From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Wed, 24 Nov 2021 10:55:53 +0000 (+0100)
Subject: Add support for the min-width display property
X-Git-Tag: emacs-29.0.90~2852^2~77
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=a13b437c81f1f2e54555e7281480ea7e8eee8753;p=emacs.git
Add support for the min-width display property
* doc/lispref/display.texi (Display Property): Document
get-display-property.
(Other Display Specs): Document min-width property.
* src/dispextern.h (struct it): Add fields for min-width handling.
* src/xdisp.c (find_display_property, get_display_property): New
helper functions.
(display_min_width): Insert stretch glyphs based on the min width.
(Fget_display_property): New defun.
(handle_display_prop): Handle min-width ends.
(handle_single_display_spec): Handle min-width starts.
---
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 6b1c52b4859..dc53eeff9bf 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -4874,9 +4874,7 @@ window on a minibuffer-less frame.
The @code{display} text property (or overlay property) is used to
insert images into text, and to control other aspects of how text
-displays. The value of the @code{display} property should be a
-display specification, or a list or vector containing several display
-specifications. Display specifications in the same @code{display}
+displays. Display specifications in the same @code{display}
property value generally apply in parallel to the text they cover.
If several sources (overlays and/or a text property) specify values
@@ -4884,6 +4882,28 @@ for the @code{display} property, only one of the values takes effect,
following the rules of @code{get-char-property}. @xref{Examining
Properties}.
+ The value of the @code{display} property should be a display
+specification, or a list or vector containing several display
+specifications.
+
+@defun get-display-property position prop &optional object properties
+This convenience function can be used to get a specific display
+property, no matter whether the @code{display} property is a vector, a
+list or a simple property. This is like @code{get-text-property}
+(@pxref{Examining Properties}), but works on the @code{display}
+property only.
+
+@var{position} is the position in the buffer or string to examine, and
+@var{prop} is the @code{display} property to return. The optional
+@var{object} argument should be either a string or a buffer, and
+defaults to the current buffer. If the optional @var{properties}
+argument is non-@code{nil}, it should be a @code{display} property,
+and in that case, @var{position} and @var{object} are ignored. (This
+can be useful if you've already gotten the @code{display} property
+with @code{get-char-property}, for instance (@pxref{Examining
+Properties}).
+@end defun
+
@cindex display property, unsafe evaluation
@cindex security, and display specifications
Some of the display specifications allow inclusion of Lisp forms,
@@ -5159,6 +5179,22 @@ text that has the specification. It displays all of these spaces
be an integer or float. Characters other than spaces are not affected
at all; in particular, this has no effect on tab characters.
+@item (min-width (@var{width}))
+This display specification adds padding to the end of the text if the
+text is shorter than @var{width}. The text is partitioned using the
+identity of the parameter, which is why the parameter is a list with
+one element. For instance:
+
+@lisp
+(insert (propertize "foo" '(display (min-width (6.0)))))
+@end lisp
+
+This will add padding after @samp{foo} bringing the total width up to
+the width of six normal characters. Note that the ``range'' is
+identified by the @code{(6.0)} list, compared with @code{eq}. The
+width can be either a character width or a pixel specification
+(@pxref{Pixel Specification}).
+
@item (height @var{height})
This display specification makes the text taller or shorter.
Here are the possibilities for @var{height}:
diff --git a/etc/NEWS b/etc/NEWS
index 0bf3d9368b6..1cd49c5289c 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -668,6 +668,13 @@ Use 'exif-parse-file' and 'exif-field' instead.
* Lisp Changes in Emacs 29.1
+** New function 'get-display-property'.
+This is like 'get-text-property', but works on the 'display' text
+property.
+
+** New 'min-width' 'display' property.
+This allows setting a minimum width for a region.
+
** Keymaps and key definitions
+++
diff --git a/src/dispextern.h b/src/dispextern.h
index a698f6546b1..088297157ac 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2746,6 +2746,12 @@ struct it
/* For iterating over bidirectional text. */
struct bidi_it bidi_it;
bidi_dir_t paragraph_embedding;
+
+ /* For handling the :min-width property. The object is the text
+ property we're testing the `eq' of (nil if none), and the integer
+ is the x position of the start of the run of glyphs. */
+ Lisp_Object min_width_property;
+ int min_width_start;
};
diff --git a/src/xdisp.c b/src/xdisp.c
index 11ea8360343..4d3b4878058 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -822,6 +822,9 @@ bool help_echo_showing_p;
/* Functions to mark elements as needing redisplay. */
enum { REDISPLAY_SOME = 2}; /* Arbitrary choice. */
+static bool calc_pixel_width_or_height (double *, struct it *, Lisp_Object,
+ struct font *, bool, int *);
+
void
redisplay_other_windows (void)
{
@@ -5141,6 +5144,149 @@ setup_for_ellipsis (struct it *it, int len)
it->ellipsis_p = true;
}
+
+static Lisp_Object
+find_display_property (Lisp_Object disp, Lisp_Object prop)
+{
+ if (NILP (disp))
+ return Qnil;
+ /* We have a vector of display specs. */
+ if (VECTORP (disp))
+ {
+ for (ptrdiff_t i = 0; i < ASIZE (disp); i++)
+ {
+ Lisp_Object elem = AREF (disp, i);
+ if (CONSP (elem)
+ && CONSP (XCDR (elem))
+ && EQ (XCAR (elem), prop))
+ return XCAR (XCDR (elem));
+ }
+ return Qnil;
+ }
+ /* We have a list of display specs. */
+ else if (CONSP (disp)
+ && CONSP (XCAR (disp)))
+ {
+ while (!NILP (disp))
+ {
+ Lisp_Object elem = XCAR (disp);
+ if (CONSP (elem)
+ && CONSP (XCDR (elem))
+ && EQ (XCAR (elem), prop))
+ return XCAR (XCDR (elem));
+
+ /* Check that we have a proper list before going to the next
+ element. */
+ if (CONSP (XCDR (disp)))
+ disp = XCDR (disp);
+ else
+ disp = Qnil;
+ }
+ return Qnil;
+ }
+ /* A simple display spec. */
+ else if (CONSP (disp)
+ && CONSP (XCDR (disp))
+ && EQ (XCAR (disp), prop))
+ return XCAR (XCDR (disp));
+ else
+ return Qnil;
+}
+
+static Lisp_Object get_display_property (ptrdiff_t bufpos, Lisp_Object prop,
+ Lisp_Object object)
+{
+ return find_display_property (Fget_text_property (make_fixnum (bufpos),
+
+ Qdisplay, object),
+ prop);
+}
+
+static void
+display_min_width (struct it *it, ptrdiff_t bufpos,
+ Lisp_Object object, Lisp_Object width_spec)
+{
+ /* We're being called at the end of the `min-width' sequence,
+ probably. */
+ if (!NILP (it->min_width_property)
+ && !EQ (width_spec, it->min_width_property))
+ {
+ if (!it->glyph_row)
+ return;
+
+ /* Check that we're really right after the sequence of
+ characters covered by this `min-width'. */
+ if (bufpos > BEGV
+ && EQ (it->min_width_property,
+ get_display_property (bufpos - 1, Qmin_width, object)))
+ {
+ Lisp_Object w = Qnil;
+ double width;
+#ifdef HAVE_WINDOW_SYSTEM
+ if (FRAME_WINDOW_P (it->f))
+ {
+ struct font *font = NULL;
+ struct face *face = FACE_FROM_ID (it->f, it->face_id);
+ font = face->font ? face->font : FRAME_FONT (it->f);
+ calc_pixel_width_or_height (&width, it,
+ XCAR (it->min_width_property),
+ font, true, NULL);
+ width -= it->current_x - it->min_width_start;
+ w = list1 (make_int (width));
+ }
+ else
+#endif
+ {
+ calc_pixel_width_or_height (&width, it,
+ XCAR (it->min_width_property),
+ NULL, true, NULL);
+ width -= (it->current_x - it->min_width_start) /
+ FRAME_COLUMN_WIDTH (it->f);
+ w = make_int (width);
+ }
+
+ /* Insert the stretch glyph. */
+ it->object = list3 (Qspace, QCwidth, w);
+ produce_stretch_glyph (it);
+ it->min_width_property = Qnil;
+ }
+ }
+
+ /* We're at the start of a `min-width' sequence -- record the
+ position and the property, so that we can later see if we're at
+ the end. */
+ if (CONSP (width_spec))
+ {
+ if (bufpos == BEGV
+ || (bufpos > BEGV
+ && !EQ (width_spec,
+ get_display_property (bufpos - 1, Qmin_width, object))))
+ {
+ it->min_width_property = width_spec;
+ it->min_width_start = it->current_x;
+ }
+ }
+}
+
+DEFUN ("get-display-property", Fget_display_property,
+ Sget_display_property, 2, 4, 0,
+ doc: /* Get the `display' property PROP at POSITION.
+If OBJECT, this should be a buffer or string where the property is
+fetched from. This defaults to the current buffer.
+
+If PROPERTIES, use those properties instead of the properties at
+POSITION. */)
+ (Lisp_Object position, Lisp_Object prop, Lisp_Object object,
+ Lisp_Object properties)
+{
+ if (NILP (properties))
+ properties = Fget_text_property (position, Qdisplay, object);
+ else
+ CHECK_LIST (properties);
+
+ return find_display_property (properties, prop);
+}
+
/***********************************************************************
@@ -5187,16 +5333,22 @@ handle_display_prop (struct it *it)
if (!it->string_from_display_prop_p)
it->area = TEXT_AREA;
+ if (!STRINGP (it->string))
+ object = it->w->contents;
+
propval = get_char_property_and_overlay (make_fixnum (position->charpos),
Qdisplay, object, &overlay);
+
+ /* Handle min-width ends. */
+ if (! NILP (it->min_width_property)
+ && NILP (find_display_property (propval, Qmin_width)))
+ display_min_width (it, bufpos, object, Qnil);
+
if (NILP (propval))
return HANDLED_NORMALLY;
/* Now OVERLAY is the overlay that gave us this property, or nil
if it was a text property. */
- if (!STRINGP (it->string))
- object = it->w->contents;
-
display_replaced = handle_display_spec (it, propval, object, overlay,
position, bufpos,
FRAME_WINDOW_P (it->f));
@@ -5250,6 +5402,7 @@ handle_display_spec (struct it *it, Lisp_Object spec, Lisp_Object object,
&& !(CONSP (XCAR (spec)) && EQ (XCAR (XCAR (spec)), Qmargin))
&& !EQ (XCAR (spec), Qleft_fringe)
&& !EQ (XCAR (spec), Qright_fringe)
+ && !EQ (XCAR (spec), Qmin_width)
&& !NILP (XCAR (spec)))
{
for (; CONSP (spec); spec = XCDR (spec))
@@ -5483,6 +5636,17 @@ handle_single_display_spec (struct it *it, Lisp_Object spec, Lisp_Object object,
return 0;
}
+ /* Handle `(min-width (WIDTH))'. */
+ if (CONSP (spec)
+ && EQ (XCAR (spec), Qmin_width)
+ && CONSP (XCDR (spec))
+ && CONSP (XCAR (XCDR (spec))))
+ {
+ if (it)
+ display_min_width (it, bufpos, object, XCAR (XCDR (spec)));
+ return 0;
+ }
+
/* Handle `(slice X Y WIDTH HEIGHT)'. */
if (CONSP (spec)
&& EQ (XCAR (spec), Qslice))
@@ -7186,6 +7350,7 @@ reseat_1 (struct it *it, struct text_pos pos, bool set_stop_p)
}
/* This make the information stored in it->cmp_it invalidate. */
it->cmp_it.id = -1;
+ it->min_width_property = Qnil;
}
@@ -35121,6 +35286,7 @@ be let-bound around code that needs to disable messages temporarily. */);
defsubr (&Smove_point_visually);
defsubr (&Sbidi_find_overridden_directionality);
defsubr (&Sdisplay__line_is_continued_p);
+ defsubr (&Sget_display_property);
DEFSYM (Qmenu_bar_update_hook, "menu-bar-update-hook");
DEFSYM (Qoverriding_terminal_local_map, "overriding-terminal-local-map");
diff --git a/test/src/xdisp-tests.el b/test/src/xdisp-tests.el
index cc67aef8e15..ae4aacd9c7c 100644
--- a/test/src/xdisp-tests.el
+++ b/test/src/xdisp-tests.el
@@ -154,4 +154,20 @@ int main () {
nil)
138))))
+(ert-deftest test-get-display-property ()
+ (with-temp-buffer
+ (insert (propertize "foo" 'face 'bold 'display '(height 2.0)))
+ (should (equal (get-display-property 2 'height) 2.0)))
+ (with-temp-buffer
+ (insert (propertize "foo" 'face 'bold 'display '((height 2.0)
+ (space-width 2.0))))
+ (should (equal (get-display-property 2 'height) 2.0))
+ (should (equal (get-display-property 2 'space-width) 2.0)))
+ (with-temp-buffer
+ (insert (propertize "foo bar" 'face 'bold
+ 'display '[(height 2.0)
+ (space-width 20)]))
+ (should (equal (get-display-property 2 'height) 2.0))
+ (should (equal (get-display-property 2 'space-width) 20))))
+
;;; xdisp-tests.el ends here