Re: Hollow cursor under images

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

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пн, 27 янв. 2020 г. в 21:33, Eli Zaretskii <eliz@gnu.org>:

> > From: Evgeny Zajcev <lg.zevlg@gmail.com>
> > Date: Mon, 27 Jan 2020 15:54:56 +0300
> > Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel <emacs-devel@gnu.org>
> >
> > This patch implements (box . WIDTH) cursor type, allowing user to define
> his own notion for "Large" image
>
> Thanks.  This needs a NEWS entry and also an update for the ELisp
> manual.  See also a few comments below.
>
> > From 6406d198e9f3f5b2d93987ed0fd4fe22bd590624 Mon Sep 17 00:00:00 2001
> > From: Zajcev Evgeny <zevlg@yandex.ru>
> > Date: Mon, 27 Jan 2020 15:49:46 +0300
> > Subject: [PATCH] * Support for (box . WIDTH) `cursor-type'
> >
> > Before this commit, block cursor becomes hollow under "large" masked
> > images.  Notion for "large" was hardcoded to be image larger then
> > 32x32 in any dimension.
> >
> > This patch allows user to define his own notion for "large" image,
> > taking full control of block cursor look under masked images.
> >
> > With cursor-type equal to `box' cursor will always be block under
> > masked images.  This differs from former behavior for box cursor.
> > To get former behavior, set `cursor-type' to (box . 32)
>
> Please include in the log message a ChangeLog-style list of files and
> functions where you are making changes.
>
> > +  (box . WIDTH)   display a filled box cursor, but make it
> > +                  hollow if cursor is under masked image larger then
> > +                  WIDTH in either dimention.
>                                      ^^^^^^^^^
> "dimension"
>
> Also, please make it clear that WIDTH is measured in pixels.
>
> > +Except for (box . WIDTH) case.
>
> This is not a complete sentence, please clarify it.
>
> > +  if (CONSP (arg)
> > +      && EQ (XCAR (arg), Qbox)
> > +      && RANGED_FIXNUMP (0, XCDR (arg), INT_MAX))
> > +    {
> > +      *width = XFIXNUM (XCDR (arg));
>
> This calls XFIXNUM no less than 3 times.  I wonder if we could tweak
> the code to do that only once.
>
> > +      return FILLED_BOX_CURSOR;
> > +    }
> > +
> >    if (EQ (arg, Qhollow))
> >      return HOLLOW_BOX_CURSOR;
>
> If the condition above is not fulfilled, you then make the code do 5
> more gratuitous comparisons, before it falls back on
> HOLLOW_BOX_CURSOR.  It is much better to return HOLLOW_BOX_CURSOR
> right away if the conditions for FILLED_BOX_CURSOR weren't satisfied,
> it makes the code which implements this feature much easier to read
> and understand.
>

I tried to fulfill all the review comments in this updated patch

Thanks

-- 
lg

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From d4b74b56d7fb3fa1ac48d5049b18ac126e800d60 Mon Sep 17 00:00:00 2001
From: Zajcev Evgeny <zevlg@yandex.ru>
Date: Mon, 27 Jan 2020 15:49:46 +0300
Subject: [PATCH] Support for (box . WIDTH) `cursor-type'

* buffer.c (cursor-type): Add commentary about (box . WIDTH)
  cursor-type

* xdisp.c (get_specified_cursor_type): Check for `cursor-type' in form
  (box . WIDTH)

* xdisp.c (get_window_cursor_type): Check masked image size for
  (box . WIDTH) cursor-type.

* doc/emacs/display.texi, doc/emacs/display.texi: Add description
  for (box . WIDTH) `cursor-type'

* etc/NEWS: Add note about (box . WIDTH) `cursor-type'
---
 doc/emacs/display.texi  |  2 ++
 doc/lispref/frames.texi |  3 +++
 etc/NEWS                |  5 +++++
 src/buffer.c            |  5 +++++
 src/xdisp.c             | 28 ++++++++++++++--------------
 5 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/doc/emacs/display.texi b/doc/emacs/display.texi
index cb37ef4..bbfa938 100644
--- a/doc/emacs/display.texi
+++ b/doc/emacs/display.texi
@@ -1647,6 +1647,8 @@ Cursor Display
 the text shown under the cursor is drawn using the frame's background
 color.)  To change its shape, customize the buffer-local variable
 @code{cursor-type}; possible values are @code{box} (the default),
+@code{(box . @var{width})} (box cursor becoming a hollow box under
+masked images larger than @var{width} in either dimension),
 @code{hollow} (a hollow box), @code{bar} (a vertical bar), @code{(bar
 . @var{n})} (a vertical bar @var{n} pixels wide), @code{hbar} (a
 horizontal bar), @code{(hbar . @var{n})} (a horizontal bar @var{n}
diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 81a3dc6..67a4998 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -2219,6 +2219,9 @@ Cursor Parameters
 @table @code
 @item box
 Display a filled box.  (This is the default.)
+@item (box . @var{width})
+Display a filled box.  However, display it as a hollow box if point is
+under masked image larger than @var{width} in either dimension.
 @item hollow
 Display a hollow box.
 @item nil
diff --git a/etc/NEWS b/etc/NEWS
index dd33950..9cc0b1f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -30,6 +30,11 @@ applies, and please also update docstrings as needed.
 \f
 * Changes in Emacs 28.1
 
+** Support for `(box . WIDTH)' cursor-type.  By default, `box' cursor
+always has a filled box shape.  Unless you specify cursor-type to be
+`(box . WIDTH)'.  In such case, cursor becomes a hollow box if the
+point is under masked image larger than `WIDTH' in any dimension.
+
 \f
 * Editing Changes in Emacs 28.1
 
diff --git a/src/buffer.c b/src/buffer.c
index 80eaa97..a490d5f 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -6247,6 +6247,9 @@ from (abs POSITION).  If POSITION is positive, point was at the front
   t               use the cursor specified for the frame
   nil             don't display a cursor
   box             display a filled box cursor
+  (box . WIDTH)   display a filled box cursor, but make it
+                  hollow if cursor is under masked image larger than
+                  WIDTH pixels in either dimension.
   hollow          display a hollow box cursor
   bar             display a vertical bar cursor with default width
   (bar . WIDTH)   display a vertical bar cursor with width WIDTH
@@ -6255,6 +6258,8 @@ from (abs POSITION).  If POSITION is positive, point was at the front
   ANYTHING ELSE   display a hollow box cursor
 
 WIDTH and HEIGHT can't exceed the frame's canonical character size.
+Except for (box . WIDTH) case, where WIDTH specifies the size of a
+masked image, not the size of the cursor.
 
 When the buffer is displayed in a non-selected window, the
 cursor's appearance is instead controlled by the variable
diff --git a/src/xdisp.c b/src/xdisp.c
index 3080f89..eb2bf1c 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -30692,14 +30692,6 @@ get_specified_cursor_type (Lisp_Object arg, int *width)
       return BAR_CURSOR;
     }
 
-  if (CONSP (arg)
-      && EQ (XCAR (arg), Qbar)
-      && RANGED_FIXNUMP (0, XCDR (arg), INT_MAX))
-    {
-      *width = XFIXNUM (XCDR (arg));
-      return BAR_CURSOR;
-    }
-
   if (EQ (arg, Qhbar))
     {
       *width = 2;
@@ -30707,11 +30699,16 @@ get_specified_cursor_type (Lisp_Object arg, int *width)
     }
 
   if (CONSP (arg)
-      && EQ (XCAR (arg), Qhbar)
       && RANGED_FIXNUMP (0, XCDR (arg), INT_MAX))
     {
       *width = XFIXNUM (XCDR (arg));
-      return HBAR_CURSOR;
+
+      if (EQ (XCAR (arg), Qbox))
+          return FILLED_BOX_CURSOR;
+      else if (EQ (XCAR (arg), Qbar))
+          return BAR_CURSOR;
+      else if (EQ (XCAR (arg), Qhbar))
+          return HBAR_CURSOR;
     }
 
   /* Treat anything unknown as "hollow box cursor".
@@ -30849,12 +30846,15 @@ get_window_cursor_type (struct window *w, struct glyph *glyph, int *width,
 	      struct image *img = IMAGE_OPT_FROM_ID (f, glyph->u.img_id);
 	      if (img != NULL && IMAGEP (img->spec))
 		{
-		  /* Arbitrarily, interpret "Large" as >32x32 and >NxN
+		  /* Interpret "large" as >WIDTHxWIDTH and >NxN
+                     where WIDTH is the value from cursor-type in form (box . WIDTH),
 		     where N = size of default frame font size.
-		     This should cover most of the "tiny" icons people may use.  */
+                     So, setting cursor-type to (box . 32) should cover most of
+                     the "tiny" icons people may use.  */
 		  if (!img->mask
-		      || img->width > max (32, WINDOW_FRAME_COLUMN_WIDTH (w))
-		      || img->height > max (32, WINDOW_FRAME_LINE_HEIGHT (w)))
+                      || (CONSP (BVAR (b, cursor_type))
+                          && img->width > max (*width, WINDOW_FRAME_COLUMN_WIDTH (w))
+                          && img->height > max (*width, WINDOW_FRAME_LINE_HEIGHT (w))))
 		    cursor_type = HOLLOW_BOX_CURSOR;
 		}
 	    }
-- 
2.7.4