Re: [PATCH] Add support for `ch' and `cw' dimension specifiers for the image

[Evgeny Zajcev <lg.zevlg@gmail.com>]

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чт, 21 мар. 2024 г. в 19:57, Eli Zaretskii <eliz@gnu.org>:

> > From: Evgeny Zajcev <lg.zevlg@gmail.com>
> > Date: Thu, 21 Mar 2024 17:53:09 +0300
> >
> > With applied patch and image specified as:
> >
> >   (list 'image :type 'svg :file "file.svg" :scale 1.0 :ascent 'center
> >          :width '(2 . cw)
> >          :max-height '(1 . ch))
>
> ENOPATCH
>

:)) sorry, here it is

-- 
lg

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From b13bae3e21c6f8f503e7cbd00003694813acdaca Mon Sep 17 00:00:00 2001
From: Zajcev Evgeny <zevlg@yandex.ru>
Date: Thu, 21 Mar 2024 17:47:29 +0300
Subject: [PATCH] Add support for `ch' and `cw' dimension specifiers for the
 image

---
 doc/lispref/display.texi |  7 +++++--
 src/dispextern.h         |  5 +++++
 src/image.c              | 19 ++++++++++++++++---
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 4dbb4afb20d..73671a21e7f 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -5788,8 +5788,11 @@ Image Descriptors
 length in @dfn{ems}@footnote{In typography an em is a distance
 equivalent to the height of the type.  For example when using 12 point
 type 1 em is equal to 12 points.  Its use ensures distances and type
-remain proportional.}.  One em is equivalent to the height of the font
-and @var{value} may be an integer or a float.
+remain proportional.}.  One em is equivalent to the size of the font
+and @var{value} may be an integer or a float.  Also, dimension can be
+specified in @code{(@var{value} . ch)} and @code{(@var{value} . cw)}
+forms, where @code{ch} means height of the canonical character and
+@code{cw} means width of the canonical character.
 
   The following is a list of properties that are meaningful for all
 image types (there are also properties which are meaningful only for
diff --git a/src/dispextern.h b/src/dispextern.h
index 3a4d6095f73..462b370b810 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -3176,6 +3176,11 @@ reset_mouse_highlight (Mouse_HLInfo *hlinfo)
   int face_font_size;
   char *face_font_family;
 
+  /* Details of the font used to calculate image size relative to the
+     canonical character size, with `ch' and `cw' specifiers. */
+  int face_font_height;
+  int face_font_width;
+
   /* True if this image has a `transparent' background -- that is, is
      uses an image mask.  The accessor macro for this is
      `IMAGE_BACKGROUND_TRANSPARENT'.  */
diff --git a/src/image.c b/src/image.c
index 9a465f0b180..eb0460759f0 100644
--- a/src/image.c
+++ b/src/image.c
@@ -2557,9 +2557,18 @@ image_get_dimension (struct image *img, Lisp_Object symbol)
 
   if (FIXNATP (value))
     return min (XFIXNAT (value), INT_MAX);
-  if (CONSP (value) && NUMBERP (CAR (value)) && EQ (Qem, CDR (value)))
-    return scale_image_size (img->face_font_size, 1, XFLOATINT (CAR (value)));
-
+  if (CONSP (value) && NUMBERP (CAR (value)))
+    {
+      if (EQ (Qem, CDR (value)))
+        return scale_image_size (img->face_font_size,
+                                 1, XFLOATINT (CAR (value)));
+      if (EQ (Qch, CDR (value)))
+        return scale_image_size (img->face_font_height,
+                                 1, XFLOATINT (CAR (value)));
+      if (EQ (Qcw, CDR (value)))
+        return scale_image_size (img->face_font_width,
+                                 1, XFLOATINT (CAR (value)));
+    }
   return -1;
 }
 
@@ -3383,6 +3392,8 @@ lookup_image (struct frame *f, Lisp_Object spec, int face_id)
       img->face_foreground = foreground;
       img->face_background = background;
       img->face_font_size = font_size;
+      img->face_font_height = face->font->height;
+      img->face_font_width = face->font->average_width;
       img->face_font_family = xmalloc (strlen (font_family) + 1);
       strcpy (img->face_font_family, font_family);
       img->load_failed_p = ! img->type->load_img (f, img);
@@ -12760,6 +12771,8 @@ syms_of_image (void)
   DEFSYM (QCmax_height, ":max-height");
 
   DEFSYM (Qem, "em");
+  DEFSYM (Qch, "ch");
+  DEFSYM (Qcw, "cw");
 
 #ifdef HAVE_NATIVE_TRANSFORMS
   DEFSYM (Qscale, "scale");
-- 
2.25.1