Canvas: add a nice new syntax for constraint packing

libs/canvas/constraint_test4.cc

@@ -0,0 +1,128 @@
+#include <iostream>
+
+#include <gtkmm/adjustment.h>
+#include <gtkmm/main.h>
+#include <gtkmm/window.h>
+
+#include "gtkmm2ext/colors.h"
+
+#include "canvas/box.h"
+#include "canvas/canvas.h"
+#include "canvas/cbox.h"
+#include "canvas/circle.h"
+#include "canvas/constrained_item.h"
+#include "canvas/constraint_packer.h"
+#include "canvas/rectangle.h"
+#include "canvas/text.h"
+
+using namespace ArdourCanvas;
+using namespace Gtk;
+using std::cerr;
+using std::endl;
+
+int
+main (int argc, char* argv[])
+{
+	Gtk::Main app (&argc, &argv);
+
+	Gtk::Window win;
+	Gtk::Adjustment hadj (0, 0, 1000, 1, 10);
+	Gtk::Adjustment vadj (0, 0, 1000, 1, 10);
+	GtkCanvasViewport cview (hadj, vadj);
+	Canvas* c = cview.canvas ();
+
+	c->set_background_color (0xffffffff);
+
+	srandom (time ((time_t) 0));
+
+	cview.set_size_request (100, 100);
+
+	win.add (cview);
+
+	/* Make some items */
+
+	Rectangle* r1 = new Rectangle (c);
+	Rectangle* r2 = new Rectangle (c);
+	Rectangle* r3 = new Rectangle (c);
+
+	r1->set_fill_color (Gtkmm2ext::random_color());
+	r2->set_fill_color (Gtkmm2ext::random_color());
+	r3->set_fill_color (Gtkmm2ext::random_color());
+
+	r1->name = "L";
+	r2->name = "R";
+	r3->name = "C";
+
+	r1->set_intrinsic_size (20, 20);
+	r2->set_intrinsic_size (30, 30);
+	r3->set_intrinsic_size (40, 40);
+
+	Text* txt = new Text (c);
+	txt->name = "text";
+	Pango::FontDescription font ("Sans");
+	txt->set_font_description (font);
+	txt->set ("hello world");
+
+	Rectangle* bb = new Rectangle (c);
+	bb->set_fill_color (Gtkmm2ext::random_color());
+
+	Circle* circ = new Circle (c);
+	circ->name = "circle";
+	circ->set_fill_color (Gtkmm2ext::random_color());
+	circ->set_outline_color (Gtkmm2ext::random_color());
+
+	/* create a container */
+
+	ConstraintPacker* packer = new ConstraintPacker (c->root());
+
+	/* add stuff */
+
+	ConstrainedItem* left = packer->add_constrained (r1);
+	ConstrainedItem* right = packer->add_constrained (r2);
+	ConstrainedItem* center = packer->add_constrained (r3);
+	ConstrainedItem* text = packer->add_constrained (txt);
+	ConstrainedItem* bens_box = packer->add_constrained (bb);
+	ConstrainedItem* circle = packer->add_constrained (circ);
+
+	/* first, constraints that connect an item dimension to the container dimensions or a constant */
+	packer->constrain (left->left() == 0);
+	packer->constrain (left->height() == packer->height);
+	packer->constrain (left->top() == 0);
+	packer->constrain (left->width() == 0.5 * packer->width);
+	packer->constrain (right->right() == packer->width);
+	packer->constrain (center->height() == 0.5 * packer->height);
+
+	/* second, constraints that connect an item dimension to other items */
+	center->right_of (*left, 50);
+	right->right_of (*center);
+	center->same_width_as (*right);
+	right->same_width_as (*center);
+	right->same_height_as (*left);
+	center->top_aligned_with (*left);
+	right->top_aligned_with (*center);
+
+	/* XXX this needs to somehow move into ConstraintPacker but I currently
+	 * see no way to build a constraint from a container of
+	 * ConstrainedItems
+	 */
+
+	packer->constrain (left->width() + right->width() + center->width() +
+	                   left->left_padding() + left->right_padding() +
+	                   center->left_padding() + center->right_padding() +
+	                   right->left_padding() + right->right_padding()
+	                   == packer->width);
+
+	/* Text at a fixed position */
+	text->at (Duple (150, 50));
+	/* Rectangle of fixed position and size */
+	bens_box->box (Rect (40, 40, 80, 80));
+
+	/* a circle sized and centered */
+	circle->size (Duple (30, 30));
+	circle->centered_on (*center);
+
+	win.show_all ();
+	app.run ();
+
+	return 0;
+}