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#include "demolayout.h"
struct _DemoLayout
{
GtkLayoutManager parent_instance;
float position;
int pos[16];
};
struct _DemoLayoutClass
{
GtkLayoutManagerClass parent_class;
};
G_DEFINE_TYPE (DemoLayout, demo_layout, GTK_TYPE_LAYOUT_MANAGER)
static void
demo_layout_measure (GtkLayoutManager *layout_manager,
GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
GtkWidget *child;
int minimum_size = 0;
int natural_size = 0;
for (child = gtk_widget_get_first_child (widget);
child != NULL;
child = gtk_widget_get_next_sibling (child))
{
int child_min = 0, child_nat = 0;
if (!gtk_widget_should_layout (child))
continue;
gtk_widget_measure (child, orientation, -1,
&child_min, &child_nat,
NULL, NULL);
minimum_size = MAX (minimum_size, child_min);
natural_size = MAX (natural_size, child_nat);
}
/* A back-of-a-napkin calculation to reserve enough
* space for arranging 16 children in a circle.
*/
*minimum = 16 * minimum_size / G_PI + minimum_size;
*natural = 16 * natural_size / G_PI + natural_size;
}
static void
demo_layout_allocate (GtkLayoutManager *layout_manager,
GtkWidget *widget,
int width,
int height,
int baseline)
{
DemoLayout *self = DEMO_LAYOUT (layout_manager);
GtkWidget *child;
int i;
int child_width = 0;
int child_height = 0;
int x0, y0;
float r;
float t;
t = self->position;
for (child = gtk_widget_get_first_child (widget);
child != NULL;
child = gtk_widget_get_next_sibling (child))
{
GtkRequisition child_req;
if (!gtk_widget_should_layout (child))
continue;
gtk_widget_get_preferred_size (child, &child_req, NULL);
child_width = MAX (child_width, child_req.width);
child_height = MAX (child_height, child_req.height);
}
/* the center of our layout */
x0 = (width / 2);
y0 = (height / 2);
/* the radius for our circle of children */
r = 8 * child_width / G_PI;
for (child = gtk_widget_get_first_child (widget), i = 0;
child != NULL;
child = gtk_widget_get_next_sibling (child), i++)
{
GtkRequisition child_req;
float a = self->pos[i] * G_PI / 8;
int gx, gy;
int cx, cy;
int x, y;
if (!gtk_widget_should_layout (child))
continue;
gtk_widget_get_preferred_size (child, &child_req, NULL);
/* The grid position of child. */
gx = x0 + (i % 4 - 2) * child_width;
gy = y0 + (i / 4 - 2) * child_height;
/* The circle position of child. Note that we
* are adjusting the position by half the child size
* to place the center of child on a centered circle.
* This assumes that the children don't use align flags
* or uneven margins that would shift the center.
*/
cx = x0 + sin (a) * r - child_req.width / 2;
cy = y0 + cos (a) * r - child_req.height / 2;
/* we interpolate between the two layouts according to
* the position value that has been set on the layout.
*/
x = t * cx + (1 - t) * gx;
y = t * cy + (1 - t) * gy;
gtk_widget_size_allocate (child,
&(const GtkAllocation){ x, y, child_width, child_height},
-1);
}
}
static GtkSizeRequestMode
demo_layout_get_request_mode (GtkLayoutManager *layout_manager,
GtkWidget *widget)
{
return GTK_SIZE_REQUEST_CONSTANT_SIZE;
}
static void
demo_layout_class_init (DemoLayoutClass *klass)
{
GtkLayoutManagerClass *layout_class = GTK_LAYOUT_MANAGER_CLASS (klass);
layout_class->get_request_mode = demo_layout_get_request_mode;
layout_class->measure = demo_layout_measure;
layout_class->allocate = demo_layout_allocate;
}
static void
demo_layout_init (DemoLayout *self)
{
int i;
for (i = 0; i < 16; i++)
self->pos[i] = i;
}
GtkLayoutManager *
demo_layout_new (void)
{
return g_object_new (DEMO_TYPE_LAYOUT, NULL);
}
void
demo_layout_set_position (DemoLayout *layout,
float position)
{
layout->position = position;
}
/* Shuffle the circle positions of the children.
* Should be called when we are in the grid layout.
*/
void
demo_layout_shuffle (DemoLayout *layout)
{
int i, j, tmp;
for (i = 0; i < 16; i++)
{
j = g_random_int_range (0, i + 1);
tmp = layout->pos[i];
layout->pos[i] = layout->pos[j];
layout->pos[j] = tmp;
}
}
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