Hi Everyone
Apologies if these questions are really more C++ then FLTK....
In the test folder of the source there is a program called inactive.cxx.
I will copy and past the full program at the end of the email.
There is this line:
Fl_Group *the_group=(Fl_Group *)0;
and this one:
static void cb_active(Fl_Button*, void*) {
the_group->activate();
}
The object "the_group" is also instantiated here:
the_group = new Fl_Group(25, 25, 375, 295, "activate()/deactivate()
called on this Fl_Group");
I don't fully understand what is happening here. It looks like they are
both pointers to a group that will become deactivated by the callback
initiated by clicking on another button, they look to be in different
scopes.
Is the global one a pointer to a group or all of the groups instantiated
by the Fl_Group constructor? I am really mixed up.
In my own code I tried to make one button deactivate a spinner. I tried
to create a global pointer to the one that will be deactivated:
Fl_Spinner *fc2_num_tubes=(Fl_Spinner *)0;
but I get a segmentation fault when the callback is called. Please help
me to understand what is going on in the inactive example so I can debug
my own code.
I hope it's okay to create a digest of questions? I don't want to spam
the list......
I would also like to double check that I understand what is happening here:
{ Fl_Check_Button* o = new Fl_Check_Button(50, 170, 105, 25, "red");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)1);
o->labelcolor((Fl_Color)1);
} // Fl_Check_Button* o
{ Fl_Check_Button* o = new Fl_Check_Button(50, 190, 105, 25,
"green");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)2);
o->labelcolor((Fl_Color)2);
} // Fl_Check_Button* o
By enclosing each snippet in curly braces, each instantiation is created
in it's own scope right ? and each instance can can access callbacks
defined in it's parental scope right?
Thanks for reading-Patrick
-----------------------------------------------------------------------------------------------------------------------------------
// generated by Fast Light User Interface Designer (fluid) version 1.0300
#include "inactive.h"
Fl_Group *the_group=(Fl_Group *)0;
Fl_Menu_Item menu_menu[] = {
{"item", 0, 0, 0, 0, FL_NORMAL_LABEL, 0, 14, 0},
{"item", 0, 0, 0, 0, FL_NORMAL_LABEL, 0, 14, 0},
{"item", 0, 0, 0, 0, FL_NORMAL_LABEL, 0, 14, 0},
{"item", 0, 0, 0, 0, FL_NORMAL_LABEL, 0, 14, 0},
{"item", 0, 0, 0, 0, FL_NORMAL_LABEL, 0, 14, 0},
{0,0,0,0,0,0,0,0,0}
};
static void cb_active(Fl_Button*, void*) {
the_group->activate();
}
static void cb_inactive(Fl_Button*, void*) {
the_group->deactivate();
}
int main(int argc, char **argv) {
Fl_Double_Window* w;
{ Fl_Double_Window* o = new Fl_Double_Window(420, 369);
w = o;
{ the_group = new Fl_Group(25, 25, 375, 295,
"activate()/deactivate() called on this Fl_Group");
the_group->box(FL_ENGRAVED_FRAME);
the_group->align(Fl_Align(FL_ALIGN_TOP|FL_ALIGN_INSIDE));
{ new Fl_Button(50, 50, 105, 25, "button");
} // Fl_Button* o
{ Fl_Light_Button* o = new Fl_Light_Button(50, 80, 105, 25,
"light button");
o->value(1);
o->align(Fl_Align(FL_ALIGN_CENTER|FL_ALIGN_INSIDE));
} // Fl_Light_Button* o
{ Fl_Group* o = new Fl_Group(50, 130, 105, 125, "Child group");
o->box(FL_DOWN_FRAME);
{ Fl_Check_Button* o = new Fl_Check_Button(50, 170, 105, 25,
"red");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)1);
o->labelcolor((Fl_Color)1);
} // Fl_Check_Button* o
{ Fl_Check_Button* o = new Fl_Check_Button(50, 190, 105, 25,
"green");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)2);
o->labelcolor((Fl_Color)2);
} // Fl_Check_Button* o
{ Fl_Check_Button* o = new Fl_Check_Button(50, 210, 105, 25,
"blue");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)4);
o->labelcolor((Fl_Color)4);
} // Fl_Check_Button* o
{ Fl_Check_Button* o = new Fl_Check_Button(50, 230, 105, 25,
"white");
o->type(102);
o->down_box(FL_DIAMOND_DOWN_BOX);
o->selection_color((Fl_Color)55);
o->labelcolor((Fl_Color)55);
} // Fl_Check_Button* o
{ Fl_Check_Button* o = new Fl_Check_Button(50, 130, 105, 25,
"check");
o->down_box(FL_DOWN_BOX);
} // Fl_Check_Button* o
{ Fl_Round_Button* o = new Fl_Round_Button(50, 150, 105, 25,
"round");
o->down_box(FL_ROUND_DOWN_BOX);
} // Fl_Round_Button* o
o->end();
} // Fl_Group* o
{ Fl_Slider* o = new Fl_Slider(165, 50, 24, 205, "Fl_Slider");
o->value(0.5);
} // Fl_Slider* o
{ Fl_Input* o = new Fl_Input(195, 50, 195, 30);
o->static_value("Fl_Input");
} // Fl_Input* o
{ Fl_Menu_Button* o = new Fl_Menu_Button(245, 90, 130, 30, "menu");
o->menu(menu_menu);
} // Fl_Menu_Button* o
{ Fl_Value_Output* o = new Fl_Value_Output(245, 130, 130, 30,
"value:");
o->maximum(10000);
o->step(1);
o->textfont(5);
o->textsize(24);
o->textcolor((Fl_Color)4);
} // Fl_Value_Output* o
{ Fl_Box* o = new Fl_Box(245, 170, 140, 50, "Fl_Box");
o->box(FL_EMBOSSED_FRAME);
o->labeltype(FL_SHADOW_LABEL);
o->labelfont(3);
o->labelsize(38);
} // Fl_Box* o
{ Fl_Scrollbar* o = new Fl_Scrollbar(40, 274, 180, 20, "scrollbar");
o->type(1);
} // Fl_Scrollbar* o
{ new Fl_Roller(235, 230, 25, 65, "roller");
} // Fl_Roller* o
{ new Fl_Dial(275, 235, 50, 50, "dial");
} // Fl_Dial* o
{ new Fl_Clock(335, 235, 50, 50, "clock");
} // Fl_Clock* o
the_group->end();
Fl_Group::current()->resizable(the_group);
} // Fl_Group* the_group
{ Fl_Button* o = new Fl_Button(25, 330, 185, 25, "active");
o->type(102);
o->value(1);
o->callback((Fl_Callback*)cb_active);
} // Fl_Button* o
{ Fl_Button* o = new Fl_Button(220, 330, 180, 25, "inactive");
o->type(102);
o->callback((Fl_Callback*)cb_inactive);
} // Fl_Button* o
o->end();
} // Fl_Double_Window* o
w->show(argc, argv);
return Fl::run();
}
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