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)