added @mighty-scroll-show-indicator option

fixes #5

Author: noscript

README.md

@@ -64,6 +64,7 @@ $ tmux source ~/.tmux.conf
 |`@mighty-scroll-by-page`|`'irssi vi'`|List|Space separated list of processes that will be scrolled by page.|
 |`@mighty-scroll-pass-through`|`'vim nvim'`|List|Space separated list of processes that will receive mouse scroll events as is.|
 |`@mighty-scroll-fallback-mode`|`'history'`|`'history'`, `'by-line'`, `'by-page'`|Scroll mode when in alternate screen but the process didn't match `by-line` and `by-page` lists from above.|
+|`@mighty-scroll-show-indicator`|`off`|`on`, `off`|If enabled, shows the position indicator in the top right with current position and the number of lines in the history.|
 
 Scrolling modes:
 

mighty-scroll.tmux

@@ -29,9 +29,16 @@ else
   set_tmux_environment "MIGHTY_SCROLL_SELECT_PANE" "false"
 fi
 
+if [ "$(get_tmux_option "$show_indicator_option" "$show_indicator_default")" = "on" ]; then
+  show_indicator_arg=''
+else
+  show_indicator_arg='-H'
+fi
+
 # FIXME: move to tmux.conf after https://github.com/tmux/tmux/issues/3791
 tmux set-option -g command-alias[630] mighty_scroll_select_pane='if-shell "$MIGHTY_SCROLL_SELECT_PANE" {select-pane -t "{mouse}"}'
 tmux set-option -g command-alias[631] mighty_scroll_with_interval='send-keys -t "{mouse}" -N $MIGHTY_SCROLL_INTERVAL'
 tmux set-option -g command-alias[632] mighty_scroll_exit_mode_if_bottom='if-shell -F -t "{mouse}" "#{&&:#{pane_in_mode},#{==:#{scroll_position},0}}" {send-keys -t "{mouse}" -X cancel}'
+tmux set-option -g command-alias[633] mighty_scroll_enter_copy_mode="copy-mode $show_indicator_arg -t '{mouse}'"
 
 tmux source-file "$CURRENT_DIR/tmux.conf"

scripts/variables.sh

@@ -15,3 +15,6 @@ pass_through_default="vim nvim"
 
 fallback_mode_option="@mighty-scroll-fallback-mode"
 fallback_mode_default="history"
+
+show_indicator_option="@mighty-scroll-show-indicator"
+show_indicator_default="off"

tmux.conf

@@ -9,7 +9,7 @@ bind-key -T root WheelUpPane {
       if-shell -t "{mouse}" "$PSCHECK #{pane_pid} $MIGHTY_SCROLL_BY_PAGE || ( [ '$MIGHTY_SCROLL_FALLBACK_MODE' = 'by-page' ] && #{?alternate_on,true,false} )" {
         send-keys -t "{mouse}" PageUp
       } {
-        copy-mode -t "{mouse}"
+        mighty_scroll_enter_copy_mode
         mighty_scroll_with_interval -X scroll-up
       }
     }