Autoscrolling, 2nd try

[Matthias Koester]

Hi,

i've updated my patch.  The autoscrolling now works like Jeffrey has
suggested it. You must leave the canvas with the mouse, to scroll. The
scroll-amount depends on the distance between the mouse-pointer and the
border of the canvas. Because i think that not only the modify-tool
should enable autoscrolling,
i've added a function gboolean ddisplay_autoscroll(ddisp* ddsp, int x,
int y) in which you pass in the coordinates of the mouse-pointer. If the
mouse-pointer is outside the canvas, the canvas is scrolled and the
function returns TRUE. Otherwise it returns FALSE.
I've only added a call to the function in the file modify_tool.c .

The patch is attached to this mail, it's adiff from the lastest CVS.

Matthias
--
Adresse : Matthias K�ster, Alexanderstr.388, 26127 Oldenburg
Tel.    : 0441/6835359
eMail   : [EMAIL PROTECTED]


--- dia/app/display.h   Thu Jan 14 15:34:27 1999
+++ display.h   Fri Jan 29 19:55:27 1999
@@ -52,6 +52,8 @@
 
   Grid grid;                      /* the grid in this display          */
 
+  gboolean autoscroll;
+
   RendererGdk *renderer;
   
   GSList *update_areas;           /* Update areas list                 */
@@ -101,9 +103,12 @@
 extern void ddisplay_set_all_cursor(GdkCursor *cursor);
 
 extern void ddisplay_scroll(DDisplay *ddisp, Point *delta);
+extern gboolean ddisplay_autoscroll(DDisplay *ddisp, int x, int y);
 extern void ddisplay_scroll_up(DDisplay *ddisp);
 extern void ddisplay_scroll_down(DDisplay *ddisp);
 extern void ddisplay_scroll_left(DDisplay *ddisp);
 extern void ddisplay_scroll_right(DDisplay *ddisp);
 #endif /* DDISPLAY_H */
+
+
 
--- dia/app/display.c   Mon Jan 25 14:24:12 1999
+++ display.c   Fri Jan 29 19:55:29 1999
@@ -67,7 +67,9 @@
   ddisp->grid.dialog = NULL;
   ddisp->grid.entry_x = NULL;
   ddisp->grid.entry_y = NULL;
-  
+
+  ddisp->autoscroll = TRUE;
+
   ddisp->renderer = NULL;
   
   ddisp->update_areas = NULL;
@@ -427,6 +429,54 @@
   ddisplay_update_scrollbars(ddisp);
   ddisplay_add_update_all(ddisp);
   ddisplay_flush(ddisp);
+}
+
+gboolean
+ddisplay_autoscroll(DDisplay *ddisp, int x, int y)
+{
+  guint16 width, height;
+  Point scroll;
+  
+  if (! ddisp->autoscroll)
+    return FALSE;
+
+  scroll.x = scroll.y = 0;
+
+  width = GTK_WIDGET(ddisp->canvas)->allocation.width;
+  height = GTK_WIDGET(ddisp->canvas)->allocation.height;
+
+  if (x < 0)
+  {
+    scroll.x = x;
+  }
+  else if ( x > width)
+  {
+    scroll.x = x - width;
+  }
+
+  if (y < 0)
+  {
+    scroll.y = y;
+  }
+  else if (y > height)
+  {
+    scroll.y = y - height;
+  }
+
+  if ((scroll.x != 0) || (scroll.y != 0))
+  {
+    scroll.x = ddisplay_untransform_length(ddisp, scroll.x);
+    scroll.y = ddisplay_untransform_length(ddisp, scroll.y);
+
+    ddisplay_scroll(ddisp, &scroll);
+    ddisplay_flush(ddisp);
+
+    return TRUE;
+  }
+  else
+  {
+    return FALSE;
+  }
 }
 
 void ddisplay_scroll(DDisplay *ddisp, Point *delta)
--- dia/app/modify_tool.c       Wed Jan 27 21:45:01 1999
+++ modify_tool.c       Fri Jan 29 19:55:29 1999
@@ -266,10 +266,13 @@
 {
   Point to;
   Point now, delta;
+  gboolean auto_scroll;
   ConnectionPoint *connectionpoint;
 
   if (tool->state==STATE_NONE)
     return; /* Fast path... */
+
+  auto_scroll = ddisplay_autoscroll(ddisp, event->x, event->y);
   
   ddisplay_untransform_coords(ddisp, event->x, event->y, &to.x, &to.y);
 
@@ -322,13 +325,16 @@
     diagram_flush(ddisp->diagram);
     break;
   case STATE_BOX_SELECT:
-    
-    gdk_draw_rectangle (ddisp->renderer->pixmap, tool->gc, FALSE,
-                       tool->x1, tool->y1,
-                       tool->x2 - tool->x1, tool->y2 - tool->y1);
-    ddisplay_add_display_area(ddisp,
-                             tool->x1-1, tool->y1-1,
-                             tool->x2+1, tool->y2+1);
+
+    if (! auto_scroll)
+    {
+      gdk_draw_rectangle (ddisp->renderer->pixmap, tool->gc, FALSE,
+                         tool->x1, tool->y1,
+                         tool->x2 - tool->x1, tool->y2 - tool->y1);
+      ddisplay_add_display_area(ddisp,
+                               tool->x1-1, tool->y1-1,
+                               tool->x2+1, tool->y2+1);
+    }
 
     tool->end_box = to;