[gimp/metadata-browser] transformtool: Add option for locking pivot to canvas, add code to transform the pivot along with al

[Roman Joost <romanofski src gnome org>]

commit 5c07d8bbfbff3a47e1824cd60ff77bd2d10c3845
Author: Mikael Magnusson <mikachu src gnome org>
Date:   Wed Aug 1 06:58:05 2012 +0200

    transformtool: Add option for locking pivot to canvas, add code to transform the pivot along with all transformations

 app/tools/gimptransformoptions.c     |   34 +++++++++++++++++--------
 app/tools/gimptransformoptions.h     |    1 +
 app/tools/gimpunifiedtransformtool.c |   45 ++++++++++++++++++++++++++++++++-
 3 files changed, 67 insertions(+), 13 deletions(-)
---
diff --git a/app/tools/gimptransformoptions.c b/app/tools/gimptransformoptions.c
index 111749a..966715c 100644
--- a/app/tools/gimptransformoptions.c
+++ b/app/tools/gimptransformoptions.c
@@ -58,6 +58,7 @@ enum
   PROP_FROMPIVOT,
   PROP_FREESHEAR,
   PROP_CORNERSNAP,
+  PROP_FIXEDPIVOT,
 };
 
 
@@ -164,6 +165,11 @@ gimp_transform_options_class_init (GimpTransformOptionsClass *klass)
                                     NULL,
                                     FALSE,
                                     GIMP_PARAM_STATIC_STRINGS);
+  GIMP_CONFIG_INSTALL_PROP_BOOLEAN (object_class, PROP_FIXEDPIVOT,
+                                    "fixedpivot",
+                                    NULL,
+                                    FALSE,
+                                    GIMP_PARAM_STATIC_STRINGS);
 }
 
 static void
@@ -221,6 +227,9 @@ gimp_transform_options_set_property (GObject      *object,
     case PROP_CORNERSNAP:
       options->cornersnap = g_value_get_boolean (value);
       break;
+    case PROP_FIXEDPIVOT:
+      options->fixedpivot = g_value_get_boolean (value);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -276,6 +285,9 @@ gimp_transform_options_get_property (GObject    *object,
     case PROP_CORNERSNAP:
       g_value_set_boolean (value, options->cornersnap);
       break;
+    case PROP_FIXEDPIVOT:
+      g_value_set_boolean (value, options->fixedpivot);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -416,29 +428,29 @@ gimp_transform_options_gui (GimpToolOptions *tool_options)
   //TODO: check that the selection tools use the gimp_get_*_mask() functions for constrain/etc or change to what they use
   else if (tool_options->tool_info->tool_type == GIMP_TYPE_UNIFIED_TRANSFORM_TOOL)
     {
+      GdkModifierType shift = gimp_get_extend_selection_mask ();
+      GdkModifierType ctrl = gimp_get_constrain_behavior_mask ();
       struct {
-        gboolean shift;
+        GdkModifierType mod;
         gchar *name;
         gchar *desc;
       } opt_list[] = {
-        { TRUE, "keepaspect", "Keep aspect (%s)" },
-        { TRUE, "freeshear", "Move edge freely in shearing (%s)" },
-        { FALSE, "frompivot", "Scale from pivot / Symmetric shearing (%s)" },
-        { FALSE, "cornersnap", "Snap pivot point to corners/center (%s)" },
-        { FALSE, "constrain", "Constrain movement (%s)" },
+        { shift, "keepaspect", "Keep aspect (%s)" },
+        { shift, "freeshear", "Move edge freely in shearing (%s)" },
+        { ctrl, "frompivot", "Scale from pivot / Symmetric shearing (%s)" },
+        { ctrl, "cornersnap", "Snap pivot point to corners/center (%s)" },
+        { ctrl, "constrain", "Constrain movement (%s)" },
+        { 0, "fixedpivot", "Lock pivot to canvas" },
       };
 
       GtkWidget *button;
       gchar     *label;
       gint       i;
 
-      for (i = 0; i < 5; i++)
+      for (i = 0; i < 6; i++)
         {
           label = g_strdup_printf (opt_list[i].desc,
-                                   gimp_get_mod_string (
-                                     opt_list[i].shift
-                                       ? gimp_get_extend_selection_mask ()
-                                       : gimp_get_constrain_behavior_mask ()));
+                                   gimp_get_mod_string (opt_list[i].mod));
 
           button = gimp_prop_check_button_new (config, opt_list[i].name, label);
           gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
diff --git a/app/tools/gimptransformoptions.h b/app/tools/gimptransformoptions.h
index f483ed8..df3060e 100644
--- a/app/tools/gimptransformoptions.h
+++ b/app/tools/gimptransformoptions.h
@@ -51,6 +51,7 @@ struct _GimpTransformOptions
   gboolean                  frompivot;
   gboolean                  freeshear;
   gboolean                  cornersnap;
+  gboolean                  fixedpivot;
 };
 
 
diff --git a/app/tools/gimpunifiedtransformtool.c b/app/tools/gimpunifiedtransformtool.c
index 4c75864..155599f 100644
--- a/app/tools/gimpunifiedtransformtool.c
+++ b/app/tools/gimpunifiedtransformtool.c
@@ -763,6 +763,7 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
   gboolean frompivot = options->frompivot;
   gboolean freeshear = options->freeshear;
   gboolean cornersnap = options->cornersnap;
+  gboolean fixedpivot = options->fixedpivot;
 
   TransformAction function = transform_tool->function;
 
@@ -825,8 +826,11 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
         *x[i] = px[i] + dx;
         *y[i] = py[i] + dy;
       }
-      *pivot_x = ppivot_x + dx;
-      *pivot_y = ppivot_y + dy;
+      if (!fixedpivot) {
+        *pivot_x = ppivot_x + dx;
+        *pivot_y = ppivot_y + dy;
+        fixedpivot = TRUE;
+      }
     }
 
   /* rotate */
@@ -849,6 +853,7 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
         *x[i] = m.x;
         *y[i] = m.y;
       }
+      fixedpivot = TRUE;
     }
 
   /* move rotation axis */
@@ -880,6 +885,7 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
         }
       *pivot_x = ppivot_x + dx;
       *pivot_y = ppivot_y + dy;
+      fixedpivot = TRUE;
     }
 
   /* scaling via corner */
@@ -1019,6 +1025,7 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
               *x[i] -= comp_x - pivot.x;
               *y[i] -= comp_y - pivot.y;
             }
+          fixedpivot = TRUE;
         }
     }
 
@@ -1130,6 +1137,7 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
               *x[i] -= comp_x - pivot.x;
               *y[i] -= comp_y - pivot.y;
             }
+          fixedpivot = TRUE;
         }
     }
 
@@ -1271,6 +1279,39 @@ gimp_unified_transform_tool_motion (GimpTransformTool *transform_tool)
       *x[this] = px[this] + dx;
       *y[this] = py[this] + dy;
     }
+
+  if (!fixedpivot)
+    {
+      //TODO don't duplicate this code from above
+      GimpMatrix3 transform_before, transform_after;
+      gdouble comp_x, comp_y;
+      gimp_matrix3_identity (&transform_before);
+      gimp_matrix3_identity (&transform_after);
+      gimp_transform_matrix_perspective (&transform_before,
+                                         transform_tool->x1,
+                                         transform_tool->y1,
+                                         transform_tool->x2 - transform_tool->x1,
+                                         transform_tool->y2 - transform_tool->y1,
+                                         px[0], py[0],
+                                         px[1], py[1],
+                                         px[2], py[2],
+                                         px[3], py[3]);
+      gimp_transform_matrix_perspective (&transform_after,
+                                         transform_tool->x1,
+                                         transform_tool->y1,
+                                         transform_tool->x2 - transform_tool->x1,
+                                         transform_tool->y2 - transform_tool->y1,
+                                         *x[0], *y[0],
+                                         *x[1], *y[1],
+                                         *x[2], *y[2],
+                                         *x[3], *y[3]);
+      gimp_matrix3_invert(&transform_before);
+      GimpMatrix3 transform = transform_before;
+      gimp_matrix3_mult(&transform_after, &transform);
+      gimp_matrix3_transform_point(&transform, ppivot_x, ppivot_y, &comp_x, &comp_y);
+      *pivot_x = comp_x;
+      *pivot_y = comp_y;
+    }
 }
 
 static void