bug#28182: maybe implement CTRL++ to zoom text

[Stefan Kangas <stefan@marxist.se>]

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tags 28182 + patch
quit

Tak Kunihiro <homeros.misasa@gmail.com> writes:

> Richard Stallman <rms@gnu.org> writes:
>
>>   > Did you try "C-x C-+"?
>>
>> I don't think it would occur to people to try that key sequence.
>> It's not what other programs use.
>>
>> How about if we make C-+ and C-- do this, as they do in many
>> other programs?
>
> I think that people want to increase size of font when they are in an
> environment with mouse.  Thus I suggest <C-wheel-up> and <C-wheel-down>.

I think this is a good idea, which has the usability benefit to mirror
what happens in many common browsers, and other common text editors.
I remember myself that I was struggling to find the binding to change
the font size when I was an Emacs beginner.

I have implemented this suggestion in the attached patch.

However, this will be an incompatible change, since this was
previously bound to scrolling up and down by close to a full screen.
I therefore moved that binding to the meta modifier and wrote a NEWS
item that explains how to get the old functionality back.

How does it look?

Best regards,
Stefan Kangas

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From 698a00393dbb119a56e70ee6da71993a6b2901f3 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefankangas@gmail.com>
Date: Wed, 21 Aug 2019 03:38:49 +0200
Subject: [PATCH] Bind changing font size to C-mouse-4 and C-mouse-5

* lisp/mouse.el ([C-mouse-4], [C-mouse-5]): Bind to
text-scale-increase and text-scale-decrease.  (Bug#28182)
* lisp/mwheel.el (mouse-wheel-scroll-amount): Use the meta modifier
for scrolling by near full screen instead of control.
* etc/NEWS: Announce it.
---
 etc/NEWS       | 14 ++++++++++++++
 lisp/mouse.el  |  3 +++
 lisp/mwheel.el |  2 +-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/etc/NEWS b/etc/NEWS
index 56e5fd2f83..f15fc81314 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2021,6 +2021,20 @@ valid event type.
 ---
 ** The obsolete package xesam.el (since Emacs 24) has been removed.
 
+---
+** 'C-mouse-4' and 'C-mouse-5' will now decrease or increase the font size.
+This commonly corresponds to holding the control key and using the
+scroll wheel available on many mice.
+
+Previously, the control key modifier was used to scroll up or down by
+an amount which was close to near a full screen.  This functionality
+is now instead available by holding down the meta modifier key.  You
+can get the old functionality back by adding the following to your
+Emacs init file:
+
+(customize-set-variable 'mouse-wheel-scroll-amount
+                        '(5 ((shift) . 1) ((control) . nil)))
+
 \f
 * Lisp Changes in Emacs 27.1
 
diff --git a/lisp/mouse.el b/lisp/mouse.el
index e947e16d47..4b1afe261d 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -2728,6 +2728,9 @@ function-key-map
                   (mouse-menu-bar-map)
                 (mouse-menu-major-mode-map)))))
 
+(global-set-key [C-mouse-4] 'text-scale-increase)
+(global-set-key [C-mouse-5] 'text-scale-decrease)
+
 ;; Binding mouse-1 to mouse-select-window when on mode-, header-, or
 ;; vertical-line prevents Emacs from signaling an error when the mouse
 ;; button is released after dragging these lines, on non-toolkit
diff --git a/lisp/mwheel.el b/lisp/mwheel.el
index dfea55374b..d75c1d88c1 100644
--- a/lisp/mwheel.el
+++ b/lisp/mwheel.el
@@ -84,7 +84,7 @@ mouse-wheel-inhibit-click-time
   :group 'mouse
   :type 'number)
 
-(defcustom mouse-wheel-scroll-amount '(5 ((shift) . 1) ((control) . nil))
+(defcustom mouse-wheel-scroll-amount '(5 ((shift) . 1) ((meta) . nil))
   "Amount to scroll windows by when spinning the mouse wheel.
 This is an alist mapping the modifier key to the amount to scroll when
 the wheel is moved with the modifier key depressed.
-- 
2.20.1