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gtk-demo: Connet to draw signal in drawingarea example

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This commit is contained in:
Benjamin Otte 2010-09-08 21:50:16 +02:00
parent 3f10e45ea1
commit ef56ba83f8
1 changed files with 19 additions and 35 deletions
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54
demos/gtk-demo/drawingarea.c
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@ -51,19 +51,12 @@ scribble_configure_event (GtkWidget *widget,
/* Redraw the screen from the surface */
static gboolean
scribble_expose_event (GtkWidget *widget,
GdkEventExpose *event,
gpointer data)
scribble_draw (GtkWidget *widget,
cairo_t *cr,
gpointer data)
{
cairo_t *cr;
cr = gdk_cairo_create (gtk_widget_get_window (widget));
cairo_set_source_surface (cr, surface, 0, 0);
gdk_cairo_rectangle (cr, &event->area);
cairo_fill (cr);
cairo_destroy (cr);
cairo_paint (cr);
return FALSE;
}
@ -144,45 +137,38 @@ scribble_motion_notify_event (GtkWidget *widget,
static gboolean
checkerboard_expose (GtkWidget *da,
GdkEventExpose *event,
gpointer data)
checkerboard_draw (GtkWidget *da,
cairo_t *cr,
gpointer data)
{
GtkAllocation allocation;
gint i, j, xcount, ycount;
cairo_t *cr;
gint i, j, xcount, ycount, width, height;
#define CHECK_SIZE 10
#define SPACING 2
/* At the start of an expose handler, a clip region of event->area
* is set on the window, and event->area has been cleared to the
/* At the start of a draw handler, a clip region has been set on
* the Cairo context, and the contents have been cleared to the
* widget's background color. The docs for
* gdk_window_begin_paint_region() give more details on how this
* works.
*/
cr = gdk_cairo_create (gtk_widget_get_window (da));
gdk_cairo_rectangle (cr, &event->area);
cairo_clip (cr);
gtk_widget_get_allocation (da, &allocation);
xcount = 0;
width = gtk_widget_get_allocated_width (da);
height = gtk_widget_get_allocated_height (da);
i = SPACING;
while (i < allocation.width)
while (i < width)
{
j = SPACING;
ycount = xcount % 2; /* start with even/odd depending on row */
while (j < allocation.height)
while (j < height)
{
if (ycount % 2)
cairo_set_source_rgb (cr, 0.45777, 0, 0.45777);
else
cairo_set_source_rgb (cr, 1, 1, 1);
/* If we're outside event->area, this will do nothing.
* It might be mildly more efficient if we handled
* the clipping ourselves, but again we're feeling lazy.
/* If we're outside the clip, this will do nothing.
*/
cairo_rectangle (cr, i, j, CHECK_SIZE, CHECK_SIZE);
cairo_fill (cr);
@ -195,8 +181,6 @@ checkerboard_expose (GtkWidget *da,
++xcount;
}
cairo_destroy (cr);
/* return TRUE because we've handled this event, so no
* further processing is required.
*/
@ -255,8 +239,8 @@ do_drawingarea (GtkWidget *do_widget)
gtk_container_add (GTK_CONTAINER (frame), da);
g_signal_connect (da, "expose-event",
G_CALLBACK (checkerboard_expose), NULL);
g_signal_connect (da, "draw",
G_CALLBACK (checkerboard_draw), NULL);
/*
* Create the scribble area
@ -279,8 +263,8 @@ do_drawingarea (GtkWidget *do_widget)
/* Signals used to handle backing surface */
g_signal_connect (da, "expose-event",
G_CALLBACK (scribble_expose_event), NULL);
g_signal_connect (da, "draw",
G_CALLBACK (scribble_draw), NULL);
g_signal_connect (da,"configure-event",
G_CALLBACK (scribble_configure_event), NULL);