputeRowBounds ( geom , section , row )
XkbGeometryPtr geom ; /* geometry that contains the section */
XkbSectionPtr section ; /* section that contains the row */
XkbRowPtr row ; /* row to be examined and updated */

XkbComputeRowBounds checks the bounds of all keys in the row and updates the bounding box of the row if necessary. XkbComputeRowBounds returns False if any of the arguments is NULL ; otherwise, it returns True .

If you add or delete a row to or from a section, or if you change the geometry of any of the rows in that section, you may need to update the bounding box for that section. To update the bounding box of a section, use XkbComputeSectionBounds.

Bool XkbComputeSectionBounds ( geom , section )
XkbGeometryPtr geom ; /* geometry that contains the section */
XkbSectionPtr section ; /* section to be examined and updated */

XkbComputeSectionBounds examines all the rows of the section and updates the bounding box of that section so that it contains all rows. XkbComputeSectionBounds returns False if any of the arguments is NULL ; otherwise, it returns True .

Keys that can generate multiple keycodes may be associated with multiple names. Such keys have a primary name and an alternate name. To find the alternate name by using the primary name for a key that is part of an overlay, use XkbFindOverlayForKey.

char * XkbFindOverlayForKey ( geom , section , under )
XkbGeometryPtr geom ; /* geometry that contains the section */
XkbSectionPtr section ; /* section to be searched for matching keys */
char * under . /* primary name of the key to be considered */

XkbFindOverlayForKey uses the primary name of the key, under , to look up the alternate name, which it returns.

## Adding Elements to a Keyboard Geometry

Xkb provides functions to add a single new element to the top-level keyboard geometry. In each case the num_ * fields of the corresponding structure is incremented by 1. These functions do not change sz_ * unless there is no more room in the array. Some of these functions fill in the values of the element’s structure from the arguments. For other functions, you must explicitly write code to fill the structure’s elements.

The top-level geometry description includes a list of geometry properties . A geometry property associates an arbitrary string with an equally arbitrary name. Programs that display images of keyboards can use geometry properties as hints, but they are not interpreted by Xkb. No other geometry structures refer to geometry properties.

To add one property to an existing keyboard geometry description, use XkbAddGeomProperty .

XkbPropertyPtr XkbAddGeomProperty ( geom , name , value )
XkbGeometryPtr geom ; /* geometry to be updated */
char * name ; /* name of the new property */
char * value ; /* value for the new property */

XkbAddGeomProperty adds one property with the specified name and value to the keyboard geometry specified by geom. XkbAddGeomProperty returns NULL if any of the parameters is empty or if it was not able to allocate space for the property. To allocate space for an arbitrary number of properties, use the XkbAllocGeomProps function.

To add one key alias to an existing keyboard geometry description, use XkbAddGeomKeyAlias .

XkbKeyAliasPtr XkbAddGeomKeyAlias ( geom , alias, real )
XkbGeometryPtr geom ; /* geometry to be updated */
char * alias ; /* alias to be added */
char * real ; /* real name to be bound to the new alias */

XkbAddGeomKeyAlias adds one key alias with the value alias to the geometry geom, and associates it with the key whose real name is real. XkbAddGeomKeyAlias returns NULL if any of the parameters is empty or if it was not able to allocate space for the alias. To allocate space for an arbitrary number of aliases, use the XkbAllocGeomKeyAliases function.

To add one color name to an existing keyboard geometry description, use XkbAddGeomColor .

XkbColorPtr XkbAddGeomColor ( geom , spec , pixel )
XkbGeometryPtr geom ; /* geometry to be updated */
char * spec ; /* color to be added */
unsigned int pixel ; /* color to be added */

XkbAddGeomColor adds the specified color name and pixel to the specified geometry geom . The top-level geometry description includes a list of up to MaxColors (32) color names . A color name is a string whose interpretation is not specified by Xkb and neither is the pixel value’s interpretation. All other geometry data structures refer to colors using their indices in this global list or pointers to colors in this list. XkbAddGeomColor returns NULL if any of the parameters is empty or if it was not able to allocate space for the color. To allocate space for an arbitrary number of colors to a geometry, use the XkbAllocGeomColors function.

To add one outline to an existing shape, use XkbAddGeomOutline.

XkbOutlinePtr XkbAddGeomOutline ( shape , sz_points )
XkbShapePtr shape ; /* shape to be updated */
int sz_points ; /* number of points to be reserved */

An outline consists of an arbitrary number of points. XkbAddGeomOutline adds an outline to the specified shape by reserving sz_points points for it. The new outline is allocated and zeroed. XkbAddGeomOutline returns NULL if any of the parameters is empty or if it was not able to allocate space. To allocate space for an arbitrary number of outlines to a shape, use XkbAllocGeomOutlines.

To add a shape to a keyboard geometry, use XkbAddGeomShape .

XkbShapePtr XkbAddGeomShape ( geom , name , sz_outlines )
XkbGeometryPtr geom ; /* geometry to be updated */
Atom name ; /* name of the new shape */
int sz_outlines ; /* number of outlines to be reserved */

A geometry contains an arbitrary number of shapes, each of which is made up of an arbitrary number of outlines. XkbAddGeomShape adds a shape to a geometry geom by allocating space for sz_outlines outlines for it and giving it the name specified by name. If a shape with name name already exists in the geometry, a pointer to the existing shape is returned. XkbAddGeomShape returns NULL if any of the parameters is empty or if it was not able to allocate space. To allocate space for an arbitrary number of geometry shapes, use XkbAllocGeomShapes .

To add one key at the end of an existing row of keys, use XkbAddGeomKey .

XkbKeyPtr XkbAddGeomKey ( row )
XkbRowPtr row ; /* row to be updated */

Keys are grouped into rows. XkbAddGeomKey adds one key to the end of the specified row . The key is allocated and zeroed. XkbAddGeomKey returns NULL if row is empty or if it was not able to allocate space for the key. To allocate space for an arbitrary number of keys to a row, use XkbAllocGeomKeys.

To add one section to an existing keyboard geometry, use XkbAddGeomSection .

XkbSectionPtr XkbAddGeomSection ( geom , name , sz_rows , sz_doodads , sz_overlays )
XkbGeometryPtr geom ; /* geometry to be updated */
Atom name ; /* name of the new section */
int sz_rows ; /* number of rows to reserve in the section */
int sz_doodads ; /* number of doodads to reserve in the section */
int sz_overlays ; /* number of overlays to reserve in the section */

A keyboard geometry contains an arbitrary number of sections. XkbAddGeomSection adds one section to an existing keyboard geometry geom . The new section contains space for the number of rows, doodads, and overlays specified by sz_rows , sz_doodads , and sz_overlays . The new section is allocated and zeroed and given the name specified by name . If a section with name name already exists in the geometry, a pointer to the existing section is returned. XkbAddGeomSection returns NULL if any of the parameters is empty or if it was not able to allocate space for the section. To allocate space for an arbitrary number of sections to a geometry, use XkbAllocGeomSections.

To add a row to a section, use XkbAddGeomRow .

XkbRowPtr XkbAddGeomRow ( section , sz_keys )
XkbSectionPtr section ; /* section to be updated */
int sz_keys ; /* number of keys to be reserved */

One of the components of a keyboard geometry section is one or more rows of keys. XkbAddGeomRow adds one row to the specified section . The newly created row contains space for the number of keys specified in sz_keys . They are allocated and zeroed, but otherwise uninitialized. XkbAddGeomRow returns NULL if any of the parameters is empty or if it was not able to allocate space for the row. To allocate space for an arbitrary number of rows to a section, use the XkbAllocGeomRows function.

To add one doodad to a section of a keyboard geometry or to the top-level geometry, use XkbAddGeomDoodad .

XkbDoodadPtr XkbAddGeomDoodad ( geom , section , name )
XkbGeometryPtr geom ; /* geometry to which the doodad is added */
XkbSectionPtr section ; /* section, if any, to which the doodad is added */
Atom name ; /* name of the new doodad */

A doodad describes some visible aspect of the keyboard that is not a key and is not a section. XkbAddGeomDoodad adds a doodad with name specified by name to the geometry geom if section is NULL or to the section of the geometry specified by section if section is not NULL . XkbAddGeomDoodad returns NULL if any of the parameters is empty or if it was not able to allocate space for the doodad. If there is already a doodad with the name name in the doodad array for the geometry (if section is NULL ) or the section (if section is non- NULL ), a pointer to that doodad is returned. To allocate space for an arbitrary number of doodads to a section, use the XkbAllocGeomSectionDoodads function. To allocate space for an arbitrary number of doodads to a keyboard geometry, use the XkbAllocGeomDoodads function.

To add one overlay to a section, use XkbAddGeomOverlay .

XkbOverlayPtr XkbAddGeomOverlay ( section , name , sz_rows )
XkbSectionPtr section ; /* section to which an overlay will be added */
Atom name ; /* name of the overlay */
int sz_rows ; /* number of rows to reserve in the overlay */

XkbAddGeomOverlay adds an overlay with the specified name to the specified section . The new overlay is created with space allocated for sz_rows rows. If an overlay with name name already exists in the section, a pointer to the existing overlay is returned. XkbAddGeomOverlay returns NULL if any of the parameters is empty or if it was not able to allocate space for the overlay. To allocate space for an arbitrary number of overlays to a section, use the XkbAllocGeomOverlay function.

To add a row to an existing overlay, use XkbAddGeomOverlayRow .

XkbOverlayRowPtr XkbAddGeomOverlayRow ( overlay , row_under, sz_keys )
XkbOverlayPtr overlay ; /* overlay to be updated */
XkbRowPtr row_under ; /* row to be overlayed in the section overlay overlays */
int sz_keys ; /* number of keys to reserve in the row */

XkbAddGeomOverlayRow adds one row to the overlay . The new row contains space for sz_keys keys. If row_under specifies a row that doesn’t exist on the underlying section, XkbAddGeomOverlayRow returns NULL and doesn’t change the overlay. XkbAddGeomOverlayRow returns NULL if any of the parameters is empty or if it was not able to allocate space for the overlay.

To add a key to an existing overlay row, use XkbAddGeomOverlayKey .

XkbOverlayKeyPtr XkbAddGeomOverlayKey ( overlay , row, under )
XkbOverlayPtr overlay ; /* overlay to be updated */
XkbRowPtr row ; /* row in overlay to be updated */
char * under ; /* primary name of the key to be considered */

XkbAddGeomOverlayKey adds one key to the row in the overlay . If there is no key named under in the row of the underlying section, XkbAddGeomOverlayKey returns NULL .

## Allocating and Freeing Geometry Components

Xkb provides a number of functions to allocate and free subcomponents of a keyboard geometry. Use these functions to create or modify keyboard geometries. Note that these functions merely allocate space for the new element(s), and it is up to you to fill in the values explicitly in your code. These allocation functions increase sz_ * but never touch num_ * (unless there is an allocation failure, in which case they reset both sz_ * and num_ * to zero). These functions return Success if they succeed, BadAlloc if they are not able to allocate space, or BadValue if a parameter is not as expected.

To allocate space for an arbitrary number of outlines to a shape, use XkbAllocGeomOutlines.

Status XkbAllocGeomOutlines ( shape , num_needed )
XkbShapePtr shape ; /* shape for which outlines should be allocated */
int num_needed ; /* number of new outlines required */

XkbAllocGeomOutlines allocates space for num_needed outlines in the specified shape . The outlines are not initialized.

To free geometry outlines, use XkbFreeGeomOutlines .

void XkbFreeGeomOutlines ( shape , first , count , free_all )
XkbShapePtr shape ; /* shape in which outlines should be freed */
int first ; /* first outline to be freed */
int count ; /* number of outlines to be freed */
Bool free_all; /* True => all outlines are freed */

If free_all is True , all outlines are freed regardless of the value of first or count. Otherwise, count outlines are freed beginning with the one specified by first.

To allocate space for an arbitrary number of keys to a row, use XkbAllocGeomKeys.

Status XkbAllocGeomKeys ( row , num_needed )
XkbRowPtr row ; /* row to which keys should be allocated */
int num_needed ; /* number of new keys required */

XkbAllocGeomKeys allocates num_needed keys and adds them to the row. No initialization of the keys is done.

To free geometry keys, use XkbFreeGeomKeys .

void XkbFreeGeomKeys ( row , first , count , free_all )
XkbRowPtr row ; /* row in which keys should be freed */
int first ; /* first key to be freed */
int count ; /* number of keys to be freed */
Bool free_all; /* True => all keys are freed */

If free_all is True , all keys are freed regardless of the value of first or count. Otherwise, count keys are freed beginning with the one specified by first.

To allocate geometry properties, use XkbAllocGeomProps .

Status XkbAllocGeomProps ( geom , num_needed )
XkbGeometryPtr geom ; /* geometry for which properties should be allocated */
int num_needed ; /* number of new properties required */

XkbAllocGeomProps allocates space for num_needed properties and adds them to the specified geometry geom . No initialization of the properties is done. A geometry property associates an arbitrary string with an equally arbitrary name. Geometry properties can be used to provide hints to programs that display images of keyboards, but they are not interpreted by Xkb. No other geometry structures refer to geometry properties.

To free geometry properties, use XkbFreeGeomProperties .

void XkbFreeGeomProperties ( geom , first , count , free_all )
XkbGeometryPtr geom ; /* geometry in which properties should be freed */
int first ; /* first property to be freed */
int count ; /* number of properties to be freed */
Bool free_all; /* True => all properties are freed */

If free_all is True , all properties are freed regardless of the value of first or count. Otherwise, count properties are freed beginning with the one specified by first.

To allocate geometry key aliases, use XkbAllocGeomKeyAliases .

Status XkbAllocGeomKeyAliases ( geom , num_needed )
XkbGeometryPtr geom ; /* geometry for which key aliases should be allocated */
int num_needed ; /* number of new key aliases required */

XkbAllocGeomKeyAliases allocates space for num_needed key aliases and adds them to the specified geometry geom . A key alias is a pair of strings that associates an alternate name for a key with the real name for that key.

To free geometry key aliases, use XkbFreeGeomKeyAliases .

void XkbFreeGeomKeyAliases ( geom , first , count , free_all )
XkbGeometryPtr geom ; /* geometry in which key aliases should be freed */
int first ; /* first key alias to be freed */
int count ; /* number of key aliases to be freed */
Bool free_all; /* True => all key aliases are freed */

If free_all is True , all aliases in the top level of the specified geometry geom are freed regardless of the value of first or count. Otherwise, count aliases in geom are freed beginning with the one specified by first.

To allocate geometry colors, use XkbAllocGeomColors .

Status XkbAllocGeomColors ( geom , num_needed )
XkbGeometryPtr geom ; /* geometry for which colors should be allocated */
int num_needed ; /* number of new colors required. */

XkbAllocGeomColors allocates space for num_needed colors and adds them to the specified geometry geom . A color name is a string whose interpretation is not specified by Xkb. All other geometry data structures refer to colors using their indices in this global list or pointers to colors in this list.

To free geometry colors, use XkbFreeGeomColors .

void XkbFreeGeomColors ( geom , first , count , free_all )
XkbGeometryPtr geom ; /* geometry in which colors should be freed */
int first ; /* first color to be freed */
int count ; /* number of colors to be freed */
Bool free_all; /* True => all colors are freed */

If free_all is True , all colors are freed regardless of the value of first or count. Otherwise, count colors are freed beginning with the one specified by first.

To allocate points in an outline, use XkbAllocGeomPoints .

Status XkbAllocGeomPoints ( outline , num_needed )
XkbOutlinePtr outline ; /* outline for which points should be allocated */
int num_needed ; /* number of new points required */

XkbAllocGeomPoints allocates space for num_needed points in the specified outline . The points are not initialized.

To free points in a outline, use XkbFreeGeomPoints .

void XkbFreeGeomPoints ( outline , first , count , free_all )
XkbOutlinePtr outline ; /* outline in which points should be freed */
int first ; /* first point to be freed. */
int count ; /* number of points to be freed */
Bool free_all; /* True => all points are freed */

If free_all is True , all points are freed regardless of the value of first and count. Otherwise, the number of points specified by count are freed, beginning with the point specified by first in the specified outline.

To allocate space for an arbitrary number of geometry shapes, use XkbAllocGeomShapes .

Status XkbAllocGeomShapes ( geom , num_needed )
XkbGeometryPtr geom ; /* geometry for which shapes should be allocated */
int num_needed ; /* number of new shapes required */

XkbAllocGeomShapes allocates space for num_needed shapes in the specified geometry geom . The shapes are not initialized.

To free geometry shapes, use XkbFreeGeomShapes .

void XkbFreeGeomShapes ( geom , first , count , f ree_all )
XkbGeometryPtr geom ; /* geometry in which shapes should be freed */
int first ; /* first shape to be freed */
int count ; /* number of shapes to be freed */
Bool free_all; /* True => all shapes are freed */

If free_all is True , all shapes in the geometry are freed regardless of the values of first and count. Otherwise, count shapes are freed, beginning with the shape specified by first.

To allocate geometry sections, use XkbAllocGeomSections .

Status XkbAllocGeomSections ( geom , num_needed )
XkbGeometryPtr geom ; /*geometry for which sections should be allocated */
int num_needed ; /* number of new sections required */

XkbAllocGeomSections allocates num_needed sections and adds them to the geometry geom. No initialization of the sections is done.

To free geometry sections, use XkbFreeGeomSections .

void XkbFreeGeomSections ( geom , first , count , free_all )
XkbGeometryPtr geom ; /* geometry in which sections should be freed */
int first ; /* first section to be freed. */
int count ; /* number of sections to be freed */
Bool free_all; /* True => all sections are freed */

If free_all is True , all sections are freed regardless of the value of first and count. Otherwise, the number of sections specified by count are freed, beginning with the section specified by first in the specified geometry.

To allocate rows in a section, use XkbAllocGeomRows .

Status XkbAllocGeomRows ( section , num_needed )
XkbSectionPtr section ; /* section for which rows should be allocated */
int num_needed ; /* number of new rows required */

XkbAllocGeomRows allocates num_needed rows and adds them to the section. No initialization of the rows is done.

To free rows in a section, use XkbFreeGeomRows .

void XkbFreeGeomRows ( section , first , count , free_all )
XkbSectionPtr section ; /* section in which rows should be freed */
int first ; /* first row to be freed. */
int count ; /* number of rows to be freed */
Bool free_all; /* True => all rows are freed */

If free_all is True , all rows are freed regardless of the value of first and count. Otherwise, the number of rows specified by count are freed, beginning with the row specified by first in the specified section.

To allocate overlays in a section, use XkbAllocGeomOverlays .

Status XkbAllocGeomOverlays ( section , num_needed )
XkbSectionPtr section ; /* section for which overlays should be allocated */
int num_needed ; /* number of new overlays required */

XkbAllocGeomRows allocates num_needed overlays and adds them to the section. No initialization of the overlays is done.

To free rows in an section, use XkbFreeGeomOverlays .

void XkbFreeGeomOverlays ( section , first , count , free_all )
XkbSectionPtr section ; /* section in which overlays should be freed */
int first ; /* first overlay to be freed. */
int count ; /* number of overlays to be freed */
Bool free_all; /* True => all overlays are freed */

If free_all is True , all overlays are freed regardless of the value of first and count. Otherwise, the number of overlays specified by count are freed, beginning with the overlay specified by first in the specified section.

To allocate rows in a overlay, use XkbAllocGeomOverlayRows .

Status XkbAllocGeomOverlayRows ( overlay , num_needed )
XkbSectionPtr overlay ; /* section for which rows should be allocated */
int num_needed ; /* number of new rows required */

XkbAllocGeomOverlayRows allocates num_needed rows and adds them to the overlay. No initialization of the rows is done.

To free rows in an overlay, use XkbFreeGeomOverlayRows .

void XkbFreeGeomOverlayRows ( overlay , first , count , free_all )
XkbSectionPtr overlay ; /* section in which rows should be freed */
int first ; /* first row to be freed. */
int count ; /* number of rows to be freed */
Bool free_all; /* True => all rows are freed */

If free_all is True , all rows are freed regardless of the value of first and count. Otherwise, the number of rows specified by count are freed, beginning with the row specified by first in the specified overlay.

To allocate keys in an overlay row, use XkbAllocGeomOverlayKeys .

Status XkbAllocGeomOverlayKeys ( row , num_needed )
XkbRowPtr row ; /* section for which rows should be allocated */
int num_needed ; /* number of new rows required */

XkbAllocGeomOverlayKeys allocates num_needed keys and adds them to the row. No initialization of the keys is done.

To free keys in an overlay row, use XkbFreeGeomOverlayKeys .

void XkbFreeGeomOverlayKeys ( row , first , count , free_all )
XkbRowPtr row ; /* row in which keys should be freed */
int first ; /* first key to be freed. */
int count ; /* number of keys to be freed */
Bool free_all; /* True => all keys are freed */

If free_all is True , all keys are freed regardless of the value of first and count. Otherwise, the number of keys specified by count are freed, beginning with the key specified by first in the specified row.

To allocate doodads that are global to a keyboard geometry, use XkbAllocGeomDoodads .

Status XkbAllocGeomDoodads ( geom , num_needed )
XkbGeometryPtr geom ; /* geometry for which doodads should be allocated */
int num_needed ; /* number of new doodads required */

XkbAllocGeomDoodads allocates num_needed doodads and adds them to the specified geometry geom . No initialization of the doodads is done.

To allocate doodads that are specific to a section, use XkbAllocGeomSectionDoodads .

Status XkbAllocGeomSectionDoodads ( section , num_needed )
XkbSectionPtr section ; /* section for which doodads should be allocated */
int num_needed ; /* number of new doodads required */

XkbAllocGeomSectionDoodads allocates num_needed doodads and adds them to the specified section . No initialization of the doodads is done.

To free geometry doodads, use XkbFreeGeomDoodads .

void XkbFreeGeomDoodads ( doodads , count , free_all )
XkbDoodadPtr doodads ; /* doodads to be freed */
int count ; /* number of doodads to be freed */
Bool free_all; /* True => all doodads are freed */

If free_all is True , all doodads in the array are freed, regardless of the value of count. Otherwise, count doodads are freed.

To allocate an entire geometry, use XkbAllocGeometry .

Status XkbAllocGeometry ( xkb , sizes )
XkbDescPtr xkb ; /* keyboard description for which geometry is to be allocated */
XkbGeometrySizesPtr sizes ; /* initial sizes for all geometry components */

XkbAllocGeometry allocates a keyboard geometry and adds it to the keyboard description specified by xkb. The keyboard description should be obtained via the XkbGetKeyboard or XkbAllockeyboard functions. The sizes parameter specifies the number of elements to be reserved for the subcomponents of the keyboard geometry and can be zero or more. These subcomponents include the properties, colors, shapes, sections, and doodads.

To free an entire geometry, use XkbFreeGeometry .

void XkbFreeGeometry ( geom , which , free_all )
XkbGeometryPtr geom ; /* geometry to be freed */
unsigned int which ; /* mask of geometry components to be freed */
Bool free_all; /* True => the entire geometry is freed. */

The values of which and free_all determine how much of the specified geometry is freed. The valid values for which are:

    #define      XkbGeomPropertiesMask  (1<<0)
    #define      XkbGeomColorsMask      (1<<1)
    #define      XkbGeomShapesMask      (1<<2)
    #define      XkbGeomSectionsMask    (1<<3)
    #define      XkbGeomDoodadsMask     (1<<4)
    #define      XkbGeomAllMask         (0x1f)

If free_all is True , the entire geometry is freed regardless of the value of which. Otherwise, the portions of the geometry specified by which are freed.