org.gnu.gtk

Class TextView


public class TextView
extends Container

Widget for displaying textual data.

Conceptual Overview

java-gnome has an extremely powerful framework for multiline text editing. The primary objects involved in the process are TextBuffer, which represents the text being edited, and TextView, a widget which can display a TextBuffer. Each buffer can be displayed by any number of views.

One of the important things to remember about text in java-gnome is that it's in the UTF-8 encoding. This means that one character can be encoded as multiple bytes. Character counts are usually referred to as offsets, while byte counts are called indexes. If you confuse these two, things will work fine with ASCII, but as soon as your buffer contains multibyte characters, bad things will happen.

Text in a buffer can be marked with tags. A tag is an attribute that can be applied to some range of text. For example, a tag might be called "bold" and make the text inside the tag bold. However, the tag concept is more general than that; tags don't have to affect appearance. They can instead affect the behavior of mouse and key presses, "lock" a range of text so the user can't edit it, or countless other things. A tag is represented by a TextTag object. One TextTag can be applied to any number of text ranges in any number of buffers.

Each tag is stored in a TextTagTable. A tag table defines a set of tags that can be used together. Each buffer has one tag table associated with it; only tags from that tag table can be used with the buffer. A single tag table can be shared between multiple buffers, however.

Tags can have names, which is convenient sometimes (for example, you can name your tag that makes things bold "bold"), but they can also be anonymous (which is convenient if you're creating tags on-the-fly).

Most text manipulation is accomplished with iterators, represented by a TextIter. An iterator represents a position between two characters in the text buffer. Iterators are not valid indefinitely; whenever the buffer is modified in a way that affects the number of characters in the buffer, all outstanding iterators become invalid. (Note that deleting 5 characters and then reinserting 5 still invalidates iterators, though you end up with the same number of characters you pass through a state with a different number).

Because of this, iterators can't be used to preserve positions across buffer modifications. To preserve a position, the TextMark object is ideal. You can think of a mark as an invisible cursor or insertion point; it floats in the buffer, saving a position. If the text surrounding the mark is deleted, the mark remains in the position the text once occupied; if text is inserted at the mark, the mark ends up either to the left or to the right of the new text, depending on its gravity. The standard text cursor in left-to-right languages is a mark with right gravity, because it stays to the right of inserted text.

Like tags, marks can be either named or anonymous. There are two marks built-in to TextBuffer; these are named "insert" and "selection_bound" and refer to the insertion point and the boundary of the selection which is not the insertion point, respectively. If no text is selected, these two marks will be in the same position. You can manipulate what is selected and where the cursor appears by moving these marks around.

Text buffers always contain at least one line, but may be empty (that is, buffers can contain zero characters). The last line in the text buffer never ends in a line separator (such as newline); the other lines in the buffer always end in a line separator. Line separators count as characters when computing character counts and character offsets. Note that some Unicode line separators are represented with multiple bytes in UTF-8, and the two-character sequence "\r\n" is also considered a line separator.

Nested Class Summary

static class
TextView.VerticalLineRange
Class to handle returns from TextView.VerticalLineRange.

Constructor Summary

TextView()
Constructs a new TextView.
TextView(Handle handle)
Construct a TextView from a handle to a native resource.
TextView(TextBuffer buffer)
Creates a new TextView widget displaying the buffer buffer.

Method Summary

void
addChild(Widget child, TextChildAnchor anchor)
Adds a child widget in the text buffer, at the given anchor.
void
addListener(TextViewListener listener)
Register an object to receive text view event notification.
Point
bufferToWindowCoords(TextWindowType winType, int xCoord, int yCoord)
Converts coordinate (xCoord, yCoord) to coordinates for the window winType.
boolean
getAcceptsTab()
Returns whether pressing the Tab key inserts a tab characters.
int
getBorderWindowSize(TextWindowType type)
Gets the width of the specified border window.
TextBuffer
getBuffer()
Returns the buffer being used
boolean
getCursorVisible()
Find out whether the cursor is being displayed.
TextAttributes
getDefaultAttributes()
Obtains a copy of the default text attributes.
boolean
getEditable()
Returns the default editability of the GtkTextView.
Class
getEventListenerClass(String signal)
EventType
getEventType(String signal)
Adjustment
getHAdjustment()
int
getIndent()
Gets the default indentation of paragraphs in text_view.
TextIter
getIterAtLocation(int x, int y)
Returns an iterator for the location pointed to by the coordinates x and y within the buffer.
TextIter
getIterAtLocation(Point bufferCoords)
Returns an iterator for the location pointed to by bufferCoords, representing coordinates within the buffer.
Justification
getJustification()
Gets the default justification of text in this TextView.
int
getLeftMargin()
Gets the default left margin size of paragraphs in the TextView.
TextView.VerticalLineRange
getLineYRange(TextIter iter)
Gets the y coordinate of the top of the line containing iter, and the height of the line.
boolean
getOverwrite()
Returns whether the TextView is in overwrite mode or not.
int
getPixelsAboveLines()
Gets the default number of pixels to put above paragraphs.
int
getPixelsBelowLines()
Gets the default number of pixels of blank space to put below paragraphs.
int
getPixelsInsideWrap()
Gets the default number of pixels of blank space to leave between display/wrapped lines within a paragraph.
int
getRightMargin()
Gets the default right margin size of paragraphs in the TextView.
TabArray
getTabs()
Gets the default tabs for text_view.
static TextView
getTextView(Handle handle)
Internal static factory method to be used by Java-Gnome only.
static Type
getType()
Retrieve the runtime type used by the GLib library.
Adjustment
getVAdjustment()
Rectangle
getVisibleRectangle()
Returns a Rectangle with the currently-visible region of the buffer, in buffer coordinates.
Window
getWindow(TextWindowType type)
Retrieves the Window corresponding to an area of the text view; possible windows include the overall widget window, child windows on the left, right, top, bottom, and the window that displays the text buffer.
TextWindowType
getWindowType(Window win)
Usually used to find out which window an event corresponds to.
WrapMode
getWrapMode()
Gets the line wrapping for the view.
boolean
moveCursorOnScreen()
Moves the cursor to the currently visible region of the buffer, it it isn't there already.
boolean
moveMarkOnScreen(TextMark mark)
Moves a mark within the buffer so that it's located within the currently-visible text area.
void
removeListener(TextViewListener listener)
Unregister an object that was receiving text view event notification.
void
scrollMarkOnScreen(TextMark mark)
Scrolls this the minimum distance such that mark is contained within the visible area of the widget.
boolean
scrollToIter(TextIter iter, double withinMargin)
Scrolls text view so that iter is on the screen.
boolean
scrollToIter(TextIter iter, double withinMargin, double xAlign, double yAlign)
Scrolls text view so that iter is on the screen in the position indicated by xalign and yalign.
void
scrollToMark(TextMark mark, double withinMargin)
Scrolls the view so that mark is on the screen.
void
scrollToMark(TextMark mark, double withinMargin, boolean useAlign, double xAlign, double yAlign)
Scrolls the view so that mark is on the screen in the position indicated by xAlign and yAlign.
void
setAcceptsTab(boolean acceptsTab)
Sets the behavior of the text widget when the Tab key is pressed.
void
setBorderWindowSize(TextWindowType type, int size)
Sets the width of the TextWindowType.LEFT or TextWindowType.RIGHT windows, or the height of TextWindowType.TOP or TextWindowType.BOTTOM Windows.
void
setBuffer(TextBuffer buffer)
Sets buffer as the buffer being displayed by the view.
void
setCursorVisible(boolean setting)
Toggles whether the insertion point is displayed.
void
setEditable(boolean setting)
Sets the default editability of the GtkTextView.
void
setIndent(int indent)
Sets the default indentation for paragraphs in text_view.
void
setJustification(Justification justification)
Sets the default justification of text in text_view.
void
setLeftMargin(int leftMargin)
Sets the default left margin for text in text_view.
void
setOverwrite(boolean overwrite)
Changes the overwrite mode (whether text is overwritten)
void
setPixelsAboveLines(int pixelsAboveLines)
Sets the default number of blank pixels above paragraphs in text_view.
void
setPixelsBelowLine(int pixelsBelowLines)
Deprecated. Use setPixelsBelowLines(int) instead.
void
setPixelsBelowLines(int pixelsBelowLines)
Sets the default number of pixels of blank space to put below paragraphs in text_view.
void
setPixelsInsideWrap(int pixelsInsideWrap)
Sets the default number of pixels of blank space to leave between display/wrapped lines within a paragraph.
void
setRightMargin(int rightMargin)
Sets the default right margin for text in text_view.
void
setTabs(TabArray tabStops)
Sets the default tab stops for paragraphs in text_view.
void
setWrapMode(WrapMode wrapMode)
Sets the line wrapping for the view.
Point
windowToBufferCoords(TextWindowType winType, int xCoord, int yCoord)
Converts coordinates on the window identified by the winType to buffer coordinates.

Methods inherited from class org.gnu.gtk.Container

add, addListener, getBooleanChildProperty, getBorderWidth, getChildProperty, getChildren, getEventListenerClass, getEventType, getIntChildProperty, getResizeMode, getType, remove, removeListener, resizeChildren, setBooleanChildProperty, setBorderWidth, setChildProperty, setIntChildProperty, setResizeMode

Methods inherited from class org.gnu.gtk.Widget

activate, addAccelerator, addEvents, addListener, addListener, addListener, addListener, addListener, addListener, addListener, addListener, addListener, addListener, addListener, canActivateAccel, createContext, createLayout, draw, drawArea, drawArea, finish, getAccessible, getAllocation, getCanFocus, getColormap, getContext, getData, getDisplay, getDragData, getEventListenerClass, getEventType, getExtensionEvents, getModifierStyle, getName, getParent, getParentWindow, getPointer, getRootWindow, getScreen, getSensitive, getStyle, getToplevel, getType, getWidget, getWindow, grabDefault, grabFocus, hasFocus, hasScreen, hide, hideAll, highlight, highlight, intersect, isAncestor, makeWidget, modifyStyle, popColormap, pushColormap, realize, removeAccelerator, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, removeListener, reparent, setBackgroundColor, setBaseColor, setCanFocus, setColormap, setDoubleBuffered, setDragDestination, setDragIcon, setDragIconPixbuf, setDragIconStock, setDragSource, setEvents, setExtensionEvents, setFont, setForegroundColor, setMinimumSize, setName, setNoDragDestination, setNoDragSource, setSensitive, setTextColor, shapeCombineMask, show, showAll, unHighlight, unHighlight

Methods inherited from class org.gnu.gtk.GtkObject

destroy, getType, sink

Constructor Details

TextView

public TextView()
Constructs a new TextView. If you don't specify a buffer before using it, a default one will be created for you.

TextView

public TextView(Handle handle)
Construct a TextView from a handle to a native resource.

TextView

public TextView(TextBuffer buffer)
Creates a new TextView widget displaying the buffer buffer. One buffer can be shared among many widgets.
Parameters:
buffer - Buffer to use

Method Details

addChild

public void addChild(Widget child,
                     TextChildAnchor anchor)
Adds a child widget in the text buffer, at the given anchor.
Parameters:
child - A Widget
anchor - A TextChildAnchor in the TextBuffer for his view

addListener

public void addListener(TextViewListener listener)
Register an object to receive text view event notification.
Parameters:
listener - The object that has implemented the TextViewListener interface that is to receive the text view events.

bufferToWindowCoords

public Point bufferToWindowCoords(TextWindowType winType,
                                  int xCoord,
                                  int yCoord)
Converts coordinate (xCoord, yCoord) to coordinates for the window winType. Note that you can't convert coordinates for a non-existing window (see setBorderWindowSize(TextWindowType,int).
Parameters:
winType - a TextWindowType
xCoord - buffer X coordinate
yCoord - buffer Y coordinate
Returns:
the corresponding window coordinates

getAcceptsTab

public boolean getAcceptsTab()
Returns whether pressing the Tab key inserts a tab characters.
Since:
2.4

getBorderWindowSize

public int getBorderWindowSize(TextWindowType type)
Gets the width of the specified border window.
Parameters:
type - The window to return size from
Returns:
The size of the window
See Also:
.

getBuffer

public TextBuffer getBuffer()
Returns the buffer being used
Returns:
The buffer used in the widget.

getCursorVisible

public boolean getCursorVisible()
Find out whether the cursor is being displayed.
Returns:
Whether the insertion cursor is visible

getDefaultAttributes

public TextAttributes getDefaultAttributes()
Obtains a copy of the default text attributes. These are the attributes used for text unless a tag overrides them.
Returns:
The text attributes being used

getEditable

public boolean getEditable()
Returns the default editability of the GtkTextView. Tags in the buffer may override this setting for some ranges of text.
Returns:
true if the widget is editable.

getEventListenerClass

public Class getEventListenerClass(String signal)
Overrides:
getEventListenerClass in interface Container

getEventType

public EventType getEventType(String signal)
Overrides:
getEventType in interface Container

getHAdjustment

public Adjustment getHAdjustment()

getIndent

public int getIndent()
Gets the default indentation of paragraphs in text_view. Tags in the view's buffer may override the default. The indentation may be negative.
Returns:
The number of pixels of indentation

getIterAtLocation

public TextIter getIterAtLocation(int x,
                                  int y)
Returns an iterator for the location pointed to by the coordinates x and y within the buffer. Coordinates obtained in relation to the widget must be converted to buffer coordinates using windowToBufferCoords before passing them into this method.
Parameters:
x - x buffer coordinate
y - y buffer coordinate
Returns:
an iterator to a given x-y coordinate location

getIterAtLocation

public TextIter getIterAtLocation(Point bufferCoords)
Returns an iterator for the location pointed to by bufferCoords, representing coordinates within the buffer. Coordinates obtained in relation to the widget must be converted to buffer coordinates using windowToBufferCoords.
Parameters:
bufferCoords - a Point representing a pair of buffer coordinates
Returns:
an iterator to a given x-y coordinate location

getJustification

public Justification getJustification()
Gets the default justification of text in this TextView. Tags in the buffer may override the default.
Returns:
The default justification

getLeftMargin

public int getLeftMargin()
Gets the default left margin size of paragraphs in the TextView. Tags in the buffer may override the default.
Returns:
The left margin, in pixels

getLineYRange

public TextView.VerticalLineRange getLineYRange(TextIter iter)
Gets the y coordinate of the top of the line containing iter, and the height of the line. The coordinate is a buffer coordinate; convert to window coordinates with windowToBufferCoords(TextWindowType,int,int).
Parameters:
iter - A valid TextIter
Returns:
The y-coordinate and Height of the line containing iter

getOverwrite

public boolean getOverwrite()
Returns whether the TextView is in overwrite mode or not.
Since:
2.4

getPixelsAboveLines

public int getPixelsAboveLines()
Gets the default number of pixels to put above paragraphs.
Returns:
the default number of pixels to put above paragraphs.

getPixelsBelowLines

public int getPixelsBelowLines()
Gets the default number of pixels of blank space to put below paragraphs.
Returns:
the default number of pixels of blank space to put below paragraphs

getPixelsInsideWrap

public int getPixelsInsideWrap()
Gets the default number of pixels of blank space to leave between display/wrapped lines within a paragraph.
Returns:
the default number of pixels of blank space to leave between display/wrapped lines within a paragraph.

getRightMargin

public int getRightMargin()
Gets the default right margin size of paragraphs in the TextView. Tags in the buffer may override the default.
Returns:
The right margin, in pixels

getTabs

public TabArray getTabs()
Gets the default tabs for text_view. Tags in the buffer may override the defaults. The returned array will be NULL if "standard" (8-space) tabs are used.

getTextView

public static TextView getTextView(Handle handle)
Internal static factory method to be used by Java-Gnome only.

getType

public static Type getType()
Retrieve the runtime type used by the GLib library.
Overrides:
getType in interface Container

getVAdjustment

public Adjustment getVAdjustment()

getVisibleRectangle

public Rectangle getVisibleRectangle()
Returns a Rectangle with the currently-visible region of the buffer, in buffer coordinates. Convert to window coordinates with bufferToWindowCoords(TextWindowType,int,int).

getWindow

public Window getWindow(TextWindowType type)
Retrieves the Window corresponding to an area of the text view; possible windows include the overall widget window, child windows on the left, right, top, bottom, and the window that displays the text buffer. Windows are null and nonexistent if their width or height is 0, and are nonexistent before the widget has been realized.
Parameters:
type - The window to get
Returns:
The window, or null

getWindowType

public TextWindowType getWindowType(Window win)
Usually used to find out which window an event corresponds to.
Parameters:
win - A window
Returns:
The type of the window

getWrapMode

public WrapMode getWrapMode()
Gets the line wrapping for the view.
Returns:
the line wrap setting for the view.

moveCursorOnScreen

public boolean moveCursorOnScreen()
Moves the cursor to the currently visible region of the buffer, it it isn't there already.
Returns:
TRUE if the cursor had to be moved.

moveMarkOnScreen

public boolean moveMarkOnScreen(TextMark mark)
Moves a mark within the buffer so that it's located within the currently-visible text area.
Returns:
TRUE if the mark had to be moved.

removeListener

public void removeListener(TextViewListener listener)
Unregister an object that was receiving text view event notification.
Parameters:
listener - The object that is to no longer receive text view events.

scrollMarkOnScreen

public void scrollMarkOnScreen(TextMark mark)
Scrolls this the minimum distance such that mark is contained within the visible area of the widget.
Parameters:
mark - a mark in the buffer of the TextView.

scrollToIter

public boolean scrollToIter(TextIter iter,
                            double withinMargin)
Scrolls text view so that iter is on the screen. The effective screen for purposes of this function is reduced by a margin of size within_margin. NOTE: This function uses the currently-computed height of the lines in the text buffer. Note that line heights are computed in an idle handler; so this function may not have the desired effect if it's called before the height computations. To avoid oddness, consider using gtk_text_view_scroll_to_mark() which saves a point to be scrolled to after line validation.
Parameters:
iter - a TextIter
withinMargin - Margin as a [0.0,0.5) fraction of screen size.
Returns:
TRUE if scrolling occurred

scrollToIter

public boolean scrollToIter(TextIter iter,
                            double withinMargin,
                            double xAlign,
                            double yAlign)
Scrolls text view so that iter is on the screen in the position indicated by xalign and yalign. An alignment of 0.0 indicates left or top, 1.0 indicates right or bottom, 0.5 means center. The effective screen for purposes of this function is reduced by a margin of size within_margin. NOTE: This function uses the currently-computed height of the lines in the text buffer. Note that line heights are computed in an idle handler; so this function may not have the desired effect if it's called before the height computations. To avoid oddness, consider using scrollToMark(TextMark,double,boolean,double,double) which saves a point to be scrolled to after line validation.
Parameters:
iter - a TextIter
withinMargin - Margin as a [0.0,0.5) fraction of screen size.
xAlign - : horizontal alignment of mark within visible area.
yAlign - : vertical alignment of mark within visible area
Returns:
TRUE if scrolling occurred

scrollToMark

public void scrollToMark(TextMark mark,
                         double withinMargin)
Scrolls the view so that mark is on the screen. The text scrolls the minimal distance to get the mark onscreen, possibly not scrolling at all. The effective screen for purposes of this function is reduced by a margin of size withinMargin.
Parameters:
mark - A TextMark
withinMargin - Margin as a fraction of screen size

scrollToMark

public void scrollToMark(TextMark mark,
                         double withinMargin,
                         boolean useAlign,
                         double xAlign,
                         double yAlign)
Scrolls the view so that mark is on the screen in the position indicated by xAlign and yAlign. An alignment of 0.0 indicates left or top, 1.0 indicates right or bottom, 0.5 means center.
Parameters:
mark - A TextMark
withinMargin - Margin as a fraction of screen size
useAlign - Whether to use alignment arguments.
xAlign - Horizontal alignment of mark within visible area.
yAlign - : vertical alignment of mark within visible area

setAcceptsTab

public void setAcceptsTab(boolean acceptsTab)
Sets the behavior of the text widget when the Tab key is pressed. If TRUE, a tab character is inserted. If is FALSE, the keyboard focus is moved to the next widget in the focus chain.
Parameters:
acceptsTab - TRUE if pressing the Tab key should insert a tab character, FALSE, if pressing the Tab key should move the keyboard focus
Since:
2.4

setBorderWindowSize

public void setBorderWindowSize(TextWindowType type,
                                int size)
Sets the width of the TextWindowType.LEFT or TextWindowType.RIGHT windows, or the height of TextWindowType.TOP or TextWindowType.BOTTOM Windows. Automatically destroys the corresponding window if the size is set to 0, and creates the window if the size is set to non-zero. This function can only be used for the "border windows," it doesn't work with TextWindowType.WIDGET, TextWindowType.TEXT, or TextWindowType.PRIVATE.
Parameters:
type - The window to affect
size - Width or height of the window

setBuffer

public void setBuffer(TextBuffer buffer)
Sets buffer as the buffer being displayed by the view.
Parameters:
buffer - The new buffer to display

setCursorVisible

public void setCursorVisible(boolean setting)
Toggles whether the insertion point is displayed. A buffer with no editable text probably shouldn't have a visible cursor, so you may want to turn the cursor off.
Parameters:
setting - Whether to show the insertion cursor

setEditable

public void setEditable(boolean setting)
Sets the default editability of the GtkTextView. You can override this default setting with tags in the buffer, using the "editable" attribute of tags.
Parameters:
setting - Whether it's editable

setIndent

public void setIndent(int indent)
Sets the default indentation for paragraphs in text_view. Tags in the buffer may override the default.
Parameters:
indent - Indentation in pixels

setJustification

public void setJustification(Justification justification)
Sets the default justification of text in text_view. Tags in the view's buffer may override the default.
Parameters:
justification - The justification to use.

setLeftMargin

public void setLeftMargin(int leftMargin)
Sets the default left margin for text in text_view. Tags in the buffer may override the default.
Parameters:
leftMargin - Size of left margin, in pixels

setOverwrite

public void setOverwrite(boolean overwrite)
Changes the overwrite mode (whether text is overwritten)
Parameters:
overwrite - TRUE to turn on overwrite mode, FALSE to turn it off
Since:
2.4

setPixelsAboveLines

public void setPixelsAboveLines(int pixelsAboveLines)
Sets the default number of blank pixels above paragraphs in text_view. Tags in the buffer for text_view may override the defaults.
Parameters:
pixelsAboveLines - Pixels above paragraphs

setPixelsBelowLine

public void setPixelsBelowLine(int pixelsBelowLines)

Deprecated. Use setPixelsBelowLines(int) instead.

Sets the default number of pixels of blank space to put below paragraphs in text_view. May be overridden by tags applied to text_view's buffer.
Parameters:
pixelsBelowLines - Pixels below paragraphs

setPixelsBelowLines

public void setPixelsBelowLines(int pixelsBelowLines)
Sets the default number of pixels of blank space to put below paragraphs in text_view. May be overridden by tags applied to text_view's buffer.
Parameters:
pixelsBelowLines - Pixels below paragraphs

setPixelsInsideWrap

public void setPixelsInsideWrap(int pixelsInsideWrap)
Sets the default number of pixels of blank space to leave between display/wrapped lines within a paragraph. May be overridden by tags in text_view's buffer.
Parameters:
pixelsInsideWrap - Default number of pixels between wrapped lines

setRightMargin

public void setRightMargin(int rightMargin)
Sets the default right margin for text in text_view. Tags in the buffer may override the default.
Parameters:
rightMargin - Size of right margin, in pixels

setTabs

public void setTabs(TabArray tabStops)
Sets the default tab stops for paragraphs in text_view. Tags in the buffer may override the default.
Parameters:
tabStops - tabs as a PangoTabArray

setWrapMode

public void setWrapMode(WrapMode wrapMode)
Sets the line wrapping for the view.
Parameters:
wrapMode - A WrapMode

windowToBufferCoords

public Point windowToBufferCoords(TextWindowType winType,
                                  int xCoord,
                                  int yCoord)
Converts coordinates on the window identified by the winType to buffer coordinates.
Parameters:
winType - a TextWindowType.
xCoord - the x-coordinate in relation to the Window win
yCoord - the y-coordinate in relation to the Window win
Returns:
a Point representing the buffer coordinates