for #410 - add emeus-constraint-layout - will require lots of work

* for this commit, just enough to get the Gtk out.

shoes/layout/emeus-constraint-layout-private.h

@@ -0,0 +1,104 @@
+/* emeus-constraint-layout-private.h: The constraint layout manager
+ *
+ * Copyright 2016  Endless
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "emeus-constraint-layout.h"
+#include "emeus-types-private.h"
+#include "shoes/layout/gshoes-ele.h"
+
+G_BEGIN_DECLS
+
+struct _EmeusConstraintLayoutChild
+{
+  //GtkBin parent_instance;
+  GshoesEle *parent_instance;
+
+  /* An optional name for the child, to be used when building
+   * constraints from string descriptions
+   */
+  char *name;
+
+  /* Position in the layout's GSequence */
+  GSequenceIter *iter;
+
+  /* Back pointer to the solver in the layout */
+  SimplexSolver *solver;
+
+  /* HashTable<static string, Variable>; a hash table of variables,
+   * one for each attribute; we use these to query and suggest the
+   * values for the solver. The string is static and does not need
+   * to be freed.
+   */
+  GHashTable *bound_attributes;
+
+  /* HashSet<EmeusConstraint>; the set of constraints on the
+   * widget, using the public API objects.
+   */
+  GHashTable *constraints;
+
+  double intrinsic_width;
+  double intrinsic_height;
+
+  /* Internal constraints, created to satisfy specific bound
+   * attributes; may be unset.
+   */
+  Constraint *right_constraint;
+  Constraint *bottom_constraint;
+  Constraint *center_x_constraint;
+  Constraint *center_y_constraint;
+  Constraint *width_constraint;
+  Constraint *height_constraint;
+};
+
+struct _EmeusConstraintLayout
+{
+  //GtkContainer parent_instance;
+  void * parent_instance;  // points to shoes_layout struct 
+
+  GSequence *children;
+
+  SimplexSolver solver;
+
+  GHashTable *bound_attributes;
+
+  /* HashSet<EmeusConstraint>; the set of constraints on the
+   * widget, using the public API objects.
+   */
+  GHashTable *constraints;
+
+  /* Internal constraints */
+  struct {
+    Constraint *top;
+    Constraint *left;
+    Constraint *width;
+    Constraint *height;
+  } stays;
+};
+
+SimplexSolver * emeus_constraint_layout_get_solver      (EmeusConstraintLayout *layout);
+
+gboolean        emeus_constraint_layout_has_child_data  (EmeusConstraintLayout *layout,
+                                                         GshoesEle             *widget);
+
+void            emeus_constraint_layout_activate_constraint     (EmeusConstraintLayout *layout,
+                                                                 EmeusConstraint       *constraint);
+void            emeus_constraint_layout_deactivate_constraint   (EmeusConstraintLayout *layout,
+                                                                 EmeusConstraint       *constraint);
+
+G_END_DECLS