[eog/wip/baedert/gtkimageview: 68/75] scroll-view: Fix image dragging

[Timm Bäder <baedert src gnome org>]

commit 1f410a19213a63cb735ab46a4fc7e1a559eed857
Author: Timm Bäder <mail baedert org>
Date:   Sat Mar 19 13:59:33 2016 +0100

    scroll-view: Fix image dragging

 src/eog-scroll-view.c |   99 +++++++++++++++++++++---------------------------
 1 files changed, 43 insertions(+), 56 deletions(-)
---
diff --git a/src/eog-scroll-view.c b/src/eog-scroll-view.c
index c7356e5..e725d20 100644
--- a/src/eog-scroll-view.c
+++ b/src/eog-scroll-view.c
@@ -118,9 +118,6 @@ struct _EogScrollViewPrivate {
        /* the minimum possible (reasonable) zoom factor */
        double min_zoom;
 
-       /* Current scrolling offsets */
-       int xofs, yofs;
-
        /* handler ID for paint idle callback */
        guint idle_id;
 
@@ -377,54 +374,35 @@ create_background_surface (EogScrollView *view)
 
 /* Scrolls the view to the specified offsets.  */
 static void
-scroll_to (EogScrollView *view, int x, int y, gboolean change_adjustments)
+scroll_to (EogScrollView *view, int x, int y)
 {
-       EogScrollViewPrivate *priv;
+       EogScrollViewPrivate *priv = view->priv;
        GtkAllocation allocation;
        int xofs, yofs;
-#if 0
-       int src_x, src_y;
-       int dest_x, dest_y;
-       int twidth, theight;
-#endif
 
-       priv = view->priv;
+       if (!gtk_widget_is_drawable (priv->display))
+               goto out;
+
 
        /* Check bounds & Compute offsets */
-       /*if (gtk_widget_get_visible (priv->hbar)) {*/
-               x = CLAMP (x, 0, gtk_adjustment_get_upper (priv->hadj)
-                                - gtk_adjustment_get_page_size (priv->hadj));
-               xofs = x - priv->xofs;
-       /*} else*/
-               /*xofs = 0;*/
-
-       /*if (gtk_widget_get_visible (priv->vbar)) {*/
-               y = CLAMP (y, 0, gtk_adjustment_get_upper (priv->vadj)
-                                - gtk_adjustment_get_page_size (priv->vadj));
-               yofs = y - priv->yofs;
-       /*} else*/
-               /*yofs = 0;*/
+       x = CLAMP (x, 0, gtk_adjustment_get_upper (priv->hadj)
+                        - gtk_adjustment_get_page_size (priv->hadj));
+       xofs = x - (int) gtk_adjustment_get_value (priv->hadj);
+
+       y = CLAMP (y, 0, gtk_adjustment_get_upper (priv->vadj)
+                        - gtk_adjustment_get_page_size (priv->vadj));
+       yofs = y - (int) gtk_adjustment_get_value (priv->vadj);
 
        if (xofs == 0 && yofs == 0)
                return;
 
-       priv->xofs = x;
-       priv->yofs = y;
-
-       if (!gtk_widget_is_drawable (priv->display))
-               goto out;
-
        gtk_widget_get_allocation (priv->display, &allocation);
 
        if (abs (xofs) >= allocation.width || abs (yofs) >= allocation.height) {
                gtk_widget_queue_draw (GTK_WIDGET (priv->display));
-               goto out;
        }
 
- out:
-       if (!change_adjustments)
-               return;
-
+out:
        g_signal_handlers_block_matched (
                priv->hadj, G_SIGNAL_MATCH_DATA,
                0, 0, NULL, NULL, view);
@@ -450,10 +428,14 @@ static void
 scroll_by (EogScrollView *view, int xofs, int yofs)
 {
        EogScrollViewPrivate *priv;
+       int _xofs, _yofs;
 
        priv = view->priv;
 
-       scroll_to (view, priv->xofs + xofs, priv->yofs + yofs, TRUE);
+       _xofs = (int) gtk_adjustment_get_value (priv->hadj);
+       _yofs = (int) gtk_adjustment_get_value (priv->vadj);
+
+       scroll_to (view, _xofs + xofs, _yofs + yofs);
 }
 
 /* Drags the image to the specified position */
@@ -471,7 +453,7 @@ drag_to (EogScrollView *view, int x, int y)
        x = priv->drag_ofs_x + dx;
        y = priv->drag_ofs_y + dy;
 
-       scroll_to (view, x, y, TRUE);
+       scroll_to (view, x, y);
 }
 
 static void
@@ -707,12 +689,12 @@ eog_scroll_view_button_press_event (GtkWidget *widget, GdkEventButton *event, gp
                gtk_widget_grab_focus (GTK_WIDGET (priv->display));
 
        if (priv->dragging)
-               return FALSE;
+               return GDK_EVENT_PROPAGATE;
 
        switch (event->button) {
                case 1:
                case 2:
-                        if (event->button == 1 && !priv->scroll_wheel_zoom &&
+                       if (event->button == 1 && !priv->scroll_wheel_zoom &&
                            !(event->state & GDK_CONTROL_MASK))
                                break;
 
@@ -723,16 +705,16 @@ eog_scroll_view_button_press_event (GtkWidget *widget, GdkEventButton *event, gp
                                priv->drag_anchor_x = event->x;
                                priv->drag_anchor_y = event->y;
 
-                               priv->drag_ofs_x = priv->xofs;
-                               priv->drag_ofs_y = priv->yofs;
+                               priv->drag_ofs_x = (int) gtk_adjustment_get_value (priv->hadj);
+                               priv->drag_ofs_y = (int) gtk_adjustment_get_value (priv->vadj);
 
-                               return TRUE;
+                               return GDK_EVENT_STOP;
                        }
                default:
                        break;
        }
 
-       return FALSE;
+       return GDK_EVENT_PROPAGATE;
 }
 
 /* Button release event handler for the image view */
@@ -777,17 +759,18 @@ eog_scroll_view_motion_event (GtkWidget *widget, GdkEventMotion *event, gpointer
        priv = view->priv;
 
        if (!priv->dragging)
-               return FALSE;
+               return GDK_EVENT_PROPAGATE;
 
-       if (event->is_hint)
-               gdk_window_get_device_position (gtk_widget_get_window (GTK_WIDGET (priv->display)), 
event->device, &x, &y, &mods);
-       else {
+       if (event->is_hint) {
+               gdk_window_get_device_position (gtk_widget_get_window (GTK_WIDGET (priv->display)),
+                                               event->device, &x, &y, &mods);
+       } else {
                x = event->x;
                y = event->y;
        }
 
        drag_to (view, x, y);
-       return TRUE;
+       return GDK_EVENT_STOP;
 }
 
 static void
@@ -819,16 +802,18 @@ display_size_change (GtkWidget *widget, GdkEventConfigure *event, gpointer data)
                gtk_widget_queue_draw (priv->display);
        } else {
                int scaled_width, scaled_height;
+               int xofs = (int) gtk_adjustment_get_value (priv->hadj);
+               int yofs = (int) gtk_adjustment_get_value (priv->vadj);
                int x_offset = 0;
                int y_offset = 0;
 
                compute_scaled_size (view, priv->zoom, &scaled_width, &scaled_height);
 
-               if (priv->xofs + event->width > scaled_width)
-                       x_offset = scaled_width - event->width - priv->xofs;
+               if (xofs + event->width > scaled_width)
+                       x_offset = scaled_width - event->width - xofs;
 
-               if (priv->yofs + event->height > scaled_height)
-                       y_offset = scaled_height - event->height - priv->yofs;
+               if (yofs + event->height > scaled_height)
+                       y_offset = scaled_height - event->height - yofs;
 
                scroll_by (view, x_offset, y_offset);
        }
@@ -911,7 +896,7 @@ display_draw (GtkWidget *widget, cairo_t *cr, gpointer data)
                return TRUE;
 
 
-       scaled_width = (int)gtk_adjustment_get_upper (priv->hadj);
+       scaled_width  = (int)gtk_adjustment_get_upper (priv->hadj);
        scaled_height = (int)gtk_adjustment_get_upper (priv->vadj);
 
        gtk_widget_get_allocation (priv->display, &allocation);
@@ -2232,7 +2217,9 @@ eog_scroll_view_get_image_coords (EogScrollView *view, gint *x, gint *y,
 {
        EogScrollViewPrivate *priv = view->priv;
        GtkAllocation allocation;
-       gint scaled_width, scaled_height, xofs, yofs;
+       int scaled_width, scaled_height, xofs, yofs;
+       int _xofs = (int) gtk_adjustment_get_value (priv->hadj);
+       int _yofs = (int) gtk_adjustment_get_value (priv->vadj);
 
        compute_scaled_size (view, priv->zoom, &scaled_width, &scaled_height);
 
@@ -2252,12 +2239,12 @@ eog_scroll_view_get_image_coords (EogScrollView *view, gint *x, gint *y,
        if (scaled_width <= allocation.width)
                xofs = (allocation.width - scaled_width) / 2;
        else
-               xofs = -priv->xofs;
+               xofs = -_xofs;
 
        if (scaled_height <= allocation.height)
                yofs = (allocation.height - scaled_height) / 2;
        else
-               yofs = -priv->yofs;
+               yofs = -_yofs;
 
        if (G_LIKELY (x))
                *x = xofs;