fltk/documentation/Fl_Scrollbar.html
Michael R Sweet 09daf20b81 Documentation updates galore (up to chapter 7, still need to do chapter
8 and 9, tweek the appendices, and recapture the screenshots...)


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2001-11-29 19:24:00 +00:00

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<HTML><BODY>
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<H2><A name=Fl_Scrollbar>class Fl_Scrollbar</A></H2>
<HR>
<H3>Class Hierarchy</H3>
<UL>
<PRE>
<A href=Fl_Slider.html#Fl_Slider>Fl_Slider</A>
|
+----<B>Fl_Scrollbar</B>
</PRE>
</UL>
<H3>Include Files</H3>
<UL>
<PRE>
#include &lt;FL/Fl_Scrollbar.H&gt;
</PRE>
</UL>
<H3>Description</H3>
The <TT>Fl_Scrollbar</TT> widget displays a slider with arrow buttons
at the ends of the scrollbar. Clicking on the arrows move up/left and
down/right by <TT>linesize()</TT>. Scrollbars also accept <TT>
FL_SHORTCUT</TT> events: the arrows move by <TT>linesize()</TT>, and
vertical scrollbars take Page Up/Down (they move by the page size minus <TT>
linesize()</TT>) and Home/End (they jump to the top or bottom).
<P>Scrollbars have <TT>step(1)</TT> preset (they always return
integers). If desired you can set the <TT>step()</TT> to non-integer
values. You will then have to use casts to get at the floating-point
versions of <TT>value()</TT> from <TT>Fl_Slider</TT>. </P>
<P ALIGN=CENTER><IMG src="scrollbar.gif" ALT="Fl_Scrollbar widget."></P>
<H3>Methods</H3>
<UL>
<LI><A href=#Fl_Scrollbar.Fl_Scrollbar>Fl_Scrollbar</A></LI>
<LI><A href=#Fl_Scrollbar.~Fl_Scrollbar>~Fl_Scrollbar</A></LI>
<LI><A href=#Fl_Scrollbar.linesize>linesize</A></LI>
<LI><A href=#Fl_Scrollbar.value>value</A></LI>
</UL>
<H4><A name=Fl_Scrollbar.Fl_Scrollbar>Fl_Scrollbar::Fl_Scrollbar(int x,
int y, int w, int h, const char *label = 0)</A></H4>
Creates a new <TT>Fl_Scrollbar</TT> widget using the given position,
size, and label string. You need to do <TT>type(FL_HORIZONTAL)</TT> if
you want a horizontal scrollbar.
<H4><A name=Fl_Scrollbar.~Fl_Scrollbar>virtual
Fl_Scrollbar::~Fl_Scrollbar()</A></H4>
Destroys the valuator.
<H4><A name=Fl_Scrollbar.linesize>int Fl_Scrollbar::linesize() const
<BR> void Fl_Scrollbar::linesize(int i)</A></H4>
This number controls how big the steps are that the arrow keys do. In
addition page up/down move by the size last sent to <TT>value()</TT>
minus one <TT>linesize()</TT>. The default is 16.
<H4><A name=Fl_Scrollbar.value>int Fl_Scrollbar::value()
<BR> int Fl_Scrollbar::value(int position, int size, int top, int total)</A>
</H4>
The first form returns the integer value of the scrollbar. You can get
the floating point value with <TT>Fl_Slider::value()</TT>. The second
form sets <TT>value()</TT>, <TT>range()</TT>, and <TT>slider_size()</TT>
to make a variable-sized scrollbar. You should call this every time
your window changes size, your data changes size, or your scroll
position changes (even if in response to a callback from this
scrollbar). All necessary calls to <TT>redraw()</TT> are done. </BODY></HTML>