Ian MacArthur wrote:
> Following Ivano's query, I thought I'd put together a simple demo of changing
> the slider widget colour in response to focus changing.
>
> Using 1.1.9, this turned out to be trickier than I had initially expected: my
> sub-classed Fl_Slider widget doesn't receive FL_FOCUS events for mouse
> clicks, so I had to handle that event via the callback method, but with the
> callback when() set to FL_WHEN_RELEASE_ALWAYS - which I actually knew, in
> retrospect, as I've done this before... Oh well, worked example below, in
> case anyone finds it useful!
The solution without using your special callback is to use take_focus()
in the FL_PUSH event handling. Fl_Slider doesn't do this, and I'm not
sure if this is a bug or not ....
See attached modified version. This one also has 2 horizontal sliders
added. Note that they use left/right arrows for keyboard modification.
Albrecht
// demo of handling enter/leave events for sliders
// fltk-config --compile slider-focus.cxx
#include <FL/Fl.H>
#include <FL/Fl_Double_Window.H>
#include <FL/Fl_Slider.H>
#include <FL/Fl_Button.H>
static Fl_Double_Window *main_win=(Fl_Double_Window *)0;
static Fl_Button *exit_bt=(Fl_Button *)0;
class mod_slider : public Fl_Slider {
public:
mod_slider(int X, int Y, int W, int H, const char *L) :
Fl_Slider(X,Y,W,H,L){};
int handle(int ev);
};
int mod_slider::handle(int ev) {
int res = Fl_Slider::handle(ev);
switch(ev){
case FL_FOCUS:
selection_color(FL_YELLOW);
break;
case FL_UNFOCUS:
selection_color(FL_BLUE);
break;
case FL_PUSH: // <<<--- added !
take_focus();
break;
default:
break;
}
return res;
} // handle
static mod_slider *slider1=(mod_slider *)0;
static mod_slider *slider2=(mod_slider *)0;
static mod_slider *slider3=(mod_slider *)0;
static mod_slider *slider4=(mod_slider *)0;
static mod_slider *slider5=(mod_slider *)0;
static mod_slider *slider6=(mod_slider *)0;
/* we don't need this, use take_focus() instead (see above)
static void cb_slider(mod_slider *w, void*) {
w->selection_color(FL_YELLOW);
w->redraw();
}
*/
static void cb_exit_bt(Fl_Button*, void*) {
main_win->hide();
}
int main(int argc, char **argv) {
main_win = new Fl_Double_Window(600, 440, "Slider Test Window");
main_win->begin();
slider1 = new mod_slider(25, 24, 48, 251, "Chan 1");
slider1->type(4);
slider1->selection_color(FL_BLUE);
// slider1->callback((Fl_Callback*)cb_slider);
// slider1->when(FL_WHEN_RELEASE_ALWAYS);
slider2 = new mod_slider(151, 24, 48, 251, "Chan 2");
slider2->type(4);
slider2->selection_color(FL_BLUE);
// slider2->callback((Fl_Callback*)cb_slider);
// slider2->when(FL_WHEN_RELEASE_ALWAYS);
slider3 = new mod_slider(278, 24, 48, 251, "Chan 3");
slider3->type(4);
slider3->selection_color(FL_BLUE);
// slider3->callback((Fl_Callback*)cb_slider);
// slider3->when(FL_WHEN_RELEASE_ALWAYS);
slider4 = new mod_slider(405, 24, 48, 251, "Chan 4");
slider4->type(4);
slider4->selection_color(FL_BLUE);
// slider4->callback((Fl_Callback*)cb_slider);
// slider4->when(FL_WHEN_RELEASE_ALWAYS);
slider5 = new mod_slider(75,305,251, 48, "Chan 5 ");
slider5->align(FL_ALIGN_LEFT);
slider5->type(FL_HOR_NICE_SLIDER);
slider5->selection_color(FL_BLUE);
slider6 = new mod_slider(75,365,251, 48, "Chan 6 ");
slider6->align(FL_ALIGN_LEFT);
slider6->type(FL_HOR_NICE_SLIDER);
slider6->selection_color(FL_BLUE);
exit_bt = new Fl_Button(500, 256, 70, 29, "Exit");
exit_bt->box(FL_THIN_UP_BOX);
exit_bt->callback((Fl_Callback*)cb_exit_bt);
main_win->end();
main_win->show(argc, argv);
return Fl::run();
} // main
/* end of file */
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