[fltk.general] delay in displaying window contents

[Oguz Akyuz]

Hello,

In FLTK 1.1.X, I'm observing unexpected delay in displaying window contents, if 
I there is a CPU consuming operation before displaying the window. I'm 
attaching an example code that shows this problem. To compile it save it as 
test.cpp and just type:

g++ test.cpp -o test `fltk-config --ldflags`

Note that the tm_function executes a busy for loop followed by creating and 
displaying a window. The problem is that the Fl_Button in the window is shown 
about 1 or 2 seconds later than the window itself is shown.

I would expect both the window and the button in it to be shown at the same 
time.

Any help in shedding light to this problem is appreciated.
Oguz


#include <FL/Fl.H>
#include <FL/Fl_Double_Window.H>
#include <Fl/Fl_Button.H>
#include <cmath>
#include <cstdio>
#include <pthread.h>

void* tm_function(void* data)
{
    for(int i = 0; i < 10000000; ++i)
    {
        double x = pow(i / 10000000., 2.2);
    }

    Fl_Double_Window* testWnd = new Fl_Double_Window(400, 400, "Test Window");
    Fl_Button* btn = new Fl_Button(100, 100, 60, 25, "Button");
    testWnd->end();
    testWnd->redraw();
    testWnd->show();
    Fl::check();
}

void btn_callback(Fl_Widget* o, void* data)
{
    Fl_Double_Window* mainWindow = (Fl_Double_Window*) o->parent();
    mainWindow->hide();

    //Fl::add_timeout(0.1, tm_function, NULL);
    pthread_t tid;
    pthread_create(&tid, NULL, tm_function, NULL);
}

int main(int argc, char *argv[])
{
    Fl::scheme("plastic");


    Fl_Double_Window* wnd2 = new Fl_Double_Window(800, 600, "Big Window");
    wnd2->end();
    wnd2->show();

    Fl_Double_Window* wnd = new Fl_Double_Window(500, 500, "My Window");
    Fl_Button* btn = new Fl_Button(100, 100, 100, 25, "Press Me!");
    wnd->end();
    wnd->show();


    btn->callback(btn_callback, NULL);

    Fl::run();
    return 0;
}

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