[vte/wip/fedora-0-64: 4/10] Add a property to configure the scroll speed

[Christian Persch <chpe src gnome org>]

commit 876198b3a6ca20d9f859f8b2f28e14d55a4befc2
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Mar 22 19:02:31 2021 +0100

    Add a property to configure the scroll speed
    
    By default, it is set to zero which gives the current behaviour of
    moving the buffer by a function of the number of visible rows.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1103380

 doc/reference/vte-sections.txt |  1 +
 src/vte.cc                     | 19 +++++++++++++++++-
 src/vte/vteterminal.h          |  4 ++++
 src/vtegtk.cc                  | 45 ++++++++++++++++++++++++++++++++++++++++++
 src/vtegtk.hh                  |  1 +
 src/vteinternal.hh             |  2 ++
 6 files changed, 71 insertions(+), 1 deletion(-)
---
diff --git a/doc/reference/vte-sections.txt b/doc/reference/vte-sections.txt
index c69181da..dba88c15 100644
--- a/doc/reference/vte-sections.txt
+++ b/doc/reference/vte-sections.txt
@@ -54,6 +54,7 @@ vte_terminal_get_cursor_blink_mode
 vte_terminal_set_cursor_blink_mode
 vte_terminal_get_text_blink_mode
 vte_terminal_set_text_blink_mode
+vte_terminal_set_scroll_speed
 vte_terminal_set_scrollback_lines
 vte_terminal_get_scrollback_lines
 vte_terminal_set_font
diff --git a/src/vte.cc b/src/vte.cc
index 9aacccb4..c3046ddc 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -9293,6 +9293,7 @@ vte_cairo_get_clip_region (cairo_t *cr)
 bool
 Terminal::widget_mouse_scroll(vte::platform::ScrollEvent const& event)
 {
+       gdouble scroll_speed;
        gdouble v;
        gint cnt, i;
        int button;
@@ -9327,7 +9328,13 @@ Terminal::widget_mouse_scroll(vte::platform::ScrollEvent const& event)
                return true;
        }
 
-        v = MAX (1., ceil (gtk_adjustment_get_page_increment (m_vadjustment.get()) / 10.));
+       if (m_scroll_speed == 0) {
+               scroll_speed = ceil (gtk_adjustment_get_page_increment (m_vadjustment.get()) / 10.);
+       } else {
+               scroll_speed = m_scroll_speed;
+       }
+
+       v = MAX (1., scroll_speed);
        _vte_debug_print(VTE_DEBUG_EVENTS,
                        "Scroll speed is %d lines per non-smooth scroll unit\n",
                        (int) v);
@@ -9641,6 +9648,16 @@ Terminal::decscusr_cursor_shape() const noexcept
         }
 }
 
+bool
+Terminal::set_scroll_speed(unsigned int scroll_speed)
+{
+        if (scroll_speed == m_scroll_speed)
+                return false;
+
+        m_scroll_speed = scroll_speed;
+        return true;
+}
+
 bool
 Terminal::set_scrollback_lines(long lines)
 {
diff --git a/src/vte/vteterminal.h b/src/vte/vteterminal.h
index 668a7dbe..ea4fba19 100644
--- a/src/vte/vteterminal.h
+++ b/src/vte/vteterminal.h
@@ -310,6 +310,10 @@ void vte_terminal_set_cursor_shape(VteTerminal *terminal,
 _VTE_PUBLIC
 VteCursorShape vte_terminal_get_cursor_shape(VteTerminal *terminal) _VTE_CXX_NOEXCEPT _VTE_GNUC_NONNULL(1);
 
+_VTE_PUBLIC
+void vte_terminal_set_scroll_speed(VteTerminal *terminal,
+                                   guint scroll_speed) _VTE_GNUC_NONNULL(1);
+
 /* Set the number of scrollback lines, above or at an internal minimum. */
 _VTE_PUBLIC
 void vte_terminal_set_scrollback_lines(VteTerminal *terminal,
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 8c31a289..c5c8eb2f 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -758,6 +758,9 @@ try
                 case PROP_REWRAP_ON_RESIZE:
                         g_value_set_boolean (value, vte_terminal_get_rewrap_on_resize (terminal));
                         break;
+                case PROP_SCROLL_SPEED:
+                        g_value_set_uint (value, impl->m_scroll_speed);
+                        break;
                 case PROP_SCROLLBACK_LINES:
                         g_value_set_uint (value, vte_terminal_get_scrollback_lines(terminal));
                         break;
@@ -876,6 +879,9 @@ try
                 case PROP_REWRAP_ON_RESIZE:
                         vte_terminal_set_rewrap_on_resize (terminal, g_value_get_boolean (value));
                         break;
+                case PROP_SCROLL_SPEED:
+                        vte_terminal_set_scroll_speed (terminal, g_value_get_uint (value));
+                        break;
                 case PROP_SCROLLBACK_LINES:
                         vte_terminal_set_scrollback_lines (terminal, g_value_get_uint (value));
                         break;
@@ -1966,6 +1972,21 @@ vte_terminal_class_init(VteTerminalClass *klass)
                                       TRUE,
                                       (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | 
G_PARAM_EXPLICIT_NOTIFY));
 
+        /**
+         * VteTerminal:scroll-speed:
+         *
+         * The number of lines by which the buffer is moved when
+         * scrolling with a mouse wheel on top of the terminal
+         * Setting it to zero will cause the buffer to be moved by an
+         * amount depending on the number of visible rows the widget
+         * can display.
+         */
+        pspecs[PROP_SCROLL_SPEED] =
+                g_param_spec_uint ("scroll-speed", NULL, NULL,
+                                   0, G_MAXUINT,
+                                   0,
+                                   (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | 
G_PARAM_EXPLICIT_NOTIFY));
+
         /**
          * VteTerminal:scrollback-lines:
          *
@@ -5367,6 +5388,30 @@ catch (...)
         return -1;
 }
 
+/**
+ * vte_terminal_set_scroll_speed:
+ * @terminal: a #VteTerminal
+ * @scroll_speed: move the buffer by this number of lines while scrolling
+ *
+ * Sets the number of lines by which the buffer is moved when
+ * scrolling with a mouse wheel. Setting it to zero will cause the
+ * buffer to be moved by an amount depending on the number of visible
+ * rows the widget can display.
+ */
+void
+vte_terminal_set_scroll_speed(VteTerminal *terminal, guint scroll_speed)
+{
+        g_return_if_fail(VTE_IS_TERMINAL(terminal));
+
+        GObject *object = G_OBJECT(terminal);
+        g_object_freeze_notify(object);
+
+        if (IMPL(terminal)->set_scroll_speed(scroll_speed))
+                g_object_notify_by_pspec(object, pspecs[PROP_SCROLL_SPEED]);
+
+        g_object_thaw_notify(object);
+}
+
 /**
  * vte_terminal_set_scrollback_lines:
  * @terminal: a #VteTerminal
diff --git a/src/vtegtk.hh b/src/vtegtk.hh
index 389b86d2..24063c30 100644
--- a/src/vtegtk.hh
+++ b/src/vtegtk.hh
@@ -90,6 +90,7 @@ enum {
         PROP_MOUSE_POINTER_AUTOHIDE,
         PROP_PTY,
         PROP_REWRAP_ON_RESIZE,
+        PROP_SCROLL_SPEED,
         PROP_SCROLLBACK_LINES,
         PROP_SCROLL_ON_KEYSTROKE,
         PROP_SCROLL_ON_OUTPUT,
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 38aaf421..fd1a8b90 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -399,6 +399,7 @@ public:
         bool m_fallback_scrolling{true};
         bool m_scroll_on_output{false};
         bool m_scroll_on_keystroke{true};
+        guint m_scroll_speed;
         vte::grid::row_t m_scrollback_lines{0};
 
         /* Restricted scrolling */
@@ -1232,6 +1233,7 @@ public:
         bool set_input_enabled(bool enabled);
         bool set_mouse_autohide(bool autohide);
         bool set_rewrap_on_resize(bool rewrap);
+        bool set_scroll_speed(unsigned int scroll_speed);
         bool set_scrollback_lines(long lines);
         bool set_fallback_scrolling(bool set);
         auto fallback_scrolling() const noexcept { return m_fallback_scrolling; }