286 lines
10 KiB
C
286 lines
10 KiB
C
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/* Constraints/Simple Constraints
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* #Keywords: GtkLayoutManager
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*
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* GtkConstraintLayout provides a layout manager that uses relations
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* between widgets (also known as “constraints”) to compute the position
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* and size of each child.
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*
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* In addition to child widgets, the constraints can involve spacer
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* objects (also known as “guides”). This example has a guide between
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* the two buttons in the top row.
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*
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* Try resizing the window to see how the constraints react to update
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* the layout.
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*/
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#include <glib/gi18n.h>
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#include <gtk/gtk.h>
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G_DECLARE_FINAL_TYPE (SimpleGrid, simple_grid, SIMPLE, GRID, GtkWidget)
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struct _SimpleGrid
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{
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GtkWidget parent_instance;
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GtkWidget *button1, *button2;
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GtkWidget *button3;
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};
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G_DEFINE_TYPE (SimpleGrid, simple_grid, GTK_TYPE_WIDGET)
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static void
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simple_grid_dispose (GObject *object)
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{
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SimpleGrid *self = SIMPLE_GRID (object);
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g_clear_pointer (&self->button1, gtk_widget_unparent);
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g_clear_pointer (&self->button2, gtk_widget_unparent);
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g_clear_pointer (&self->button3, gtk_widget_unparent);
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G_OBJECT_CLASS (simple_grid_parent_class)->dispose (object);
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}
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static void
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simple_grid_class_init (SimpleGridClass *klass)
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{
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GObjectClass *object_class = G_OBJECT_CLASS (klass);
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GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
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object_class->dispose = simple_grid_dispose;
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gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CONSTRAINT_LAYOUT);
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}
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/* Layout:
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*
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* +-------------------------------------+
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* | +-----------++-------++-----------+ |
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* | | Child 1 || Space || Child 2 | |
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* | +-----------++-------++-----------+ |
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* | +---------------------------------+ |
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* | | Child 3 | |
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* | +---------------------------------+ |
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* +-------------------------------------+
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*
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* Constraints:
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*
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* super.start = child1.start - 8
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* child1.width = child2.width
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* child1.end = space.start
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* space.end = child2.start
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* child2.end = super.end - 8
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* super.start = child3.start - 8
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* child3.end = super.end - 8
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* super.top = child1.top - 8
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* super.top = child2.top - 8
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* child1.bottom = child3.top - 12
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* child2.bottom = child3.top - 12
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* child3.height = child1.height
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* child3.height = child2.height
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* child3.bottom = super.bottom - 8
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*
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* To add some flexibility, we make the space
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* stretchable:
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*
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* space.width >= 10
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* space.width = 100
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* space.width <= 200
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*/
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static void
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build_constraints (SimpleGrid *self,
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GtkConstraintLayout *manager)
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{
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GtkConstraintGuide *guide;
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guide = gtk_constraint_guide_new ();
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gtk_constraint_guide_set_name (guide, "space");
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gtk_constraint_guide_set_min_size (guide, 10, 10);
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gtk_constraint_guide_set_nat_size (guide, 100, 10);
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gtk_constraint_guide_set_max_size (guide, 200, 20);
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gtk_constraint_guide_set_strength (guide, GTK_CONSTRAINT_STRENGTH_STRONG);
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gtk_constraint_layout_add_guide (manager, guide);
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new_constant (GTK_CONSTRAINT_TARGET (self->button1),
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GTK_CONSTRAINT_ATTRIBUTE_WIDTH,
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GTK_CONSTRAINT_RELATION_LE,
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200.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (NULL,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_WIDTH,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_WIDTH,
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1.0,
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0.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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GTK_CONSTRAINT_RELATION_EQ,
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guide,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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1.0,
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0.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (guide,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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1.0,
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0.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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GTK_CONSTRAINT_RELATION_EQ,
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NULL,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (NULL,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_START,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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GTK_CONSTRAINT_RELATION_EQ,
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NULL,
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GTK_CONSTRAINT_ATTRIBUTE_END,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (NULL,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (NULL,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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1.0,
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-12.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_TOP,
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1.0,
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-12.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_HEIGHT,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button1,
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GTK_CONSTRAINT_ATTRIBUTE_HEIGHT,
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1.0,
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0.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_HEIGHT,
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GTK_CONSTRAINT_RELATION_EQ,
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self->button2,
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GTK_CONSTRAINT_ATTRIBUTE_HEIGHT,
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1.0,
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0.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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gtk_constraint_layout_add_constraint (manager,
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gtk_constraint_new (self->button3,
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GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
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GTK_CONSTRAINT_RELATION_EQ,
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NULL,
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GTK_CONSTRAINT_ATTRIBUTE_BOTTOM,
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1.0,
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-8.0,
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GTK_CONSTRAINT_STRENGTH_REQUIRED));
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}
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static void
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simple_grid_init (SimpleGrid *self)
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{
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GtkWidget *widget = GTK_WIDGET (self);
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self->button1 = gtk_button_new_with_label ("Child 1");
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gtk_widget_set_parent (self->button1, widget);
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self->button2 = gtk_button_new_with_label ("Child 2");
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gtk_widget_set_parent (self->button2, widget);
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self->button3 = gtk_button_new_with_label ("Child 3");
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gtk_widget_set_parent (self->button3, widget);
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GtkLayoutManager *manager = gtk_widget_get_layout_manager (GTK_WIDGET (self));
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build_constraints (self, GTK_CONSTRAINT_LAYOUT (manager));
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}
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GtkWidget *
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do_constraints (GtkWidget *do_widget)
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{
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static GtkWidget *window;
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if (!window)
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{
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GtkWidget *box, *grid;
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window = gtk_window_new ();
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gtk_window_set_display (GTK_WINDOW (window), gtk_widget_get_display (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Simple Constraints");
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gtk_window_set_default_size (GTK_WINDOW (window), 260, -1);
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g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
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box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 12);
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gtk_window_set_child (GTK_WINDOW (window), box);
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grid = g_object_new (simple_grid_get_type (), NULL);
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gtk_widget_set_hexpand (grid, TRUE);
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gtk_widget_set_vexpand (grid, TRUE);
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gtk_box_append (GTK_BOX (box), grid);
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_set_visible (window, TRUE);
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else
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gtk_window_destroy (GTK_WINDOW (window));
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return window;
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}
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