Implement touch_scroll_multiplier

Author: max-baz

kitty/config_data.py

@@ -356,6 +356,12 @@ def scrollback_pager_history_size(x):
 as macOS and Wayland. Use negative numbers to change scroll direction.'''))
 # }}}
 
+o('touch_scroll_multiplier', 1.0, long_text=_('''
+Modify the amount scrolled by a touchpad. Note this is only used for high
+precision scrolling devices on platforms such as macOS and Wayland.
+Use negative numbers to change scroll direction.'''))
+# }}}
+
 g('mouse')  # {{{
 
 o('url_color', '#0087BD', option_type=to_color, long_text=_('''

kitty/mouse.c

@@ -549,7 +549,7 @@ scroll_event(double UNUSED xoffset, double yoffset, int flags) {
     int s;
     bool is_high_resolution = flags & 1;
     if (is_high_resolution) {
-        yoffset *= global_state.callback_os_window->viewport_y_ratio * OPT(wheel_scroll_multiplier);
+        yoffset *= OPT(touch_scroll_multiplier);
         if (yoffset * global_state.callback_os_window->pending_scroll_pixels < 0) {
             global_state.callback_os_window->pending_scroll_pixels = 0;  // change of direction
         }

kitty/state.c

@@ -373,6 +373,7 @@ PYWRAP1(set_options) {
     S(tab_bar_edge, PyLong_AsLong);
     S(mouse_hide_wait, PyFloat_AsDouble);
     S(wheel_scroll_multiplier, PyFloat_AsDouble);
+    S(touch_scroll_multiplier, PyFloat_AsDouble);
     S(open_url_modifiers, convert_mods);
     S(rectangle_select_modifiers, convert_mods);
     S(click_interval, PyFloat_AsDouble);

kitty/state.h

@@ -13,7 +13,7 @@
 typedef enum { LEFT_EDGE, TOP_EDGE, RIGHT_EDGE, BOTTOM_EDGE } Edge;
 
 typedef struct {
-    double visual_bell_duration, cursor_blink_interval, cursor_stop_blinking_after, mouse_hide_wait, click_interval, wheel_scroll_multiplier;
+    double visual_bell_duration, cursor_blink_interval, cursor_stop_blinking_after, mouse_hide_wait, click_interval, wheel_scroll_multiplier, touch_scroll_multiplier;
     bool enable_audio_bell;
     CursorShape cursor_shape;
     unsigned int open_url_modifiers;