/* Constraints/Simple Constraints * #Keywords: GtkLayoutManager * * GtkConstraintLayout provides a layout manager that uses relations * between widgets (also known as “constraints”) to compute the position * and size of each child. * * In addition to child widgets, the constraints can involve spacer * objects (also known as “guides”). This example has a guide between * the two buttons in the top row. * * Try resizing the window to see how the constraints react to update * the layout. */ #include #include G_DECLARE_FINAL_TYPE (SimpleGrid, simple_grid, SIMPLE, GRID, GtkWidget) struct _SimpleGrid { GtkWidget parent_instance; GtkWidget *button1, *button2; GtkWidget *button3; }; G_DEFINE_TYPE (SimpleGrid, simple_grid, GTK_TYPE_WIDGET) static void simple_grid_dispose (GObject *object) { SimpleGrid *self = SIMPLE_GRID (object); g_clear_pointer (&self->button1, gtk_widget_unparent); g_clear_pointer (&self->button2, gtk_widget_unparent); g_clear_pointer (&self->button3, gtk_widget_unparent); G_OBJECT_CLASS (simple_grid_parent_class)->dispose (object); } static void simple_grid_class_init (SimpleGridClass *klass) { GObjectClass *object_class = G_OBJECT_CLASS (klass); GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass); object_class->dispose = simple_grid_dispose; gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CONSTRAINT_LAYOUT); } /* Layout: * * +-------------------------------------+ * | +-----------++-------++-----------+ | * | | Child 1 || Space || Child 2 | | * | +-----------++-------++-----------+ | * | +---------------------------------+ | * | | Child 3 | | * | +---------------------------------+ | * +-------------------------------------+ * * Constraints: * * super.start = child1.start - 8 * child1.width = child2.width * child1.end = space.start * space.end = child2.start * child2.end = super.end - 8 * super.start = child3.start - 8 * child3.end = super.end - 8 * super.top = child1.top - 8 * super.top = child2.top - 8 * child1.bottom = child3.top - 12 * child2.bottom = child3.top - 12 * child3.height = child1.height * child3.height = child2.height * child3.bottom = super.bottom - 8 * * To add some flexibility, we make the space * stretchable: * * space.width >= 10 * space.width = 100 * space.width <= 200 */ static void build_constraints (SimpleGrid *self, GtkConstraintLayout *manager) { GtkConstraintGuide *guide; guide = gtk_constraint_guide_new (); gtk_constraint_guide_set_name (guide, "space"); gtk_constraint_guide_set_min_size (guide, 10, 10); gtk_constraint_guide_set_nat_size (guide, 100, 10); gtk_constraint_guide_set_max_size (guide, 200, 20); gtk_constraint_guide_set_strength (guide, GTK_CONSTRAINT_STRENGTH_STRONG); gtk_constraint_layout_add_guide (manager, guide); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new_constant (GTK_CONSTRAINT_TARGET (self->button1), GTK_CONSTRAINT_ATTRIBUTE_WIDTH, GTK_CONSTRAINT_RELATION_LE, 200.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_START, GTK_CONSTRAINT_RELATION_EQ, self->button1, GTK_CONSTRAINT_ATTRIBUTE_START, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button1, GTK_CONSTRAINT_ATTRIBUTE_WIDTH, GTK_CONSTRAINT_RELATION_EQ, self->button2, GTK_CONSTRAINT_ATTRIBUTE_WIDTH, 1.0, 0.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button1, GTK_CONSTRAINT_ATTRIBUTE_END, GTK_CONSTRAINT_RELATION_EQ, guide, GTK_CONSTRAINT_ATTRIBUTE_START, 1.0, 0.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (guide, GTK_CONSTRAINT_ATTRIBUTE_END, GTK_CONSTRAINT_RELATION_EQ, self->button2, GTK_CONSTRAINT_ATTRIBUTE_START, 1.0, 0.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button2, GTK_CONSTRAINT_ATTRIBUTE_END, GTK_CONSTRAINT_RELATION_EQ, NULL, GTK_CONSTRAINT_ATTRIBUTE_END, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_START, GTK_CONSTRAINT_RELATION_EQ, self->button3, GTK_CONSTRAINT_ATTRIBUTE_START, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button3, GTK_CONSTRAINT_ATTRIBUTE_END, GTK_CONSTRAINT_RELATION_EQ, NULL, GTK_CONSTRAINT_ATTRIBUTE_END, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_TOP, GTK_CONSTRAINT_RELATION_EQ, self->button1, GTK_CONSTRAINT_ATTRIBUTE_TOP, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (NULL, GTK_CONSTRAINT_ATTRIBUTE_TOP, GTK_CONSTRAINT_RELATION_EQ, self->button2, GTK_CONSTRAINT_ATTRIBUTE_TOP, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button1, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM, GTK_CONSTRAINT_RELATION_EQ, self->button3, GTK_CONSTRAINT_ATTRIBUTE_TOP, 1.0, -12.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button2, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM, GTK_CONSTRAINT_RELATION_EQ, self->button3, GTK_CONSTRAINT_ATTRIBUTE_TOP, 1.0, -12.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button3, GTK_CONSTRAINT_ATTRIBUTE_HEIGHT, GTK_CONSTRAINT_RELATION_EQ, self->button1, GTK_CONSTRAINT_ATTRIBUTE_HEIGHT, 1.0, 0.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button3, GTK_CONSTRAINT_ATTRIBUTE_HEIGHT, GTK_CONSTRAINT_RELATION_EQ, self->button2, GTK_CONSTRAINT_ATTRIBUTE_HEIGHT, 1.0, 0.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); gtk_constraint_layout_add_constraint (manager, gtk_constraint_new (self->button3, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM, GTK_CONSTRAINT_RELATION_EQ, NULL, GTK_CONSTRAINT_ATTRIBUTE_BOTTOM, 1.0, -8.0, GTK_CONSTRAINT_STRENGTH_REQUIRED)); } static void simple_grid_init (SimpleGrid *self) { GtkWidget *widget = GTK_WIDGET (self); self->button1 = gtk_button_new_with_label ("Child 1"); gtk_widget_set_parent (self->button1, widget); self->button2 = gtk_button_new_with_label ("Child 2"); gtk_widget_set_parent (self->button2, widget); self->button3 = gtk_button_new_with_label ("Child 3"); gtk_widget_set_parent (self->button3, widget); GtkLayoutManager *manager = gtk_widget_get_layout_manager (GTK_WIDGET (self)); build_constraints (self, GTK_CONSTRAINT_LAYOUT (manager)); } GtkWidget * do_constraints (GtkWidget *do_widget) { static GtkWidget *window; if (!window) { GtkWidget *box, *grid; window = gtk_window_new (); gtk_window_set_display (GTK_WINDOW (window), gtk_widget_get_display (do_widget)); gtk_window_set_title (GTK_WINDOW (window), "Simple Constraints"); gtk_window_set_default_size (GTK_WINDOW (window), 260, -1); g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window); box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 12); gtk_window_set_child (GTK_WINDOW (window), box); grid = g_object_new (simple_grid_get_type (), NULL); gtk_widget_set_hexpand (grid, TRUE); gtk_widget_set_vexpand (grid, TRUE); gtk_box_append (GTK_BOX (box), grid); } if (!gtk_widget_get_visible (window)) gtk_widget_set_visible (window, TRUE); else gtk_window_destroy (GTK_WINDOW (window)); return window; }