mirror of https://github.com/fltk/fltk
124 lines
4.0 KiB
C++
124 lines
4.0 KiB
C++
//
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// Choice header file for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2010 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// https://www.fltk.org/COPYING.php
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//
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// Please see the following page on how to report bugs and issues:
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//
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// https://www.fltk.org/bugs.php
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//
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/* \file
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Fl_Choice widget . */
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#ifndef Fl_Choice_H
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#define Fl_Choice_H
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#include "Fl_Menu_.H"
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/**
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\class Fl_Choice
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\brief A button that is used to pop up a menu.
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\image html choice.png
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\image latex choice.png "Fl_Choice" width=4cm
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This is a button that, when pushed, pops up a menu (or hierarchy of menus)
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defined by an array of Fl_Menu_Item objects.
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Motif calls this an OptionButton.
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The only difference between this and a Fl_Menu_Button is that the name of
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the most recent chosen menu item is displayed inside the box, while the
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label is displayed outside the box. However, since the use of this is most
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often to control a single variable rather than do individual callbacks,
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some of the Fl_Menu_Button methods are redescribed here in those terms.
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When the user clicks a menu item, value() is set to that item
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and then:
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- The item's callback is done if one has been set; the
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Fl_Choice is passed as the Fl_Widget* argument,
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along with any userdata configured for the callback.
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- If the item does not have a callback, the Fl_Choice widget's
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callback is done instead, along with any userdata configured
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for it. The callback can determine which item was picked using
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value(), mvalue(), item_pathname(), etc.
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All three mouse buttons pop up the menu. The Forms behavior of the first
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two buttons to increment/decrement the choice is not implemented. This
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could be added with a subclass, however.
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The menu will also pop up in response to shortcuts indicated by putting
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a '\&' character in the label(). See Fl_Button::shortcut(int s) for a
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description of this.
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Typing the shortcut() of any of the items will do exactly the same as when
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you pick the item with the mouse. The '\&' character in item names are
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only looked at when the menu is popped up, however.
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The inherited Fl_Widget::changed() and related methods can be used as follows:
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\li <tt>int Fl_Widget::changed() const</tt>
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This value is true when the user picks a different value. <em>It is turned
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off by value() and just before doing a callback (the callback can turn
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it back on if desired).</em>
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\li <tt>void Fl_Widget::set_changed()</tt>
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This method sets the changed() flag.
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\li <tt>void Fl_Widget::clear_changed()</tt>
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This method clears the changed() flag.
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The inherited Fl_Menu_::down_box() methods can be used as follows:
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\li <tt>Fl_Boxtype Fl_Menu_::down_box() const</tt>
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Gets the current down box, which is used when the menu is popped up.
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The default down box type is \c FL_DOWN_BOX.
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\li <tt>void Fl_Menu_::down_box(Fl_Boxtype b)</tt>
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Sets the current down box type to \p b.
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Simple example:
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\par
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\code
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#include <FL/Fl.H>
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#include <FL/Fl_Window.H>
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#include <FL/Fl_Choice.H>
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int main() {
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Fl_Window *win = new Fl_Window(300,200);
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Fl_Choice *choice = new Fl_Choice(100,10,100,25,"Choice:");
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choice->add("Zero");
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choice->add("One");
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choice->add("Two");
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choice->add("Three");
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choice->value(2); // make "Two" selected by default (zero based!)
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win->end();
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win->show();
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return Fl::run();
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}
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\endcode
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*/
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class FL_EXPORT Fl_Choice : public Fl_Menu_ {
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protected:
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void draw() FL_OVERRIDE;
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public:
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int handle(int) FL_OVERRIDE;
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Fl_Choice(int X, int Y, int W, int H, const char *L = 0);
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/**
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Gets the index of the last item chosen by the user.
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The index is -1 initially.
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*/
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int value() const {return Fl_Menu_::value();}
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int value(int v);
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int value(const Fl_Menu_Item* v);
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};
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#endif
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