[gtk/constraints-grid: 3/4] Add a constraint grid demo

[Matthias Clasen <matthiasc src gnome org>]

commit 170ce886c924cb901a35b512611a27f73d96e1da
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jun 25 04:55:48 2019 +0000

    Add a constraint grid demo
    
    This shows a cross made from overlapping grids.

 demos/gtk-demo/constraints2.c     | 190 ++++++++++++++++++++++++++++++++++++++
 demos/gtk-demo/demo.gresource.xml |   1 +
 demos/gtk-demo/meson.build        |   1 +
 3 files changed, 192 insertions(+)
---
diff --git a/demos/gtk-demo/constraints2.c b/demos/gtk-demo/constraints2.c
new file mode 100644
index 0000000000..cb5c86afd4
--- /dev/null
+++ b/demos/gtk-demo/constraints2.c
@@ -0,0 +1,190 @@
+/* Constraints/Grid
+ *
+ * GtkConstraintLayout lets you define complex layouts
+ * like grids.
+ */
+
+#include <glib/gi18n.h>
+#include <gtk/gtk.h>
+
+G_DECLARE_FINAL_TYPE (ComplexGrid, complex_grid, COMPLEX, GRID, GtkWidget)
+
+struct _ComplexGrid
+{
+  GtkWidget parent_instance;
+
+  GtkWidget *button1, *button2, *button3;
+  GtkWidget *button4, *button5;
+};
+
+G_DEFINE_TYPE (ComplexGrid, complex_grid, GTK_TYPE_WIDGET)
+
+static void
+complex_grid_destroy (GtkWidget *widget)
+{
+  ComplexGrid *self = COMPLEX_GRID (widget);
+
+  g_clear_pointer (&self->button1, gtk_widget_destroy);
+  g_clear_pointer (&self->button2, gtk_widget_destroy);
+  g_clear_pointer (&self->button3, gtk_widget_destroy);
+  g_clear_pointer (&self->button4, gtk_widget_destroy);
+  g_clear_pointer (&self->button5, gtk_widget_destroy);
+
+  GTK_WIDGET_CLASS (complex_grid_parent_class)->destroy (widget);
+}
+
+static void
+complex_grid_class_init (ComplexGridClass *klass)
+{
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+
+  widget_class->destroy = complex_grid_destroy;
+
+  gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CONSTRAINT_LAYOUT);
+}
+
+/* Layout:
+ *
+ *   +--------------------------------------+
+ *   |             +-----------+            |
+ *   |             |  Child 4  |            |
+ *   | +-----------+-----------+----------+ |
+ *   | |  Child 1  |  Child 2  |  Child 3 | |
+ *   | +-----------+-----------+----------+ |
+ *   |             |  Child 5  |            |
+ *   |             +-----------+            |
+ *   +--------------------------------------+
+ *
+ */
+static void
+build_constraints (ComplexGrid         *self,
+                   GtkConstraintLayout *manager)
+{
+  GtkGridConstraint *constraint;
+  GtkConstraint *s;
+
+  s = gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_LEFT,
+                          GTK_CONSTRAINT_RELATION_EQ,
+                          self->button1, GTK_CONSTRAINT_ATTRIBUTE_LEFT,
+                          1.0, 0.0,
+                          GTK_CONSTRAINT_STRENGTH_REQUIRED);
+  gtk_constraint_layout_add_constraint (manager, s);
+
+  s = gtk_constraint_new (self->button3, GTK_CONSTRAINT_ATTRIBUTE_RIGHT,
+                          GTK_CONSTRAINT_RELATION_EQ,
+                          NULL, GTK_CONSTRAINT_ATTRIBUTE_RIGHT,
+                          1.0, 0.0,
+                          GTK_CONSTRAINT_STRENGTH_REQUIRED);
+  gtk_constraint_layout_add_constraint (manager, s);
+
+  s = gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_TOP,
+                          GTK_CONSTRAINT_RELATION_EQ,
+                          self->button4, GTK_CONSTRAINT_ATTRIBUTE_TOP,
+                          1.0, 0.0,
+                          GTK_CONSTRAINT_STRENGTH_REQUIRED);
+  gtk_constraint_layout_add_constraint (manager, s);
+
+  s = gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
+                          GTK_CONSTRAINT_RELATION_EQ,
+                          self->button5, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
+                          1.0, 0.0,
+                          GTK_CONSTRAINT_STRENGTH_REQUIRED);
+  gtk_constraint_layout_add_constraint (manager, s);
+
+  constraint = gtk_grid_constraint_new ();
+  g_object_set (constraint, "column-homogeneous", TRUE, NULL);
+  gtk_grid_constraint_add (constraint,
+                           self->button1,
+                           0, 1, 0, 1);
+  gtk_grid_constraint_add (constraint,
+                           self->button2,
+                           1, 2, 0, 1);
+  gtk_grid_constraint_add (constraint,
+                           self->button3,
+                           2, 3, 0, 1);
+  gtk_constraint_layout_add_grid_constraint (manager, constraint);
+
+  constraint = gtk_grid_constraint_new ();
+  g_object_set (constraint, "row-homogeneous", TRUE, NULL);
+  gtk_grid_constraint_add (constraint,
+                           self->button4,
+                           0, 1, 0, 1);
+  gtk_grid_constraint_add (constraint,
+                           self->button2,
+                           0, 1, 1, 2);
+  gtk_grid_constraint_add (constraint,
+                           self->button5,
+                           0, 1, 2, 3);
+  gtk_constraint_layout_add_grid_constraint (manager, constraint);
+}
+
+static void
+complex_grid_init (ComplexGrid *self)
+{
+  GtkWidget *widget = GTK_WIDGET (self);
+  GtkLayoutManager *manager = gtk_widget_get_layout_manager (GTK_WIDGET (self));
+
+  self->button1 = gtk_button_new_with_label ("Child 1");
+  gtk_widget_set_parent (self->button1, widget);
+  gtk_widget_set_name (self->button1, "button1");
+
+  self->button2 = gtk_button_new_with_label ("Child 2");
+  gtk_widget_set_parent (self->button2, widget);
+  gtk_widget_set_name (self->button2, "button2");
+
+  self->button3 = gtk_button_new_with_label ("Child 3");
+  gtk_widget_set_parent (self->button3, widget);
+  gtk_widget_set_name (self->button3, "button3");
+
+  self->button4 = gtk_button_new_with_label ("Child 4");
+  gtk_widget_set_parent (self->button4, widget);
+  gtk_widget_set_name (self->button4, "button4");
+
+  self->button5 = gtk_button_new_with_label ("Child 5");
+  gtk_widget_set_parent (self->button5, widget);
+  gtk_widget_set_name (self->button5, "button5");
+
+  build_constraints (self, GTK_CONSTRAINT_LAYOUT (manager));
+}
+
+GtkWidget *
+do_constraints2 (GtkWidget *do_widget)
+{
+ static GtkWidget *window;
+
+ if (!window)
+   {
+     GtkWidget *header, *box, *grid, *button;
+
+     window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+     gtk_window_set_display (GTK_WINDOW (window), gtk_widget_get_display (do_widget));
+
+     header = gtk_header_bar_new ();
+     gtk_header_bar_set_title (GTK_HEADER_BAR (header), "Constraints");
+     gtk_header_bar_set_show_title_buttons (GTK_HEADER_BAR (header), FALSE);
+     gtk_window_set_titlebar (GTK_WINDOW (window), header);
+     g_signal_connect (window, "destroy",
+                       G_CALLBACK (gtk_widget_destroyed), &window);
+
+     box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 12);
+     gtk_container_add (GTK_CONTAINER (window), box);
+
+     grid = g_object_new (complex_grid_get_type (), NULL);
+     gtk_widget_set_hexpand (grid, TRUE);
+     gtk_widget_set_vexpand (grid, TRUE);
+     gtk_container_add (GTK_CONTAINER (box), grid);
+
+     button = gtk_button_new_with_label ("Close");
+     gtk_container_add (GTK_CONTAINER (box), button);
+     gtk_widget_set_hexpand (grid, TRUE);
+     g_signal_connect_swapped (button, "clicked",
+                               G_CALLBACK (gtk_widget_destroy), window);
+   }
+
+ if (!gtk_widget_get_visible (window))
+   gtk_widget_show (window);
+ else
+   gtk_widget_destroy (window);
+
+ return window;
+}
diff --git a/demos/gtk-demo/demo.gresource.xml b/demos/gtk-demo/demo.gresource.xml
index 124eeeaee4..f3d400bba3 100644
--- a/demos/gtk-demo/demo.gresource.xml
+++ b/demos/gtk-demo/demo.gresource.xml
@@ -151,6 +151,7 @@
     <file>colorsel.c</file>
     <file>combobox.c</file>
     <file>constraints.c</file>
+    <file>constraints2.c</file>
     <file>css_accordion.c</file>
     <file>css_basics.c</file>
     <file>css_blendmodes.c</file>
diff --git a/demos/gtk-demo/meson.build b/demos/gtk-demo/meson.build
index e60d7e32a8..6d4bd03fad 100644
--- a/demos/gtk-demo/meson.build
+++ b/demos/gtk-demo/meson.build
@@ -9,6 +9,7 @@ demos = files([
   'colorsel.c',
   'combobox.c',
   'constraints.c',
+  'constraints2.c',
   'css_accordion.c',
   'css_basics.c',
   'css_blendmodes.c',