[vte/vte-0-36] widget: Support for smooth scrolling

[Christian Persch <chpe src gnome org>]

commit 7efb04fbcec9a39512847204d75350fb0b119c9f
Author: Egmont Koblinger <egmont gmail com>
Date:   Wed Oct 23 00:02:00 2013 +0200

    widget: Support for smooth scrolling
    
    https://bugzilla.gnome.org/show_bug.cgi?id=710426

 src/vte-private.h |    1 +
 src/vte.c         |   86 +++++++++++++++++++++++++++++++---------------------
 src/vteseq.c      |   22 ++++++++++---
 3 files changed, 69 insertions(+), 40 deletions(-)
---
diff --git a/src/vte-private.h b/src/vte-private.h
index 4282ebf..42bc254 100644
--- a/src/vte-private.h
+++ b/src/vte-private.h
@@ -313,6 +313,7 @@ struct _VteTerminalPrivate {
        guint mouse_autoscroll_tag;
        gboolean mouse_xterm_extension;
        gboolean mouse_urxvt_extension;
+       double mouse_smooth_scroll_delta;
 
        /* State variables for handling match checks. */
        char *match_contents;
diff --git a/src/vte.c b/src/vte.c
index de9c55a..3c21662 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -9219,6 +9219,9 @@ vte_terminal_realize(GtkWidget *widget)
                                GDK_EXPOSURE_MASK |
                                GDK_VISIBILITY_NOTIFY_MASK |
                                GDK_FOCUS_CHANGE_MASK |
+#if GTK_CHECK_VERSION (3, 4, 0)
+                               GDK_SMOOTH_SCROLL_MASK |
+#endif
                                GDK_SCROLL_MASK |
                                GDK_BUTTON_PRESS_MASK |
                                GDK_BUTTON_RELEASE_MASK |
@@ -11443,40 +11446,52 @@ vte_terminal_scroll(GtkWidget *widget, GdkEventScroll *event)
 {
        GtkAdjustment *adj;
        VteTerminal *terminal;
+       gdouble delta_x, delta_y;
        gdouble v;
+       gint cnt, i;
        int button;
 
        terminal = VTE_TERMINAL(widget);
 
        vte_terminal_read_modifiers (terminal, (GdkEvent*) event);
 
-       _VTE_DEBUG_IF(VTE_DEBUG_EVENTS)
-               switch (event->direction) {
-               case GDK_SCROLL_UP:
-                       g_printerr("Scroll up.\n");
-                       break;
-               case GDK_SCROLL_DOWN:
-                       g_printerr("Scroll down.\n");
-                       break;
-               default:
-                       break;
-               }
+       switch (event->direction) {
+       case GDK_SCROLL_UP:
+               terminal->pvt->mouse_smooth_scroll_delta -= 1.;
+               _vte_debug_print(VTE_DEBUG_EVENTS, "Scroll up\n");
+               break;
+       case GDK_SCROLL_DOWN:
+               terminal->pvt->mouse_smooth_scroll_delta += 1.;
+               _vte_debug_print(VTE_DEBUG_EVENTS, "Scroll down\n");
+               break;
+#if GTK_CHECK_VERSION (3, 3, 18)
+       case GDK_SCROLL_SMOOTH:
+               gdk_event_get_scroll_deltas ((GdkEvent*) event, &delta_x, &delta_y);
+               terminal->pvt->mouse_smooth_scroll_delta += delta_y;
+               _vte_debug_print(VTE_DEBUG_EVENTS,
+                               "Smooth scroll by %f, delta now at %f\n",
+                               delta_y, terminal->pvt->mouse_smooth_scroll_delta);
+               break;
+#endif
+       default:
+               break;
+       }
 
        /* If we're running a mouse-aware application, map the scroll event
         * to a button press on buttons four and five. */
        if (terminal->pvt->mouse_tracking_mode) {
-               switch (event->direction) {
-               case GDK_SCROLL_UP:
-                       button = 4;
-                       break;
-               case GDK_SCROLL_DOWN:
-                       button = 5;
-                       break;
-               default:
-                       button = 0;
-                       break;
-               }
-               if (button != 0) {
+               cnt = terminal->pvt->mouse_smooth_scroll_delta;
+               if (cnt == 0)
+                       return TRUE;
+               terminal->pvt->mouse_smooth_scroll_delta -= cnt;
+               _vte_debug_print(VTE_DEBUG_EVENTS,
+                               "Scroll application by %d lines, smooth scroll delta set back to %f\n",
+                               cnt, terminal->pvt->mouse_smooth_scroll_delta);
+
+               button = cnt > 0 ? 5 : 4;
+               if (cnt < 0)
+                       cnt = -cnt;
+               for (i = 0; i < cnt; i++) {
                        /* Encode the parameters and send them to the app. */
                        vte_terminal_send_mouse_button_internal(terminal,
                                                                button,
@@ -11489,22 +11504,22 @@ vte_terminal_scroll(GtkWidget *widget, GdkEventScroll *event)
 
        adj = terminal->adjustment;
        v = MAX (1., ceil (gtk_adjustment_get_page_increment (adj) / 10.));
-       switch (event->direction) {
-       case GDK_SCROLL_UP:
-               v = -v;
-               break;
-       case GDK_SCROLL_DOWN:
-               break;
-       default:
-               return FALSE;
-       }
+       _vte_debug_print(VTE_DEBUG_EVENTS,
+                       "Scroll speed is %d lines per non-smooth scroll unit\n",
+                       (int) v);
+       cnt = v * terminal->pvt->mouse_smooth_scroll_delta;
+       if (cnt == 0)
+               return TRUE;
+       terminal->pvt->mouse_smooth_scroll_delta -= cnt / v;
+       _vte_debug_print(VTE_DEBUG_EVENTS,
+                       "Scroll by %d lines, smooth scroll delta set back to %f\n",
+                       cnt, terminal->pvt->mouse_smooth_scroll_delta);
 
        if (terminal->pvt->screen == &terminal->pvt->alternate_screen &&
             terminal->pvt->alternate_screen_scroll) {
                char *normal;
                gssize normal_length;
                const gchar *special;
-               gint i, cnt = v;
 
                /* In the alternate screen there is no scrolling,
                 * so fake a few cursor keystrokes. */
@@ -11533,8 +11548,8 @@ vte_terminal_scroll(GtkWidget *widget, GdkEventScroll *event)
                g_free (normal);
        } else {
                /* Perform a history scroll. */
-               v += terminal->pvt->screen->scroll_delta;
-               vte_terminal_queue_adjustment_value_changed_clamped (terminal, v);
+               cnt += terminal->pvt->screen->scroll_delta;
+               vte_terminal_queue_adjustment_value_changed_clamped (terminal, cnt);
        }
 
        return TRUE;
@@ -14328,6 +14343,7 @@ vte_terminal_reset(VteTerminal *terminal,
        pvt->mouse_last_y = 0;
        pvt->mouse_xterm_extension = FALSE;
        pvt->mouse_urxvt_extension = FALSE;
+       pvt->mouse_smooth_scroll_delta = 0.;
        /* Clear modifiers. */
        pvt->modifiers = 0;
        /* Cause everything to be redrawn (or cleared). */
diff --git a/src/vteseq.c b/src/vteseq.c
index 2ccd58e..774cd36 100644
--- a/src/vteseq.c
+++ b/src/vteseq.c
@@ -616,6 +616,13 @@ vte_sequence_handler_multiple_r(VteTerminal *terminal,
                                               terminal->column_count - 
terminal->pvt->screen->cursor_current.col);
 }
 
+static void
+vte_reset_mouse_smooth_scroll_delta(VteTerminal *terminal,
+                                    GValueArray *params)
+{
+       terminal->pvt->mouse_smooth_scroll_delta = 0.;
+}
+
 /* Manipulate certain terminal attributes. */
 static void
 vte_sequence_handler_decset_internal(VteTerminal *terminal,
@@ -672,7 +679,8 @@ vte_sequence_handler_decset_internal(VteTerminal *terminal,
                {9, NULL, &terminal->pvt->mouse_tracking_mode, NULL,
                 GINT_TO_POINTER(0),
                 GINT_TO_POINTER(MOUSE_TRACKING_SEND_XY_ON_CLICK),
-                NULL, NULL,},
+                vte_reset_mouse_smooth_scroll_delta,
+                vte_reset_mouse_smooth_scroll_delta,},
                /* 12: disallowed, cursor blinks is set by user. */
                {12, NULL, NULL, NULL, NULL, NULL, NULL, NULL,},
                /* 18: print form feed. */
@@ -716,22 +724,26 @@ vte_sequence_handler_decset_internal(VteTerminal *terminal,
                {1000, NULL, &terminal->pvt->mouse_tracking_mode, NULL,
                 GINT_TO_POINTER(0),
                 GINT_TO_POINTER(MOUSE_TRACKING_SEND_XY_ON_BUTTON),
-                NULL, NULL,},
+                vte_reset_mouse_smooth_scroll_delta,
+                vte_reset_mouse_smooth_scroll_delta,},
                /* 1001: Hilite tracking. */
                {1001, NULL, &terminal->pvt->mouse_tracking_mode, NULL,
                 GINT_TO_POINTER(0),
                 GINT_TO_POINTER(MOUSE_TRACKING_HILITE_TRACKING),
-                NULL, NULL,},
+                vte_reset_mouse_smooth_scroll_delta,
+                vte_reset_mouse_smooth_scroll_delta,},
                /* 1002: Cell motion tracking. */
                {1002, NULL, &terminal->pvt->mouse_tracking_mode, NULL,
                 GINT_TO_POINTER(0),
                 GINT_TO_POINTER(MOUSE_TRACKING_CELL_MOTION_TRACKING),
-                NULL, NULL,},
+                vte_reset_mouse_smooth_scroll_delta,
+                vte_reset_mouse_smooth_scroll_delta,},
                /* 1003: All motion tracking. */
                {1003, NULL, &terminal->pvt->mouse_tracking_mode, NULL,
                 GINT_TO_POINTER(0),
                 GINT_TO_POINTER(MOUSE_TRACKING_ALL_MOTION_TRACKING),
-                NULL, NULL,},
+                vte_reset_mouse_smooth_scroll_delta,
+                vte_reset_mouse_smooth_scroll_delta,},
                /* 1006: Extended mouse coordinates. */
                {1006, &terminal->pvt->mouse_xterm_extension, NULL, NULL,
                 GINT_TO_POINTER(FALSE),