TextDisplay - unstructured text display
A TextDisplay manages and displays an array of lines of text. Operations are
provided to insert and delete lines, to insert and delete text within a line,
and to scroll the display. TextDisplays are typically used to implement
interactors that require non-trivial display of unstructured text.
The array is addressed by a line number and an index into the
line. Text can be inserted or deleted at arbitrary positions. By default,
the first character in line number zero is positioned with its top left
corner at the top left corner of the TextDisplay. The display is
automatically updated following modifications to the text or when scrolling.
Each character in the array has an associated text style. Operations are
provided to apply, add, or remove font styles to a range of the text.
TextDisplay can be used with both constant-width and proportionally-spaced
fonts and with arbitrary geometric transformations.
- ~TextDisplay(boolean autosized = false)
- Create or destroy a TextDisplay. If autosized is true, the
TextDisplay will automatically grow its size as text is added. The default
is to keep the size constant.
- void LineHeight(Coord lineheight)
- void TabWidth(Coord tabwidth)
- Lines of text will be positioned with baselines separated by
lineheight. Tab characters in the text will cause the following
character to be positioned an integral multiple of tabwidth from
the beginning of the line.
- void Resize(Coord xmin, Coord ymin, Coord xmax, Coord ymax)
- void Bounds(Coord& xmin, Coord& ymin, Coord& xmax,
- Specify or query the size of the display. Only lines of text that fall
completely inside the specified region will be displayed. TextDisplay will
not draw on any part of the canvas outside the specified bounds.
Conversely, TextDisplay is free to draw on any part of the canvas within
the specified bounds.
- void Draw(Painter*, Canvas*)
- Specify the painter and canvas to use for drawing operations; the painter
specifies the font, colors, and geometric transformation. Draw should be
called before performing any operation on the TextDisplay which produces
output or requires graphical information, or when there is a possibility
that the painter or canvas has changed since the function was last
- void Redraw(Coord left, Coord bottom, Coord right, Coord top)
- Redraw a specified region of the display.
- void Scroll(int line, Coord x, Coord y)
- Scroll the display so that line line is positioned with its
upper-left corner at (x, y). There are no restrictions on
the arguments: it is possible to scroll the display so that no lines are
- void InsertLinesAfter(int line, int count)
- void InsertLinesBefore(int line, int count)
- void DeleteLinesAfter(int line, int count)
- void DeleteLinesBefore(int line, int count)
- Insert or delete whole lines of text. Line line is not affected by
the operation. Other lines will move up or down to accommodate the
changes. Newly inserted lines are blank. The specified line need not refer
to an existing line.
- void InsertText(int line, int index, const char*, int count)
- void DeleteText(int line, int index, int count)
- void ReplaceText(int line, const char*, int count)
- Modify the text within line line. InsertText and DeleteText will
cause the following characters on the line to move to accommodate the
changes. ReplaceText replaces the entire text of the line. If the
specified line is non-existent, a new line will be created.
- void Style(int line1, int index1, int line2, int index2, int
- void AddStyle(int line1, int index1, int line2, int index2, int
- void RemoveStyle(int line1, int index1, int line2, int index2, int
- Modify the styling of a range of text. Style replaces any existing style;
AddStyle adds style style in addition to any existing styles;
RemoveStyle removes style style without affecting other existing
styles. Styles are specified as any combination of the constants Plain,
Boldface, Underlined, and Reversed.
- void CaretStyle(int style)
- void Caret(int line, int index)
- Control the shape and position of a caret. Valid caret styles are
currently NoCaret, BarCaret, UnderscoreCaret and OutlineCaret. TextDisplay
does not automatically adjust the position of the caret following
insertions and deletions.
- int LineNumber(Coord y)
- int LineIndex(int line, Coord x)
- Map x and y display coordinates into line and index text coordinates.
LineNumber returns the number of the line that contains the specified
vertical position y. LineIndex returns the index into line
line that best corresponds to the specified horizontal position
- Coord Width()
- Coord Height()
- Return the width or the height of the text currently displayed by the
TextDisplay. Width returns the width of the longest line in the display.
Height returns the distance from the top of the topmost line to the bottom
of the bottommost line. Note that these dimensions do not necessarily
correspond to the TextDisplay's bounds as returned by Bounds.
- Coord Base(int line)
- Coord Top(int line)
- Coord Left(int line, int index)
- Coord Right(int line, int index)
- Map line and index text coordinates into x and y display coordinates. The
return values define a bounding box for the character specified by
line and index.