StringEditor (3I)

#include <InterViews/streditor.h>

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.

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.

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.

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.

Interactor(3I), Button(3I)