public class GlyphView extends View implements TabableView, Cloneable
A GlyphView is a styled chunk of text that represents a view mapped over an element in the text model. This view is generally responsible for displaying text glyphs using character level attributes in some way. An implementation of the GlyphPainter class is used to do the actual rendering and model/view translations. This separates rendering from layout and management of the association with the model.
The view supports breaking for the purpose of formatting. The fragments produced by breaking share the view that has primary responsibility for the element (i.e. they are nested classes and carry only a small amount of state of their own) so they can share its resources.
Since this view represents text that may have tabs embedded in it, it implements the TabableView interface. Tabs will only be expanded if this view is embedded in a container that does tab expansion. ParagraphView is an example of a container that does tab expansion.
| Modifier and Type | Class and Description |
|---|---|
static class |
GlyphView.GlyphPainter A class to perform rendering of the glyphs. |
BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST public GlyphView(Element elem)
Constructs a new view wrapped on an element.
elem - the elementprotected final Object clone()
Creates a shallow copy. This is used by the createFragment and breakView methods.
public GlyphView.GlyphPainter getGlyphPainter()
Fetch the currently installed glyph painter. If a painter has not yet been installed, and a default was not yet needed, null is returned.
public void setGlyphPainter(GlyphView.GlyphPainter p)
Sets the painter to use for rendering glyphs.
public Segment getText(int p0,
int p1) Fetch a reference to the text that occupies the given range. This is normally used by the GlyphPainter to determine what characters it should render glyphs for.
p0 - the starting document offset >= 0p1 - the ending document offset >= p0Segment containing the textpublic Color getBackground()
Fetch the background color to use to render the glyphs. If there is no background color, null should be returned. This is implemented to call StyledDocument.getBackground if the associated document is a styled document, otherwise it returns null.
public Color getForeground()
Fetch the foreground color to use to render the glyphs. If there is no foreground color, null should be returned. This is implemented to call StyledDocument.getBackground if the associated document is a StyledDocument. If the associated document is not a StyledDocument, the associated components foreground color is used. If there is no associated component, null is returned.
public Font getFont()
Fetch the font that the glyphs should be based upon. This is implemented to call StyledDocument.getFont if the associated document is a StyledDocument. If the associated document is not a StyledDocument, the associated components font is used. If there is no associated component, null is returned.
public boolean isUnderline()
Determine if the glyphs should be underlined. If true, an underline should be drawn through the baseline.
public boolean isStrikeThrough()
Determine if the glyphs should have a strikethrough line. If true, a line should be drawn through the center of the glyphs.
public boolean isSubscript()
Determine if the glyphs should be rendered as superscript.
public boolean isSuperscript()
Determine if the glyphs should be rendered as subscript.
public TabExpander getTabExpander()
Fetch the TabExpander to use if tabs are present in this view.
protected void checkPainter()
Check to see that a glyph painter exists. If a painter doesn't exist, a default glyph painter will be installed.
public float getTabbedSpan(float x,
TabExpander e) Determines the desired span when using the given tab expansion implementation.
getTabbedSpan in interface TabableView
x - the position the view would be located at for the purpose of tab expansion >= 0.e - how to expand the tabs when encountered.TabableView.getTabbedSpan(float, javax.swing.text.TabExpander)public float getPartialSpan(int p0,
int p1) Determines the span along the same axis as tab expansion for a portion of the view. This is intended for use by the TabExpander for cases where the tab expansion involves aligning the portion of text that doesn't have whitespace relative to the tab stop. There is therefore an assumption that the range given does not contain tabs.
This method can be called while servicing the getTabbedSpan or getPreferredSize. It has to arrange for its own text buffer to make the measurements.
getPartialSpan in interface TabableView
p0 - the starting document offset >= 0p1 - the ending document offset >= p0public int getStartOffset()
Fetches the portion of the model that this view is responsible for.
getStartOffset in class View
View.getStartOffset()public int getEndOffset()
Fetches the portion of the model that this view is responsible for.
getEndOffset in class View
View.getEndOffset()public void paint(Graphics g,
Shape a) Renders a portion of a text style run.
paint in class View
g - the rendering surface to usea - the allocated region to render intopublic float getMinimumSpan(int axis)
Determines the minimum span for this view along an axis.
This implementation returns the longest non-breakable area within the view as a minimum span for View.X_AXIS.
getMinimumSpan in class View
axis - may be either View.X_AXIS or View.Y_AXIS
IllegalArgumentException - if the axis parameter is invalidView.getMinimumSpan(int)public float getPreferredSpan(int axis)
Determines the preferred span for this view along an axis.
getPreferredSpan in class View
axis - may be either View.X_AXIS or View.Y_AXISView.getPreferredSpan(int)public float getAlignment(int axis)
Determines the desired alignment for this view along an axis. For the label, the alignment is along the font baseline for the y axis, and the superclasses alignment along the x axis.
getAlignment in class View
axis - may be either View.X_AXIS or View.Y_AXISpublic 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.
modelToView in class View
pos - the position to convert >= 0a - the allocated region to render intob - either Position.Bias.Forward or Position.Bias.Backward
BadLocationException - if the given position does not represent a valid location in the associated documentView.modelToView(int, java.awt.Shape, javax.swing.text.Position.Bias)public int viewToModel(float x,
float y,
Shape a,
Position.Bias[] biasReturn) Provides a mapping from the view coordinate space to the logical coordinate space of the model.
viewToModel in class View
x - the X coordinate >= 0y - the Y coordinate >= 0a - the allocated region to render intobiasReturn - either Position.Bias.Forward or Position.Bias.Backward is returned as the zero-th element of this arrayView.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])public int getBreakWeight(int axis,
float pos,
float len) Determines how attractive a break opportunity in this view is. This can be used for determining which view is the most attractive to call breakView on in the process of formatting. The higher the weight, the more attractive the break. A value equal to or lower than View.BadBreakWeight should not be considered for a break. A value greater than or equal to View.ForcedBreakWeight should be broken.
This is implemented to forward to the superclass for the Y_AXIS. Along the X_AXIS the following values may be returned.
getBreakWeight in class View
axis - may be either View.X_AXIS or View.Y_AXISpos - the potential location of the start of the broken view >= 0. This may be useful for calculating tab positions.len - specifies the relative length from pos where a potential break is desired >= 0.LabelView, ParagraphView, View.BadBreakWeight, View.GoodBreakWeight, View.ExcellentBreakWeight, View.ForcedBreakWeight
public View breakView(int axis,
int p0,
float pos,
float len) Breaks this view on the given axis at the given length. This is implemented to attempt to break on a whitespace location, and returns a fragment with the whitespace at the end. If a whitespace location can't be found, the nearest character is used.
breakView in class View
axis - may be either View.X_AXIS or View.Y_AXISp0 - the location in the model where the fragment should start it's representation >= 0.pos - the position along the axis that the broken view would occupy >= 0. This may be useful for things like tab calculations.len - specifies the distance along the axis where a potential break is desired >= 0.View.breakView(int, int, float, float)public View createFragment(int p0,
int p1) Creates a view that represents a portion of the element. This is potentially useful during formatting operations for taking measurements of fragments of the view. If the view doesn't support fragmenting (the default), it should return itself.
This view does support fragmenting. It is implemented to return a nested class that shares state in this view representing only a portion of the view.
createFragment in class View
p0 - the starting offset >= 0. This should be a value greater or equal to the element starting offset and less than the element ending offset.p1 - the ending offset > p0. This should be a value less than or equal to the elements end offset and greater than the elements starting offset.LabelViewpublic int getNextVisualPositionFrom(int pos,
Position.Bias b,
Shape a,
int direction,
Position.Bias[] biasRet)
throws BadLocationException Provides a way to determine the next visually represented model location that one might place a caret. Some views may not be visible, they might not be in the same order found in the model, or they just might not allow access to some of the locations in the model. This method enables specifying a position to convert within the range of >=0. If the value is -1, a position will be calculated automatically. If the value < -1, the BadLocationException will be thrown.
getNextVisualPositionFrom in class View
pos - the position to converta - the allocated region to render intodirection - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard. This may be SwingConstants.WEST, SwingConstants.EAST, SwingConstants.NORTH, or SwingConstants.SOUTH.BadLocationException - the given position is not a valid position within the documentIllegalArgumentException - for an invalid directionpublic void insertUpdate(DocumentEvent e,
Shape a,
ViewFactory f) Gives notification that something was inserted into the document in a location that this view is responsible for. This is implemented to call preferenceChanged along the axis the glyphs are rendered.
insertUpdate in class View
e - the change information from the associated documenta - the current allocation of the viewf - the factory to use to rebuild if the view has childrenView.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)public void removeUpdate(DocumentEvent e,
Shape a,
ViewFactory f) Gives notification that something was removed from the document in a location that this view is responsible for. This is implemented to call preferenceChanged along the axis the glyphs are rendered.
removeUpdate in class View
e - the change information from the associated documenta - the current allocation of the viewf - the factory to use to rebuild if the view has childrenView.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)public void changedUpdate(DocumentEvent e,
Shape a,
ViewFactory f) Gives notification from the document that attributes were changed in a location that this view is responsible for. This is implemented to call preferenceChanged along both the horizontal and vertical axis.
changedUpdate in class View
e - the change information from the associated documenta - the current allocation of the viewf - the factory to use to rebuild if the view has childrenView.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)
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