Robb Main wrote:
In the code below, the PNG image I'm loading is not displayed immediately. I've
been unable to overcome the delay before it is displayed, although I'm told the
image should be ready to display immediately after loading (i.e., the
constructor returns). What am I doing wrong?
Thanks,
Robb.
As Matthias suggested, you should separate the splash screen code and the main
window code - this would make your code much easier and better to understand.
Please read his suggestions ...
However, your code works almost okay, but ...
Fl_Window *pWin = new myWindow(0, 0, 640, 480);
// wait while splash is displayed
/*
There is a noticeable delay before the PNG image appears,
because the
picture is NOT rendered by the first itteration of the loop
below.
The picture is rendered when Fl::check() is called.
I tried numerous different things (see constructor above), in
order to
"flush" the PNG image to the display immediately, but nothing
worked.
*/
for (int i=0; i<3; i++ ) {
usleep( 1000000 );
Fl::check();
}
you wrote it yourself. The splash screen will only be displayed, when you call
Fl::check(), but this is called at the end of your loop after usleep(). Change
this (move Fl::check() at the beginning of the loop, or call it once before the
loop, and there will be no visible delay.
// Now show the main window - this will remove the splash screen
pWin->show();
return Fl::run();
}
------------------------
<end code>
Although I would recommend to separate the two windows, like Matthias said, I'll
append a slimline version of your code, just to show you another approach that
closely matches your way.
Albrecht
// compile with fltk-config --use-images --compile splash.cxx
#include <FL/Fl.H>
#include <FL/Fl_Shared_Image.H>
#include <FL/Fl_Single_Window.H>
#include <FL/Fl_PNG_Image.H>
#include <FL/Fl_Button.H>
// for usleep (Sleep) used in main()
#ifdef WIN32
#include <windows.h> // usleep doesn't work for Windows (?)
#else
#include <unistd.h>
#endif // WIN32
class splashWindow : public Fl_Window {
Fl_PNG_Image *pBGImage;
protected:
virtual void draw() {
Fl_Window::draw(); // Draw window widget first
if ( pBGImage )
pBGImage->draw(10,10); // draw PNG image over the above
}
public:
// Constructor
splashWindow(int X, int Y, int W, int H, char *pszTitle, char *pszBGImage)
: Fl_Window(X,Y,W,H) {
pBGImage = new Fl_PNG_Image( pszBGImage );
// resize(X,Y,pBGImage->w()+20,pBGImage->h()+20); // make it as big as
the image
border(0);
end();
}
};
class myWindow : public Fl_Window {
splashWindow *pSplashWin;
public:
void show() {
Fl_Window::show(); // Show main window widget first
if (pSplashWin) {
// Cleanup
// ** remove( pSplashWin ); // no need to remove splash window
delete( pSplashWin ); // deallocate it
pSplashWin = 0;
}
} // show()
// Constructor
myWindow(int X, int Y, int W, int H) : Fl_Window(X,Y,W,H) {
pSplashWin = 0;
// Add a button to the main screen, so we know when it's displayed.
Fl_Button *btn1 = new Fl_Button(40, 40, 200, 200, "MAIN WINDOW" );
end();
// Create *Independent* Splash Screen window *after* end()
pSplashWin = new splashWindow( X, Y, W, H, "My Splash",
"./splash-bg3.png" );
pSplashWin->show();
}
};
int main(int argc, char ** argv) {
fl_register_images();
Fl::scheme("plastic");
Fl_Window *pWin = new myWindow(200, 200, 640, 480);
// wait while splash is displayed
/*
There is a noticeable delay before the PNG image appears, because the
picture is NOT rendered by the first itteration of the loop below.
The picture is rendered when Fl::check() is called.
I tried numerous different things (see constructor above), in order to
"flush" the PNG image to the display immediately, but nothing worked.
*/
for (int i=0; i<9; i++ ) {
Fl::check(); // call this first
#ifdef WIN32
Sleep ( 1000 );
#else
usleep( 1000000 );
#endif
}
// Now show the main window - this will remove the splash screen
pWin->show(argc,argv);
return Fl::run();
}
//
// compile with fltk-config --use-images --compile splash.cxx
//
#include <FL/Fl.H>
#include <FL/Fl_Shared_Image.H>
#include <FL/Fl_Single_Window.H>
#include <FL/Fl_PNG_Image.H>
#include <FL/Fl_Button.H>
// for usleep (Sleep) used in main()
#ifdef WIN32
#include <windows.h> // usleep doesn't work for Windows (?)
#else
#include <unistd.h>
#endif // WIN32
class splashWindow : public Fl_Window {
Fl_PNG_Image *pBGImage;
protected:
virtual void draw() {
Fl_Window::draw(); // Draw window widget first
if ( pBGImage )
pBGImage->draw(10,10); // draw PNG image over the above
}
public:
// Constructor
splashWindow(int X, int Y, int W, int H, char *pszTitle, char *pszBGImage)
: Fl_Window(X,Y,W,H) {
pBGImage = new Fl_PNG_Image( pszBGImage );
// resize(X,Y,pBGImage->w()+20,pBGImage->h()+20); // make it as big as
the image
border(0); // this would be useless for a child window
end();
}
};
class myWindow : public Fl_Window {
splashWindow *pSplashWin;
public:
void show() {
Fl_Window::show(); // Show main window widget first
if (pSplashWin) {
// Cleanup
// ** remove( pSplashWin ); // no need to remove splash window
delete( pSplashWin ); // deallocate it
pSplashWin = 0;
}
} // show()
// Constructor
myWindow(int X, int Y, int W, int H) : Fl_Window(X,Y,W,H) {
pSplashWin = 0;
// Add a button to the main screen, so we know when it's displayed.
Fl_Button *btn1 = new Fl_Button(40, 40, 200, 200, "MAIN WINDOW" );
end();
// Create *Independent* Splash Screen window *after* end()
pSplashWin = new splashWindow( X, Y, W, H, "My Splash",
"./splash-bg3.png" );
pSplashWin->show();
}
};
int main(int argc, char ** argv) {
fl_register_images();
Fl::scheme("plastic");
Fl_Window *pWin = new myWindow(200, 200, 640, 480);
// wait while splash is displayed
/*
There is a noticeable delay before the PNG image appears, because the
picture is NOT rendered by the first itteration of the loop below.
The picture is rendered when Fl::check() is called.
I tried numerous different things (see constructor above), in order to
"flush" the PNG image to the display immediately, but nothing worked.
*/
for (int i=0; i<3; i++ ) {
Fl::check(); // call this first
#ifdef WIN32
Sleep ( 1000 );
#else
usleep( 1000000 );
#endif
}
// Now show the main window - this will remove the splash screen
pWin->show(argc,argv);
return Fl::run();
}
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