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authormarha <marha@users.sourceforge.net>2011-03-25 10:41:05 +0000
committermarha <marha@users.sourceforge.net>2011-03-25 10:41:05 +0000
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xserver fontconfig glproto libXau libXft libXmu libfontenc libxcb mesa mkfontscale pixman randrproto xkeyboard-config xtrans xwininfo updated following packages: xproto-7.0.21 xineramaproto-1.2.1 libXt-1.1.1 libxkbfile-1.0.7 libXpm-3.5.9 libXfont-1.4.3 libXaw-1.0.9 bdftopcf-1.0.3 encodings-1.0.4 fixesproto-5.0 font-adobe-100dpi-1.0.3 font-adobe-75dpi-1.0.3 font-adobe-utopia-100dpi-1.0.4 font-adobe-utopia-75dpi-1.0.4 font-adobe-utopia-type1-1.0.4 font-alias-1.0.3 font-arabic-misc-1.0.3 font-bh-100dpi-1.0.3 font-bh-75dpi-1.0.3 font-bh-lucidatypewriter-100dpi-1.0.3 font-bh-lucidatypewriter-75dpi-1.0.3 font-bh-ttf-1.0.3 font-bh-type1-1.0.3 font-bitstream-100dpi-1.0.3 font-bitstream-75dpi-1.0.3 font-bitstream-speedo-1.0.2 font-bitstream-type1-1.0.3 font-cronyx-cyrillic-1.0.3 font-cursor-misc-1.0.3 font-daewoo-misc-1.0.3 font-dec-misc-1.0.3 font-ibm-type1-1.0.3 font-isas-misc-1.0.3 font-jis-misc-1.0.3 font-micro-misc-1.0.3 font-misc-cyrillic-1.0.3 font-misc-ethiopic-1.0.3 font-misc-meltho-1.0.3 font-misc-misc-1.1.2 font-mutt-misc-1.0.3 font-schumacher-misc-1.1.2 font-screen-cyrillic-1.0.4 font-sony-misc-1.0.3 font-sun-misc-1.0.3 font-util-1.2.0 font-winitzki-cyrillic-1.0.3 font-xfree86-type1-1.0.4
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+<sect1 id="Scrollbar_Widget">
+<title>Scrollbar Widget</title>
+
+<literallayout class="monospaced">
+Application header file &lt;X11/Xaw/Scrollbar.h&gt;
+Class header file &lt;X11/Xaw/ScrollbarP.h&gt;
+Class scrollbarWidgetClass
+Class Name Scrollbar
+Superclass Simple
+</literallayout>
+
+<para>
+A Scrollbar widget is a rectangle, called the ``canvas,'' on
+which another rectangle, the ``thumb,'' moves in one
+dimension, either vertically or horizontally. A Scrollbar
+can be used alone, as a value generator, or it can be used
+within a composite widget (for example, a Viewport). When a
+Scrollbar is used to move, or ``scroll,'' the contents of
+another widget, the size and the position of the thumb usually give
+feedback as to what portion of the other widget's contents
+are visible.
+</para>
+
+<para>
+Each pointer button invokes a specific action. Pointer
+buttons 1 and 3 do not move the thumb automatically.
+Instead, they return the pixel position of the cursor on the
+scroll region. When pointer button 2 is clicked, the thumb
+moves to the current pointer position. When pointer button
+2 is held down and the pointer is moved, the thumb follows
+the pointer.
+</para>
+
+<para>
+The pointer cursor in the scroll region changes depending on the current
+action. When no pointer button is pressed, the cursor appears as a
+double-headed arrow that points in the direction that scrolling can
+occur. When pointer button 1 or 3 is pressed, the cursor appears as a
+single-headed arrow that points in the logical direction that the thumb
+will move. When pointer button 2 is pressed, the cursor
+appears as an arrow that points to the top or the left of the thumb.
+</para>
+
+<para>
+When the user scrolls, the application receives notification
+through callback procedures. For both discrete scrolling actions, the
+callback returns the Scrollbar widget, the client_data, and the pixel
+position of the pointer when the button was released. For continuous
+scrolling, the callback routine returns the scroll bar widget, the
+client data, and the current relative position of the thumb. When the
+thumb is moved using pointer button 2, the callback procedure is invoked
+continuously. When either button 1 or 3 is pressed, the callback
+procedure is invoked only when the button is released and the client
+callback procedure is responsible for moving the thumb.
+</para>
+
+<sect2 id="scrollbar_resources">
+<title>Resources</title>
+
+<para>
+When creating a Scrollbar widget instance, the following resources are
+retrieved from the argument list or from the resource database:
+</para>
+
+<informaltable>
+ <tgroup cols='5' align='center'>
+ <colspec colname='c1'/>
+ <colspec colname='c2'/>
+ <colspec colname='c3'/>
+ <colspec colname='c4'/>
+ <colspec colname='c5'/>
+ <thead>
+ <row>
+ <entry>Name</entry>
+ <entry>Class</entry>
+ <entry>Type</entry>
+ <entry>Notes</entry>
+ <entry>Default Value</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>accelerators</entry>
+ <entry>Accelerators</entry>
+ <entry>AcceleratorTable</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>ancestorSensitive</entry>
+ <entry>AncestorSensitive</entry>
+ <entry>Boolean</entry>
+ <entry>D</entry>
+ <entry>True</entry>
+ </row>
+ <row>
+ <entry>background</entry>
+ <entry>Background</entry>
+ <entry>Pixel</entry>
+ <entry></entry>
+ <entry>XtDefaultBackground</entry>
+ </row>
+ <row>
+ <entry>backgroundPixmap</entry>
+ <entry>Pixmap</entry>
+ <entry>Pixmap</entry>
+ <entry></entry>
+ <entry>XtUnspecifiedPixmap</entry>
+ </row>
+ <row>
+ <entry>borderColor</entry>
+ <entry>BorderColor</entry>
+ <entry>Pixel</entry>
+ <entry></entry>
+ <entry>XtDefaultForeground</entry>
+ </row>
+ <row>
+ <entry>borderPixmap</entry>
+ <entry>Pixmap</entry>
+ <entry>Pixmap</entry>
+ <entry></entry>
+ <entry>XtUnspecifiedPixmap</entry>
+ </row>
+ <row>
+ <entry>borderWidth</entry>
+ <entry>BorderWidth</entry>
+ <entry>Dimension</entry>
+ <entry></entry>
+ <entry>1</entry>
+ </row>
+ <row>
+ <entry>colormap</entry>
+ <entry>Colormap</entry>
+ <entry>Colormap</entry>
+ <entry></entry>
+ <entry>parent's Colormap</entry>
+ </row>
+ <row>
+ <entry>cursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>None</entry>
+ </row>
+ <row>
+ <entry>cursorName</entry>
+ <entry>Cursor</entry>
+ <entry>String</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>depth</entry>
+ <entry>Depth</entry>
+ <entry>int</entry>
+ <entry>C</entry>
+ <entry>parent's Depth</entry>
+ </row>
+ <row>
+ <entry>destroyCallback</entry>
+ <entry>Callback</entry>
+ <entry>XtCallbackList</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>foreground</entry>
+ <entry>Foreground</entry>
+ <entry>Pixel</entry>
+ <entry></entry>
+ <entry>XtDefaultForeground</entry>
+ </row>
+ <row>
+ <entry>height</entry>
+ <entry>Height</entry>
+ <entry>Dimension</entry>
+ <entry>A</entry>
+ <entry>depends on orientation</entry>
+ </row>
+ <row>
+ <entry>insensitiveBorder</entry>
+ <entry>Insensitive</entry>
+ <entry>Pixmap</entry>
+ <entry></entry>
+ <entry>GreyPixmap</entry>
+ </row>
+ <row>
+ <entry>international</entry>
+ <entry>International</entry>
+ <entry>Boolean</entry>
+ <entry>C</entry>
+ <entry>False</entry>
+ </row>
+ <row>
+ <entry>jumpProc</entry>
+ <entry>Callback</entry>
+ <entry>XtCallbackList</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>length</entry>
+ <entry>Length</entry>
+ <entry>Dimension</entry>
+ <entry></entry>
+ <entry>1</entry>
+ </row>
+ <row>
+ <entry>mappedWhenManaged</entry>
+ <entry>MappedWhenManaged</entry>
+ <entry>Boolean</entry>
+ <entry></entry>
+ <entry>True</entry>
+ </row>
+ <row>
+ <entry>minimumThumb</entry>
+ <entry>MinimumThumb</entry>
+ <entry>Dimension</entry>
+ <entry></entry>
+ <entry>7</entry>
+ </row>
+ <row>
+ <entry>orientation</entry>
+ <entry>Orientation</entry>
+ <entry>Orientation</entry>
+ <entry></entry>
+ <entry>XtorientVertical (vertical)</entry>
+ </row>
+ <row>
+ <entry>pointerColor</entry>
+ <entry>Foreground</entry>
+ <entry>Pixel</entry>
+ <entry></entry>
+ <entry>XtDefaultForeground</entry>
+ </row>
+ <row>
+ <entry>pointerColorBackground</entry>
+ <entry>Background</entry>
+ <entry>Pixel</entry>
+ <entry></entry>
+ <entry>XtDefaultBackground</entry>
+ </row>
+ <row>
+ <entry>screen</entry>
+ <entry>Screen</entry>
+ <entry>Screen</entry>
+ <entry>R</entry>
+ <entry>parent's Screen</entry>
+ </row>
+ <row>
+ <entry>scrollDCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_down_arrow</entry>
+ </row>
+ <row>
+ <entry>scrollHCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_h_double_arrow</entry>
+ </row>
+ <row>
+ <entry>scrollLCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_left_arrow</entry>
+ </row>
+ <row>
+ <entry>scrollProc</entry>
+ <entry>Callback</entry>
+ <entry>XtCallbackList</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>scrollRCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_right_arrow</entry>
+ </row>
+ <row>
+ <entry>scrollUCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_up_arrow</entry>
+ </row>
+ <row>
+ <entry>scrollVCursor</entry>
+ <entry>Cursor</entry>
+ <entry>Cursor</entry>
+ <entry></entry>
+ <entry>XC_sb_v_arrow</entry>
+ </row>
+ <row>
+ <entry>sensitive</entry>
+ <entry>Sensitive</entry>
+ <entry>Boolean</entry>
+ <entry></entry>
+ <entry>True</entry>
+ </row>
+ <row>
+ <entry>shown</entry>
+ <entry>Shown</entry>
+ <entry>Float</entry>
+ <entry></entry>
+ <entry>0.0</entry>
+ </row>
+ <row>
+ <entry>thickness</entry>
+ <entry>Thickness</entry>
+ <entry>Dimension</entry>
+ <entry></entry>
+ <entry>14</entry>
+ </row>
+ <row>
+ <entry>thumb</entry>
+ <entry>Thumb</entry>
+ <entry>Bitmap</entry>
+ <entry></entry>
+ <entry>GreyPixmap</entry>
+ </row>
+ <row>
+ <entry>thumbProc</entry>
+ <entry>Callback</entry>
+ <entry>XtCallbackList</entry>
+ <entry></entry>
+ <entry>NULL</entry>
+ </row>
+ <row>
+ <entry>topOfThumb</entry>
+ <entry>TopOfThumb</entry>
+ <entry>Float</entry>
+ <entry></entry>
+ <entry>0.0</entry>
+ </row>
+ <row>
+ <entry>translations</entry>
+ <entry>Translations</entry>
+ <entry>TranslationTable</entry>
+ <entry></entry>
+ <entry>See below</entry>
+ </row>
+ <row>
+ <entry>width</entry>
+ <entry>Width</entry>
+ <entry>Dimension</entry>
+ <entry>A</entry>
+ <entry>depends on orientation</entry>
+ </row>
+ <row>
+ <entry>x</entry>
+ <entry>Position</entry>
+ <entry>Position</entry>
+ <entry></entry>
+ <entry>0</entry>
+ </row>
+ <row>
+ <entry>y</entry>
+ <entry>Position</entry>
+ <entry>Position</entry>
+ <entry></entry>
+ <entry>0</entry>
+ </row>
+ </tbody>
+ </tgroup>
+</informaltable>
+
+<variablelist>
+ <varlistentry>
+ <term>
+ <function>foreground</function>
+ </term>
+ <listitem>
+ <para>
+A pixel value which indexes the widget's colormap to derive the color
+used to draw the thumb.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>jumpProc</function>
+ </term>
+ <listitem>
+ <para>
+All functions on this callback list are called when the
+<function>NotifyThumb</function> action is invoked. See the <function>Scrollbar
+Actions</function> section for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>length</function>
+ </term>
+ <listitem>
+ <para>
+The height of a vertical scrollbar or the width of a horizontal scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>minimumThumb</function>
+ </term>
+ <listitem>
+ <para>
+The smallest size, in pixels, to which the thumb can shrink.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>orientation</function>
+ </term>
+ <listitem>
+ <para>
+The orientation is the direction that the thumb will be allowed to move.
+This value can be either <function>XtorientVertical</function> or
+<function>XtorientHorizontal</function>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollDCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when scrolling backward in a vertical scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollHCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when a horizontal scrollbar is inactive.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollLCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when scrolling forward in a horizontal scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollProc</function>
+ </term>
+ <listitem>
+ <para>
+All functions on this callback list may be called when the
+<function>NotifyScroll</function> action is invoked. See the \fBScrollbar
+Actions\fP section for details.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollRCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when scrolling backward in a horizontal scrollbar,
+or when thumbing a vertical scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollUCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when scrolling forward in a vertical scrollbar, or when
+thumbing a horizontal scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>scrollVCursor</function>
+ </term>
+ <listitem>
+ <para>
+This cursor is used when a vertical scrollbar is inactive.
+<!-- .Se -->
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>shown</function>
+ </term>
+ <listitem>
+ <para>
+This is the size of the thumb, expressed as a percentage (0.0 - 1.0)
+of the length of the scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>thickness</function>
+ </term>
+ <listitem>
+ <para>
+The width of a vertical scrollbar or the height of a horizontal scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>thumb</function>
+ </term>
+ <listitem>
+ <para>
+This pixmap is used to tile (or stipple) the thumb of the scrollbar. If
+no tiling is desired, then set this resource to <function>None</function>. This
+resource will accept either a bitmap or a pixmap that is the same depth
+as the window. The resource converter for this resource constructs
+bitmaps from the contents of files. (See <function>Converting Bitmaps</function> for
+details.)
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>topOfThumb</function>
+ </term>
+ <listitem>
+ <para>
+The location of the top of the thumb, as a percentage (0.0 - 1.0)
+of the length of the scrollbar. This resource was called <function>top</function> in
+previous versions of the Athena widget set. The name collided with the
+a Form widget constraint resource, and had to be changed.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+</sect2>
+
+<sect2 id="Scrollbar_Actions">
+<title>Scrollbar Actions</title>
+<para>
+<!-- .LP -->
+The actions supported by the Scrollbar widget are:
+</para>
+<variablelist>
+ <varlistentry>
+ <term>
+ <function>StartScroll</function>(<emphasis remap='I'>value</emphasis>)
+ </term>
+ <listitem>
+ <para>
+The possible <emphasis remap='I'>values</emphasis> are Forward, Backward, or Continuous.
+This must be the first action to begin a new movement.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>NotifyScroll</function>(<emphasis remap='I'>value</emphasis>)
+ </term>
+ <listitem>
+ <para>
+The possible <emphasis remap='I'>values</emphasis> are Proportional or FullLength. If the
+argument to StartScroll was Forward or Backward, NotifyScroll executes
+the <function>scrollProc</function> callbacks and passes either; the position of the
+pointer, if <emphasis remap='I'>value</emphasis> is Proportional, or the full length of the
+scroll bar, if <emphasis remap='I'>value</emphasis> is FullLength. If the argument to
+StartScroll was Continuous, NotifyScroll returns without executing any
+callbacks.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>EndScroll</function>(\^)
+ </term>
+ <listitem>
+ <para>
+This must be the last action after a movement is complete.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>MoveThumb</function>(\^)
+ </term>
+ <listitem>
+ <para>
+Repositions the Scrollbar's thumb to the current pointer location.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <function>NotifyThumb</function>(\^)\
+ </term>
+ <listitem>
+ <para>
+Calls the
+<!-- .PN jumpProc -->
+callbacks and passes the relative position of the
+pointer as a percentage of the scroll bar length.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<para>
+The default bindings for Scrollbar are:
+<!-- .IN "Scrollbar widget" "default translation table" -->
+</para>
+
+<literallayout class="monospaced">
+ &lt;Btn1Down&gt;: StartScroll(Forward)
+ &lt;Btn2Down&gt;: StartScroll(Continuous) MoveThumb(\|) NotifyThumb(\|)
+ &lt;Btn3Down&gt;: StartScroll(Backward)
+ &lt;Btn2Motion&gt;: MoveThumb(\|) NotifyThumb(\|)
+ &lt;BtnUp&gt;: NotifyScroll(Proportional) EndScroll(\|)
+</literallayout>
+
+<para>
+Examples of additional bindings a user might wish to specify in a
+resource file are:
+</para>
+
+<literallayout class="monospaced">
+*Scrollbar.Translations: \\
+ ~Meta&lt;Key&gt;space: StartScroll(Forward) NotifyScroll(FullLength) \\n\\
+ Meta&lt;Key&gt;space: StartScroll(Backward) NotifyScroll(FullLength) \\n\\
+ EndScroll(\|)
+</literallayout>
+
+</sect2>
+
+<sect2 id="Scrollbar_Callbacks">
+<title>Scrollbar Callbacks</title>
+<!-- .IN "Scrollbar widget" "callbacks" -->
+<para>
+<!-- .LP -->
+There are two callback lists provided by the Scrollbar widget.
+The procedural interface for these functions is described here.
+</para>
+
+<para>
+<!-- .LP -->
+The calling interface to the <function>scrollProc</function> callback procedure is:
+<!-- .IN "ScrollProc" "" "@DEF@" -->
+</para>
+<funcsynopsis>
+<funcprototype>
+ <funcdef>void<function> ScrollProc</function></funcdef>
+ <paramdef>Widget<parameter> scrollbar</parameter></paramdef>
+ <paramdef>XtPointer<parameter> client_data</parameter></paramdef>
+ <paramdef>XtPointer<parameter> position</parameter></paramdef>
+</funcprototype>
+</funcsynopsis>
+
+<variablelist>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>scrollbar</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the Scrollbar widget.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>client_data</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the client data.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>position</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies a pixel position in integer form.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<para>
+The <function>scrollProc</function> callback is used for incremental scrolling
+and is called by the <function>NotifyScroll</function> action.
+The position argument is a signed quantity and should be cast to an int
+when used. Using the default button bindings, button 1 returns a
+positive value, and button 3 returns a negative value. In both cases,
+the magnitude of the value is the distance of the pointer in
+pixels from the top (or left) of the Scrollbar. The value will never
+be greater than the length of the Scrollbar.
+</para>
+
+<para>
+The calling interface to the <function>jumpProc</function> callback procedure is:
+</para>
+<!-- .IN "jumpProc" "" "@DEF@" -->
+<funcsynopsis>
+<funcprototype>
+ <funcdef>void<function> JumpProc</function></funcdef>
+ <paramdef>Widget<parameter> scrollbar</parameter></paramdef>
+ <paramdef>XtPointer<parameter> client_data</parameter></paramdef>
+ <paramdef>XtPointer<parameter> percent_ptr</parameter></paramdef>
+</funcprototype>
+</funcsynopsis>
+
+<!-- .FN -->
+<variablelist>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>scrollbar</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the ID of the scroll bar widget.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>client_data</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the client data.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>percent_ptr</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the floating point position of the thumb (0.0 \- 1.0).
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<para>
+The <function>jumpProc</function> callback is used to implement smooth scrolling and
+is called by the <function>NotifyThumb</function> action. Percent_ptr must be cast
+to a pointer to float before use; i.e.
+</para>
+
+<literallayout class="monospaced">
+ float percent = *(float*)percent_ptr;
+</literallayout>
+
+<para>
+With the default button bindings, button 2 moves the thumb interactively,
+and the <function>jumpProc</function> is called on each new position of the pointer,
+while the pointer button remains down. The value specified by
+<emphasis remap='I'>percent_ptr</emphasis> is the current location of the thumb (from the top or
+left of the Scrollbar) expressed as a percentage of the length of the
+Scrollbar.
+</para>
+
+</sect2>
+
+<sect2 id="Convenience_Routines">
+<title>Convenience Routines</title>
+<para>
+<!-- .IN "Scrollbar widget" "setting thumb values" -->
+To set the position and length of a Scrollbar thumb, use
+<!-- .PN XawScrollbarSetThumb . -->
+<!-- .IN "XawScrollbarSetThumb" "" "@DEF@" -->
+</para>
+<funcsynopsis>
+<funcprototype>
+ <funcdef>void<function> XawScrollbarSetThumb</function></funcdef>
+ <paramdef>Widget<parameter> w</parameter></paramdef>
+ <paramdef>float<parameter> top</parameter></paramdef>
+ <paramdef>float<parameter> shown</parameter></paramdef>
+</funcprototype>
+</funcsynopsis>
+
+<variablelist>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>w</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the Scrollbar widget.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>top</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the position of the top of the thumb as a fraction of the
+length of the Scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <emphasis remap='I'>shown</emphasis>
+ </term>
+ <listitem>
+ <para>
+Specifies the length of the thumb as a fraction of the total length
+of the Scrollbar.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<para>
+<function>XawScrollbarThumb</function>
+moves the visible thumb to a new position (0.0 \- 1.0) and length (0.0 \- 1.0).
+Either the top or shown arguments can be specified as \-1.0,
+in which case the current value is left unchanged.
+Values greater than 1.0 are truncated to 1.0.
+</para>
+
+<para>
+If called from <function>jumpProc</function>, <function>XawScrollbarSetThumb</function> has no effect.
+</para>
+
+</sect2>
+
+<sect2 id="Setting_Float_Resources">
+<title>Setting Float Resources</title>
+<!-- .IN "float resources" "setting" -->
+<para>
+The <function>shown</function> and <function>topOfThumb</function> resources are of type
+<emphasis remap='I'>float</emphasis>. These resources can be difficult to get into an
+argument list. The reason is that C performs an automatic cast of
+the float value to an integer value, usually truncating the important
+information. The following code fragment is one portable method of
+getting a float into an argument list.
+</para>
+<literallayout class="monospaced">
+ top = 0.5;
+ if (sizeof(float) &gt; sizeof(XtArgVal)) {
+ /*
+ \ * If a float is larger than an XtArgVal then pass this
+ \ * resource value by reference.
+ \ */
+ XtSetArg(args[0], XtNshown, &amp;top);
+ }
+ else {
+ /*
+ \ * Convince C not to perform an automatic conversion, which
+ \ * would truncate 0.5 to 0.
+ \ */
+ XtArgVal * l_top = (XtArgVal *) &amp;top;
+ XtSetArg(args[0], XtNshown, *l_top);
+ }
+</literallayout>
+
+</sect2>
+</sect1>