Not redrawing image

Invincible · #1 20-Dec-2007, 01:49

Hi all,

Coming straight to the problem

I am drawing a rectangle using API fl_rect( x,y,w,h )
after that I am filling certain area inside that rectangle using fl_rectf(x,y,w/2,h/2)
So far everything goes fine

but when I try to toggle the state of drawing using FUNCTION KEY F9 that area is not redrawing

CPP / C++ / C Code:

mywindow::draw()
{
    fl_rect( x,y,w,h );
  if(background){
    fl_rectf(x,y,w/2,h/2)
 }
  redraw();
}

CPP / C++ / C Code:

int mywindow::handle(int event)
{
	Fl_Window::handle(event);
	
	switch( event ) {
		case FL_KEYUP:
			if ( (FL_F+9)	==	Fl::event_key() ){	

                       //bool background  
                       // default value of background= false 

			background = (! background );
			flush();
			}
			break;
	}
}

What might be the reason I tried Fl::flush also but doesn't work?

ykhuang · #2 20-Dec-2007, 10:18

You should call draw() in handle(), not flush().

Invincible · #3 20-Dec-2007, 20:00

Thanks for your precious reply

Initially i tired with redraw() but it was not refreshing the screen

With redraw() or flush() it faces the same problem of not refreshing the screen ,
but when screen is minimized and maximized it refreshes the screen
for now I have replaced redraw() or flush() with (hide() ,show()) it works fine but this is not the required solution because if I do this ,noticeable flickering is there .

Can anyone tell me the better solution ?

ykhuang · #4 20-Dec-2007, 20:20

Quote:

Originally Posted by Invincible

Thanks for your precious reply

Initially i tired with redraw() but it was not refreshing the screen

I think redraw() method should work.

I also implement some widget, here's its handle section.

CPP / C++ / C Code:

int myButton::handle(int event)
{
        switch(event) {
                case FL_PUSH:
                        bgbox.box(FL_DOWN_BOX);
                        redraw();
                        do_callback();
                        return 1;
                case FL_DRAG:
                        return 1;
                case FL_RELEASE:
                        bgbox.box(FL_UP_BOX);
                        redraw();
                        return 1;
                default:
                        return 0;
        };
}

Invincible · #5 20-Dec-2007, 20:46

Yes it does but in the case I have mentioned I is not doing that ...

When it's a question of painting in void window it is doing that beautifully but when you want to erase what you have painted it is creating problem

ykhuang · #6 20-Dec-2007, 20:57

Quote:

Originally Posted by Invincible

Yes it does but in the case I have mentioned I is not doing that ...

When it's a question of painting in void window it is doing that beautifully but when you want to erase what you have painted it is creating problem

If you are talking about flickering, to my experience it is probably unavoidable, especially on some platform.

I implement the same code both on ARM SoC and x86 version testing on VMWare. It looks flawless on PC but flickers on ARM platform.

Invincible · #7 20-Dec-2007, 21:38

You got me right

I am using ARM processor only

,though I am bit concern about flickering but my major concern is about refreshing screen .

My requirement is I want dynamically to paint half rectangle and erase that half portion

so that it appears half filled when FUNCTION KEY say F9 is pressed once and full empty when it is again pressed without minimizing and maximizing of window

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