An easy way to use a scrollbar inside a GlWindow is to create your window and a
scrollbar, then as the value of the scrollbar changes, modify a global variable
(or static class member) and call redraw() on the glWindow. Inside your draw
function, use glTranslatef() with the values your scrollbar sets. This
effectively works as a crude way to scroll, though it can get expensive.
You can further optimise this with a boolean flag if you don't need to redraw
your entire window's contents.
A brief example is shown below. I've stolen some of Greg's code to draw an X as
an example, but feel free to fill in your own drawing code as you see fit.
Regards,
Ben
----------------------------------------------------------------
// Scrollbar + GlWindow
// Compile with fltk2-config --use-gl --compile
#include <fltk/Scrollbar.h>
#include <fltk/GlWindow.h>
#include <fltk/run.h>
#include <fltk/Window.h>
#include <fltk/gl.h>
using namespace fltk;
float xpan;
class myGlWindow : public GlWindow {
public:
bool changed;
void draw(){
glPushMatrix();
glTranslatef(0, xpan, 0);
if(changed) {
// First time? init viewport, etc.
if (!valid()) {
valid(1);
glLoadIdentity();
glViewport(0,0,w(),h());
glOrtho(-w(),w(),-h(),h(),-1,1);
}
// Clear screen
glClear(GL_COLOR_BUFFER_BIT);
// Draw white 'X'
glColor3f(1.0, 1.0, 1.0);
glBegin(GL_LINE_STRIP); glVertex2f(w(), h());
glVertex2f(-w(),-h()); glEnd();
glBegin(GL_LINE_STRIP); glVertex2f(w(),-h()); glVertex2f(-w(),
h()); glEnd();
changed = 0;
}
glPopMatrix();
}
// HANDLE WINDOW RESIZING
// If window reshaped, need to readjust viewport/ortho
//
void resize(int X,int Y,int W,int H) {
GlWindow::resize(X,Y,W,H);
glLoadIdentity();
glViewport(0,0,W,H);
glOrtho(-W,W,-H,H,-1,1);
redraw();
}
myGlWindow(int x, int y, int w, int h) : GlWindow(x,y,w,h), changed(1) {};
};
void scrollCB(Widget* w, void* v){
xpan = ((Scrollbar*)w)->value();
((myGlWindow*)v)->changed = 1;
((myGlWindow*)v)->redraw();
}
int main(){
Window win(800, 600);
win.begin();
myGlWindow mainWin(20, 0, 780, 600);
Scrollbar scroll(0, 0, 20, 600);
scroll.align(ALIGN_LEFT);
scroll.set_vertical();
scroll.minimum(25);
scroll.maximum(-25);
scroll.step(0.1);
scroll.callback(scrollCB, (void*)&mainWin);
win.end();
win.show();
return run();
}
> Date: Mon, 21 Feb 2011 15:59:32 +0000
> From: [email protected]
> To: [email protected]
> Subject: Re: [fltk.development] glwindow inside scrollgroup,fltk2
>
>
> > after few experiments I noticed in documentation that I can't
> > use glwindow within scrollGroup, therefore I can't have
> > scrollbars for glwindow.
> >
> > I was wondering if exists any workaround how to achieve
> > scrollbars for glwindow.
>
>
> Presumably you have looked at the CubeView demo?
> Does that not do what you want?
> Maybe want to use Fl_Scrollbar widgets in place of the Fl_Sliders that
> the CubeView demo uses, but otherwise the idea would be the same, I
> think.
>
>
>
>
>
>
> SELEX Galileo Ltd
> Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14
> 3EL
> A company registered in England & Wales. Company no. 02426132
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