This is ../info/lispref.info, produced by makeinfo version 4.0b from lispref/lispref.texi. INFO-DIR-SECTION XEmacs Editor START-INFO-DIR-ENTRY * Lispref: (lispref). XEmacs Lisp Reference Manual. END-INFO-DIR-ENTRY Edition History: GNU Emacs Lisp Reference Manual Second Edition (v2.01), May 1993 GNU Emacs Lisp Reference Manual Further Revised (v2.02), August 1993 Lucid Emacs Lisp Reference Manual (for 19.10) First Edition, March 1994 XEmacs Lisp Programmer's Manual (for 19.12) Second Edition, April 1995 GNU Emacs Lisp Reference Manual v2.4, June 1995 XEmacs Lisp Programmer's Manual (for 19.13) Third Edition, July 1995 XEmacs Lisp Reference Manual (for 19.14 and 20.0) v3.1, March 1996 XEmacs Lisp Reference Manual (for 19.15 and 20.1, 20.2, 20.3) v3.2, April, May, November 1997 XEmacs Lisp Reference Manual (for 21.0) v3.3, April 1998 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc. Copyright (C) 1994, 1995 Sun Microsystems, Inc. Copyright (C) 1995, 1996 Ben Wing. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the section entitled "GNU General Public License" is included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the section entitled "GNU General Public License" may be included in a translation approved by the Free Software Foundation instead of in the original English.  File: lispref.info, Node: Merging Faces, Next: Basic Face Functions, Up: Faces Merging Faces for Display ------------------------- Here are all the ways to specify which face to use for display of text: * With defaults. Each frame has a "default face", which is used for all text that doesn't somehow specify another face. The face named `default' applies to the text area, while the faces `left-margin' and `right-margin' apply to the left and right margin areas. * With text properties. A character may have a `face' property; if so, it's displayed with that face. (Text properties are actually implemented in terms of extents.) *Note Text Properties::. * With extents. An extent may have a `face' property, which applies to all the text covered by the extent; in addition, if the `highlight' property is set, the `highlight' property applies when the mouse moves over the extent or if the extent is explicitly highlighted. *Note Extents::. * With annotations. Annotations that are inserted into a buffer can specify their own face. (Annotations are actually implemented in terms of extents.) *Note Annotations::. If these various sources together specify more than one face for a particular character, XEmacs merges the properties of the various faces specified. Extents, text properties, and annotations all use the same underlying representation (as extents). When multiple extents cover one character, an extent with higher priority overrides those with lower priority. *Note Extents::. If no extent covers a particular character, the `default' face is used. If a background pixmap is specified, it determines what will be displayed in the background of text characters. If the background pixmap is actually a pixmap, with its colors specified, those colors are used; if it is a bitmap, the face's foreground and background colors are used to color it.  File: lispref.info, Node: Basic Face Functions, Next: Face Properties, Prev: Merging Faces, Up: Faces Basic Functions for Working with Faces -------------------------------------- The properties a face can specify include the font, the foreground color, the background color, the background pixmap, the underlining, the display table, and (for TTY devices) whether the text is to be highlighted, dimmed, blinking, or displayed in reverse video. The face can also leave these unspecified, causing them to assume the value of the corresponding property of the `default' face. Here are the basic primitives for working with faces. - Function: make-face name &optional doc-string temporary This function defines and returns a new face named NAME, initially with all properties unspecified. It does nothing if there is already a face named NAME. Optional argument DOC-STRING specifies an explanatory string used for descriptive purposes. If optional argument TEMPORARY is non-`nil', the face will automatically disappear when there are no more references to it anywhere in text or Lisp code (otherwise, the face will continue to exist indefinitely even if it is not used). - Function: face-list &optional temporary This function returns a list of the names of all defined faces. If TEMPORARY is `nil', only the permanent faces are included. If it is `t', only the temporary faces are included. If it is any other non-`nil' value both permanent and temporary are included. - Function: facep object This function returns `t' if OBJECT is a face, else `nil'. - Function: copy-face old-face new-name &optional locale tag-set exact-p how-to-add This function defines a new face named NEW-NAME which is a copy of the existing face named OLD-FACE. If there is already a face named NEW-NAME, then it alters the face to have the same properties as OLD-FACE. LOCALE, TAG-SET, EXACT-P and HOW-TO-ADD let you copy just parts of the old face rather than the whole face, and are as in `copy-specifier' (*note Specifiers::).  File: lispref.info, Node: Face Properties, Next: Face Convenience Functions, Prev: Basic Face Functions, Up: Faces Face Properties --------------- You can examine and modify the properties of an existing face with the following functions. The following symbols have predefined meanings: `foreground' The foreground color of the face. `background' The background color of the face. `font' The font used to display text covered by this face. `display-table' The display table of the face. `background-pixmap' The pixmap displayed in the background of the face. Only used by faces on X devices. `underline' Underline all text covered by this face. `highlight' Highlight all text covered by this face. Only used by faces on TTY devices. `dim' Dim all text covered by this face. Only used by faces on TTY devices. `blinking' Blink all text covered by this face. Only used by faces on TTY devices. `reverse' Reverse the foreground and background colors. Only used by faces on TTY devices. `doc-string' Description of what the face's normal use is. NOTE: This is not a specifier, unlike all the other built-in properties, and cannot contain locale-specific values. - Function: set-face-property face property value &optional locale tag-set how-to-add This function changes a property of a FACE. For built-in properties, the actual value of the property is a specifier and you cannot change this; but you can change the specifications within the specifier, and that is what this function will do. For user-defined properties, you can use this function to either change the actual value of the property or, if this value is a specifier, change the specifications within it. If PROPERTY is a built-in property, the specifications to be added to this property can be supplied in many different ways: If VALUE is a simple instantiator (e.g. a string naming a font or color) or a list of instantiators, then the instantiator(s) will be added as a specification of the property for the given LOCALE (which defaults to `global' if omitted). If VALUE is a list of specifications (each of which is a cons of a locale and a list of instantiators), then LOCALE must be `nil' (it does not make sense to explicitly specify a locale in this case), and specifications will be added as given. If VALUE is a specifier (as would be returned by `face-property' if no LOCALE argument is given), then some or all of the specifications in the specifier will be added to the property. In this case, the function is really equivalent to `copy-specifier' and LOCALE has the same semantics (if it is a particular locale, the specification for the locale will be copied; if a locale type, specifications for all locales of that type will be copied; if `nil' or `all', then all specifications will be copied). HOW-TO-ADD should be either `nil' or one of the symbols `prepend', `append', `remove-tag-set-prepend', `remove-tag-set-append', `remove-locale', `remove-locale-type', or `remove-all'. See `copy-specifier' and `add-spec-to-specifier' for a description of what each of these means. Most of the time, you do not need to worry about this argument; the default behavior usually is fine. In general, it is OK to pass an instance object (e.g. as returned by `face-property-instance') as an instantiator in place of an actual instantiator. In such a case, the instantiator used to create that instance object will be used (for example, if you set a font-instance object as the value of the `font' property, then the font name used to create that object will be used instead). If some cases, however, doing this conversion does not make sense, and this will be noted in the documentation for particular types of instance objects. If PROPERTY is not a built-in property, then this function will simply set its value if LOCALE is `nil'. However, if LOCALE is given, then this function will attempt to add VALUE as the instantiator for the given LOCALE, using `add-spec-to-specifier'. If the value of the property is not a specifier, it will automatically be converted into a `generic' specifier. - Function: remove-face-property face property &optional locale tag-set exact-p This function removes a property of a FACE. For built-in properties, this is analogous to `remove-specifier'. For more information, *Note Other Specification Functions::. When PROPERTY is not a built-in property, this function will just remove its value if LOCALE is `nil' or `all'. However, if LOCALE is other than that, this function will attempt to remove VALUE as the instantiator for the given LOCALE with `remove-specifier'. If the value of the property is not a specifier, it will be converted into a `generic' specifier automatically. - Function: face-property face property &optional locale tag-set exact-p This function returns FACE's value of the given PROPERTY. If LOCALE is omitted, the FACE's actual value for PROPERTY will be returned. For built-in properties, this will be a specifier object of a type appropriate to the property (e.g. a font or color specifier). For other properties, this could be anything. If LOCALE is supplied, then instead of returning the actual value, the specification(s) for the given locale or locale type will be returned. This will only work if the actual value of PROPERTY is a specifier (this will always be the case for built-in properties, but not or not may apply to user-defined properties). If the actual value of PROPERTY is not a specifier, this value will simply be returned regardless of LOCALE. The return value will be a list of instantiators (e.g. strings specifying a font or color name), or a list of specifications, each of which is a cons of a locale and a list of instantiators. Specifically, if LOCALE is a particular locale (a buffer, window, frame, device, or `global'), a list of instantiators for that locale will be returned. Otherwise, if LOCALE is a locale type (one of the symbols `buffer', `window', `frame', or `device'), the specifications for all locales of that type will be returned. Finally, if LOCALE is `all', the specifications for all locales of all types will be returned. The specifications in a specifier determine what the value of PROPERTY will be in a particular "domain" or set of circumstances, which is typically a particular Emacs window along with the buffer it contains and the frame and device it lies within. The value is derived from the instantiator associated with the most specific locale (in the order buffer, window, frame, device, and `global') that matches the domain in question. In other words, given a domain (i.e. an Emacs window, usually), the specifier for PROPERTY will first be searched for a specification whose locale is the buffer contained within that window; then for a specification whose locale is the window itself; then for a specification whose locale is the frame that the window is contained within; etc. The first instantiator that is valid for the domain (usually this means that the instantiator is recognized by the device [i.e. the X server or TTY device] that the domain is on). The function `face-property-instance' actually does all this, and is used to determine how to display the face. - Function: face-property-instance face property &optional domain default no-fallback This function returns the instance of FACE's PROPERTY in the specified DOMAIN. Under most circumstances, DOMAIN will be a particular window, and the returned instance describes how the specified property actually is displayed for that window and the particular buffer in it. Note that this may not be the same as how the property appears when the buffer is displayed in a different window or frame, or how the property appears in the same window if you switch to another buffer in that window; and in those cases, the returned instance would be different. The returned instance will typically be a color-instance, font-instance, or pixmap-instance object, and you can query it using the appropriate object-specific functions. For example, you could use `color-instance-rgb-components' to find out the RGB (red, green, and blue) components of how the `background' property of the `highlight' face is displayed in a particular window. The results might be different from the results you would get for another window (perhaps the user specified a different color for the frame that window is on; or perhaps the same color was specified but the window is on a different X server, and that X server has different RGB values for the color from this one). DOMAIN defaults to the selected window if omitted. DOMAIN can be a frame or device, instead of a window. The value returned for a such a domain is used in special circumstances when a more specific domain does not apply; for example, a frame value might be used for coloring a toolbar, which is conceptually attached to a frame rather than a particular window. The value is also useful in determining what the value would be for a particular window within the frame or device, if it is not overridden by a more specific specification. If PROPERTY does not name a built-in property, its value will simply be returned unless it is a specifier object, in which case it will be instanced using `specifier-instance'. Optional arguments DEFAULT and NO-FALLBACK are the same as in `specifier-instance'. *Note Specifiers::.  File: lispref.info, Node: Face Convenience Functions, Next: Other Face Display Functions, Prev: Face Properties, Up: Faces Face Convenience Functions -------------------------- - Command: set-face-foreground face color &optional locale tag-set how-to-add - Command: set-face-background face color &optional locale tag-set how-to-add These functions set the foreground (respectively, background) color of face FACE to COLOR. The argument COLOR should be a string (the name of a color) or a color object as returned by `make-color' (*note Colors::). - Command: set-face-background-pixmap face pixmap &optional locale tag-set how-to-add This function sets the background pixmap of face FACE to PIXMAP. The argument PIXMAP should be a string (the name of a bitmap or pixmap file; the directories listed in the variable `x-bitmap-file-path' will be searched) or a glyph object as returned by `make-glyph' (*note Glyphs::). The argument may also be a list of the form `(WIDTH HEIGHT DATA)' where WIDTH and HEIGHT are the size in pixels, and DATA is a string, containing the raw bits of the bitmap. - Command: set-face-font face font &optional locale tag-set how-to-add This function sets the font of face FACE. The argument FONT should be a string or a font object as returned by `make-font' (*note Fonts::). - Command: set-face-underline-p face underline-p &optional locale tag-set how-to-add This function sets the underline property of face FACE. - Function: face-foreground face &optional locale tag-set exact-p - Function: face-background face &optional locale tag-set exact-p These functions return the foreground (respectively, background) color specifier of face FACE. *Note Colors::. - Function: face-background-pixmap face &optional locale tag-set exact-p This function return the background-pixmap glyph object of face FACE. - Function: face-font face &optional locale tag-set exact-p This function returns the font specifier of face FACE. (Note: This is not the same as the function `face-font' in FSF Emacs.) *Note Fonts::. - Function: face-font-name face &optional domain This function returns the name of the font of face FACE, or `nil' if it is unspecified. This is basically equivalent to `(font-name (face-font FACE) DOMAIN)' except that it does not cause an error if FACE's font is `nil'. (This function is named `face-font' in FSF Emacs.) - Function: face-underline-p face &optional locale This function returns the underline property of face FACE. - Function: face-foreground-instance face &optional domain - Function: face-background-instance face &optional domain These functions return the foreground (respectively, background) color specifier of face FACE. *Note Colors::. - Function: face-background-pixmap-instance face &optional domain This function return the background-pixmap glyph object of face FACE. - Function: face-font-instance face &optional domain This function returns the font specifier of face FACE. *Note Fonts::.  File: lispref.info, Node: Other Face Display Functions, Prev: Face Convenience Functions, Up: Faces Other Face Display Functions ---------------------------- - Command: invert-face face &optional locale Swap the foreground and background colors of face FACE. If the face doesn't specify both foreground and background, then its foreground and background are set to the default background and foreground. - Function: face-equal face1 face2 &optional domain This returns `t' if the faces FACE1 and FACE2 will display in the same way. DOMAIN is as in `face-property-instance'. - Function: face-differs-from-default-p face &optional domain This returns `t' if the face FACE displays differently from the default face. DOMAIN is as in `face-property-instance'.  File: lispref.info, Node: Fonts, Next: Colors, Prev: Faces, Up: Faces and Window-System Objects Fonts ===== This section describes how to work with font specifier and font instance objects, which encapsulate fonts in the window system. * Menu: * Font Specifiers:: Specifying how a font will appear. * Font Instances:: What a font specifier gets instanced as. * Font Instance Names:: The name of a font instance. * Font Instance Size:: The size of a font instance. * Font Instance Characteristics:: Display characteristics of font instances. * Font Convenience Functions:: Convenience functions that automatically instance and retrieve the properties of a font specifier.  File: lispref.info, Node: Font Specifiers, Next: Font Instances, Up: Fonts Font Specifiers --------------- - Function: font-specifier-p object This predicate returns `t' if OBJECT is a font specifier, and `nil' otherwise. - Function: make-font-specifier spec-list Return a new `font' specifier object with the given specification list. SPEC-LIST can be a list of specifications (each of which is a cons of a locale and a list of instantiators), a single instantiator, or a list of instantiators. *Note Specifiers::, for more information about specifiers. Valid instantiators for font specifiers are: * A string naming a font (e.g. under X this might be "-*-courier-medium-r-*-*-*-140-*-*-*-*-iso8859-*" for a 14-point upright medium-weight Courier font). * A font instance (use that instance directly if the device matches, or use the string that generated it). * A vector of no elements (only on TTY's; this means to set no font at all, thus using the "natural" font of the terminal's text). * A vector of one element (a face to inherit from).  File: lispref.info, Node: Font Instances, Next: Font Instance Names, Prev: Font Specifiers, Up: Fonts Font Instances -------------- - Function: font-instance-p object This predicate returns `t' if OBJECT is a font instance, and `nil' otherwise. - Function: make-font-instance name &optional device noerror This function creates a new font-instance object of the specified name. DEVICE specifies the device this object applies to and defaults to the selected device. An error is signalled if the font is unknown or cannot be allocated; however, if NOERROR is non-`nil', `nil' is simply returned in this case. The returned object is a normal, first-class lisp object. The way you "deallocate" the font is the way you deallocate any other lisp object: you drop all pointers to it and allow it to be garbage collected. When these objects are GCed, the underlying X data is deallocated as well.  File: lispref.info, Node: Font Instance Names, Next: Font Instance Size, Prev: Font Instances, Up: Fonts Font Instance Names ------------------- - Function: list-fonts pattern &optional device This function returns a list of font names matching the given pattern. DEVICE specifies which device to search for names, and defaults to the currently selected device. - Function: font-instance-name font-instance This function returns the name used to allocate FONT-INSTANCE. - Function: font-instance-truename font-instance This function returns the canonical name of the given font instance. Font names are patterns which may match any number of fonts, of which the first found is used. This returns an unambiguous name for that font (but not necessarily its only unambiguous name).  File: lispref.info, Node: Font Instance Size, Next: Font Instance Characteristics, Prev: Font Instance Names, Up: Fonts Font Instance Size ------------------ - Function: x-font-size font This function returns the nominal size of the given font. This is done by parsing its name, so it's likely to lose. X fonts can be specified (by the user) in either pixels or 10ths of points, and this returns the first one it finds, so you have to decide which units the returned value is measured in yourself ... - Function: x-find-larger-font font &optional device This function loads a new, slightly larger version of the given font (or font name). Returns the font if it succeeds, `nil' otherwise. If scalable fonts are available, this returns a font which is 1 point larger. Otherwise, it returns the next larger version of this font that is defined. - Function: x-find-smaller-font font &optional device This function loads a new, slightly smaller version of the given font (or font name). Returns the font if it succeeds, `nil' otherwise. If scalable fonts are available, this returns a font which is 1 point smaller. Otherwise, it returns the next smaller version of this font that is defined.  File: lispref.info, Node: Font Instance Characteristics, Next: Font Convenience Functions, Prev: Font Instance Size, Up: Fonts Font Instance Characteristics ----------------------------- - Function: font-instance-properties font-instance This function returns the properties (an alist or `nil') of FONT-INSTANCE. - Function: x-make-font-bold font &optional device Given an X font specification, this attempts to make a "bold" font. If it fails, it returns `nil'. - Function: x-make-font-unbold font &optional device Given an X font specification, this attempts to make a non-bold font. If it fails, it returns `nil'. - Function: x-make-font-italic font &optional device Given an X font specification, this attempts to make an "italic" font. If it fails, it returns `nil'. - Function: x-make-font-unitalic font &optional device Given an X font specification, this attempts to make a non-italic font. If it fails, it returns `nil'. - Function: x-make-font-bold-italic font &optional device Given an X font specification, this attempts to make a "bold-italic" font. If it fails, it returns `nil'.  File: lispref.info, Node: Font Convenience Functions, Prev: Font Instance Characteristics, Up: Fonts Font Convenience Functions -------------------------- - Function: font-name font &optional domain This function returns the name of the FONT in the specified DOMAIN, if any. FONT should be a font specifier object and DOMAIN is normally a window and defaults to the selected window if omitted. This is equivalent to using `specifier-instance' and applying `font-instance-name' to the result. - Function: font-truename font &optional domain This function returns the truename of the FONT in the specified DOMAIN, if any. FONT should be a font specifier object and DOMAIN is normally a window and defaults to the selected window if omitted. This is equivalent to using `specifier-instance' and applying `font-instance-truename' to the result. - Function: font-properties font &optional domain This function returns the properties of the FONT in the specified DOMAIN, if any. FONT should be a font specifier object and DOMAIN is normally a window and defaults to the selected window if omitted. This is equivalent to using `specifier-instance' and applying `font-instance-properties' to the result.  File: lispref.info, Node: Colors, Prev: Fonts, Up: Faces and Window-System Objects Colors ====== * Menu: * Color Specifiers:: Specifying how a color will appear. * Color Instances:: What a color specifier gets instanced as. * Color Instance Properties:: Properties of color instances. * Color Convenience Functions:: Convenience functions that automatically instance and retrieve the properties of a color specifier.  File: lispref.info, Node: Color Specifiers, Next: Color Instances, Up: Colors Color Specifiers ---------------- - Function: color-specifier-p object This function returns non-`nil' if OBJECT is a color specifier. - Function: make-color-specifier spec-list Return a new `color' specifier object with the given specification list. SPEC-LIST can be a list of specifications (each of which is a cons of a locale and a list of instantiators), a single instantiator, or a list of instantiators. *Note Specifiers::, for a detailed description of how specifiers work. Valid instantiators for color specifiers are: * A string naming a color (e.g. under X this might be "lightseagreen2" or "#F534B2"). * A color instance (use that instance directly if the device matches, or use the string that generated it). * A vector of no elements (only on TTY's; this means to set no color at all, thus using the "natural" color of the terminal's text). * A vector of one or two elements: a face to inherit from, and optionally a symbol naming which property of that face to inherit, either `foreground' or `background' (if omitted, defaults to the same property that this color specifier is used for; if this specifier is not part of a face, the instantiator would not be valid). - Function: make-face-boolean-specifier spec-list Return a new `face-boolean' specifier object with the given spec list. SPEC-LIST can be a list of specifications (each of which is a cons of a locale and a list of instantiators), a single instantiator, or a list of instantiators. *Note Specifiers::, for a detailed description of how specifiers work. Valid instantiators for face-boolean specifiers are * t or nil. * A vector of two or three elements: a face to inherit from, optionally a symbol naming the property of that face to inherit from (if omitted, defaults to the same property that this face-boolean specifier is used for; if this specifier is not part of a face, the instantiator would not be valid), and optionally a value which, if non-`nil', means to invert the sense of the inherited property.  File: lispref.info, Node: Color Instances, Next: Color Instance Properties, Prev: Color Specifiers, Up: Colors Color Instances --------------- A "color-instance object" is an object describing the way a color specifier is instanced in a particular domain. Functions such as `face-background-instance' return a color-instance object. For example, (face-background-instance 'default (next-window)) => # The color-instance object returned describes the way the background color of the `default' face is displayed in the next window after the selected one. - Function: color-instance-p object This function returns non-`nil' if OBJECT is a color-instance.  File: lispref.info, Node: Color Instance Properties, Next: Color Convenience Functions, Prev: Color Instances, Up: Colors Color Instance Properties ------------------------- - Function: color-instance-name color-instance This function returns the name used to allocate COLOR-INSTANCE. - Function: color-instance-rgb-components color-instance This function returns a three element list containing the red, green, and blue color components of COLOR-INSTANCE. (color-instance-rgb-components (face-background-instance 'default (next-window))) => (65535 58596 46517)  File: lispref.info, Node: Color Convenience Functions, Prev: Color Instance Properties, Up: Colors Color Convenience Functions --------------------------- - Function: color-name color &optional domain This function returns the name of the COLOR in the specified DOMAIN, if any. COLOR should be a color specifier object and DOMAIN is normally a window and defaults to the selected window if omitted. This is equivalent to using `specifier-instance' and applying `color-instance-name' to the result. - Function: color-rgb-components color &optional domain This function returns the RGB components of the COLOR in the specified DOMAIN, if any. COLOR should be a color specifier object and DOMAIN is normally a window and defaults to the selected window if omitted. This is equivalent to using `specifier-instance' and applying `color-instance-rgb-components' to the result. (color-rgb-components (face-background 'default (next-window))) => (65535 58596 46517)  File: lispref.info, Node: Glyphs, Next: Annotations, Prev: Faces and Window-System Objects, Up: Top Glyphs ****** A "glyph" is an object that is used for pixmaps, widgets and images of all sorts, as well as for things that "act" like pixmaps, such as non-textual strings ("annotations") displayed in a buffer or in the margins. It is used in begin-glyphs and end-glyphs attached to extents, marginal and textual annotations, overlay arrows (`overlay-arrow-*' variables), toolbar buttons, mouse pointers, frame icons, truncation and continuation markers, and the like. (Basically, any place there is an image or something that acts like an image, there will be a glyph object representing it.) The actual image that is displayed (as opposed to its position or clipping) is defined by an "image specifier" object contained within the glyph. The separation between an image specifier object and a glyph object is made because the glyph includes other properties than just the actual image: e.g. the face it is displayed in (for text images), the alignment of the image (when it is in a buffer), etc. - Function: glyphp object This function returns `t' if OBJECT is a glyph. * Menu: * Glyph Functions:: Functions for working with glyphs. * Images:: Graphical images displayed in a frame. * Glyph Types:: Each glyph has a particular type. * Mouse Pointer:: Controlling the mouse pointer. * Redisplay Glyphs:: Glyphs controlling various redisplay functions. * Subwindows:: Inserting an externally-controlled subwindow into a buffer.  File: lispref.info, Node: Glyph Functions, Next: Images, Up: Glyphs Glyph Functions =============== * Menu: * Creating Glyphs:: Creating new glyphs. * Glyph Properties:: Accessing and modifying a glyph's properties. * Glyph Convenience Functions:: Convenience functions for accessing particular properties of a glyph. * Glyph Dimensions:: Determining the height, width, etc. of a glyph.  File: lispref.info, Node: Creating Glyphs, Next: Glyph Properties, Up: Glyph Functions Creating Glyphs --------------- - Function: make-glyph &optional spec-list type This function creates a new glyph object of type TYPE. SPEC-LIST is used to initialize the glyph's image. It is typically an image instantiator (a string or a vector; *Note Image Specifiers::), but can also be a list of such instantiators (each one in turn is tried until an image is successfully produced), a cons of a locale (frame, buffer, etc.) and an instantiator, a list of such conses, or any other form accepted by `canonicalize-spec-list'. *Note Specifiers::, for more information about specifiers. TYPE specifies the type of the glyph, which specifies in which contexts the glyph can be used, and controls the allowable image types into which the glyph's image can be instantiated. TYPE should be one of `buffer' (used for glyphs in an extent, the modeline, the toolbar, or elsewhere in a buffer), `pointer' (used for the mouse-pointer), or `icon' (used for a frame's icon), and defaults to `buffer'. *Note Glyph Types::. A glyph in XEmacs does *NOT* refer to a single unit of textual display (the XEmacs term for this is "rune"), but rather is an object encapsulating a graphical element, such as an image or widget (an element such as a button or text field; "widget" is the term for this under X Windows, and it's called a "control" under MS Windows). This graphical element could appear in a buffer, a margin, a gutter, or a toolbar, or as a mouse pointer or an icon, for example. Creating a glyph using `make-glyph' does not specify _where_ the glyph will be used, but it does specify _what_ the glyph will look like. In particular, SPEC-LIST is used to specify this, and it's used to initialize the glyph's `image' property, which is an image specifier. (Note that "image" as used in the context of a glyph's `image' property or in the terms "image specifier", "image instantiator", or "image instance" does not refer to what people normally think of as an image (which in XEmacs is called a "pixmap"), but to any graphical element--a pixmap, a widget, or even a block of text, when used in the places that call for a glyph.) The format of the SPEC-LIST is typically an image instantiator (a string or a vector; *Note Image Specifiers::), but can also be a list of such instantiators (each one in turn is tried until an image is successfully produced), a cons of a locale (frame, buffer, etc.) and an instantiator, a list of such conses, or any other form accepted by `canonicalize-spec-list'. *Note Specifiers::, for more information about specifiers. If you're not familiar with specifiers, you should be in order to understand how glyphs work. The clearest introduction to specifiers is in the Lispref manual, available under Info. (Choose Help->Info->Info Contents on the menubar or type C-h i.) You can also see `make-specifier' for a capsule summary. What's important to keep in mind is that a specifier lets you set a different value for any particular buffer, window, frame, device, or console. This allows for a great deal of flexibility; in particular, only one global glyph needs to exist for a particular purpose (e.g. the icon used to represent an iconified frame, the mouse pointer used over particular areas of a frame, etc.), and in these cases you do not create your own glyph, but rather modify the existing one. As well as using SPEC-LIST to initialize the glyph, you can set specifications using `set-glyph-image'. Note that, due to a possibly questionable historical design decision, a glyph itself is not actually a specifier, but rather is an object containing an image specifier (as well as other, seldom-used properties). Therefore, you cannot set or access specifications for the glyph's image by directly using `set-specifier', `specifier-instance' or the like on the glyph; instead use them on `(glyph-image GLYPH)' or use the convenience functions `set-glyph-image', `glyph-image-instance', and `glyph-image'. Once you have created a glyph, you specify where it will be used as follows: * To insert a glyph into a buffer, create an extent in the buffer and then use `set-extent-begin-glyph' or `set-extent-end-glyph' to set a glyph to be displayed at the corresponding edge of the extent. (It is common to create zero-width extents for this purpose.) * To insert a glyph into the left or right margin of a buffer, first make sure the margin is visible by setting a value for the specifiers `left-margin-width' or `right-margin-width'. (Not strictly necessary when using margin glyphs with layout policy `whitespace'.) Then follow the same procedure above for inserting a glyph in a buffer, and then set a non-default layout policy for the glyph using `set-extent-begin-glyph-layout' or `set-extent-end-glyph-layout'. Alternatively, use the high-level annotations API (see `make-annotation'). (In point of fact, you can also use the annotations API for glyphs in a buffer, by setting a layout policy of `text'.) * To insert a glyph into the modeline, just put the glyph directly as one of the modeline elements. (Unfortunately you can't currently put a begin glyph or end glyph on one of the modeline extents--they're ignored.) * To insert a glyph into a toolbar, specify it as part of a toolbar instantiator (typically set on the specifier `default-toolbar'). See `default-toolbar' for more information. (Note that it is standard practice to use a symbol in place of the glyph list in the toolbar instantiator; the symbol is evalled to get the glyph list. This facilitates both creating the toolbar instantiator and modifying individual glyphs in a toolbar later on. For example, you can change the way that the Mail toolbar button looks by modifying the value of the variable `toolbar-mail-icon' (in general, `toolbar-*-icon') and then calling `(set-specifier-dirty-flag default-toolbar)'. (#### Unfortunately this doesn't quite work the way it should; the change will appear in new frames, but not existing ones. * To insert a glyph into a gutter, create or modify a gutter instantiator (typically set on the specifier `default-gutter'). Gutter instantiators consist of strings or lists of strings, so to insert a glyph, create an extent over the string, and use `set-extent-begin-glyph' or `set-extent-end-glyph' to set a glyph to be displayed at the corresponding edge of the extent, just like for glyphs in a buffer. * To use a glyph as the icon for a frame, you do not actually create a new glyph; rather, you change the specifications for the existing glyph `frame-icon-glyph'. (Remember that, because of the specifier nature of glyphs, you can set different values for any particular buffer or frame.) * To use a glyph as the mouse pointer, in general you do not create a new glyph, but rather you change the specifications of various existing glyphs, such as `text-pointer-glyph' for the pointer used over text, `modeline-pointer-glyph' for the pointer used over the modeline, etc. Do an apropos over `*-pointer-glyph' to find all of them. (Note also that you can temporarily set the mouse pointer to some specific shape by using `set-frame-pointer', which takes an image instance, as obtained from calling `glyph-image-instance' on a glyph of type `pointer' - either one of the above-mentioned variables or one you created yourself. (See below for what it means to create a glyph of type `pointer'.) This pointer will last only until the next mouse motion event is processed or certain other things happen, such as creating or deleting a window. (In fact, the above-mentioned pointer glyph variables are implemented as part of the default handler for mouse motion events. If you want to customize this behavior, take a look at `mode-motion-hook', or `mouse-motion-handler' if you really want to get low-level.) * To use a glyph to control the shape of miscellaneous redisplay effects such as the truncation and continuation markers, set the appropriate existing glyph variables, as for icons and pointers above. See `continuation-glyph', `control-arrow-glyph', `hscroll-glyph', `invisible-text-glyph', `octal-escape-glyph', and `truncation-glyph'. See also `overlay-arrow-string', an odd redisplay leftover which can be set to a glyph you created, and will cause the glyph to be displayed on top of the text position specified in the marker stored in `overlay-arrow-position'. * To use a glyph in a display table (i.e. to control the appearance of any individual character), create the appropriate character glyphs and then set a specification for the specifier `current-display-table', which controls the appearance of characters. You can also set an overriding display table for use with text displayed in a particular face; see `set-face-display-table' and `make-display-table'. #### Note: Display tables do not currently support general Mule characters. They will be overhauled at some point to support this and to provide other features required under Mule. * To use a glyph as the background pixmap of a face: Note that the background pixmap of a face is actually an image specifier - probably the only place in XEmacs where an image specifier occurs outside of a glyph. Similarly to how the glyph's image specifier works, you don't create your own image specifier, but rather add specifications to the existing one (using `set-face-background-pixmap'). Note that the image instance that is generated in order to actually display the background pixmap is of type `mono-pixmap', meaning that it's a two-color image and the foreground and background of the image get filled in with the corresponding colors from the face. It is extremely rare that you will ever have to specify a value for TYPE, which should be one of `buffer' (used for glyphs in an extent, the modeline, the toolbar, or elsewhere in a buffer), `pointer' (used for the mouse-pointer), or `icon' (used for a frame's icon), and defaults to `buffer'. The only cases where it needs to be specified is when creating icon or pointer glyphs, and in both cases the necessary glyphs have already been created at startup and are accessed through the appropriate variables, e.g. `text-pointer-glyph' (or in general, `*-pointer-glyph') and `frame-icon-glyph'. *Note Glyph Types::. - Function: make-glyph-internal &optional type This function creates a new, uninitialized glyph of type TYPE. - Function: make-pointer-glyph &optional spec-list Return a new `pointer-glyph' object with the specification list SPEC-LIST. This function is equivalent to calling `make-glyph' with a TYPE of `pointer'. It is extremely unlikely that you will ever need to create a pointer glyph. Instead, you probably want to be calling `set-glyph-image' on an existing glyph, e.g. `text-pointer-glyph'. - Function: make-icon-glyph &optional spec-list Return a new `pointer-glyph' object with the specification list SPEC-LIST. This function is equivalent to calling `make-glyph' with a TYPE of `icon'. It is extremely unlikely that you will ever need to create a pointer glyph. Instead, you probably want to be calling `set-glyph-image' on an existing glyph, e.g. `text-pointer-glyph'.