VkEZ(3x)VkEZ(3x)NAMEVkEZ - A simple "widget wrapper" package to make using Motif easier
HEADER FILE
#include <Vk/VkEZ.h>
PUBLIC PROTOCOL SUMMARY
General interface
EZ(Widget w)
Operators
=
+=
-=
<<
String
int
foreground=
background=
x=
y=
width=
height=
Description
VkEZ is a simple mechanism for performing many common operations on Motif
widgets in a consistent way, without knowing the details of the Motif API
required to perform them.
NOTE: VkEZ trades ease of use for programming efficiency. While it is
faster to use VkEZ in many cases, the resulting operations can easily
cost far more than the equivalent Motif operations. VkEZ is best used for
demos and quick prototypes. SGI does not recommend VkEZ for production
code.
The VkEZ mechanism works by wrapping a widget temporarily in a C++ class
that supports various operators. It also makes assumptions about what is
interesting about any given widget. For example, if one assigns an
integer to a Motif Scale widget, it will move the scale's slider.
Assigning the same integer to a XmLabel widget will display the value in
the label.
To wrap a widget, simply type:
EZ(widget)VkEZ supports two kinds of operators that can be applied to wrapped
widgets.
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General operators, which are applied directly to the object. For example:
EZ(widget) = "a label";
Operators applied to an attribute (resource) supported by
the widget. For example:
EZ(widget).foreground = "red";
The following descriptions of each operator lists the widgets that
support that operator and defines how the operator works on each
widget.
General Operators
Operator: String()String() returns a character string from the widget. For example:
char *s = EZ(text); strcpy(buffer, s); XtFree(s);
The application should free the string with XtFree(). This example
copies the contents of a text widget into buffer.
The following list describes the behavior of this operator for each
widget that supports it.
XmLabel, XmLabelGadget, and subclasses
Returns the current value of the XmNlabelString resource as a character
string
XmText, XmTextField
Returns the contents of the text widget
XmList
Returns the text associated with the currently selected item
Operator: int()int() returns an integer value from the widget. For example:
int value = EZ(dial);
This example assigns the current value of a dial widget to value.
The following list describes the behavior of this operator for each
widget that supports it.
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XmToggleButton and XmToggleButtonGadget
Returns 1 if set, 0 if not set
XmScrollBar, XmScale
Returns the current position of the slider
SgDial
Returns the current position of the pointer
XmText, XmTextField
Returns the result of calling atoi(3C) on the current contents of the
text widget
XmList
Returns the currently selected position
Assignment Operators
EZ& operator=(int);
EZ& operator=(float);
EZ& operator=(const char *);
Assignment operators assign integer, floating point, and character values
to a widget. For example:
EZ(text) = 12345;
This example displays the integer 12345 in a text field.
The following list describes the behavior of the integer assignment
operator for each widget that supports it.
XmToggle, XmToggleButtonGadget
If the specified value is zero, turns the toggle off; if the specified
value is non-zero, turns the toggle on
XmScrollBar, XmScale
Sets the current slider position to the specified value
SgDial
Sets the current pointer position to the specified value
XmLabel, XmLabelGadget, and subclasses (except toggle)
Displays the specified value as the XmNlabelString resource
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XmText, XmTextField
Displays the specified value as the XmNvalue resource
XmList
Sets the current position index to the specified value
The following list describes the behavior of the floating point
assignment operator for each widget that supports it.
XmScrollBar, XmScale
Sets the current slider position to the integer equivalent of the
specified value (the floating point value is truncated)
SgDial
Sets the current pointer position to the integer equivalent of the
specified value (the floating point value is truncated)
XmLabel, XmLabelGadget and subclasses
Displays the specified floating point value as the XmNlabelString
resource
XmText, XmTextField
Displays the specified floating point value as the XmNvalue resource
XmList
Sets the current position index to the integer equivalent of the
specified value (the floating point value is truncated)
The following list describes the behavior of the character string
assignment operator for each widget that supports it.
XmScale
Sets the title to the specified string
XmLabel, XmLabelGadget, and subclasses
Displays the specified string as the XmNlabelString resource
XmText, XmTextField
Displays the specified string as the XmNvalue resource
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XmList
Treats the specified string as comma-separated list of items and sets the
list widget to display the new items, removing old contents
Append Operators
EZ& operator+=(int);
EZ& operator+=(float);
EZ& operator+=(const char *);
EZ& operator<<(int);
EZ& operator<<(float);
EZ& operator<<(const char *);
Append operators append the right side expression to the current value of
a widget. Logically, the += operators make more sense for numerical
operations, while the << operators seem more suitable for strings, but
they are actually equivalent and either can be used.
The following list describes the behavior of the integer and floating
point append operators for each widget that supports them.
XmToggle, XmToggleButtonGadget
Increments the current value of XmNset by the specified value, so
EZ(toggle) += 0;
does nothing, while
EZ(toggle) +=1;
sets toggle if it is not already set
XmScale, XmScrollBar
Increases the position of the slider by the specified value
SgDial
Increases the position of the pointer by the specified value
XmLabel, XmLabelGadget, and subclasses
Appends the specified value to the current XmNlabelString resource
XmText, XmTextField
Appends the specified value to the current XmNvalue resource
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XmList
Increments the current position index by the specified value
The following list describes the behavior of the character string append
operator for each widget that supports it.
XmLabel, XmLabelGadget and subclasses
Appends the given string to the current value of the XmNlabelString
resource
XmScale
Appends the give string to the current value of the XmNtitle resource
XmText, XmTextField
Appends the value to the XmNvalue resource
XmList
Treats the string as a comma-separated list of items and adds the items
to the list widget's current contents
Decrement Operator
EZ& operator-=(int);
The decrement operator decrements the current value associated with a
widget.
The following list describes the behavior of the decrement operator for
each widget that supports it.
XmToggle, XmToggleButtonGadget
Decrements the current value of XmNset by the specified value, so
EZ(toggle) -= 0;
does nothing, while
EZ(toggle) -= 1;
unsets toggle if it is not already unset
XmScale, XmScrollBar
Decreases the position of the slider by the specified value
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SgDial
Decreases the position of the pointer by the specified value
XmList
Decrements the current position index by the specified value
Attributes
The following are attributes that can be modified using VkEZ:
Attributes supported by all widgets: border, width, height, x, y
Attributes supported by all widgets that have setting support for Pixel
or char *: background, foreground
Attributes supported by XmLabel, XmLabelGadget and subclasses: label
Attributes supported by XmScale, XmScrollBar, SgDial: value, minimum,
maximum
Each of these attributes can be retrieved or set. For example:
int width = EZ(widget).width;
EZ(widget).width = 20;
EZ(widget).foreground = "red";
Pixel index = EZ(widget).background;
SEE ALSO
ViewKit Programmer's Guide
The X Window System, DEC Press, Bob Sheifler and Jim Gettys
The X Window System Toolkit, DEC Press, Paul Asente and Ralph Swick
The OSF/Motif Programmers Reference, Prentice Hall, OSF
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