[gimp] app: swap base and balance slider order in spiral

[N/A <ell src gnome org>]

commit 06a4e1549fe4ec195c1ce8a8c736123681c5797d
Author: Ell <ell_se yahoo com>
Date:   Sun Jul 30 07:27:10 2017 -0400

    app: swap base and balance slider order in spiral
    
    ... so that when the base and balance sliders overlap, the base
    slider is the one that's picked, since the balance slider is
    constrained by the base, but not the other way around.

 app/propgui/gimppropgui-spiral.c |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)
---
diff --git a/app/propgui/gimppropgui-spiral.c b/app/propgui/gimppropgui-spiral.c
index 1e3eb9d..e7c57fa 100644
--- a/app/propgui/gimppropgui-spiral.c
+++ b/app/propgui/gimppropgui-spiral.c
@@ -90,7 +90,7 @@ slider_line_callback (GObject                    *config,
       {
         gdouble old_base = base;
 
-        base = 1.0 / sliders[0].value;
+        base = 1.0 / sliders[1].value;
         base = MIN (base, 1000000.0);
 
         /* keep "balance" fixed when changing "base", or when "base" is 1, in
@@ -99,7 +99,7 @@ slider_line_callback (GObject                    *config,
          */
         if (base == old_base && base > 1.0)
           {
-            balance = -4.0 * log (sliders[1].value) / log (base) - 1.0;
+            balance = -4.0 * log (sliders[0].value) / log (base) - 1.0;
             balance = CLAMP (balance, -1.0, 1.0);
           }
       }
@@ -156,6 +156,7 @@ config_notify (GObject          *config,
   case GEGL_SPIRAL_TYPE_LINEAR:
     n_sliders = 1;
 
+    /* balance */
     sliders[0].min   = 0.5;
     sliders[0].max   = 1.0;
     sliders[0].value = 0.5 + (1.0 - balance) / 4.0;
@@ -165,13 +166,15 @@ config_notify (GObject          *config,
   case GEGL_SPIRAL_TYPE_LOGARITHMIC:
     n_sliders = 2;
 
-    sliders[0].min   = 0.0;
+    /* balance */
+    sliders[0].min   = 1.0 / sqrt (base);
     sliders[0].max   = 1.0;
-    sliders[0].value = 1.0 / base;
+    sliders[0].value = pow (base, -(balance + 1.0) / 4.0);
 
-    sliders[1].min   = 1.0 / sqrt (base);
+    /* base */
+    sliders[1].min   = 0.0;
     sliders[1].max   = 1.0;
-    sliders[1].value = pow (base, -(balance + 1.0) / 4.0);
+    sliders[1].value = 1.0 / base;
 
     break;
   }