Update doc about Ctrl/+/-/0/ zoom shortcuts

1 files changed, 15 insertions, 12 deletions

diff --git a/documentation/src/events.dox b/documentation/src/events.dox
index 5c43850d1..9a6ad6328 100644
--- a/documentation/src/events.dox
+++ b/documentation/src/events.dox
@@ -191,16 +191,19 @@ A global shortcut will work no matter what windows are displayed
 or which one has the focus.
 
 Since version 1.4, FLTK has 3 default global shortcuts (\c Ctrl/+/-/0/
-or \c Cmd/+/-/0/ under macOS) that change the value of the GUI scaling
+ [\c Cmd/+/-/0/ under macOS]) that change the value of the GUI scaling
 factor. \c Ctrl+ zooms-in all app windows of the focussed display
 (all displays under macOS);
 \c Ctrl- zooms-out these windows; \c Ctrl 0 restores the initial value of the
-scaling factor. Although characters '+' and '0' are located in
-the shifted position of their keyboard key in some
-keyboard layouts, these shortcuts are to be used without pressing
-the shift key, for user convenience. In other words, press only
-\c Ctrl (or \c Cmd) and the key labelled '+' or '0' independently of
-whether '+' or '0' is in shifted or unshifted position on the keyboard.
+scaling factor. If any window of the display is fullscreen or maximized,
+scaling shortcuts have no effect. It's possible to deactivate FLTK's default
+scaling shortcuts with function Fl::keyboard_screen_scaling().
+
+Option Fl::OPTION_SIMPLE_ZOOM_SHORTCUT can
+facilitate the typing necessary to trigger the zoom-in operation
+with those keyboard layouts where character '+' is located in
+the shifted position of its key: when this option is On
+it's not necessary to press also the Shift key to zoom-in.
 
 These scaling shortcuts are installed when the FLTK
 library opens the display. They have a lower priority than any shortcut
@@ -208,12 +211,12 @@ defined in any menu and than any user-provided event handler
 (see Fl::add_handler()) installed after FLTK opened the display.
 Therefore, if a menu item of an FLTK app is given FL_COMMAND+'+'
 as shortcut, that item's callback rather than FLTK's default zooming-in
-routine is triggered when \c Ctrl+ (or \c Cmd+) is pressed .
-If any window of the display is fullscreen or maximized,
-scaling shortcuts have no effect.
+routine is triggered when \c Ctrl+ (\c Cmd+ under macOS) is pressed.
 
-It's possible to deactivate FLTK's default scaling shortcuts with function
-Fl::keyboard_screen_scaling();
+FLTK sends the \ref FL_ZOOM_EVENT when the scaling factor value changes, to which a
+callback can be associated with Fl::add_handler().
+By default, FLTK displays the new scaling factor value in a yellow, transient window.
+This can be changed with option Fl::OPTION_SHOW_SCALING.
 
 \section events_widget Widget Events