[gimp] app: add a "scale_limit" API to GimpSpinScale

[Michael Natterer <mitch src gnome org>]

commit d300ec655686aeeb36e219373f25601e253a4dd2
Author: Michael Natterer <mitch gimp org>
Date:   Mon Apr 18 21:01:48 2011 +0200

    app: add a "scale_limit" API to GimpSpinScale
    
    which allows to restrict the scale to a range that is smaller than
    that of the model GtkAdjustment. This way we can enter large values in
    the entry or by dragging beyond the end of the scale, but keep a
    reasonably usable scale range for "normal" values.

 app/widgets/gimpspinscale.c |  115 +++++++++++++++++++++++++++++++++++++++----
 app/widgets/gimpspinscale.h |   18 +++++--
 2 files changed, 118 insertions(+), 15 deletions(-)
---
diff --git a/app/widgets/gimpspinscale.c b/app/widgets/gimpspinscale.c
index 64eebac..a85b300 100644
--- a/app/widgets/gimpspinscale.c
+++ b/app/widgets/gimpspinscale.c
@@ -50,6 +50,10 @@ typedef struct _GimpSpinScalePrivate GimpSpinScalePrivate;
 struct _GimpSpinScalePrivate
 {
   gchar    *label;
+  gboolean  scale_limits_set;
+  gdouble   scale_lower;
+  gdouble   scale_upper;
+
   gboolean  changing_value;
   gboolean  relative_change;
   gdouble   start_x;
@@ -321,6 +325,28 @@ gimp_spin_scale_get_target (GtkWidget *widget,
 }
 
 static void
+gimp_spin_scale_get_limits (GimpSpinScale *scale,
+                            gdouble       *lower,
+                            gdouble       *upper)
+{
+  GimpSpinScalePrivate *private = GET_PRIVATE (scale);
+
+  if (private->scale_limits_set)
+    {
+      *lower = private->scale_lower;
+      *upper = private->scale_upper;
+    }
+  else
+    {
+      GtkSpinButton *spin_button = GTK_SPIN_BUTTON (scale);
+      GtkAdjustment *adjustment  = gtk_spin_button_get_adjustment (spin_button);
+
+      *lower = gtk_adjustment_get_lower (adjustment);
+      *upper = gtk_adjustment_get_upper (adjustment);
+    }
+}
+
+static void
 gimp_spin_scale_change_value (GtkWidget *widget,
                               gdouble    x)
 {
@@ -328,9 +354,13 @@ gimp_spin_scale_change_value (GtkWidget *widget,
   GtkSpinButton        *spin_button = GTK_SPIN_BUTTON (widget);
   GtkAdjustment        *adjustment  = gtk_spin_button_get_adjustment (spin_button);
   GdkWindow            *text_window = gtk_entry_get_text_window (GTK_ENTRY (widget));
+  gdouble               lower;
+  gdouble               upper;
   gint                  width;
   gdouble               value;
 
+  gimp_spin_scale_get_limits (GIMP_SPIN_SCALE (widget), &lower, &upper);
+
   width = gdk_window_get_width (text_window);
 
   if (private->relative_change)
@@ -338,9 +368,7 @@ gimp_spin_scale_change_value (GtkWidget *widget,
       gdouble diff;
       gdouble step;
 
-      step = ((gtk_adjustment_get_upper (adjustment) -
-               gtk_adjustment_get_lower (adjustment)) +
-              gtk_adjustment_get_lower (adjustment)) / width / 10.0;
+      step = ((upper - lower) + lower) / width / 10.0;
 
       diff = x - private->start_x;
 
@@ -352,9 +380,7 @@ gimp_spin_scale_change_value (GtkWidget *widget,
 
       fraction = x / (gdouble) width;
 
-      value = (fraction * (gtk_adjustment_get_upper (adjustment) -
-                           gtk_adjustment_get_lower (adjustment)) +
-               gtk_adjustment_get_lower (adjustment));
+      value = fraction * (upper - lower) + lower;
     }
 
   gtk_adjustment_set_value (adjustment, value);
@@ -476,14 +502,21 @@ static void
 gimp_spin_scale_value_changed (GtkSpinButton *spin_button)
 {
   GtkAdjustment *adjustment = gtk_spin_button_get_adjustment (spin_button);
+  gdouble        lower;
+  gdouble        upper;
+  gdouble        value;
+
+  gimp_spin_scale_get_limits (GIMP_SPIN_SCALE (spin_button), &lower, &upper);
+
+  value = CLAMP (gtk_adjustment_get_value (adjustment), lower, upper);
 
   gtk_entry_set_progress_fraction (GTK_ENTRY (spin_button),
-                                   (gtk_adjustment_get_value (adjustment) -
-                                    gtk_adjustment_get_lower (adjustment)) /
-                                   (gtk_adjustment_get_upper (adjustment) -
-                                    gtk_adjustment_get_lower (adjustment)));
+                                   (value - lower) / (upper - lower));
 }
 
+
+/*  public functions  */
+
 GtkWidget *
 gimp_spin_scale_new (GtkAdjustment *adjustment,
                      const gchar   *label,
@@ -497,3 +530,65 @@ gimp_spin_scale_new (GtkAdjustment *adjustment,
                        "digits",     digits,
                        NULL);
 }
+
+void
+gimp_spin_scale_set_scale_limits (GimpSpinScale *scale,
+                                  gdouble        lower,
+                                  gdouble        upper)
+{
+  GimpSpinScalePrivate *private;
+  GtkSpinButton        *spin_button;
+  GtkAdjustment        *adjustment;
+
+  g_return_if_fail (GIMP_IS_SPIN_SCALE (scale));
+
+  private     = GET_PRIVATE (scale);
+  spin_button = GTK_SPIN_BUTTON (scale);
+  adjustment  = gtk_spin_button_get_adjustment (spin_button);
+
+  g_return_if_fail (lower >= gtk_adjustment_get_lower (adjustment));
+  g_return_if_fail (upper <= gtk_adjustment_get_upper (adjustment));
+
+  private->scale_limits_set = TRUE;
+  private->scale_lower      = lower;
+  private->scale_upper      = upper;
+
+  gimp_spin_scale_value_changed (spin_button);
+}
+
+void
+gimp_spin_scale_unset_scale_limits (GimpSpinScale *scale)
+{
+  GimpSpinScalePrivate *private;
+
+  g_return_if_fail (GIMP_IS_SPIN_SCALE (scale));
+
+  private = GET_PRIVATE (scale);
+
+  private->scale_limits_set = FALSE;
+  private->scale_lower      = 0.0;
+  private->scale_upper      = 0.0;
+
+  gimp_spin_scale_value_changed (GTK_SPIN_BUTTON (scale));
+}
+
+gboolean
+gimp_spin_scale_get_scale_limits (GimpSpinScale *scale,
+                                  gdouble       *lower,
+                                  gdouble       *upper)
+{
+  GimpSpinScalePrivate *private;
+
+  g_return_val_if_fail (GIMP_IS_SPIN_SCALE (scale), FALSE);
+
+  private = GET_PRIVATE (scale);
+
+  if (lower)
+    *lower = private->scale_lower;
+
+  if (upper)
+    *upper = private->scale_upper;
+
+  return private->scale_limits_set;
+}
+
diff --git a/app/widgets/gimpspinscale.h b/app/widgets/gimpspinscale.h
index 4f3c58a..d896845 100644
--- a/app/widgets/gimpspinscale.h
+++ b/app/widgets/gimpspinscale.h
@@ -44,11 +44,19 @@ struct _GimpSpinScaleClass
 };
 
 
-GType       gimp_spin_scale_get_type (void) G_GNUC_CONST;
-
-GtkWidget * gimp_spin_scale_new      (GtkAdjustment *adjustment,
-                                      const gchar   *label,
-                                      gint           digits);
+GType       gimp_spin_scale_get_type           (void) G_GNUC_CONST;
+
+GtkWidget * gimp_spin_scale_new                (GtkAdjustment *adjustment,
+                                                const gchar   *label,
+                                                gint           digits);
+
+void        gimp_spin_scale_set_scale_limits   (GimpSpinScale *scale,
+                                                gdouble        lower,
+                                                gdouble        upper);
+void        gimp_spin_scale_unset_scale_limits (GimpSpinScale *scale);
+gboolean    gimp_spin_scale_get_scale_limits   (GimpSpinScale *scale,
+                                                gdouble       *lower,
+                                                gdouble       *upper);
 
 
 #endif  /*  __GIMP_SPIN_SCALE_H__  */