for #410 - add emeus cassowary C code.

* compiles and links linux, osx, mxe (not xwin7 - needs newer glib)
* doesn't run

Tests/layout/l3.rb

@@ -5,7 +5,7 @@
 include Cassowary
 class CassowaryLayout 
   attr_accessor :canvas, :widgets, :solver, :attrs, :left_limit,
-	:right_limit, :top_limit, :height_limit, :right_limit_stay,
+	:right_limit, :top_limit, :height_limit, :rl_stay, :hl_stay,
   :canvas_set, :canvas_w, :canvas_h
 
   def initialize()
@@ -40,8 +40,11 @@ def setup(canvas, attr)
 		@right_limit = Variable.new(name: 'width', value: wid)
 		@top_limit = Variable.new(name: "top", value: 0.0)
 		@height_limit = Variable.new(name: "height", value: hgt)
-		@solver.add_stay(@left_limit)
-		@solver.add_stay(@right_limit, Strength::WeakStrength)
+
+		@solver.add_stay(@left_limit, Strength::RequiredStrength)
+		@rl_stay = @solver.add_stay(@right_limit)
+    @solver.add_stay(@top_limit, Strength::RequiredStrength)
+    @hl_stay = @solver.add_stay(@height_limit)
     $stderr.puts "callback: setup #{wid} X #{hgt}"
   end
 
@@ -80,11 +83,17 @@ def size(canvas, pass)
       return
     else
       $stderr.puts "callback: size Change!  w: #{canvas.width} h:#{canvas.height}"
+      # reset stays for new window size
+      #@solver.remove_constraint(@rl_stay)
+      @right_limit.value = canvas.width
+      #@rl_stay = @solver.add_constraint(@right_limit, Strength::RequiredStrength)
+      #@solver.add_constraint(@rl_stay)
+      @solver.solve
+      self.finish
     end
   end
 
   def widget_defaults
-    @canvas.show
 		@widgets.each_pair do |id, ele|
 			vh = @attrs[id]['height']
       vh.value = ele.height
@@ -95,13 +104,7 @@ def widget_defaults
   end
 
   def resize(w, h)
-    @right_limit.value = w
-    @height_limit.value = h
-    #@solver.add_stay(@right_limit, Strength::RequiredStrength)
-
-    #right_limit_stay = solver.add_constraint(right_limit, strength=REQUIRED)
-    #solver.add_constraint(right_limit_stay)
- end
+  end
 
   def clear()
     $stderr.puts "callback: clear"
@@ -184,7 +187,7 @@ def method_missing(meth, *args, &block)
       @ml.add_constraint(@ml.var('b2-width').cn_equal 113, Strength::StrongStrength)
 
       # string b3 is at the bottom ? 
-      @ml.add_constraint(@ml.height_limit.cn_equal @ml.var('b3-top'))
+      @ml.add_constraint(@ml.var('b3-top').cn_equal 100)
 
       @lay.finish
       @p.text = @lay.inspect    

Tests/layout/vfl3.rb

@@ -11,7 +11,7 @@
     end
     @lay.start {
       metrics = {
-        'el1' => 80 # what does this mean or do or should be?
+        'padding' => 10 
       }
       lines = [
         "H:|-[para1(but1)]-[but1]-|",

shoes/layout/config.h

@@ -0,0 +1,35 @@
+/*
+ * Autogenerated by the Meson build system.
+ * Do not edit, your changes will be lost.
+ */
+
+#pragma once
+
+#define ENABLE_NLS 1
+
+#define GETTEXT_PACKAGE PACKAGE_NAME
+
+#define HAVE_STDBOOL_H
+
+#define HAVE_STDINT_H
+
+#define HAVE_STDLIB_H
+
+#define LOCALEDIR PACKAGE_LOCALE_DIR
+
+#define PACKAGE_DATADIR "/usr/local/share"
+
+#define PACKAGE_LIBDIR "/usr/local/lib/x86_64-linux-gnu"
+
+#define PACKAGE_LIBEXECDIR "/usr/local/libexec"
+
+#define PACKAGE_LOCALE_DIR "/usr/local/share/locale"
+
+#define PACKAGE_NAME "emeus"
+
+#define PACKAGE_STRING "emeus-0.99.1"
+
+#define PACKAGE_VERSION "0.99.1"
+
+#define _EMEUS_PUBLIC __attribute__((visibility("default")))
+

shoes/layout/emeus-constraint-private.h

@@ -0,0 +1,60 @@
+/* emeus-constraint-private.h: The base constraint object
+ *
+ * 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.h"
+//#include "emeus-constraint-layout-private.h"
+#include "emeus-types-private.h"
+
+G_BEGIN_DECLS
+
+struct _EmeusConstraint
+{
+  GInitiallyUnowned parent_instance;
+
+  gpointer target_object;
+  EmeusConstraintAttribute target_attribute;
+
+  EmeusConstraintRelation relation;
+
+  gpointer source_object;
+  EmeusConstraintAttribute source_attribute;
+
+  double multiplier;
+  double constant;
+
+  int strength;
+
+  gboolean is_active;
+
+  char *description;
+  SimplexSolver *solver;
+  Constraint *constraint;
+  EmeusConstraintLayout *layout;
+};
+
+gboolean        emeus_constraint_attach                 (EmeusConstraint       *constraint,
+                                                         EmeusConstraintLayout *layout);
+void            emeus_constraint_detach                 (EmeusConstraint       *constraint);
+
+Constraint *    emeus_constraint_get_real_constraint    (EmeusConstraint       *constraint);
+
+const char *    emeus_constraint_to_string              (EmeusConstraint       *constraint);
+
+G_END_DECLS