[gtk+] GtkPopover: Honor widget margins when calculating tail position

[Carlos Garnacho <carlosg src gnome org>]

commit ed227f9e7b7be4b3558ea9b7f8cdbf83e69f71ef
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Jun 21 12:24:05 2016 +0200

    GtkPopover: Honor widget margins when calculating tail position
    
    If there are widget margins set, the whole popover will be displaced.
    However the calculation of the tail position doesn't have this into
    account, ending up with the tail being detached from the popover if
    the margin grew too big.
    
    We should not render the arrows invariably next to the GdkWindow edge,
    but optionally displaced inside it depending on the widget margins.
    Fixes the gtk3-demo "Popovers" demo case, whose GtkEntry popovers set
    widget margins for some reason.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=767851

 gtk/gtkpopover.c |   31 +++++++++++++++++++------------
 1 files changed, 19 insertions(+), 12 deletions(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 8d170dd..bff5b14 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -683,7 +683,7 @@ gtk_popover_get_gap_coords (GtkPopover      *popover,
   GtkAllocation allocation;
   gint border_radius;
   GtkStyleContext *context;
-  GtkBorder margin, border;
+  GtkBorder margin, border, widget_margin;
   GtkStateFlags state;
 
   gtk_popover_get_pointing_to (popover, &rect);
@@ -709,11 +709,18 @@ gtk_popover_get_gap_coords (GtkPopover      *popover,
   get_margin (widget, &margin);
 
   if (gtk_widget_get_direction (widget) == GTK_TEXT_DIR_LTR)
-    rect.x += gtk_widget_get_margin_start (widget);
+    {
+      widget_margin.left = gtk_widget_get_margin_start (widget);
+      widget_margin.right = gtk_widget_get_margin_end (widget);
+    }
   else
-    rect.x += gtk_widget_get_margin_end (widget);
+    {
+      widget_margin.left = gtk_widget_get_margin_end (widget);
+      widget_margin.right = gtk_widget_get_margin_start (widget);
+    }
 
-  rect.y += gtk_widget_get_margin_top (widget);
+  widget_margin.top = gtk_widget_get_margin_top (widget);
+  widget_margin.bottom = gtk_widget_get_margin_bottom (widget);
 
   context = gtk_widget_get_style_context (widget);
   state = gtk_style_context_get_state (context);
@@ -727,20 +734,20 @@ gtk_popover_get_gap_coords (GtkPopover      *popover,
 
   if (pos == GTK_POS_BOTTOM || pos == GTK_POS_RIGHT)
     {
-      base = TAIL_HEIGHT + ((pos == GTK_POS_BOTTOM) ? border.top : border.left);
-      tip = 0;
+      tip = ((pos == GTK_POS_BOTTOM) ? border.top + widget_margin.top : border.left + widget_margin.left);
+      base = tip + TAIL_HEIGHT;
       gap_side = (priv->final_position == GTK_POS_BOTTOM) ? GTK_POS_TOP : GTK_POS_LEFT;
     }
   else if (pos == GTK_POS_TOP)
     {
-      base = allocation.height - TAIL_HEIGHT - border.bottom;
-      tip = allocation.height;
+      base = allocation.height - TAIL_HEIGHT - border.bottom - widget_margin.bottom;
+      tip = base + TAIL_HEIGHT;
       gap_side = GTK_POS_BOTTOM;
     }
   else if (pos == GTK_POS_LEFT)
     {
-      base = allocation.width - TAIL_HEIGHT - border.right;
-      tip = allocation.width;
+      base = allocation.width - TAIL_HEIGHT - border.right - widget_margin.right;
+      tip = base + TAIL_HEIGHT;
       gap_side = GTK_POS_RIGHT;
     }
   else
@@ -748,7 +755,7 @@ gtk_popover_get_gap_coords (GtkPopover      *popover,
 
   if (POS_IS_VERTICAL (pos))
     {
-      tip_pos = rect.x + (rect.width / 2);
+      tip_pos = rect.x + (rect.width / 2) + widget_margin.left;
       initial_x = CLAMP (tip_pos - TAIL_GAP_WIDTH / 2,
                          border_radius + margin.left + TAIL_HEIGHT,
                          allocation.width - TAIL_GAP_WIDTH - margin.right - border_radius - TAIL_HEIGHT);
@@ -764,7 +771,7 @@ gtk_popover_get_gap_coords (GtkPopover      *popover,
     }
   else
     {
-      tip_pos = rect.y + (rect.height / 2);
+      tip_pos = rect.y + (rect.height / 2) + widget_margin.top;
 
       initial_x = base;
       initial_y = CLAMP (tip_pos - TAIL_GAP_WIDTH / 2,