1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/* Constraints/VFL
*
* GtkConstraintLayout allows defining constraints using a
* compact syntax called Visual Format Language, or VFL.
*
* A typical example of a VFL specification looks like this:
*
* H:|-[button1(==button2)]-12-[button2]-|
*/
#include <glib/gi18n.h>
#include <gtk/gtk.h>
G_DECLARE_FINAL_TYPE (VflGrid, vfl_grid, VFL, GRID, GtkWidget)
struct _VflGrid
{
GtkWidget parent_instance;
GtkWidget *button1, *button2;
GtkWidget *button3;
};
G_DEFINE_TYPE (VflGrid, vfl_grid, GTK_TYPE_WIDGET)
static void
vfl_grid_dispose (GObject *object)
{
VflGrid *self = VFL_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 (vfl_grid_parent_class)->dispose (object);
}
static void
vfl_grid_class_init (VflGridClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
object_class->dispose = vfl_grid_dispose;
gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CONSTRAINT_LAYOUT);
}
/* Layout:
*
* +-----------------------------+
* | +-----------+ +-----------+ |
* | | Child 1 | | Child 2 | |
* | +-----------+ +-----------+ |
* | +-------------------------+ |
* | | Child 3 | |
* | +-------------------------+ |
* +-----------------------------+
*
* Constraints:
*
* super.start = child1.start - 8
* child1.width = child2.width
* child1.end = child2.start - 12
* 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
*
* Visual format:
*
* H:|-8-[view1(==view2)-12-[view2]-8-|
* H:|-8-[view3]-8-|
* V:|-8-[view1]-12-[view3(==view1)]-8-|
* V:|-8-[view2]-12-[view3(==view2)]-8-|
*/
static void
build_constraints (VflGrid *self,
GtkConstraintLayout *manager)
{
const char * const vfl[] = {
"H:|-[button1(==button2)]-12-[button2]-|",
"H:|-[button3]-|",
"V:|-[button1]-12-[button3(==button1)]-|",
"V:|-[button2]-12-[button3(==button2)]-|",
};
GError *error = NULL;
gtk_constraint_layout_add_constraints_from_description (manager, vfl, G_N_ELEMENTS (vfl),
8, 8,
&error,
"button1", self->button1,
"button2", self->button2,
"button3", self->button3,
NULL);
if (error != NULL)
{
g_printerr ("VFL parsing error:\n%s", error->message);
g_error_free (error);
}
}
static void
vfl_grid_init (VflGrid *self)
{
GtkWidget *widget = 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");
GtkLayoutManager *manager = gtk_widget_get_layout_manager (GTK_WIDGET (self));
build_constraints (self, GTK_CONSTRAINT_LAYOUT (manager));
}
GtkWidget *
do_constraints_vfl (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), "Constraints — VFL");
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 (vfl_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_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}
|
