javax.swing.text
Class PlainView

java.lang.Object
  javax.swing.text.View
      javax.swing.text.PlainView

All Implemented Interfaces:

SwingConstants, TabExpander

Direct Known Subclasses:

FieldView

public class PlainView

extends View

implements TabExpander

Implements View interface for a simple multi-line text view that has text in one font and color. The view represents each child element as a line of text.

Author:

Timothy Prinzing

See Also:

View

Field Summary

(package private) int	firstLineOffset Offset of where to draw the first character on the first line.
(package private) Font	font Font used to calculate the longest line... if this changes we need to recalculate the longest line
(package private) Segment	lineBuffer
(package private) Element	longLine The current longest line.
protected FontMetrics	metrics Font metrics for the current font.
(package private) int	sel0
(package private) int	sel1
(package private) Color	selected
(package private) int	tabBase
(package private) int	tabSize
(package private) Color	unselected

Fields inherited from class javax.swing.text.View

BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, sharedBiasReturn, X_AXIS, Y_AXIS

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Constructor Summary

PlainView(Element elem)
Constructs a new PlainView wrapped on an element.

Method Summary

(package private) Shape	adjustPaintRegion(Shape a) Should return a shape ideal for painting based on the passed in Shape a.
private void	calculateLongestLine() Iterate over the lines represented by the child elements of the element this view represents, looking for the line that is the longest.
void	changedUpdate(DocumentEvent changes, Shape a, ViewFactory f) Gives notification from the document that attributes were changed in a location that this view is responsible for.
protected void	damageLineRange(int line0, int line1, Shape a, Component host) Repaint the given line range.
private int	drawElement(int lineIndex, Element elem, Graphics g, int x, int y)
protected void	drawLine(int lineIndex, Graphics g, int x, int y) Renders a line of text, suppressing whitespace at the end and expanding any tabs.
protected int	drawSelectedText(Graphics g, int x, int y, int p0, int p1) Renders the given range in the model as selected text.
protected int	drawUnselectedText(Graphics g, int x, int y, int p0, int p1) Renders the given range in the model as normal unselected text.
protected Segment	getLineBuffer() Gives access to a buffer that can be used to fetch text from the associated document.
private int	getLineWidth(Element line) Calculate the width of the line represented by the given element.
float	getPreferredSpan(int axis) Determines the preferred span for this view along an axis.
protected int	getTabSize() Returns the tab size set for the document, defaulting to 8.
void	insertUpdate(DocumentEvent changes, Shape a, ViewFactory f) Gives notification that something was inserted into the document in a location that this view is responsible for.
protected Rectangle	lineToRect(Shape a, int line) Determine the rectangle that represents the given line.
Shape	modelToView(int pos, Shape a, Position.Bias b) Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
float	nextTabStop(float x, int tabOffset) Returns the next tab stop position after a given reference position.
void	paint(Graphics g, Shape a) Renders using the given rendering surface and area on that surface.
void	removeUpdate(DocumentEvent changes, Shape a, ViewFactory f) Gives notification that something was removed from the document in a location that this view is responsible for.
void	setSize(float width, float height) Sets the size of the view.
protected void	updateDamage(DocumentEvent changes, Shape a, ViewFactory f)
protected void	updateMetrics() Checks to see if the font metrics and longest line are up-to-date.
int	viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) Provides a mapping from the view coordinate space to the logical coordinate space of the model.

Methods inherited from class javax.swing.text.View

append, breakView, createFragment, forwardUpdate, forwardUpdateToView, getAlignment, getAttributes, getBreakWeight, getChildAllocation, getContainer, getDocument, getElement, getEndOffset, getGraphics, getMaximumSpan, getMinimumSpan, getNextVisualPositionFrom, getParent, getResizeWeight, getStartOffset, getToolTipText, getView, getViewCount, getViewFactory, getViewIndex, getViewIndex, insert, isVisible, modelToView, modelToView, preferenceChanged, remove, removeAll, replace, setParent, updateChildren, updateLayout, viewToModel

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

metrics

protected FontMetrics metrics

Font metrics for the current font.

longLine

Element longLine

The current longest line. This is used to calculate the preferred width of the view. Since the calculation is potentially expensive we try to avoid it by stashing which line is currently the longest.

font

Font font

Font used to calculate the longest line... if this changes we need to recalculate the longest line

lineBuffer

Segment lineBuffer

tabSize

int tabSize

tabBase

int tabBase

sel0

int sel0

sel1

int sel1

unselected

Color unselected

selected

Color selected

firstLineOffset

int firstLineOffset

Offset of where to draw the first character on the first line. This is a hack and temporary until we can better address the problem of text measuring. This field is actually never set directly in PlainView, but by FieldView.

Constructor Detail

PlainView

public PlainView(Element elem)

Constructs a new PlainView wrapped on an element.

Parameters:

elem - the element

Method Detail

getTabSize

protected int getTabSize()

Returns the tab size set for the document, defaulting to 8.

Returns:

the tab size

drawLine

protected void drawLine(int lineIndex,
                        Graphics g,
                        int x,
                        int y)

Renders a line of text, suppressing whitespace at the end and expanding any tabs. This is implemented to make calls to the methods drawUnselectedText and drawSelectedText so that the way selected and unselected text are rendered can be customized.

Parameters:

lineIndex - the line to draw >= 0

g - the Graphics context

x - the starting X position >= 0

y - the starting Y position >= 0

See Also:

drawUnselectedText(java.awt.Graphics, int, int, int, int), drawSelectedText(java.awt.Graphics, int, int, int, int)

drawElement

private int drawElement(int lineIndex,
                        Element elem,
                        Graphics g,
                        int x,
                        int y)
                 throws BadLocationException

Throws:

BadLocationException

drawUnselectedText

protected int drawUnselectedText(Graphics g,
                                 int x,
                                 int y,
                                 int p0,
                                 int p1)
                          throws BadLocationException

Renders the given range in the model as normal unselected text. Uses the foreground or disabled color to render the text.

Parameters:

g - the graphics context

x - the starting X coordinate >= 0

y - the starting Y coordinate >= 0

p0 - the beginning position in the model >= 0

p1 - the ending position in the model >= 0

Returns:

the X location of the end of the range >= 0

Throws:

BadLocationException - if the range is invalid

drawSelectedText

protected int drawSelectedText(Graphics g,
                               int x,
                               int y,
                               int p0,
                               int p1)
                        throws BadLocationException

Renders the given range in the model as selected text. This is implemented to render the text in the color specified in the hosting component. It assumes the highlighter will render the selected background.

Parameters:

g - the graphics context

x - the starting X coordinate >= 0

y - the starting Y coordinate >= 0

p0 - the beginning position in the model >= 0

p1 - the ending position in the model >= 0

Returns:

the location of the end of the range

Throws:

BadLocationException - if the range is invalid

getLineBuffer

protected final Segment getLineBuffer()

Gives access to a buffer that can be used to fetch text from the associated document.

Returns:

the buffer

updateMetrics

protected void updateMetrics()

Checks to see if the font metrics and longest line are up-to-date.

Since:

1.4

getPreferredSpan

public float getPreferredSpan(int axis)

Determines the preferred span for this view along an axis.

Specified by:

getPreferredSpan in class View

Parameters:

axis - may be either View.X_AXIS or View.Y_AXIS

Returns:

the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view.

Throws:

IllegalArgumentException - for an invalid axis

See Also:

View.getPreferredSpan(int)

paint

public void paint(Graphics g,
                  Shape a)

Renders using the given rendering surface and area on that surface. The view may need to do layout and create child views to enable itself to render into the given allocation.

Specified by:

paint in class View

Parameters:

g - the rendering surface to use

a - the allocated region to render into

See Also:

View.paint(java.awt.Graphics, java.awt.Shape)

adjustPaintRegion

Shape adjustPaintRegion(Shape a)

Should return a shape ideal for painting based on the passed in Shape a. This is useful if painting in a different region. The default implementation returns a.

modelToView

public Shape modelToView(int pos,
                         Shape a,
                         Position.Bias b)
                  throws BadLocationException

Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

Specified by:

modelToView in class View

Parameters:

pos - the position to convert >= 0

a - the allocated region to render into

b - the bias toward the previous character or the next character represented by the offset, in case the position is a boundary of two views; b will have one of these values:

• Position.Bias.Forward
• Position.Bias.Backward

Returns:

the bounding box of the given position

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

See Also:

View.modelToView(int, java.awt.Shape, javax.swing.text.Position.Bias)

viewToModel

public int viewToModel(float fx,
                       float fy,
                       Shape a,
                       Position.Bias[] bias)

Provides a mapping from the view coordinate space to the logical coordinate space of the model.

Specified by:

viewToModel in class View

Parameters:

fx - the X coordinate >= 0

fy - the Y coordinate >= 0

a - the allocated region to render into

Returns:

the location within the model that best represents the given point in the view >= 0

See Also:

View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])

insertUpdate

public void insertUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)

Gives notification that something was inserted into the document in a location that this view is responsible for.

Overrides:

insertUpdate in class View

Parameters:

changes - the change information from the associated document

a - the current allocation of the view

f - the factory to use to rebuild if the view has children

See Also:

View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

removeUpdate

public void removeUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)

Gives notification that something was removed from the document in a location that this view is responsible for.

Overrides:

removeUpdate in class View

Parameters:

changes - the change information from the associated document

a - the current allocation of the view

f - the factory to use to rebuild if the view has children

See Also:

View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

changedUpdate

public void changedUpdate(DocumentEvent changes,
                          Shape a,
                          ViewFactory f)

Gives notification from the document that attributes were changed in a location that this view is responsible for.

Overrides:

changedUpdate in class View

Parameters:

changes - the change information from the associated document

a - the current allocation of the view

f - the factory to use to rebuild if the view has children

See Also:

View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

setSize

public void setSize(float width,
                    float height)

Sets the size of the view. This should cause layout of the view along the given axis, if it has any layout duties.

Overrides:

setSize in class View

Parameters:

width - the width >= 0

height - the height >= 0

nextTabStop

public float nextTabStop(float x,
                         int tabOffset)

Returns the next tab stop position after a given reference position. This implementation does not support things like centering so it ignores the tabOffset argument.

Specified by:

nextTabStop in interface TabExpander

Parameters:

x - the current position >= 0

tabOffset - the position within the text stream that the tab occurred at >= 0.

Returns:

the tab stop, measured in points >= 0

updateDamage

protected void updateDamage(DocumentEvent changes,
                            Shape a,
                            ViewFactory f)

damageLineRange

protected void damageLineRange(int line0,
                               int line1,
                               Shape a,
                               Component host)

Repaint the given line range.

Parameters:

host - the component hosting the view (used to call repaint)

a - the region allocated for the view to render into

line0 - the starting line number to repaint. This must be a valid line number in the model.

line1 - the ending line number to repaint. This must be a valid line number in the model.

Since:

1.4

lineToRect

protected Rectangle lineToRect(Shape a,
                               int line)

Determine the rectangle that represents the given line.

Parameters:

a - the region allocated for the view to render into

line - the line number to find the region of. This must be a valid line number in the model.

Since:

1.4

calculateLongestLine

private void calculateLongestLine()

Iterate over the lines represented by the child elements of the element this view represents, looking for the line that is the longest. The longLine variable is updated to represent the longest line contained. The font variable is updated to indicate the font used to calculate the longest line.

getLineWidth

private int getLineWidth(Element line)

Calculate the width of the line represented by the given element. It is assumed that the font and font metrics are up-to-date.