<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 <X11/Xaw/Form.h> <!-- .IN "Form.h" "" --> Class Header file <X11/Xaw/FormP.h> <!-- .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> <<emphasis remap='I'>something</emphasis>> 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>