[gtksourceview] map: jump to click position

[Christian Hergert <chergert src gnome org>]

commit d94fbbf746dea408b1724def4fe97524cbe12d68
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jun 21 20:07:25 2021 -0700

    map: jump to click position
    
    If the user clicks, we don't want to begin handling drag code (which is
    relative to 0..height) and instead want to jump to the iter beneath the
    pointer.

 gtksourceview/gtksourcemap.c | 53 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
---
diff --git a/gtksourceview/gtksourcemap.c b/gtksourceview/gtksourcemap.c
index 3144e49e..fd51617e 100644
--- a/gtksourceview/gtksourcemap.c
+++ b/gtksourceview/gtksourcemap.c
@@ -34,6 +34,7 @@
 #include "gtksourceutils-private.h"
 
 #define SCRUBBER_MIN_HEIGHT 10
+#define DRAG_THRESHOLD      5.0
 
 /**
  * SECTION:map
@@ -201,6 +202,9 @@ typedef struct
         * class when drawing so that we get an appropriate color.
         */
        guint had_color : 1;
+
+       /* If we dragged enough to reach a drag threshold */
+       guint reached_drag_threshold : 1;
 } GtkSourceMapPrivate;
 
 enum
@@ -879,6 +883,7 @@ gtk_source_map_drag_update (GtkSourceMap   *map,
                            gdouble         y,
                            GtkGestureDrag *drag)
 {
+       GtkSourceMapPrivate *priv = gtk_source_map_get_instance_private (map);
        GtkTextBuffer *buffer;
        GtkAllocation alloc;
        GdkRectangle area;
@@ -890,6 +895,13 @@ gtk_source_map_drag_update (GtkSourceMap   *map,
        gint real_height;
        gint height;
 
+       if (!priv->reached_drag_threshold && ABS (y) < DRAG_THRESHOLD)
+       {
+               return;
+       }
+
+       priv->reached_drag_threshold = TRUE;
+
        gtk_widget_get_allocation (GTK_WIDGET (map), &alloc);
        gtk_gesture_drag_get_start_point (drag, &begin_x, &begin_y);
        y = CLAMP (begin_y + y, 0, alloc.height);
@@ -916,10 +928,42 @@ gtk_source_map_drag_begin (GtkSourceMap   *map,
                           gdouble         start_y,
                           GtkGestureDrag *drag)
 {
+       GtkSourceMapPrivate *priv = gtk_source_map_get_instance_private (map);
+
+       priv->reached_drag_threshold = FALSE;
+
        gtk_gesture_set_state (GTK_GESTURE (drag), GTK_EVENT_SEQUENCE_CLAIMED);
        gtk_source_map_drag_update (map, 0, 0, drag);
 }
 
+static void
+gtk_source_map_click_pressed (GtkSourceMap *map,
+                             int           n_presses,
+                              double        x,
+                              double        y,
+                              GtkGesture   *click)
+{
+       GtkSourceMapPrivate *priv = gtk_source_map_get_instance_private (map);
+       GtkTextIter iter;
+       int buffer_x, buffer_y;
+
+       g_assert (GTK_SOURCE_IS_MAP (map));
+       g_assert (GTK_IS_GESTURE_CLICK (click));
+
+       if (priv->view == NULL)
+       {
+               return;
+       }
+
+       gtk_gesture_set_state (click, GTK_EVENT_SEQUENCE_CLAIMED);
+
+       gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (map),
+                                              GTK_TEXT_WINDOW_WIDGET,
+                                              x, y, &buffer_x, &buffer_y);
+       gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (map), &iter, 0, buffer_y);
+       gtk_text_view_scroll_to_iter (GTK_TEXT_VIEW (priv->view), &iter,
+                                     0.0, TRUE, 1.0, 0.5);
+}
 
 static gboolean
 gtk_source_map_scroll (GtkWidget *widget,
@@ -1073,6 +1117,7 @@ gtk_source_map_init (GtkSourceMap *map)
        GtkSourceMapPrivate *priv;
        GtkSourceCompletion *completion;
        GtkEventController *scroll;
+       GtkEventController *press;
        GtkGesture *drag;
 
        priv = gtk_source_map_get_instance_private (map);
@@ -1128,6 +1173,14 @@ gtk_source_map_init (GtkSourceMap *map)
                                  G_CALLBACK (gtk_source_map_scroll),
                                  map);
        gtk_widget_add_controller (GTK_WIDGET (map), g_steal_pointer (&scroll));
+
+       press = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
+       g_signal_connect_swapped (press,
+                                 "pressed",
+                                 G_CALLBACK (gtk_source_map_click_pressed),
+                                 map);
+       gtk_event_controller_set_propagation_phase (press, GTK_PHASE_CAPTURE);
+       gtk_widget_add_controller (GTK_WIDGET (map), press);
 }
 
 /**