[gtksourceview/wip/centertext] Try to center just the text area and not the line nums etc

[Paolo Borelli <pborelli src gnome org>]

commit 6a5a6a796a9f7da74e197cbd07e8b43419117340
Author: Paolo Borelli <pborelli gnome org>
Date:   Sun Sep 1 19:09:53 2013 +0200

    Try to center just the text area and not the line nums etc
    
    A variation of the previous patch which centers the actual text
    leaving the gutters renderers for line numbers etc on the left.
    I think I like this one better, but I am not sure yet...

 gtksourceview/gtksourcegutter.c |  110 +++++++++++++++++----------------------
 gtksourceview/gtksourcegutter.h |   10 ++--
 gtksourceview/gtksourceview.c   |    3 +-
 3 files changed, 53 insertions(+), 70 deletions(-)
---
diff --git a/gtksourceview/gtksourcegutter.c b/gtksourceview/gtksourcegutter.c
index bc4af21..7ec4366 100644
--- a/gtksourceview/gtksourcegutter.c
+++ b/gtksourceview/gtksourcegutter.c
@@ -58,8 +58,7 @@ enum
        PROP_WINDOW_TYPE,
        PROP_XPAD,
        PROP_YPAD,
-       PROP_LEFT_MARGIN,
-       PROP_RIGHT_MARGIN
+       PROP_WIDTH_REQUEST
 };
 
 typedef struct
@@ -97,10 +96,9 @@ struct _GtkSourceGutterPrivate
 
        GList *renderers;
 
+       gint width_request;
        gint xpad;
        gint ypad;
-       gint left_margin;
-       gint right_margin;
 
        guint signals[LAST_EXTERNAL_SIGNAL];
 
@@ -382,10 +380,12 @@ do_redraw (GtkSourceGutter *gutter)
 
 static gint
 calculate_gutter_size (GtkSourceGutter  *gutter,
+                       gint             *renderers_offset,
                        GArray           *sizes)
 {
        GList *item;
        gint total_width = 0;
+       gint offset = 0;
 
        /* Calculate size */
        for (item = gutter->priv->renderers; item; item = g_list_next (item))
@@ -424,7 +424,16 @@ calculate_gutter_size (GtkSourceGutter  *gutter,
                total_width += gutter->priv->xpad;
        }
 
-       total_width += gutter->priv->left_margin + gutter->priv->right_margin;
+       if (total_width < gutter->priv->width_request)
+       {
+               offset = gutter->priv->width_request - total_width;
+               total_width = gutter->priv->width_request;
+       }
+
+       if (renderers_offset)
+       {
+               *renderers_offset = offset;
+       }
 
        return total_width;
 }
@@ -434,7 +443,7 @@ update_gutter_size (GtkSourceGutter *gutter)
 {
        gint width;
 
-       width = calculate_gutter_size (gutter, NULL);
+       width = calculate_gutter_size (gutter, NULL, NULL);
 
        gtk_text_view_set_border_window_size (GTK_TEXT_VIEW (gutter->priv->view),
                                              gutter->priv->window_type,
@@ -481,6 +490,20 @@ set_ypad (GtkSourceGutter *gutter,
        return set_padding (gutter, &gutter->priv->ypad, ypad, "ypad", resize);
 }
 
+static gboolean
+set_width_request (GtkSourceGutter *gutter,
+                   gint             width)
+{
+       if (width != gutter->priv->width_request)
+       {
+               gutter->priv->width_request = width;
+               update_gutter_size (gutter);
+               return TRUE;
+       }
+
+       return FALSE;
+}
+
 static void
 gtk_source_gutter_set_property (GObject       *object,
                                 guint          prop_id,
@@ -503,13 +526,8 @@ gtk_source_gutter_set_property (GObject       *object,
                case PROP_YPAD:
                        set_ypad (self, g_value_get_int (value), TRUE);
                        break;
-               case PROP_LEFT_MARGIN:
-                       self->priv->left_margin = g_value_get_int (value);
-                       update_gutter_size (self);
-                       break;
-               case PROP_RIGHT_MARGIN:
-                       self->priv->right_margin = g_value_get_int (value);
-                       update_gutter_size (self);
+               case PROP_WIDTH_REQUEST:
+                       set_width_request (self, g_value_get_int (value));
                        break;
                default:
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -601,20 +619,10 @@ gtk_source_gutter_class_init (GtkSourceGutterClass *klass)
                                                           G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
 
        g_object_class_install_property (object_class,
-                                        PROP_LEFT_MARGIN,
-                                        g_param_spec_int ("left-margin",
-                                                          _("Left Marging"),
-                                                          _("The left margin before the renderers"),
-                                                          -1,
-                                                          G_MAXINT,
-                                                          0,
-                                                          G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
-
-       g_object_class_install_property (object_class,
-                                        PROP_RIGHT_MARGIN,
-                                        g_param_spec_int ("right-margin",
-                                                          _("Right Marging"),
-                                                          _("The right margin before the renderers"),
+                                        PROP_WIDTH_REQUEST,
+                                        g_param_spec_int ("width-request",
+                                                          _("Width Request"),
+                                                          _("The minimal size of the gutter"),
                                                           -1,
                                                           G_MAXINT,
                                                           0,
@@ -954,6 +962,7 @@ on_view_draw (GtkSourceView   *view,
        GdkWindow *window;
        GtkTextView *text_view;
        GArray *sizes;
+       gint offset;
        GdkRectangle clip;
        gint x, y;
        gint y1, y2;
@@ -1026,13 +1035,13 @@ on_view_draw (GtkSourceView   *view,
        heights = g_array_new (FALSE, FALSE, sizeof (gint));
        sizes = g_array_new (FALSE, FALSE, sizeof (gint));
 
-       calculate_gutter_size (gutter, sizes);
+       calculate_gutter_size (gutter, &offset, sizes);
+
+       cairo_translate (cr, offset, 0);
 
        i = 0;
        x = 0;
 
-       cairo_translate (cr, gutter->priv->left_margin, 0);
-
        background_area.x = 0;
        background_area.height = get_lines (text_view,
                                            y1,
@@ -1650,50 +1659,25 @@ gtk_source_gutter_get_padding (GtkSourceGutter *gutter,
 }
 
 void
-gtk_source_gutter_set_margin (GtkSourceGutter *gutter,
-                              gint             left,
-                              gint             right)
+gtk_source_gutter_set_width_request (GtkSourceGutter *gutter,
+                                     gint             width)
 {
-       gboolean update = FALSE;
-
        g_return_if_fail (GTK_SOURCE_IS_GUTTER (gutter));
 
-       if (left != gutter->priv->left_margin)
-       {
-               gutter->priv->left_margin = left;
-               g_object_notify (G_OBJECT (gutter), "left-margin");
-               update = TRUE;
-       }
-
-       if (right != gutter->priv->right_margin)
+       if (set_width_request (gutter, width))
        {
-               gutter->priv->right_margin = right;
-               g_object_notify (G_OBJECT (gutter), "right-margin");
-               update = TRUE;
-       }
-
-       if (update)
-       {
-               update_gutter_size (gutter);
+               g_object_notify (G_OBJECT (gutter), "width-request");
        }
 }
 
 void
-gtk_source_gutter_get_margin (GtkSourceGutter *gutter,
-                              gint            *left,
-                              gint            *right)
+gtk_source_gutter_get_width_request (GtkSourceGutter *gutter,
+                                     gint            *width)
 {
        g_return_if_fail (GTK_SOURCE_IS_GUTTER (gutter));
+       g_return_if_fail (width != NULL);
 
-       if (left)
-       {
-               *left = gutter->priv->left_margin;
-       }
-
-       if (right)
-       {
-               *right = gutter->priv->right_margin;
-       }
+       *width = gutter->priv->width_request;
 }
 
 /**
diff --git a/gtksourceview/gtksourcegutter.h b/gtksourceview/gtksourcegutter.h
index aa081a2..3ad5624 100644
--- a/gtksourceview/gtksourcegutter.h
+++ b/gtksourceview/gtksourcegutter.h
@@ -75,13 +75,11 @@ void gtk_source_gutter_get_padding              (GtkSourceGutter         *gutter
                                                  gint                    *xpad,
                                                  gint                    *ypad);
 
-void gtk_source_gutter_set_margin               (GtkSourceGutter         *gutter,
-                                                 gint                     left,
-                                                 gint                     right);
+void gtk_source_gutter_set_width_request        (GtkSourceGutter         *gutter,
+                                                 gint                     width);
 
-void gtk_source_gutter_get_margin               (GtkSourceGutter         *gutter,
-                                                 gint                    *left,
-                                                 gint                    *right);
+void gtk_source_gutter_get_width_request        (GtkSourceGutter         *gutter,
+                                                 gint                    *width);
 
 GtkSourceGutterRenderer *
      gtk_source_gutter_get_renderer_at_pos      (GtkSourceGutter         *gutter,
diff --git a/gtksourceview/gtksourceview.c b/gtksourceview/gtksourceview.c
index 583ed4d..22d65bc 100644
--- a/gtksourceview/gtksourceview.c
+++ b/gtksourceview/gtksourceview.c
@@ -2305,12 +2305,13 @@ gtk_source_view_draw (GtkWidget *widget,
                                                  '_');
        }
 
+       /* FIXME: take into account the gutters size */
        gint alloc_w = gtk_widget_get_allocated_width (GTK_WIDGET (view));
        gint left_margin = (alloc_w - view->priv->cached_right_margin_pos) / 2;
        if (left_margin > 0)
        {
                /* FIXME: stop this draw and queua a new one after resize is done? */
-               gtk_source_gutter_set_margin (view->priv->left_gutter, left_margin, 0);
+               gtk_source_gutter_set_width_request (view->priv->left_gutter, left_margin);
        }
 
        window = gtk_text_view_get_window (text_view, GTK_TEXT_WINDOW_TEXT);