NAME¶
StringEditor - single line interactive string editor
SYNOPSIS¶
#include <InterViews/streditor.h>
DESCRIPTION¶
StringEditor is an interactor that provides a convenient mouse-based interactive
editor for text strings. It is suitable for incorporation into other
components such as dialog boxes. Clicking inside the StringEditor (or calling
the Edit function) initiates an edit. Subsequent keyboard events, which need
not be inside the StringEditor, are interpreted as editing operations on the
text. Clicking outside the StringEdit terminates the edit. StringEditor works
with either fixed width or proportionally spaced fonts.
EDITING MODEL¶
Text is selected with the mouse or with the keyboard. A single click of the left
mouse button selects a new insertion point between characters. Dragging across
the text selects a range of characters. A set of control characters is mapped
into common editing operations. A character not specifically associated with
commands is inserted in place of the the current selection, the replaced text
is lost, and the selection becomes an insertion point following the inserted
character. Commands currently defined include the following.
- CharacterLeft (^B)
- CharacterRight (^F)
- BeginningOfText (^A)
- EndOfText (^E)
- Move the selection one character position to the left or right, or to the
beginning or end of the text.
- Erase (^H, DEL)
- Delete (^D)
- Delete the text of the current selection. If the selection is an insertion
point, delete the previous character (Erase) or the next character
(Delete) instead.
- SelectAll (^U)
- SelectWord (^W)
- Select the entire text, or extend the selection to the left by one whole
word. These commands enable common editing operations to be performed
without using the mouse. For example, to replace the previous word in the
text, do a SelectWord and type the new text.
Strings that are too long to fit into the StringEditor can be scrolled
horizontally. Middle-clicking inside the StringBrowser initiates
``grab-scrolling''. While the button is held down, the StringEditor scrolls
the text to follow the mouse position, making it appear as though the user is
dragging the test. Right-clicking engages ``rate-scrolling,'' a joy-stick-like
scrolling interface in which the scrolling rate increases as the user drags
the mouse away from the initial click point. For example, dragging the mouse
rightwards after the initial click scrolls the browser rightwards at an
increasing rate; dragging leftwards thereafter reduces the rate until
scrolling stops entirely at the initial click point. Dragging left beyond this
point makes the browser scroll in the reverse direction.
PUBLIC OPERATIONS¶
- StringEditor(ButtonState*, const char* sample, const char*
done)
- Create a new StringEditor object. The ButtonState will be used to
communicate the result of editing operations. An edit of the string will
be terminated if any character in the string done is typed, and the
ButtonState will be set to the terminating character. The shape of the new
object is calculated from the length of the sample string.
- void Message(const char* text)
- Set the contents of the edit buffer to text.
- void Select(int point)
- void Select(int left, int right)
- Select an insertion point or a subrange of the edit buffer.
- void Edit()
- void Edit(const char* text, int left, int right)
- Initiate an edit. Specifying a string and selection range is short hand
for first calling Message and Select with the corresponding
parameters.
- const char* Text()
- Return the current value of the edit buffer. Note that this buffer is
owned by the StringEditor, and that its contents are subject to change. It
is the caller's responsibility to copy the string if the value will be
needed in the long term.
- Handle(Event&)
- Handle the event, and read and process subsequent events until an Accept
or Cancel command is executed or a down click occurs outside the
StringEditor's bounds.
PROTECTED OPERATIONS¶
- virtual boolean HandleChar(char)
- void InsertText(const char* text, int length)
- Subclasses of StringEditor can perform additional processing on the edit
buffer. For instance, an editor for file names might do file name
completion, or an editor for numeric input might check the validity of the
string as it is entered. Derived classes should redefine the virtual
function HandleChar as required. HandleChar should return true to indicate
that the edit is completed, or false otherwise. InsertText can be used to
insert text into the edit buffer, replacing any currently selected
text.
SEE ALSO¶
Interactor(3I), Button(3I)