Fl_Text_Selection Class Reference

This is an internal class for Fl_Text_Buffer to manage text selections. More...

#include <Fl_Text_Buffer.H>

Public Member Functions
int	end () const
	Returns the byte offset to the character after the last selected character. More...
int	includes (int pos) const
	Returns true if position pos is in the Fl_Text_Selection. More...
int	length () const
	Returns the size in bytes of the selection. More...
int	position (int *startpos, int *endpos) const
bool	selected () const
	Returns true if any text is selected. More...
void	selected (bool b)
	Modifies the 'selected' flag. More...
int	selected (int *startpos, int *endpos) const
	Returns the status and the positions of this selection. More...
void	set (int startpos, int endpos)
	Sets the selection range. More...
int	start () const
	Returns the byte offset to the first selected character. More...
void	update (int pos, int nDeleted, int nInserted)
	Updates a selection after text was modified. More...

Protected Attributes
int	mEnd
	byte offset to the character after the last selected character
bool	mSelected
	this flag is set if any text is selected
int	mStart
	byte offset to the first selected character

Friends
class	Fl_Text_Buffer

Detailed Description

This is an internal class for Fl_Text_Buffer to manage text selections.

All methods use byte (not UTF-8 character) offsets and start at 0. This class works correctly with UTF-8 strings assuming that the parameters for all calls are on character boundaries.

If the selection is inactive (not currently used), then selected() returns false and start() and end() return 0 (zero).

The stored offsets are in ascending order, hence the following conditions are true (pseudo code):

if ( !selected() ) :  (start() == 0) && (end() == 0) && (start() == end())
if (  selected() ) :  start() < end()
always             :  0 <= start() <= end()
always             :  length() == end() - start()

The selection size in bytes can always (unconditionally) be computed by

int size = sel->end() - sel->start();

See also

length()

Note

The protected member variables mStart and mEnd are not necessarily 0 (zero) if mSelected == false because they are not cleared when selected(false) is called (as of Jul 2017). This may be changed in the future.

Member Function Documentation

end()

int Fl_Text_Selection::end ( void  ) const

inline

Returns the byte offset to the character after the last selected character.

The returned offset is only valid if selected() returns true (non-zero). The offset is 0 if no text is selected (since FLTK 1.4.0).

Note

In FLTK 1.3.x the returned offset could be non-zero even if selected() would have returned 0.

Returns

byte offset or 0 if not selected.

includes()

int Fl_Text_Selection::includes

(

int

pos

)

const

Returns true if position pos is in the Fl_Text_Selection.

pos must be at a character boundary.

length()

int Fl_Text_Selection::length ( void  ) const

inline

Returns the size in bytes of the selection.

This is a convenience method. It always returns the same as

end() - start()

and it returns 0 if selected() == false.

Returns

size in bytes or 0 if not selected.

Since

FLTK 1.4.0

position()

int Fl_Text_Selection::position ( int *  startpos, int *  endpos  ) const

inline

Deprecated:

"since 1.4.0 - use selected(startpos, endpos) instead"

selected() [1/3]

bool Fl_Text_Selection::selected ( ) const

inline

Returns true if any text is selected.

Returns

true if any text has been selected, or false if no text is selected.

selected() [2/3]

void Fl_Text_Selection::selected ( bool  b )

inline

Modifies the 'selected' flag.

Parameters

b

new flag

selected() [3/3]

int Fl_Text_Selection::selected	(	int *	startpos,
		int *	endpos
	)		const

Returns the status and the positions of this selection.

This method returns the same as selected() as an int (0 or 1) in its return value and the offsets to the start of the selection in startpos and to the byte after the last selected character in endpos, if selected() is true.

If selected() is false, both offsets are set to 0.

Note

In FLTK 1.3.x startpos and endpos were not modified if selected() was false.

Parameters

startpos	return byte offset to first selected character
endpos	return byte offset pointing after last selected character

Returns

whether the selection is active (selected()) or not

Return values

0	if not selected
1	if selected

See also

selected(), start(), end()

set()

void Fl_Text_Selection::set	(	int	startpos,
		int	endpos
	)

Sets the selection range.

startpos and endpos must be at a character boundary.

If startpos != endpos selected() is set to true, else to false.

If startpos is greater than endpos they are swapped so that startpos <= endpos.

Parameters

[in]	startpos	byte offset to first selected character
[in]	endpos	byte offset pointing after last selected character

start()

int Fl_Text_Selection::start ( ) const

inline

Returns the byte offset to the first selected character.

The returned offset is only valid if selected() returns true. If the selection is not valid the returned offset is 0 since FLTK 1.4.0.

Note

In FLTK 1.3.x the returned offset could be non-zero even if selected() would have returned 0.

Returns

byte offset or 0 if not selected.

update()

void Fl_Text_Selection::update	(	int	pos,
		int	nDeleted,
		int	nInserted
	)

Updates a selection after text was modified.

Updates an individual selection for changes in the corresponding text.

Parameters

pos	byte offset into text buffer at which the change occurred
nDeleted	number of bytes deleted from the buffer
nInserted	number of bytes inserted into the buffer

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The documentation for this class was generated from the following files:

• Fl_Text_Buffer.H
• Fl_Text_Buffer.cxx