Gabriele Greco wrote:
The source file as attach was cutted, I'm pasting it inline, it's short :)
I've wrote this example code and it seems to work properly both on
Linux and Win32, I'm wandering if some GTK guru has some suggestions
to improve it, obviously it's only an example, but this will be the
structure that will be included in the application, the thread that
build the image will be an h263 decoder that get the video through the
net, this is why the simple image creation of the demo is made in a
separate thread. It works without changes both in win32/linux and uses
5/10% of CPU of pretty old machines.
I'm wandering what happens if I set an idle_function with g_idle_add()
while the previous idle cbk has not yet completed (the coherence of
the image is not a problem because I already plan to use a SpinBuffer
for it in the real app).
I'm wandering also if it's better to use gdk_flush() when I draw a
frame or it's also safe/fast to do gtk_widget_queue_redraw() for the
drawing
area widget...
Compile with:
gcc -o test gtkview.c `pkg-config gtk+-2.0 --cflags --libs`
`pkg-config gthread-2.0 --cflags --libs`
#include gtk/gtk.h
#include stdlib.h
GtkWidget *label;
GdkGC *mygc;
GdkDrawable *mydest;
gboolean blit_fast(GdkImage *img)
{
static int frames = 0;
static time_t timer = 0;
gdk_draw_image(mydest, mygc, img, 0, 0, 0, 0, img-width, img-height);
gdk_flush();
if ((frames % 100) == 0) {
time_t newtime = time(NULL);
if (timer != 0) {
char buffer[80];
newtime -= timer;
if (newtime != 0) {
sprintf(buffer, Frames: %d time: %d, %d fps, frames,
newtime, frames / newtime);
gtk_label_set(GTK_LABEL(label), buffer);
}
}
else
timer = newtime;
}
frames++;
return FALSE;
}
void *myloop(GdkImage *img)
{
static int pos = 0;
int i, j;
GTimer *t = g_timer_new();
gdouble needed = 0.0f;
g_timer_start(t);
for(;;) {
unsigned long *ptr = img-mem;
for (j = 0; j img-height; ++j) {
for (i = 0; i img-width; ++i) {
if (i pos || i (pos + 100))
*ptr = 0;
else {
*ptr = 0xff;
}
ptr++;
}
}
pos ++;
if (pos == 640)
pos = -99;
while (g_timer_elapsed(t, NULL) needed)
g_usleep(1);
g_idle_add(blit_fast, img);
needed += 0.040;
}
}
int main(int argc, char *argv[])
{
gtk_init(argc, argv);
g_thread_init(NULL);
GdkVisual *vis = gdk_visual_get_system ();
GtkWidget *win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GtkWidget *box = gtk_vbox_new(FALSE, 0);
gtk_container_add(GTK_CONTAINER(win), box);
GtkWidget *area = gtk_drawing_area_new();
gtk_widget_set_usize(area, 640, 480);
gtk_box_pack_start_defaults(GTK_BOX(box), area);
label = gtk_label_new(--- fps);
gtk_box_pack_end_defaults(GTK_BOX(box), label);
gtk_widget_set_app_paintable(area, TRUE);
//gtk_widget_set_double_buffered(win, FALSE);
gtk_widget_set_double_buffered(area, FALSE);
gtk_signal_connect(GTK_OBJECT(win), destroy,
GTK_SIGNAL_FUNC(exit), (void *)0);
GdkImage *img = gdk_image_new(GDK_IMAGE_FASTEST, vis, 640, 480);
printf(Img- %dx%d depth:%d bpp:%d bpl:%d\n, img-width, img-height,
img-depth, img-bpp, img-bpl);
if (img-bpp != 4) // actually only 32bit support since it's a test
return -1;
gtk_widget_show_all(win);
mygc = gdk_gc_new(area-window);
mydest = area-window;
g_thread_create(myloop, img, FALSE, NULL);
gtk_main();
}
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