311 lines
16 KiB
HTML
311 lines
16 KiB
HTML
<HTML><BODY>
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<HR break>
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<H2><A name=Fl_Widget>class Fl_Widget</A></H2>
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<HR>
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<H3>Class Hierarchy</H3>
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<UL>
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<PRE>
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<B>Fl_Widget</B>
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+----<A href=Fl_Box.html#Fl_Box>Fl_Box</A>, <A href=Fl_Browser_.html#Fl_Browser_>Fl_Browser_</A>, <A href=Fl_Button.html#Fl_Button>Fl_Button</A>, <A href=Fl_Chart.html#Fl_Chart>Fl_Chart</A>, <A href=Fl_Clock.html#Fl_Clock>Fl_Clock</A>,
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<A href=Fl_Free.html#Fl_Free>Fl_Free</A>, <A href=Fl_Group.html#Fl_Group>Fl_Group</A>, <A href=Fl_Input_.html#Fl_Input_>Fl_Input_</A>, <A href=Fl_Menu_.html#Fl_Menu_>Fl_Menu_</A>, <A href=Fl_Positioner.html#Fl_Positioner>Fl_Positioner</A>,
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<A href=Fl_Timer.html#Fl_Timer>Fl_Timer</A>, <A href=Fl_Valuator.html#Fl_Valuator>Fl_Valuator</A>
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</PRE>
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</UL>
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<H3>Include Files</H3>
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<UL>
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<PRE>
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#include <FL/Fl_Widget.H>
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</PRE>
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</UL>
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<H3>Description</H3>
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<TT>Fl_Widget</TT> is the base class for all widgets in FLTK. You can't
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create one of these because the constructor is not public. However you
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can <A href="#subclassing">subclass</A> it.
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<P>All "property" accessing methods, such as <TT>color()</TT>, <TT>
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parent()</TT>, or <TT>argument()</TT> are implemented as trivial inline
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functions and thus are as fast and small as accessing fields in a
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structure. Unless otherwise noted, the property setting methods such as <TT>
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color(n)</TT> or <TT>label(s)</TT> are also trivial inline functions,
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even if they change the widget's appearance. It is up to the user code
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to call <TT>redraw()</TT> after these. </P>
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<H3>Methods</H3>
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<CENTER>
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<TABLE width=90%>
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<TR><TD align=left valign=top>
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<UL>
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<LI><A href=#Fl_Widget.Fl_Widget>Fl_Widget</A></LI>
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<LI><A href=#Fl_Widget.~Fl_Widget>~Fl_Widget</A></LI>
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<LI><A href=#Fl_Widget.activate>activate</A></LI>
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<LI><A href=#Fl_Widget.active>active</A></LI>
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<LI><A href=#Fl_Widget.active_r>active_r</A></LI>
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<LI><A href=#Fl_Widget.align>align</A></LI>
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<LI><A href=#Fl_Widget.argument>argument</A></LI>
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<LI><A href=#Fl_Widget.box>box</A></LI>
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<LI><A href=#Fl_Widget.callback>callback</A></LI>
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</UL>
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</TD><TD align=left valign=top>
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<UL>
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<LI><A href=#Fl_Widget.changed>changed</A></LI>
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<LI><A href=#Fl_Widget.clear_changed>clear_changed</A></LI>
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<LI><A href=#Fl_Widget.color>color</A></LI>
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<LI><A href=#Fl_Widget.contains>contains</A></LI>
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<LI><A href=#Fl_Widget.damage>damage</A></LI>
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<LI><A href=#Fl_Widget.deactivate>deactivate</A></LI>
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<LI><A href=#Fl_Widget.default_callback>default_callback</A></LI>
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<LI><A href=#Fl_Widget.do_callback>do_callback</A></LI>
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<LI><A href=#Fl_Widget.h>h</A></LI>
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</UL>
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</TD><TD align=left valign=top>
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<UL>
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<LI><A href=#Fl_Widget.hide>hide</A></LI>
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<LI><A href=#Fl_Widget.inside>inside</A></LI>
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<LI><A href=#Fl_Widget.label>label</A></LI>
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<LI><A href=#Fl_Widget.labelcolor>labelcolor</A></LI>
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<LI><A href=#Fl_Widget.labelfont>labelfont</A></LI>
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<LI><A href=#Fl_Widget.labelsize>labelsize</A></LI>
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<LI><A href=#Fl_Widget.labeltype>labeltype</A></LI>
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<LI><A href=#Fl_Widget.output>output</A></LI>
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<LI><A href=#Fl_Widget.parent>parent</A></LI>
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</UL>
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</TD><TD align=left valign=top>
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<UL>
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<LI><A href=#Fl_Widget.position>position</A></LI>
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<LI><A href=#Fl_Widget.redraw>redraw</A></LI>
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<LI><A href=#Fl_Widget.resize>resize</A></LI>
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<LI><A href=#Fl_Widget.selection_color>selection_color</A></LI>
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<LI><A href=#Fl_Widget.set_changed>set_changed</A></LI>
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<LI><A href=#Fl_Widget.show>show</A></LI>
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<LI><A href=#Fl_Widget.size>size</A></LI>
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<LI><A href=#Fl_Widget.take_focus>take_focus</A></LI>
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<LI><A href=#Fl_Widget.takesevents>takesevents</A></LI>
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</UL>
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</TD><TD align=left valign=top>
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<UL>
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<LI><A href=#Fl_Widget.type>type</A></LI>
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<LI><A href=#Fl_Widget.user_data>user_data</A></LI>
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<LI><A href=#Fl_Widget.visible>visible</A></LI>
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<LI><A href=#Fl_Widget.visible_r>visible_r</A></LI>
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<LI><A href=#Fl_Widget.w>w</A></LI>
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<LI><A href=#Fl_Widget.when>when</A></LI>
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<LI><A href=#Fl_Widget.window>window</A></LI>
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<LI><A href=#Fl_Widget.x>x</A></LI>
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<LI><A href=#Fl_Widget.y>y</A></LI>
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</UL>
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</TD></TR>
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</TABLE>
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</CENTER>
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<H4>Fl_Widget::Fl_Widget(int x, int y, int w, int h, const char*
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label=0);</H4>
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This is the protected constructor for an Fl_Widget, but all derived
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widgets have a matching public constructor. It takes a value for x(),
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y(), w(), h(), and an optional value for label().
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<H4>virtual Fl_Widget::~Fl_Widget();</H4>
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Destroying single widgets is not very common. It is your
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responsibility to either remove() them from any enclosing group, or to
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destroy that group <I>immediately</I> after destroying the children.
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<H4>uchar Fl_Widget::type() const;</H4>
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This value is used for Forms compatability and to simulate RTTI.
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<H4><A name=Fl_Widget.x>short Fl_Widget::x() const</A>
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<BR><A name=Fl_Widget.y>short Fl_Widget::y() const</A>
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<BR><A name=Fl_Widget.w>short Fl_Widget::w() const</A>
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<BR><A name=Fl_Widget.h>short Fl_Widget::h() const</A></H4>
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The position of the upper-left corner of the widget in its enclosing
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Fl_Window (<I>not</I> its parent if that is not an Fl_Window), and its
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width and height.
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<H4><A name=Fl_Widget.resize>virtual void
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Fl_Widget::resize(int x, int y, int w, int h)</A>
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<BR><A name=Fl_Widget.position>void Fl_Widget::position(short x, short y)</A>
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<BR><A name=Fl_Widget.size>void Fl_Widget::size(short w, short h)</A></H4>
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Change the size or position of the widget. This is a virtual function
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so the widget may implement its own handling of resizing. The default
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version does <I>not</I> do redraw(), that is the parent widget's
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responsibility (this is because the parent may know a faster way to
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update the display, such as scrolling from the old position).
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<P><TT>position(x,y)</TT> is a shortcut for <TT>resize(x,y,w(),h())</TT>
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, and <TT>size(w,h)</TT> is a shortcut for <TT>resize(x(),y(),w,h)</TT>
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. </P>
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<H4><A name=Fl_Widget.window>Fl_Window* Fl_Widget::window() const;</A></H4>
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Return a pointer to the <A href=Fl_Window.html#Fl_Window><TT>Fl_Window</TT>
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</A> that this widget is in (it will skip any and all parent widgets
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between this and the window). Returns <TT>NULL</TT> if none. Note:
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for an <TT>Fl_Window</TT>, this returns its <I>parent</I> window (if
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any), not <I>this</I> window.
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<H4><A name=Fl_Widget.box>Fl_Boxtype Fl_Widget::box() const
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<BR> void Fl_Widget::box(Fl_Boxtype)</A></H4>
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The <TT>box()</TT> identifies a routine that draws the background of
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the widget. See <A href=common.html#BoxTypes>Box Types</A> for the
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available types. The default depends on the widget, but is usually <TT>
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FL_NO_BOX</TT> or <TT>FL_UP_BOX</TT>.
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<H4><A name=Fl_Widget.color>Fl_Color Fl_Widget::color() const
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<BR> void Fl_Widget::color(Fl_Color)</A></H4>
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This color is passed to the box routine. Color is an index into an
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internal table of rgb colors. For most widgets this defaults to <TT>
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FL_GRAY</TT>. See the <A href=enumerations.html#Enumerations>
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enumeration list</A> for predefined colors. Use <A href=functions.html#set_color>
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<TT>Fl::set_color()</TT></A> to redefine colors.
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<H4><A name=Fl_Widget.selection_color>Fl_Color
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Fl_Widget::selection_color() const
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<BR> void Fl_Widget::selection_color(Fl_Color)</A>
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<BR> void Fl_Widget::color(Fl_Color, Fl_Color)</H4>
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For Forms compatibility a second color is defined. This is usually
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used to color the widget when it is selected, although some widgets use
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this color for other purposes. You can set both colors at once with <TT>
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color(a,b)</TT>.
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<H4><A name=Fl_Widget.label>const char* Fl_Widget::label() const
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<BR> void Fl_Widget::label(const char*)</A></H4>
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The label is printed somewhere on the widget or next to it. The
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string is <I>not</I> copied, the passed pointer is stored unchanged in
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the widget.
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<H4><A name=Fl_Widget.labeltype>void Fl_Widget::label(Fl_Labeltype,
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const char*)
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<BR> uchar Fl_Widget::labeltype() const
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<BR> void Fl_Widget::labeltype(Fl_Labeltype)</A></H4>
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A <A href=#LabelTypes><TT>labeltype</TT></A> identifies a routine that
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draws the label of the widget. This can be used for special effects
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such as emboss, or to use the <TT>label()</TT> pointer as another form
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of data such as a bitmap. The value <TT>FL_NORMAL_LABEL</TT> prints
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the label as text.
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<H4><A name=Fl_Widget.align>Fl_Align Fl_Widget::align() const
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<BR> void Fl_Widget::align(Fl_Align)</A></H4>
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How the label is printed next to or inside the widget. The default
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value is <TT>FL_ALIGN_CENTER</TT>, which centers the label. The value
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can be any of these constants or'd together:
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<UL>
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<LI><TT>FL_ALIGN_CENTER</TT></LI>
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<LI><TT>FL_ALIGN_TOP</TT></LI>
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<LI><TT>FL_ALIGN_BOTTOM</TT></LI>
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<LI><TT>FL_ALIGN_LEFT</TT></LI>
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<LI><TT>FL_ALIGN_RIGHT</TT></LI>
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<LI><TT>FL_ALIGN_INSIDE</TT></LI>
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<LI><TT>FL_ALIGN_CLIP</TT></LI>
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<LI><TT>FL_ALIGN_WRAP</TT></LI>
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</UL>
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<H4><A name=Fl_Widget.labelcolor>Fl_Color Fl_Widget::labelcolor() const
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<BR> void Fl_Widget::labelcolor(Fl_Color)</A></H4>
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This color is passed to the labeltype routine, and is typically the
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color of the label text. This defaults to <TT>FL_BLACK</TT>.
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<H4><A name=Fl_Widget.labelfont>Fl_Font Fl_Widget::labelfont() const
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<BR> void Fl_Widget::labelfont(Fl_Font)</A></H4>
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Fonts are identified by small 8-bit indexes into a table. See the <A href=enumerations.html#Enumerations>
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enumeration list</A> for predefined typefaces. The default value uses a
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Helvetica typeface (Arial for Microsoft® Windows®). The function <A href=functions.html#set_font>
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<TT>Fl::set_font() </TT></A> can define new typefaces.
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<H4><A name=Fl_Widget.labelsize>uchar Fl_Widget::labelsize() const
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<BR> void Fl_Widget::labelsize(uchar)</A></H4>
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Fonts are further identified by a point size. The default is 14.
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<H4><A name=Fl_Widget.callback>typedef void (Fl_Callback)(Fl_Widget*,
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void*)
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<BR> Fl_Callback* Fl_Widget::callback() const
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<BR> void Fl_Widget::callback(Fl_Callback*, void* = 0)</A></H4>
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Each widget has a single callback. You can set it or examine it with
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these methods.
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<H4><A name=Fl_Widget.user_data>void* Fl_Widget::user_data() const
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<BR> void Fl_Widget::user_data(void*)</A></H4>
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You can also just change the <TT>void *</TT> second argument to the
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callback with the <TT>user_data</TT> methods.
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<H4><A name=Fl_Widget.argument>void Fl_Widget::callback(void
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(*)(Fl_Widget*, long), long = 0)
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<BR> long Fl_Widget::argument() const
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<BR> void Fl_Widget::argument(long)</A></H4>
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For convenience you can also define the callback as taking a long
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argument. This is implemented by casting this to a <TT>Fl_Callback</TT>
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and casting the <TT>long</TT> to a <TT>void *</TT> and may not be
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portable to some machines.
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<H4>void Fl_Widget::callback(void (*)(Fl_Widget*))</H4>
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For convenience you can also define the callback as taking only one
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argument. This is implemented by casting this to a <TT>Fl_Callback</TT>
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and may not be portable to some machines.
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<H4><A name=Fl_Widget.do_callback>void Fl_Widget::do_callback()
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<BR> void Fl_Widget::do_callback(Fl_Widget*, void* = 0)
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<BR> void Fl_Widget::do_callback(Fl_Widget*, long)</A></H4>
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You can cause a widget to do its callback at any time, and even pass
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arbitrary arguments.
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<H4><A name=Fl_Widget.changed>int Fl_Widget::changed() const</A>
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<BR><A name=Fl_Widget.set_changed>void Fl_Widget::set_changed()</A>
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<BR><A name=Fl_Widget.clear_changed>void Fl_Widget::clear_changed()</A></H4>
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<TT>Fl_Widget::changed()</TT> is a flag that is turned on when the user
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changes the value stored in the widget. This is only used by
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subclasses of <TT>Fl_Widget</TT> that store values, but is in the base
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class so it is easier to scan all the widgets in a panel and <TT>
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do_callback()</TT> on the changed ones in response to an "OK" button.
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<P>Most widgets turn this flag off when they do the callback, and when
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the program sets the stored value. </P>
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<H4><A name=Fl_Widget.when>Fl_When Fl_Widget::when() const
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<BR> void Fl_Widget::when(Fl_When)</A></H4>
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<TT>Fl_Widget::when()</TT> is a set of bitflags used by subclasses of <TT>
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Fl_Widget</TT> to decide when to do the callback. If the value is zero
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then the callback is never done. Other values are described in the
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individual widgets. This field is in the base class so that you can
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scan a panel and <TT>do_callback()</TT> on all the ones that don't do
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their own callbacks in response to an "OK" button.
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<H4><A name=Fl_Widget.default_callback>static void
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Fl_Widget::default_callback(Fl_Widget*, void*)</A></H4>
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The default callback, which puts a pointer to the widget on the queue
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returned by <A href=functions.html#readqueue><TT>Fl::readqueue()</TT></A>
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. You may want to call this from your own callback.
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<H4><A name=Fl_Widget.visible>int Fl_Widget::visible() const</A><BR>
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<A name=Fl_Widget.visible_r>int Fl_Widget::visible_r() const</A><BR>
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<A name=Fl_Widget.show>void Fl_Widget::show()</A><BR>
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<A name=Fl_Widget.hide>void Fl_Widget::hide()</A></H4>
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An invisible widget never gets redrawn and does not get events. The
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<TT>visible()</TT> method returns true if the widget is set to be
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visible.The <TT>visible_r()</TT> method returns true if the widget and
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all of its parents are visible. A widget is only visible if
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<TT>visible()</TT> is true on it <I>and all of its parents</I>.
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<P>Changing it will send <TT>FL_SHOW</TT> or <TT>FL_HIDE</TT>
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events to the widget. <I>Do not change it if the parent is not
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visible, as this will send false <TT>FL_SHOW</TT> or <TT>FL_HIDE</TT>
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events to the widget</I>. <TT>redraw()</TT> is called if necessary on
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this or the parent.
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<H4><A name=Fl_Widget.active>int Fl_Widget::active() const</A><BR>
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<A name=Fl_Widget.active_r>int Fl_Widget::active_r() const</A></BR>
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<A name=Fl_Widget.activate>void Fl_Widget::activate()</A></BR>
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<A name=Fl_Widget.deactivate>void Fl_Widget::deactivate()</A></H4>
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<TT>Fl_Widget::active()</TT> returns whether the widget is active.
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<TT>Fl_Widget::active_r()</TT> returns whether the widget and all of
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its parents are active. An inactive widget does not get any events,
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but it does get redrawn. A widget is only active if <TT>active()</TT> is
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true on it <I>and all of its parents</I>.
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<P>Changing this value will send <TT>FL_ACTIVATE</TT> or <TT>
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FL_DEACTIVATE</TT> to the widget if <tt>active_r()</tt> is true.
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<P>Currently you cannot deactivate <TT>Fl_Window</TT> widgets. </P>
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<H4><A name=Fl_Widget.output>int Fl_Widget::output() const</A><BR>
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<A name=Fl_Widget.set_output>void Fl_Widget::set_output()</A></BR>
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<A name=Fl_Widget.clear_output>void Fl_Widget::clear_output()</A></H4>
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<tt>output()</tt> means the same as <tt>!active()</tt> except it does
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not change how the widget is drawn. The widget will not recieve any
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events. This is useful for making scrollbars or buttons that work as
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displays rather than input devices.
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<H4><A name=Fl_Widget.takesevents>int Fl_Widget::takesevents() const</A>
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</H4>
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This is the same as <TT>(active() && visible() &&
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!output())</TT> but is faster.
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<H4><A name=Fl_Widget.redraw>void Fl_Widget::redraw()</A></H4>
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Mark the widget as needing its <TT>draw()</TT> routine called.
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<H4><A name=Fl_Widget.damage>uchar Fl_Widget::damage() const</A></H4>
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Non-zero if <TT>draw()</TT> needs to be called. Actually this is a
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bit field that the widget subclass can use to figure out what parts to
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draw.
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<H4><A name=Fl_Widget.parent>Fl_Widget *Fl_Widget::parent() const</A></H4>
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Returns a pointer to the parent widget. Usually this is a <A
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href=Fl_Group.html#Fl_Group> <TT>Fl_Group</TT></A> or <A
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HREF="Fl_Window.html#Fl_Window"><tt>Fl_Window</tt></a>. Returns
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<tt>NULL</tt> if none.
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<h4><a name="Fl_Widget.contains">int Fl_Widget::contains(Fl_Widget* b) const</A></H4>
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Returns true if <TT>b</TT> is a child of this widget, or is equal to
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this widget. Returns false if <TT>b</TT> is <TT>NULL</TT>.
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<H4><A name=Fl_Widget.inside>int Fl_Widget::inside(const Fl_Widget* a)
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const</A></H4>
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Returns true if this is a child of <TT>a</TT>, or is equal to <TT>a</TT>
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. Returns false if <TT>a</TT> is <TT>NULL</TT>.
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<H4><A name=Fl_Widget.take_focus>int Fl_Widget::take_focus()</A></H4>
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Tries to make this widget be the <TT>Fl::focus()</TT> widget, by first
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sending it an <TT>FL_FOCUS</TT> event, and if it returns non-zero,
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setting <TT>Fl::focus()</TT> to this widget. You should use this
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method to assign the focus to an widget. Returns true if the widget
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accepted the focus. </BODY></HTML>
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