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X11R7.4 - man page for xcursorlibraryloadimage (x11r4 section 3)

XCURSOR(3)			     Library Functions Manual			       XCURSOR(3)

       XCURSOR - Cursor management library

       #include <X11/Xcursor/Xcursor.h>

       Xcursor	is  a  simple  library	designed to help locate and load cursors.  Cursors can be
       loaded from files or memory.  A library of common cursors exists which map to the standard
       X  cursor  names.   Cursors can exist in several sizes and the library automatically picks
       the best size.

       Xcursor is built in a couple of layers; at the bottom layer is code which can load  cursor
       images  from files.  Above that is a layer which locates cursor files based on the library
       path and theme.	At the top is a layer which builds cursors either out of an image  loaded
       from  a file or one of the standard X cursors.  When using images loaded from files, Xcur-
       sor prefers to use the Render extension CreateCursor request if supported by the X server.
       Where  not  supported,  Xcursor	maps the cursor image to a standard X cursor and uses the
       core CreateCursor request.

       Xcursor defines a new format for cursors on disk.  Each file  holds  one  or  more  cursor
       images.	 Each  cursor  image  is  tagged with a nominal size so that the best size can be
       selected automatically.	Multiple cursors of the same nominal size can be loaded together;
       applications are expected to use them as an animated sequence.

       Cursor  files are stored as a header containing a table of contents followed by a sequence
       of chunks.  The table of contents indicates the type, subtype and position in the file  of
       each chunk.  The file header looks like:

	 magic: CARD32 'Xcur' (0x58, 0x63, 0x75, 0x72)
	 header: CARD32 bytes in this header
	 version: CARD32 file version number
	 ntoc: CARD32 number of toc entries
	 toc: LISTofTOC table of contents

       Each table of contents entry looks like:

	 type: CARD32 entry type
	 subtype: CARD32 type-specific label - size for images
	 position: CARD32 absolute byte position of table in file

       Each  chunk  in	the file has set of common header fields followed by additional type-spe-
       cific fields:

	 header: CARD32 bytes in chunk header (including type-specific fields)
	 type: CARD32 must match type in TOC for this chunk
	 subtype: CARD32 must match subtype in TOC for this chunk
	 version: CARD32 version number for this chunk type

       There are currently two chunk types defined for cursor files; comments and  images.   Com-
       ments look like:

	 header: 20 Comment headers are 20 bytes
	 type: 0xfffe0001 Comment type is 0xfffe0001
	 subtype: { 1 (COPYRIGHT), 2 (LICENSE), 3 (OTHER) }
	 version: 1
	 length: CARD32 byte length of UTF-8 string
	 string: LISTofCARD8 UTF-8 string

       Images look like:

	 header: 36 Image headers are 36 bytes
	 type: 0xfffd0002 Image type is 0xfffd0002
	 subtype: CARD32 Image subtype is the nominal size
	 version: 1
	 width: CARD32 Must be less than or equal to 0x7fff
	 height: CARD32 Must be less than or equal to 0x7fff
	 xhot: CARD32 Must be less than or equal to width
	 yhot: CARD32 Must be less than or equal to height
	 delay: CARD32 Delay between animation frames in milliseconds
	 pixels: LISTofCARD32 Packed ARGB format pixels

       Xcursor	(mostly)  follows the freedesktop.org spec for theming icons.  The default search
       path   it   uses   is	~/.icons,    /usr/local/share/icons,	/usr/local/share/pixmaps,
       /usr/local/lib/X11/icons.   Within  each of these directories, it searches for a directory
       using the theme name.  Within the theme directory, it looks for cursor files in the  'cur-
       sors' subdirectory.  It uses the first cursor file found along  the path.

       If  necessary, Xcursor also looks for a "index.theme" file in each theme directory to find
       inherited themes and searches along the path for those themes as well.

       If no theme is set, or if no cursor is found for the specified theme, Xcursor  checks  the
       "default" theme.

	      holds  a single cursor image in memory.  Each pixel in the cursor is a 32-bit value
	      containing ARGB with A in the high byte.

		  typedef struct _XcursorImage {
		      XcursorDim  size; 	/* nominal size for matching */
		      XcursorDim  width;	/* actual width */
		      XcursorDim  height;	/* actual height */
		      XcursorDim  xhot; 	/* hot spot x (must be inside image) */
		      XcursorDim  yhot;       /* hot spot y (must be inside image) */
		      XcursorPixel    *pixels;	  /* pointer to pixels */
		  } XcursorImage;

	      holds multiple XcursorImage structures.  They're all freed when  the  XcursorImages
	      is freed.

		  typedef struct _XcursorImages {
		      int	      nimage;	     /* number of images */
		      XcursorImage    **images;   /* array of XcursorImage pointers */
		  } XcursorImages;

	      Holds multiple Cursor objects.  They're all freed when the XcursorCursors is freed.
	      These are reference counted so that multiple XcursorAnimate structures can use  the
	      same XcursorCursors.

		  typedef struct _XcursorCursors {
		      Display	  *dpy;     /* Display holding cursors */
		      int	 ref;  /* reference count */
		      int	 ncursor;   /* number of cursors */
		      Cursor	 *cursors;  /* array of cursors */
		  } XcursorCursors;

	      References  a  set of cursors and a sequence within that set.  Multiple XcursorAni-
	      mate structures may reference the same XcursorCursors; each holds a reference which
	      is removed when the XcursorAnimate is freed.

		  typedef struct _XcursorAnimate {
		      XcursorCursors   *cursors;  /* list of cursors to use */
		      int	   sequence;  /* which cursor is next */
		  } XcursorAnimate;

	      Xcursor  provides  an abstract API for accessing the file data.  Xcursor provides a
	      stdio implementation of this abstract API; applications are free	to  create  addi-
	      tional  implementations.	 These	functions  parallel the stdio functions in return
	      value and expected argument values; the read and write functions flip the arguments
	      around to match the POSIX versions.

		  typedef struct _XcursorFile {
		      void   *closure;
		      int    (*read)  (XcursorFile *file, unsigned char *buf, int len);
		      int    (*write) (XcursorFile *file, unsigned char *buf, int len);
		      int    (*seek)  (XcursorFile *file, long offset, int whence);

   Object Management
       XcursorImage *XcursorImageCreate (int width, int height)
       void XcursorImageDestroy (XcursorImage *image)
	      Allocate	and  free  images.   On  allocation,  the hotspot and the pixels are left
	      uninitialized.  The size is set to the maximum of width and height.

       XcursorImages *XcursorImagesCreate (int size)
       void XcursorImagesDestroy (XcursorImages *images)
	      Allocate and free arrays to hold multiple cursor images.	On allocation, nimage  is
	      set to zero.

       XcursorCursors *XcursorCursorsCreate (Display *dpy, int size)
       void XcursorCursorsDestroy (XcursorCursors *cursors)
	      Allocate	and  free arrays to hold multiple cursors.  On allocation, ncursor is set
	      to zero, ref is set to one.

   Reading and writing images.
       XcursorImage *XcursorXcFileLoadImage (XcursorFile *file, int size)
       XcursorImages *XcursorXcFileLoadImages (XcursorFile *file, int size)
       XcursorImages *XcursorXcFileLoadAllImages (XcursorFile *file)
       XcursorBool XcursorXcFileLoad (XcursorFile *file, XcursorComments **commentsp,  XcursorIm-
       ages **imagesp)
       XcursorBool  XcursorXcFileSave  (XcursorFile *file, const XcursorComments *comments, const
       XcursorImages *images)
	      These read and write cursors from an XcursorFile handle.	After reading,	the  file
	      pointer will be left at some random place in the file.

       XcursorImage *XcursorFileLoadImage (FILE *file, int size)
       XcursorImages *XcursorFileLoadImages (FILE *file, int size)
       XcursorImages *XcursorFileLoadAllImages (FILE *file)
       XcursorBool   XcursorFileLoad  (FILE  *file,  XcursorComments  **commentsp,  XcursorImages
       XcursorBool XcursorFileSaveImages (FILE *file, const XcursorImages *images)
       XcursorBool XcursorFileSave (FILE * file, const	XcursorComments  *comments,  const  Xcur-
       sorImages *images)
	      These  read  and	write  cursors	from a stdio FILE handle.  Writing flushes before
	      returning so that any errors should be detected.

       XcursorImage *XcursorFilenameLoadImage (const char *filename, int size)
       XcursorImages *XcursorFilenameLoadImages (const char *filename, int size)
       XcursorImages *XcursorFilenameLoadAllImages (FILE *file)
       XcursorBool XcursorFilenameLoad (const char *file, XcursorComments **commentsp, XcursorIm-
       ages **imagesp)
       XcursorBool XcursorFilenameSaveImages (const char *filename, const XcursorImages *images)
       XcursorBool  XcursorFilenameSave (const char *file, const XcursorComments *comments, const
       XcursorImages *images)
	      These parallel the stdio FILE interfaces above, but take filenames.

   Reading library images
       XcursorImage *XcursorLibraryLoadImage (const char *name, const char *theme, int size)
       XcursorImages *XcursorLibraryLoadImages (const char *name, const char *theme, int size)
	      These search the library path, loading the first file found.   If  'theme'  is  not
	      NULL, these functions first try appending -theme to name and then name alone.

   Cursor APIs
       Cursor XcursorFilenameLoadCursor (Display *dpy, const char *file)
       XcursorCursors *XcursorFilenameLoadCursors (Display *dpy, const char *file)
	      These load cursors from the specified file.

       Cursor XcursorLibraryLoadCursor (Display *dpy, const char *name)
       XcursorCursors *XcursorLibraryLoadCursors (Display *dpy, const char *name)
	      These load cursors using the specified library name.  The theme comes from the dis-

   X Cursor Name APIs
       XcursorImage *XcursorShapeLoadImage (unsigned int shape, const char *theme, int size)
       XcursorImages *XcursorShapeLoadImages (unsigned int shape, const char *theme, int size)
	      These map 'shape' to a library name using the standard X cursor names and then load
	      the images.

       Cursor XcursorShapeLoadCursor (Display *dpy, unsigned int shape)
       XcursorCursors *XcursorShapeLoadCursors (Display *dpy, unsigned int shape)
	      These map 'shape' to a library name and then load the cursors.

   Display Information APIs
       XcursorBool XcursorSupportsARGB (Display *dpy)
	      Returns whether the display supports ARGB cursors or whether cursors will be mapped
	      to a core X cursor.

       XcursorBool XcursorSetDefaultSize (Display *dpy, int size)
	      Sets the default size for cursors on the specified display. When	loading  cursors,
	      those whose nominal size is closest to this size will be preferred.

       int XcursorGetDefaultSize (Display *dpy)
	      Gets the default cursor size.

       XcursorBool XcursorSetTheme (Display *dpy, const char *theme)
	      Sets the current theme name.

       char *XcursorGetTheme (Display *dpy)
	      Gets the current theme name.

       XCURSOR_PATH   This  variable  sets the list of paths to look for cursors in.  Directories
		      in this path are separated by colons (:).

       Xcursor will probably change radically in the future; weak attempts will be made to retain
       some level of source-file compatibility.

       Keith Packard

Keith Packard				 libXcursor 1.1.9			       XCURSOR(3)

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