libxaw-doc 2:1.0.13-1 / usr / share / doc / libxaw7-dev / Form.xml

<sect1 id="Form_Widget">
<title>Form Widget</title>
<para>
<!-- .LP -->
<!-- .XS -->
<!-- 	Form Widget -->
<!-- .XE -->
<!-- .IN "Form widget" "" "@DEF@" -->
<literallayout class="monospaced">
<!-- .TA 2.0i -->
<!-- .ta 2.0i -->
<!-- .sp -->
Application Header file	&lt;X11/Xaw/Form.h&gt;
<!-- .IN "Form.h" "" -->
Class Header file	&lt;X11/Xaw/FormP.h&gt;
<!-- .IN "FormP.h" "" -->
Class		formWidgetClass
<!-- .IN "formWidgetClass" "" -->
Class Name	Form
<!-- .IN "Form widget" "class name" -->
Superclass	Constraint
<!-- .sp -->
</literallayout>
</para>
<para>
<!-- .LP -->
The Form widget can contain an arbitrary number of children or
subwidgets.  The Form provides geometry management for its children,
which allows individual control of the position of each child.  Any
combination of children can be added to a Form.  The initial positions
of the children may be computed relative to the positions of previously
created children.  When the Form is resized, it computes new positions and
sizes for its children.  This computation is based upon information
provided when a child is added to the Form.
</para>
<para>
<!-- .LP -->
The default width of the Form is the minimum width needed to
enclose the children after computing their initial layout, with a
margin of <function>defaultDistance</function>
at the right and bottom edges.  If a width and height is assigned
to the Form that is too small for the layout, the children will
be clipped by the right and bottom edges of the Form.
</para>
<sect2 id='Form::Resources'>
<title>Resources</title>
<para>
<!-- .LP -->
When creating a Form widget instance, the following resources are
retrieved from the argument list or from the resource database:
</para>
<para>
<!-- .LP -->
<!-- .IN "Form widget" "resources" -->
<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>children</entry>
      <entry>ReadOnly</entry>
      <entry>WidgetList</entry>
      <entry>R</entry>
      <entry>NULL</entry>
    </row>
    <row>
      <entry>colormap</entry>
      <entry>Colormap</entry>
      <entry>Colormap</entry>
      <entry></entry>
      <entry>Parent's Colormap</entry>
    </row>
    <row>
      <entry>defaultDistance</entry>
      <entry>Thickness</entry>
      <entry>int</entry>
      <entry></entry>
      <entry>4</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>height</entry>
      <entry>Height</entry>
      <entry>Dimension</entry>
      <entry>A</entry>
      <entry>Enough space to contain all children</entry>
    </row>
    <row>
      <entry>mappedWhenManaged</entry>
      <entry>MappedWhenManaged</entry>
      <entry>Boolean</entry>
      <entry></entry>
      <entry>True</entry>
    </row>
    <row>
      <entry>numChildren</entry>
      <entry>ReadOnly</entry>
      <entry>Cardinal</entry>
      <entry>R</entry>
      <entry>0</entry>
    </row>
    <row>
      <entry>screen</entry>
      <entry>Screen</entry>
      <entry>Screen</entry>
      <entry>R</entry>
      <entry>Parent's Screen</entry>
    </row>
    <row>
      <entry>sensitive</entry>
      <entry>Sensitive</entry>
      <entry>Boolean</entry>
      <entry></entry>
      <entry>True</entry>
    </row>
    <row>
      <entry>translations</entry>
      <entry>Translations</entry>
      <entry>TranslationTable</entry>
      <entry></entry>
      <entry>NULL</entry>
    </row>
    <row>
      <entry>width</entry>
      <entry>Width</entry>
      <entry>Dimension</entry>
      <entry>A</entry>
      <entry>Enough space to contain all children</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>
    <row>
      <entry>_</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>
<!-- .Ac -->
<!-- .As -->
<!-- .Bg -->
<!-- .Gp -->
<!-- .Bc -->
<!-- .Bp -->
<!-- .Bw -->
<!-- .Ch -->
<!-- .Cm -->
<!-- .Dd Bold -->
<!-- .Dp -->
<!-- .Dc -->
<!-- .Hw -->
<!-- .Mm -->
<!-- .Nc -->
<!-- .Sc -->
<!-- .Se -->
<!-- .Tr -->
<!-- .Xy -->
</para>
</sect2>
<sect2 id='Form::Constraint_Resources'>
<title>Constraint Resources</title>
<para>
<!-- .LP -->
<!-- .IN "Form widget" "constraint resources" -->
Each child of the Form widget may request special layout resources
be applied to it.  These <emphasis remap='I'>constraint</emphasis> resources allow the Form
widget's children to specify individual layout requirements.
</para>
<para>
<!-- .LP -->
</para>
<para>
<!-- .LP -->
<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>bottom</entry>
      <entry>Edge</entry>
      <entry>XawEdgeType</entry>
      <entry></entry>
      <entry>XawRubber</entry>
    </row>
    <row>
      <entry>fromHoriz</entry>
      <entry>Widget</entry>
      <entry>Widget</entry>
      <entry></entry>
      <entry>NULL (left edge of Form)</entry>
    </row>
    <row>
      <entry>fromVert</entry>
      <entry>Widget</entry>
      <entry>Widget </entry>
      <entry></entry>
      <entry>NULL (top edge of Form)</entry>
    </row>
    <row>
      <entry>horizDistance</entry>
      <entry>Thickness</entry>
      <entry>int</entry>
      <entry></entry>
      <entry><function>defaultDistance</function> resource</entry>
    </row>
    <row>
      <entry>left</entry>
      <entry>Edge</entry>
      <entry>XawEdgeType</entry>
      <entry></entry>
      <entry>XawRubber</entry>
    </row>
    <row>
      <entry>resizable</entry>
      <entry>Boolean</entry>
      <entry>Boolean</entry>
      <entry></entry>
      <entry>FALSE</entry>
    </row>
    <row>
      <entry>right</entry>
      <entry>Edge</entry>
      <entry>XawEdgeType</entry>
      <entry></entry>
      <entry>XawRubber</entry>
    </row>
    <row>
      <entry>top</entry>
      <entry>Edge</entry>
      <entry>XawEdgeType</entry>
      <entry></entry>
      <entry>XawRubber</entry>
    </row>
    <row>
      <entry>vertDistance</entry>
      <entry>Thickness</entry>
      <entry>int</entry>
      <entry></entry>
      <entry><function>defaultDistance</function> resource</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>
<!-- .Bt Bold -->
<!-- .Fh Bold -->
<!-- .Hd Bold -->
<!-- .Rl Bold -->
</para>
<literallayout class="monospaced">
bottom
left
right
top            What to do with this edge of the child when
               the parent is resized.  This resource may be
               any edgeType.  See Layout Semantics for
               details.

fromHoriz
fromVert       Which widget this child should be placed
               underneath (or to the right of).  If a value
               of NULL is specified then this widget will be
               positioned relative to the edge of the par-
               ent.

horizDistance
vertDistance   The amount of space, in pixels, between this
               child and its left or upper neighbor.

resizable      If this resource is False then the parent
               widget will ignore all geometry request made
               by this child.  The parent may still resize
               this child itself, however.
</literallayout>
<!-- .Bt -->
</sect2>
<sect2 id='Form::Layout_Semantics'>
<title>Layout Semantics</title>
<para>
The Form widget uses two different sets of layout semantics.
One is used when initially laying out the children.  The
other is used when the Form is resized.
</para>
<para>
The first layout method uses the <function>fromVert</function>
and <function>fromHoriz</function>
resources to place the children of the Form.  A single pass
is made through the Form widget's children in the order that
they were created.  Each child is then placed in the Form
widget below or to the right of the widget specified by the
<function>fromVert</function> and <function>fromHoriz</function>
resources.  The distance the new
child is placed from its left or upper neighbor is deter-
mined by the <function>horizDistance</function> and
<function>vertDistance</function> resources.  This
implies some things about how the order of creation affects
the possible placement of the children.  The Form widget
registers a string to widget converter which does not post-
pone conversion and does not cache conversion results.
</para>
<para>
The second layout method is used when the Form is resized.
It does not matter what causes this resize, and it is possi-
ble for a resize to happen before the widget becomes visible
(due to constraints imposed by the parent of the Form).
This layout method uses the <function>bottom</function>,
<function>top</function>, <function>left</function>, and
<function>right</function>
resources.  These resources are used to determine what will
happen to each edge of the child when the Form is resized.
If a value of <function>XawChain</function>
&lt;<emphasis remap='I'>something</emphasis>&gt; is specified, the the edge
of the child will remain a fixed distance from the
<emphasis remap='I'>chain</emphasis>
edge of the Form.  For example if <function>XawChainLeft</function> is specified
for the <function>right</function> resource of a child then the right edge of
that child will remain a fixed distance from the left edge
of the Form widget.  If a value of <function>XawRubber</function> is specified,
that edge will grow by the same percentage that the Form
grew.  For instance if the Form grows by 50% the left edge
of the child (if specified as <function>XawRubber</function> will be 50% farther
from the left edge of the Form).  One must be very careful
when specifying these resources, for when they are specified
incorrectly children may overlap or completely occlude other
children when the Form widget is resized.
<!-- .LP -->
<!-- .Lt Form -->
</para>
<para>
<!-- .LP -->
<informaltable>
  <tgroup cols='3' align='center'>
  <colspec colname='c1'/>
  <colspec colname='c2'/>
  <colspec colname='c3'/>
  <thead>
    <row>
      <entry>Edge Type</entry>
      <entry>Resource Name</entry>
      <entry>Description</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry>XawChainBottom</entry>
      <entry>ChainBottom</entry>
      <entry>Edge remains a fixed distance from bottom of Form</entry>
    </row>
    <row>
      <entry>XawChainLeft</entry>
      <entry>ChainLeft</entry>
      <entry>Edge remains a fixed distance from left of Form</entry>
    </row>
    <row>
      <entry>XawChainRight</entry>
      <entry>ChainRight</entry>
      <entry>Edge remains a fixed distance from right of Form</entry>
    </row>
    <row>
      <entry>XawChainTop</entry>
      <entry>ChainTop</entry>
      <entry>Edge remains a fixed distance from top of Form</entry>
    </row>
    <row>
      <entry>XawRubber</entry>
      <entry>Rubber</entry>
      <entry>Edges will move a proportional distance</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>
</para>
<sect3 id='Form::Example'>
<title>Example</title>
<para>
<!-- .LP -->
If you wish to force the Form to never resize one or more of its
children, then set <function>left</function> and <function>right</function> to <function>XawChainLeft</function> and
<function>top</function> and <function>bottom</function> to <function>XawChainTop</function>.  This will cause the
child to remain a fixed distance from the top and left edges of the
Form, and never to resize.
</para>
</sect3>
</sect2>
<sect2 id='Form::Convenience_Routines'>
<title>Convenience Routines</title>
<para>
<!-- .LP -->
To force or defer a re-layout of the Form, use
<!-- .PN XawFormDoLayout . -->
<!-- .IN "Form widget" "re-layout" -->
<!-- .IN "XawFormDoLayout" "" "@DEF@" -->
<funcsynopsis id='XawFormDoLayout'>
<funcprototype>
  <funcdef>void<function> XawFormDoLayout</function></funcdef>
  <paramdef>Widget<parameter> w</parameter></paramdef>
  <paramdef>Boolean<parameter> do_layout</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<!-- .FN -->
<variablelist>
  <varlistentry>
    <term>
      <emphasis remap='I'>w</emphasis>
    </term>
    <listitem>
      <para>
Specifies the Form widget.
      </para>
    </listitem>
  </varlistentry>
  <varlistentry>
    <term>
      <emphasis remap='I'>do_layout</emphasis>
    </term>
    <listitem>
      <para>
Specifies whether the layout of the Form widget is enabled (<function>True</function>)
or disabled (<function>False</function>).
    </para>
  </listitem>
  </varlistentry>
</variablelist>
</para>
<para>
<!-- .LP -->
When making several changes to the children of a Form widget
after the Form has been realized, it is a good idea to disable
relayout until after all changes have been made.

</para>
</sect2>
</sect1>