[gedit] print-preview: get tile size with a getter

[Sébastien Wilmet <swilmet src gnome org>]

commit 9a6bd963dae9a240f9b40b1ac111d881c64a31c7
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Jun 28 12:35:49 2015 +0200

    print-preview: get tile size with a getter
    
    No need to store the value, since it can be computed from other values.
    
    It is not a good idea to store duplicated data. Performances aside, only
    the minimum amount of data should be stored. With duplicated data, we
    must pay attention to not have inconsistencies.
    
    Here the performances should not matter, the getter is a O(1) function.

 gedit/gedit-print-preview.c |   89 ++++++++++++++++++++++++------------------
 1 files changed, 51 insertions(+), 38 deletions(-)
---
diff --git a/gedit/gedit-print-preview.c b/gedit/gedit-print-preview.c
index eb8125c..454d4ee 100644
--- a/gedit/gedit-print-preview.c
+++ b/gedit/gedit-print-preview.c
@@ -61,13 +61,6 @@ struct _GeditPrintPreview
 
        gdouble scale;
 
-       /* The tile size is the size in pixels of the area where a page will be
-        * drawn, including the padding. The size is independent of the
-        * orientation.
-        */
-       gint tile_width;
-       gint tile_height;
-
        /* multipage support */
        gint n_columns;
 
@@ -145,26 +138,6 @@ gedit_print_preview_class_init (GeditPrintPreviewClass *klass)
        gtk_widget_class_bind_template_child (widget_class, GeditPrintPreview, layout);
 }
 
-static void
-get_adjustments (GeditPrintPreview  *preview,
-                GtkAdjustment     **hadj,
-                GtkAdjustment     **vadj)
-{
-       *hadj = gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (preview->layout));
-       *vadj = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (preview->layout));
-}
-
-static void
-update_layout_size (GeditPrintPreview *preview)
-{
-       /* force size of the drawing area to make the scrolled window work */
-       gtk_layout_set_size (preview->layout,
-                            preview->tile_width * preview->n_columns,
-                            preview->tile_height);
-
-       gtk_widget_queue_draw (GTK_WIDGET (preview->layout));
-}
-
 /* Get the paper size in points: these must be used only
  * after the widget has been mapped and the dpi is known.
  */
@@ -180,12 +153,49 @@ get_paper_height (GeditPrintPreview *preview)
        return preview->paper_height * preview->dpi;
 }
 
-/* Updates the tile size to the current zoom and page size. */
+/* The tile size is the size in pixels of the area where a page will be
+ * drawn, including the padding. The size is independent of the
+ * orientation.
+ */
+static void
+get_tile_size (GeditPrintPreview *preview,
+              gint              *tile_width,
+              gint              *tile_height)
+{
+       if (tile_width != NULL)
+       {
+               *tile_width = 2 * PAGE_PAD + round (preview->scale * get_paper_width (preview));
+       }
+
+       if (tile_height != NULL)
+       {
+               *tile_height = 2 * PAGE_PAD + round (preview->scale * get_paper_height (preview));
+       }
+}
+
 static void
-update_tile_size (GeditPrintPreview *preview)
+get_adjustments (GeditPrintPreview  *preview,
+                GtkAdjustment     **hadj,
+                GtkAdjustment     **vadj)
 {
-       preview->tile_width = 2 * PAGE_PAD + round (preview->scale * get_paper_width (preview));
-       preview->tile_height = 2 * PAGE_PAD + round (preview->scale * get_paper_height (preview));
+       *hadj = gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (preview->layout));
+       *vadj = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (preview->layout));
+}
+
+static void
+update_layout_size (GeditPrintPreview *preview)
+{
+       gint tile_width;
+       gint tile_height;
+
+       get_tile_size (preview, &tile_width, &tile_height);
+
+       /* force size of the drawing area to make the scrolled window work */
+       gtk_layout_set_size (preview->layout,
+                            tile_width * preview->n_columns,
+                            tile_height);
+
+       gtk_widget_queue_draw (GTK_WIDGET (preview->layout));
 }
 
 /* Zoom should always be set with one of these two function
@@ -197,8 +207,6 @@ set_zoom_factor (GeditPrintPreview *preview,
                 gdouble            zoom)
 {
        preview->scale = zoom;
-
-       update_tile_size (preview);
        update_layout_size (preview);
 }
 
@@ -488,10 +496,13 @@ get_page_at_coords (GeditPrintPreview *preview,
                     gint               x,
                     gint               y)
 {
+       gint tile_width, tile_height;
        GtkAdjustment *hadj, *vadj;
        gint col, page;
 
-       if (preview->tile_height <= 0 || preview->tile_width <= 0)
+       get_tile_size (preview, &tile_width, &tile_height);
+
+       if (tile_height <= 0 || tile_width <= 0)
        {
                return -1;
        }
@@ -501,10 +512,9 @@ get_page_at_coords (GeditPrintPreview *preview,
        x += gtk_adjustment_get_value (hadj);
        y += gtk_adjustment_get_value (vadj);
 
-       col = x / preview->tile_width;
+       col = x / tile_width;
 
-       if (col >= preview->n_columns ||
-           y > preview->tile_height)
+       if (col >= preview->n_columns || y > tile_height)
        {
                return -1;
        }
@@ -916,6 +926,7 @@ preview_draw (GtkWidget         *widget,
              GeditPrintPreview *preview)
 {
        GdkWindow *bin_window;
+       gint tile_width;
        gint page_num;
        gint col;
 
@@ -930,6 +941,8 @@ preview_draw (GtkWidget         *widget,
 
        gtk_cairo_transform_to_window (cr, widget, bin_window);
 
+       get_tile_size (preview, &tile_width, NULL);
+
        col = 0;
        page_num = get_first_page_displayed (preview);
 
@@ -942,7 +955,7 @@ preview_draw (GtkWidget         *widget,
                }
 
                draw_page (cr,
-                          col * preview->tile_width,
+                          col * tile_width,
                           0,
                           page_num,
                           preview);