[gtk+/gtk-3-16] GtkRange: Fix drawing of fill-level

[Matthias Clasen <matthiasc src gnome org>]

commit 1e8b89a5ceab756fd09ba758ffb20e8769c2a672
Author: Marcus Karlsson <mk acc umu se>
Date:   Tue Mar 24 22:31:52 2015 +0100

    GtkRange: Fix drawing of fill-level
    
    Compute the proportion of the range that should be filled to match the
    fill level, and use it to compute the starting point and length of the
    area between the slider and the fill level.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734741

 gtk/gtkrange.c |   56 ++++++++++++++++++++++++++++++--------------------------
 1 files changed, 30 insertions(+), 26 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index ce3f54b..bbbfe22 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2111,11 +2111,12 @@ gtk_range_draw (GtkWidget *widget,
           gtk_adjustment_get_upper (priv->adjustment) - gtk_adjustment_get_page_size (priv->adjustment) -
           gtk_adjustment_get_lower (priv->adjustment) != 0)
         {
-          gdouble  fill_level  = priv->fill_level;
-          gint     fill_x      = x;
-          gint     fill_y      = y;
-          gint     fill_width  = width;
-          gint     fill_height = height;
+          gdouble  fill_level      = priv->fill_level;
+          gint     fill_x          = x;
+          gint     fill_y          = y;
+          gint     fill_width      = width;
+          gint     fill_height     = height;
+          gdouble  fill_proportion = 0.0;
 
           gtk_style_context_save (context);
           gtk_style_context_add_class (context, GTK_STYLE_CLASS_PROGRESSBAR);
@@ -2124,33 +2125,36 @@ gtk_range_draw (GtkWidget *widget,
                               gtk_adjustment_get_upper (priv->adjustment) -
                               gtk_adjustment_get_page_size (priv->adjustment));
 
-          if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
-            {
-              fill_x     = priv->trough.x;
-              fill_width = (priv->slider.width +
-                            (fill_level - gtk_adjustment_get_lower (priv->adjustment)) /
+          fill_proportion = (fill_level - gtk_adjustment_get_lower (priv->adjustment)) /
                             (gtk_adjustment_get_upper (priv->adjustment) -
                              gtk_adjustment_get_lower (priv->adjustment) -
-                             gtk_adjustment_get_page_size (priv->adjustment)) *
-                            (priv->trough.width -
-                             priv->slider.width));
+                             gtk_adjustment_get_page_size (priv->adjustment));
 
-              if (should_invert (range))
-                fill_x += priv->trough.width - fill_width;
+          if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)
+            {
+              if (!should_invert (range))
+                {
+                  fill_x     = priv->slider.x + (priv->slider.width / 2);
+                  fill_width = (width * fill_proportion) - fill_x + x;
+                }
+              else
+                {
+                  fill_x     = x + width * (1.0 - fill_proportion);
+                  fill_width = priv->slider.x + (priv->slider.width / 2) - fill_x;
+                }
             }
           else
             {
-              fill_y      = priv->trough.y;
-              fill_height = (priv->slider.height +
-                             (fill_level - gtk_adjustment_get_lower (priv->adjustment)) /
-                             (gtk_adjustment_get_upper (priv->adjustment) -
-                              gtk_adjustment_get_lower (priv->adjustment) -
-                              gtk_adjustment_get_page_size (priv->adjustment)) *
-                             (priv->trough.height -
-                              priv->slider.height));
-
-              if (should_invert (range))
-                fill_y += priv->trough.height - fill_height;
+              if (!should_invert (range))
+                {
+                  fill_y      = priv->slider.y + (priv->slider.height / 2);
+                  fill_height = (height * fill_proportion) - fill_y + y;
+                }
+              else
+                {
+                  fill_y      = y + height * (1.0 - fill_proportion);
+                  fill_height = priv->slider.y + (priv->slider.height / 2) - fill_y;
+                }
             }
 
           gtk_render_background (context, cr, fill_x, fill_y, fill_width, fill_height);