On 14.05.2012 16:41, Eugenio Bargiacchi wrote:
Well it IS pretty convenient, for avoiding to precisely place every component.
Less lines of code, less bloated.
I've posted my code a couple of replies above, so tell me what you think of it!
=)
Fl_Scroll changes the x/y positions of its children to scroll
the contents, and Fl_Pack tries to calculate x/y positions
depending on the order of its children. Both widgets are doing
this during their draw() methods, which is a restriction that
can make things difficult.
Additionally, resizing Fl_Group changes its childrens' sizes
as well, so there are lots of effects coming together in this
scenario. Once you resize a group and/or rearrange a its children
you should also call init_sizes() to make your changes "permanent".
Otherwise the group will always try to resize the children
according to the first saved state.
Although I believe that nesting Fl_Scroll and Fl_Pack should be
avoided, I believe that I found a solution for your problem.
See the appended (reformatted and modified) sample code you posted.
You should also note that it would have been easier to understand
(at least for me ;-)) if you hadn't used templates for this sample
code.
See the comments in asker.h for what I changed, and also in asker.cxx
(your main.cpp) for additional changes:
(1) top_box was added to maintain the border (left and to spacing of
widgets inside the Fl_Scroll widget.
(2) rb (resize-box) was added to maintain the other widgets's sizes.
(3) Make both boxes invisible by commenting out their box and color
statements.
If I wanted to do such a special resizing, I would derive my own
container widget and override the resize() method to arrange the
widgets as needed (at least for the Fl_Pack).
Albrecht
// asker.h
#ifndef ASKER_H
#define ASKER_H
#include <FL/Fl_Pack.H>
#include <FL/Fl_Button.H>
#include <FL/Fl_Box.H>
#include <FL/fl_ask.H>
template <class T>
class Asker : public Fl_Pack
{
public:
Asker(int a, int b, int c, int d, const char * itemName, int s);
private:
Fl_Button * addButton;
static void add_cb( Fl_Widget * button, void * a );
int s;
int d;
};
template <class T>
Asker<T>::Asker(int a, int b, int c, int d2, const char * itemName, int s2) :
Fl_Pack( a, b, c, d2 ) , s(s2), d(d2)
{
add(addButton = new Fl_Button( a, b, c, d, itemName)); // Creates the
gen button
addButton->callback((Fl_Callback*) add_cb, this ); // Creates the
gen callback
end();
spacing(s);
}
template <class T>
void Asker<T>::add_cb( Fl_Widget * button, void * a ) {
Asker<T> * asker = ( Asker<T> * ) a; // Gets the caller
Fl_Group *group = (Fl_Group *)asker->parent(); // parent = Fl_Group (!)
Fl_Scroll *scroll = (Fl_Scroll *)group->parent(); // group's parent =
Fl_Scroll (!)
T * newWidget = new T(0 , 0 , 0 ,asker->d); // Creates the new widget, only
height matters because Fl_Pack
asker->insert(*newWidget, 0); // Inserts the new Widget on top
group->size(group->w(), group->h() + asker->d + asker->s ); // Increases
the Height of the parent by the new Widget + 1 Spacing
group->init_sizes(); // THIS IS IMPORTANT
group->redraw(); // maybe not needed (?)
scroll->redraw(); // must be done
}
#endif // ASKER_H
// end of asker.h
//----------------------------------------------------------
// asker.cxx
// (MAIN.CPP)
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Scroll.H>
#include <FL/Fl_Input.H>
#include "asker.h"
int main(int argc, char **argv) {
Fl_Window *window = new Fl_Window(340,400);
Fl_Scroll *Z = new Fl_Scroll(0,0,340,400);
Fl_Box * top_box = new Fl_Box(0,0,3,3); // to keep spacing in
Fl_Scroll
top_box->color(FL_RED); top_box->box(FL_FLAT_BOX); // make it visible
(comment this out!)
Fl_Group * A = new Fl_Group(20,40,300,300,"A");
Fl_Box * rb = new Fl_Box(320-3,340-3,3,3); // resize box
rb->color(FL_BLUE); rb->box(FL_FLAT_BOX); // make it visible
(comment this out!)
A->resizable(rb); // needed to keep the other widgets in their original
sizes
Fl_Input * A1 = new Fl_Input( 30, 50, 280, 40, "A1" );
Asker<Fl_Input> * B = new Asker<Fl_Input>(30, 100, 280, 40, "TEST", 10
); // Each Input will be 40 height, spacing is 10
A->end();
A->box(FL_UP_BOX);
Z->end();
window->end();
window->resizable(window);
window->show(argc, argv);
return Fl::run();
}
// end of asker.cxx
//----------------------------------------------------------
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