* Forcing Redisplay:: Forcing redisplay.
* Truncation:: Folding or wrapping long text lines.
* The Echo Area:: Where messages are displayed.
-* Warnings:: Displaying warning messages for the user.
* Invisible Text:: Hiding part of the buffer text.
* Selective Display:: Hiding part of the buffer text (the old way).
* Overlay Arrow:: Display of an arrow to indicate position.
* Width:: How wide a character or string is on the screen.
* Faces:: A face defines a graphics style for text characters:
font, colors, etc.
-* Fringes:: Controlling window fringes.
* Display Property:: Enabling special display features.
* Images:: Displaying images in Emacs buffers.
* Blinking:: How Emacs shows the matching open parenthesis.
which is also called @dfn{continuing} the line. (The display table can
specify alternative indicators; see @ref{Display Tables}.)
+@cindex fringes, and line continuation/truncation indicators
On a windowed display, the @samp{$} and @samp{\} indicators are
-replaced with graphics bitmaps displayed in the window fringes
-(@pxref{Fringes}).
+replaced with graphics bitmaps displayed on the thin areas right near
+the window edges, called the @dfn{fringes}.
Note that continuation is different from filling; continuation happens
on the screen only, not in the buffer contents, and it breaks a line
If the value is zero, then command input is not echoed.
@end defvar
-@node Warnings
-@section Reporting Warnings
-@cindex warnings
-
- @dfn{Warnings} are a facility for a program to inform the user of a
-possible problem, but continue running.
-
-@menu
-* Warning Basics:: Warnings concepts and functions to report them.
-* Warning Variables:: Variables programs bind to customize their warnings.
-* Warning Options:: Variables users set to control display of warnings.
-@end menu
-
-@node Warning Basics
-@subsection Warning Basics
-@cindex severity level
-
- Every warning has a textual message, which explains the problem for
-the user, and a @dfn{severity level} which is a symbol. Here are the
-possible severity levels, in order of decreasing severity, and their
-meanings:
-
-@table @code
-@item :emergency
-A problem that will seriously impair Emacs operation soon
-if you do not attend to it promptly.
-@item :error
-A report of data or circumstances that are inherently wrong.
-@item :warning
-A report of data or circumstances that are not inherently wrong, but
-raise suspicion of a possible problem.
-@item :debug
-A report of information that may be useful if you are debugging.
-@end table
-
- When your program encounters invalid input data, it can either
-signal a Lisp error by calling @code{error} or @code{signal} or report
-a warning with severity @code{:error}. Signaling a Lisp error is the
-easiest thing to do, but it means the program cannot continue
-processing. If you want to take the trouble to implement a way to
-continue processing despite the bad data, then reporting a warning of
-severity @code{:error} is the right way to inform the user of the
-problem. For instance, the Emacs Lisp byte compiler can report an
-error that way and continue compiling other functions. (If the
-program signals a Lisp error and then handles it with
-@code{condition-case}, the user won't see the error message; it could
-show the message to the user by reporting it as a warning.)
-
-@cindex warning type
- Each warning has a @dfn{warning type} to classify it. The type is a
-list of symbols. The first symbol should be the custom group that you
-use for the program's user options. For example, byte compiler
-warnings use the warning type @code{(bytecomp)}. You can also
-subcategorize the warnings, if you wish, by using more symbols in the
-list.
-
-@defun display-warning type message &optional level buffer-name
-This function reports a warning, using @var{message} as the message
-and @var{type} as the warning type. @var{level} should be the
-severity level, with @code{:warning} being the default.
-
-@var{buffer-name}, if non-@code{nil}, specifies the name of the buffer
-for logging the warning. By default, it is @samp{*Warnings*}.
-@end defun
-
-@defun lwarn type level message &rest args
-This function reports a warning using the value of @code{(format
-@var{message} @var{args}...)} as the message. In other respects it is
-equivalent to @code{display-warning}.
-@end defun
-
-@defun warn message &rest args
-This function reports a warning using the value of @code{(format
-@var{message} @var{args}...)} as the message, @code{(emacs)} as the
-type, and @code{:warning} as the severity level. It exists for
-compatibility only; we recommend not using it, because you should
-specify a specific warning type.
-@end defun
-
-@node Warning Variables
-@subsection Warning Variables
-
- Programs can customize how their warnings appear by binding
-the variables described in this section.
-
-@defvar warning-levels
-This list defines the meaning and severity order of the warning
-severity levels. Each element defines one severity level,
-and they are arranged in order of decreasing severity.
-
-Each element has the form @code{(@var{level} @var{string}
-@var{function})}, where @var{level} is the severity level it defines.
-@var{string} specifies the textual description of this level.
-@var{string} should use @samp{%s} to specify where to put the warning
-type information, or it can omit the @samp{%s} so as not to include
-that information.
-
-The optional @var{function}, if non-@code{nil}, is a function to call
-with no arguments, to get the user's attention.
-
-Normally you should not change the value of this variable.
-@end defvar
-
-@defvar warning-prefix-function
-If non-@code{nil}, te value is a function to generate prefix text for
-warnings. Programs can bind the variable to a suitable function.
-@code{display-warning} calls this function with the warnings buffer
-current, and the function can insert text in it. That text becomes
-the beginning of the warning message.
-
-The function is called with two arguments, the severity level and its
-entry in @code{warning-levels}. It should return a list to use as the
-entry (this value need not be an actual member of
-@code{warning-levels}). By constructing this value, the function to
-change the severity of the warning, or specify different handling for
-a given severity level.
-
-If the variable's value is @code{nil} then there is no function
-to call.
-@end defvar
-
-@defvar warning-series
-Programs can bind this variable to @code{t} to say that the next
-warning should begin a series. When several warnings form a series,
-that means to leave point on the first warning of the series, rather
-than keep move it for each warning so that it appears on the last one.
-The series ends when the local binding is unbound and
-@code{warning-series} becomes @code{nil} again.
-
-The value can also be a symbol with a function definition. That is
-equivalent to @code{t}, except that the next warning will also call
-the function with no arguments with the warnings buffer current. The
-function can insert text which will serve as a header for the series
-of warnings.
-
-Once a series has begun, the value is a marker which points to the
-buffer position in the warnings buffer of the start of the series.
-
-The variable's normal value is @code{nil}, which means to handle
-each warning separately.
-@end defvar
-
-@defvar warning-fill-prefix
-When this variable is non-@code{nil}, it specifies a fill prefix to
-use for filling each warning's text.
-@end defvar
-
-@defvar warning-type-format
-This variable specifies the format for displaying the warning type
-in the warning message. The result of formatting the type this way
-gets included in the message under the control of the string in the
-entry in @code{warning-levels}. The default value is @code{" (%s)"}.
-If you bind it to @code{""} then the warning type won't appear at
-all.
-@end defvar
-
-@node Warning Options
-@subsection Warning Options
-
- These variables are used by users to control what happens
-when a Lisp program reports a warning.
-
-@defopt warning-minimum-level
-This user option specifies the minimum severity level that should be
-shown immediately to the user. The default is @code{:warning}, which
-means to immediately display all warnings except @code{:debug}
-warnings.
-@end defopt
-
-@defopt warning-minimum-log-level
-This user option specifies the minimum severity level that should be
-logged in the warnings buffer. The default is @code{:warning}, which
-means to log all warnings except @code{:debug} warnings.
-@end defopt
-
-@defopt warning-suppress-types
-This list specifies which warning types should not be displayed
-immediately for the user. Each element of the list should be a list
-of symbols. If its elements match the first elements in a warning
-type, then that warning is not displayed immediately.
-@end defopt
-
-@defopt warning-suppress-log-types
-This list specifies which warning types should not be logged in the
-warnings buffer. Each element of the list should be a list of
-symbols. If it matches the first few elements in a warning type, then
-that warning is not logged.
-@end defopt
@node Invisible Text
@section Invisible Text
about to be executed.
@defvar overlay-arrow-string
+@cindex fringe, and overlay arrow display
This variable holds the string to display to call attention to a
particular line, or @code{nil} if the arrow feature is not in use.
On a graphical display the contents of the string are ignored; instead a
@table @code
@item priority
@kindex priority @r{(overlay property)}
-This property's value (which should be a nonnegative integer number)
-determines the priority of the overlay. The priority matters when two
-or more overlays cover the same character and both specify the same
-property; the one whose @code{priority} value is larger takes priority
-over the other. For the @code{face} property, the higher priority
-value does not completely replace the other; instead, its face
-attributes override the face attributes of the lower priority
-@code{face} property.
+This property's value (which should be a nonnegative number) determines
+the priority of the overlay. The priority matters when two or more
+overlays cover the same character and both specify a face for display;
+the one whose @code{priority} value is larger takes priority over the
+other, and its face attributes override the face attributes of the lower
+priority overlay.
Currently, all overlays take priority over text properties. Please
avoid using negative priority values, as we have not yet decided just
Chinese GB2312 characters has a wild card @samp{*} in the @var{family}
field.
-@node Fringes
-@section Fringes
-@cindex Fringes
-
- The @dfn{fringes} of a window are thin vertical strips down the
-sides that are used for displaying bitmaps that indicate truncation,
-continuation, and horizontal scrolling, the overlay arrow. The
-fringes normally appear between the display margins and the window
-text, but you can put them outside the display margins for a specific
-buffer by setting @code{fringes-outside-margins} buffer-locally to a
-non-@code{nil} value.
-
-@defvar fringes-outside-margins
-If the value is non-@code{nil}, the frames appear outside
-the display margins.
-@end defvar
-
-@defvar left-fringe-width
-This variable, if non-@code{nil}, specifies the width of the left
-fringe in pixels.
-@end defvar
-
-@defvar right-fringe-width
-This variable, if non-@code{nil}, specifies the width of the right
-fringe in pixels.
-@end defvar
-
- The values of these variables take effect when you display the
-buffer in a window. If you change them while the buffer is visible,
-you can call @code{set-buffer-window} to display it in a window again.
-
-@defun set-window-fringes window left &optional right outside-margins
-This function sets the fringe widthes of window @var{window}.
-If window is @code{nil}, that stands for the selected window.
-
-The argument @var{left} specifies the width in pixels of the left
-fringe, and likewise @var{right} for the right fringe. A value of
-@code{nil} for either one stands for the default width. If
-@var{outside-margins} is non-@code{nil}, that specifies that fringes
-should appear outside of the display margins.
-@end defun
-
-@defun window-fringes window
-This function returns information about the fringes of a window
-@var{window}. The value has the form @code{(@var{left-width}
-@var{right-width} @var{frames-outside-margins})}.
-@end defun
-
@node Display Property
@section The @code{display} Property
@cindex display specification
@defopt indicate-empty-lines
@tindex indicate-empty-lines
@cindex fringes, and empty line indication
-When this is non-@code{nil}, Emacs displays a special glyph in the
-fringe of each empty line at the end of the buffer, on terminals that
-support it (window systems). @xref{Fringes}.
+When this is non-@code{nil}, Emacs displays a special glyph in
+each empty line at the end of the buffer, on terminals that
+support it (window systems).
@end defopt
@defopt tab-width
the window system, and creating the initial window. Users should not
interfere with it.
@end defvar
-
-@ignore
- arch-tag: ffdf5714-7ecf-415b-9023-fbc6b409c2c6
-@end ignore
HCoop / bpt / emacs.git / blobdiff