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WrappedPlainView.javaAPI DocJava SE 5 API26734Fri Aug 26 14:58:16 BST 2005javax.swing.text

WrappedPlainView

public class WrappedPlainView extends BoxView implements TabExpander
View of plain text (text with only one font and color) that does line-wrapping. This view expects that its associated element has child elements that represent the lines it should be wrapping. It is implemented as a vertical box that contains logical line views. The logical line views are nested classes that render the logical line as multiple physical line if the logical line is too wide to fit within the allocation. The line views draw upon the outer class for its state to reduce their memory requirements.

The line views do all of their rendering through the drawLine method which in turn does all of its rendering through the drawSelectedText and drawUnselectedText methods. This enables subclasses to easily specialize the rendering without concern for the layout aspects.

author
Timothy Prinzing
version
1.38 05/26/04
see
View

Fields Summary
FontMetrics
metrics
Segment
lineBuffer
boolean
widthChanging
int
tabBase
int
tabSize
boolean
wordWrap
int
sel0
int
sel1
Color
unselected
Color
selected
Constructors Summary
public WrappedPlainView(Element elem)
Creates a new WrappedPlainView. Lines will be wrapped on character boundaries.

param
elem the element underlying the view

	this(elem, false);
    
public WrappedPlainView(Element elem, boolean wordWrap)
Creates a new WrappedPlainView. Lines can be wrapped on either character or word boundaries depending upon the setting of the wordWrap parameter.

param
elem the element underlying the view
param
wordWrap should lines be wrapped on word boundaries?

	super(elem, Y_AXIS);
	this.wordWrap = wordWrap;
    
Methods Summary
protected intcalculateBreakPosition(int p0, int p1)
This is called by the nested wrapped line views to determine the break location. This can be reimplemented to alter the breaking behavior. It will either break at word or character boundaries depending upon the break argument given at construction.

	int p;
        Segment segment = SegmentCache.getSharedSegment();
	loadText(segment, p0, p1);
        int currentWidth = getWidth();
	if (wordWrap) {
	    p = p0 + Utilities.getBreakLocation(segment, metrics,
						tabBase, tabBase + currentWidth,
						this, p0);
	} else {
	    p = p0 + Utilities.getTabbedTextOffset(segment, metrics, 
						   tabBase, tabBase + currentWidth,
						   this, p0, false);
	}
        SegmentCache.releaseSharedSegment(segment);
	return p;
    
public voidchangedUpdate(javax.swing.event.DocumentEvent e, java.awt.Shape a, javax.swing.text.ViewFactory f)
Gives notification from the document that attributes were changed in a location that this view is responsible for.

param
e the change information from the associated document
param
a the current allocation of the view
param
f the factory to use to rebuild if the view has children
see
View#changedUpdate

        updateChildren(e, a);
    
protected voiddrawLine(int p0, int p1, java.awt.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.

param
p0 the starting document location to use >= 0
param
p1 the ending document location to use >= p1
param
g the graphics context
param
x the starting X position >= 0
param
y the starting Y position >= 0
see
#drawUnselectedText
see
#drawSelectedText

        Element lineMap = getElement();
	Element line = lineMap.getElement(lineMap.getElementIndex(p0));
	Element elem;

        try {
	    if (line.isLeaf()) {
	        drawText(line, p0, p1, g, x, y);
	    } else {
		// this line contains the composed text.
		int idx = line.getElementIndex(p0);
		int lastIdx = line.getElementIndex(p1);
		for(; idx <= lastIdx; idx++) {
		    elem = line.getElement(idx);
		    int start = Math.max(elem.getStartOffset(), p0);
		    int end = Math.min(elem.getEndOffset(), p1);
		    x = drawText(elem, start, end, g, x, y);
		}
	    }
        } catch (BadLocationException e) {
            throw new StateInvariantError("Can't render: " + p0 + "," + p1);
        }
    
protected intdrawSelectedText(java.awt.Graphics g, int x, int y, int p0, int p1)
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.

param
g the graphics context
param
x the starting X coordinate >= 0
param
y the starting Y coordinate >= 0
param
p0 the beginning position in the model >= 0
param
p1 the ending position in the model >= p0
return
the location of the end of the range.
exception
BadLocationException if the range is invalid

        g.setColor(selected);
        Document doc = getDocument();
        Segment segment = SegmentCache.getSharedSegment();
        doc.getText(p0, p1 - p0, segment);
        int ret = Utilities.drawTabbedText(this, segment, x, y, g, this, p0);
        SegmentCache.releaseSharedSegment(segment);
        return ret;
    
private intdrawText(javax.swing.text.Element elem, int p0, int p1, java.awt.Graphics g, int x, int y)

        p1 = Math.min(getDocument().getLength(), p1);
	AttributeSet attr = elem.getAttributes();

	if (Utilities.isComposedTextAttributeDefined(attr)) {
	    g.setColor(unselected);
	    x = Utilities.drawComposedText(this, attr, g, x, y, 
					p0-elem.getStartOffset(), 
					p1-elem.getStartOffset());
	} else {
	    if (sel0 == sel1 || selected == unselected) {
		// no selection, or it is invisible
		x = drawUnselectedText(g, x, y, p0, p1);
	    } else if ((p0 >= sel0 && p0 <= sel1) && (p1 >= sel0 && p1 <= sel1)) {
		x = drawSelectedText(g, x, y, p0, p1);
	    } else if (sel0 >= p0 && sel0 <= p1) {
		if (sel1 >= p0 && sel1 <= p1) {
		    x = drawUnselectedText(g, x, y, p0, sel0);
		    x = drawSelectedText(g, x, y, sel0, sel1);
		    x = drawUnselectedText(g, x, y, sel1, p1);
		} else {
		    x = drawUnselectedText(g, x, y, p0, sel0);
		    x = drawSelectedText(g, x, y, sel0, p1);
		}
	    } else if (sel1 >= p0 && sel1 <= p1) {
		x = drawSelectedText(g, x, y, p0, sel1);
		x = drawUnselectedText(g, x, y, sel1, p1);
	    } else {
		x = drawUnselectedText(g, x, y, p0, p1);
	    }
	}

        return x;
    
protected intdrawUnselectedText(java.awt.Graphics g, int x, int y, int p0, int p1)
Renders the given range in the model as normal unselected text.

param
g the graphics context
param
x the starting X coordinate >= 0
param
y the starting Y coordinate >= 0
param
p0 the beginning position in the model >= 0
param
p1 the ending position in the model >= p0
return
the X location of the end of the range >= 0
exception
BadLocationException if the range is invalid

        g.setColor(unselected);
        Document doc = getDocument();
        Segment segment = SegmentCache.getSharedSegment();
        doc.getText(p0, p1 - p0, segment);
        int ret = Utilities.drawTabbedText(this, segment, x, y, g, this, p0);
        SegmentCache.releaseSharedSegment(segment);
        return ret;
    
protected final javax.swing.text.SegmentgetLineBuffer()
Gives access to a buffer that can be used to fetch text from the associated document.

return
the buffer

        if (lineBuffer == null) {
            lineBuffer = new Segment();
        }
        return lineBuffer;
    
public floatgetMaximumSpan(int axis)
Determines the maximum span for this view along an axis. This is implemented to provide the superclass behavior after first making sure that the current font metrics are cached (for the nested lines which use the metrics to determine the height of the potentially wrapped lines).

param
axis may be either View.X_AXIS or View.Y_AXIS
return
the span the view would like to be rendered into. 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.
see
View#getMaximumSpan

	updateMetrics();
	return super.getMaximumSpan(axis);
    
public floatgetMinimumSpan(int axis)
Determines the minimum span for this view along an axis. This is implemented to provide the superclass behavior after first making sure that the current font metrics are cached (for the nested lines which use the metrics to determine the height of the potentially wrapped lines).

param
axis may be either View.X_AXIS or View.Y_AXIS
return
the span the view would like to be rendered into. 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.
see
View#getMinimumSpan

	updateMetrics();
	return super.getMinimumSpan(axis);
    
public floatgetPreferredSpan(int axis)
Determines the preferred span for this view along an axis. This is implemented to provide the superclass behavior after first making sure that the current font metrics are cached (for the nested lines which use the metrics to determine the height of the potentially wrapped lines).

param
axis may be either View.X_AXIS or View.Y_AXIS
return
the span the view would like to be rendered into. 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.
see
View#getPreferredSpan

	updateMetrics();
	return super.getPreferredSpan(axis);
    
protected intgetTabSize()
Returns the tab size set for the document, defaulting to 8.

return
the tab size

        Integer i = (Integer) getDocument().getProperty(PlainDocument.tabSizeAttribute);
        int size = (i != null) ? i.intValue() : 8;
        return size;
    
public voidinsertUpdate(javax.swing.event.DocumentEvent e, java.awt.Shape a, javax.swing.text.ViewFactory f)
Gives notification that something was inserted into the document in a location that this view is responsible for. This is implemented to simply update the children.

param
e the change information from the associated document
param
a the current allocation of the view
param
f the factory to use to rebuild if the view has children
see
View#insertUpdate

        updateChildren(e, a);

        Rectangle alloc = ((a != null) && isAllocationValid()) ? 
            getInsideAllocation(a) : null;
        int pos = e.getOffset();
        View v = getViewAtPosition(pos, alloc);
        if (v != null) {
            v.insertUpdate(e, alloc, f);
        }
    
protected voidloadChildren(javax.swing.text.ViewFactory f)
Loads all of the children to initialize the view. This is called by the setParent method. Subclasses can reimplement this to initialize their child views in a different manner. The default implementation creates a child view for each child element.

param
f the view factory

        Element e = getElement();
        int n = e.getElementCount();
        if (n > 0) {
            View[] added = new View[n];
            for (int i = 0; i < n; i++) {
                added[i] = new WrappedLine(e.getElement(i));
            }
            replace(0, 0, added);
        }
    
final voidloadText(javax.swing.text.Segment segment, int p0, int p1)
Load the text buffer with the given range of text. This is used by the fragments broken off of this view as well as this view itself.

	try {
	    Document doc = getDocument();
	    doc.getText(p0, p1 - p0, segment);
	} catch (BadLocationException bl) {
	    throw new StateInvariantError("Can't get line text");
	}
    
public floatnextTabStop(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.

param
x the current position >= 0
param
tabOffset the position within the text stream that the tab occurred at >= 0.
return
the tab stop, measured in points >= 0

	if (tabSize == 0)
	    return x;
        int ntabs = ((int) x - tabBase) / tabSize;
        return tabBase + ((ntabs + 1) * tabSize);
    
public voidpaint(java.awt.Graphics g, java.awt.Shape a)
Renders using the given rendering surface and area on that surface. This is implemented to stash the selection positions, selection colors, and font metrics for the nested lines to use.

param
g the rendering surface to use
param
a the allocated region to render into
see
View#paint

	Rectangle alloc = (Rectangle) a;
	tabBase = alloc.x;
	JTextComponent host = (JTextComponent) getContainer();
	sel0 = host.getSelectionStart();
	sel1 = host.getSelectionEnd();
	unselected = (host.isEnabled()) ? 
	    host.getForeground() : host.getDisabledTextColor();
	Caret c = host.getCaret();
        selected = c.isSelectionVisible() && host.getHighlighter() != null ?
                        host.getSelectedTextColor() : unselected;
	g.setFont(host.getFont());

        // superclass paints the children
        super.paint(g, a);
    
public voidremoveUpdate(javax.swing.event.DocumentEvent e, java.awt.Shape a, javax.swing.text.ViewFactory f)
Gives notification that something was removed from the document in a location that this view is responsible for. This is implemented to simply update the children.

param
e the change information from the associated document
param
a the current allocation of the view
param
f the factory to use to rebuild if the view has children
see
View#removeUpdate

        updateChildren(e, a);

        Rectangle alloc = ((a != null) && isAllocationValid()) ? 
            getInsideAllocation(a) : null;
        int pos = e.getOffset();
        View v = getViewAtPosition(pos, alloc);
        if (v != null) {
            v.removeUpdate(e, alloc, f);
        }
    
public voidsetSize(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.

param
width the width >= 0
param
height the height >= 0

	updateMetrics();
	if ((int) width != getWidth()) {
	    // invalidate the view itself since the childrens
	    // desired widths will be based upon this views width.
	    preferenceChanged(null, true, true);
	    widthChanging = true;
	}
	super.setSize(width, height);
	widthChanging = false;
    
voidupdateChildren(javax.swing.event.DocumentEvent e, java.awt.Shape a)
Update the child views in response to a document event.

        Element elem = getElement();
        DocumentEvent.ElementChange ec = e.getChange(elem);
        if (ec != null) {
            // the structure of this element changed.
            Element[] removedElems = ec.getChildrenRemoved();
            Element[] addedElems = ec.getChildrenAdded();
            View[] added = new View[addedElems.length];
            for (int i = 0; i < addedElems.length; i++) {
                added[i] = new WrappedLine(addedElems[i]);
            }
            replace(ec.getIndex(), removedElems.length, added);

            // should damge a little more intelligently.
            if (a != null) {
                preferenceChanged(null, true, true);
                getContainer().repaint();
            }
        }

	// update font metrics which may be used by the child views
	updateMetrics();
    
final voidupdateMetrics()

	Component host = getContainer();
	Font f = host.getFont();
	metrics = host.getFontMetrics(f);
	tabSize = getTabSize() * metrics.charWidth('m");