2011/2/14 BALLABIO GERARDO <gerardo.balla...@esterni.gruppo.mps.it>:
> Hi all,
> in the last weekend I upgraded my computer to the new stable version of
> Debian (version 6.0.0, released a few days ago). After the upgrade, a gtkmm
> program of mine has become less responsive to the point of being barely
> usable. Apparently the dispatching of signals is now much slower than it used
> to be, and when a lot of them are connected (in my program there are more
> than 100), it becomes very noticeable.
The slowdown is not caused by signal emission, but by modify_bg. If
you write a custom expose handler that draws the cells, the updates
are instantaneous. See the attached file.
Regards, Krzysztof
#include <gtkmm.h>
class Cell : public Gtk::EventBox
{
private:
int number;
protected:
sigc::signal<void, int> activate;
virtual bool on_enter_notify_event(GdkEventCrossing *event)
{ activate.emit(number); return true; }
virtual bool on_expose_event(GdkEventExpose *event)
{
Glib::RefPtr<Gdk::Window> window = get_window();
if (!window) return true;
Cairo::RefPtr<Cairo::Context> cr = window->create_cairo_context();
if(event) {
cr->rectangle(event->area.x, event->area.y,
event->area.width, event->area.height);
cr->clip();
}
switch(state) {
case 0:
cr->set_source_rgb(1, 0, 0);
break;
case 1:
cr->set_source_rgb(0, 1, 0);
break;
default:
cr->set_source_rgb(0, 0, 1);
break;
}
cr->paint();
return true;
}
public:
Cell() {
add_events(Gdk::ENTER_NOTIFY_MASK | Gdk::EXPOSURE_MASK);
set_app_paintable(true);
}
void set_number(int n) { number = n; }
sigc::signal<void, int> &signal_activate() { return activate; }
int state;
};
class MainWindow : public Gtk::Window
{
private:
static const int rows = 20, cols = 20, cellsize = 20;
Gtk::Table table;
Cell cell[rows*cols];
int active;
void set_active(int n);
public:
MainWindow();
};
MainWindow::MainWindow()
{
set_default_size(cols * cellsize, rows * cellsize);
add(table);
table.set_homogeneous(true);
table.set_row_spacings(2);
table.set_col_spacings(2);
// set up cells
for (int i=0; i<rows*cols; ++i)
{
cell[i].set_number(i);
int irow = i / rows, icol = i % rows;
table.attach(cell[i], irow, irow + 1, icol, icol + 1);
// connect signal
cell[i].signal_activate().connect
(sigc::mem_fun(*this, &MainWindow::set_active));
}
set_active(-rows - 1); // start with no active row nor column
show_all_children();
}
void MainWindow::set_active(int n)
{
active = n;
// update cell colors
const Gdk::Color colors[] = {
Gdk::Color("red"), Gdk::Color("green"), Gdk::Color("blue"),
};
int arow = active / rows, acol = active % rows;
for (int i=0; i<rows*cols; ++i)
{
int irow = i / rows, icol = i % rows,
col = (irow == arow ? 1 : 0) + (icol == acol ? 1 : 0);
cell[i].state = col;
//cell[i].queue_draw();
}
// redraw
queue_draw();
}
int main(int argc, char *argv[])
{
Gtk::Main kit(argc, argv);
MainWindow window;
Gtk::Main::run(window);
return 0;
}
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