File	Doc	Category	Size	Date	Package
TextLayoutStrategy.java	API Doc	Java SE 5 API	17158	Fri Aug 26 14:58:16 BST 2005	javax.swing.text

TextLayoutStrategy

• java.lang.Object
  • javax.swing.text.FlowView$FlowStrategy

Fields Summary
private LineBreakMeasurer	measurer
private AttributedSegment	text

Constructors Summary
public TextLayoutStrategy() Constructs a layout strategy for paragraphs based upon java.awt.font.LineBreakMeasurer. text = new AttributedSegment();

Methods Summary
protected void	adjustRow(javax.swing.text.FlowView fv, int rowIndex, int desiredSpan, int x) Adjusts the given row if possible to fit within the layout span. Since all adjustments were already calculated by the LineBreakMeasurer, this is implemented to do nothing. param r the row to adjust to the current layout span. param desiredSpan the current layout span >= 0 param x the location r starts at.
public void	changedUpdate(javax.swing.text.FlowView fv, javax.swing.event.DocumentEvent e, java.awt.Rectangle alloc) Gives notification from the document that attributes were changed in a location that this view is responsible for. param changes 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 sync(fv); super.changedUpdate(fv, e, alloc);
protected javax.swing.text.View	createView(javax.swing.text.FlowView fv, int startOffset, int spanLeft, int rowIndex) Creates a unidirectional view that can be used to represent the current chunk. This can be either an entire view from the logical view, or a fragment of the view. param fv the view holding the flow param startOffset the start location for the view being created param spanLeft the about of span left to fill in the row param rowIndex the row the view will be placed into // Get the child view that contains the given starting position View lv = getLogicalView(fv); View row = fv.getView(rowIndex); boolean requireNextWord = (row.getViewCount() == 0) ? false : true; int childIndex = lv.getViewIndex(startOffset, Position.Bias.Forward); View v = lv.getView(childIndex); int endOffset = getLimitingOffset(v, startOffset, spanLeft, requireNextWord); if (endOffset == startOffset) { return null; } View frag; if ((startOffset==v.getStartOffset()) && (endOffset == v.getEndOffset())) { // return the entire view frag = v; } else { // return a unidirectional fragment. frag = v.createFragment(startOffset, endOffset); } if ((frag instanceof GlyphView) && (measurer != null)) { // install a TextLayout based renderer if the view is responsible // for glyphs. If the view represents a tab, the default // glyph painter is used (may want to handle tabs differently). boolean isTab = false; int p0 = frag.getStartOffset(); int p1 = frag.getEndOffset(); if ((p1 - p0) == 1) { // check for tab Segment s = ((GlyphView)frag).getText(p0, p1); char ch = s.first(); if (ch == '\t") { isTab = true; } } TextLayout tl = (isTab) ? null : measurer.nextLayout(spanLeft, text.toIteratorIndex(endOffset), requireNextWord); if (tl != null) { ((GlyphView)frag).setGlyphPainter(new GlyphPainter2(tl)); } } return frag;
int	getLimitingOffset(javax.swing.text.View v, int startOffset, int spanLeft, boolean requireNextWord) Calculate the limiting offset for the next view fragment. At most this would be the entire view (i.e. the limiting offset would be the end offset in that case). If the range contains a tab or a direction change, that will limit the offset to something less. This value is then fed to the LineBreakMeasurer as a limit to consider in addition to the remaining span. param v the logical view representing the starting offset. param startOffset the model location to start at. int endOffset = v.getEndOffset(); // check for direction change Document doc = v.getDocument(); if (doc instanceof AbstractDocument) { AbstractDocument d = (AbstractDocument) doc; Element bidiRoot = d.getBidiRootElement(); if( bidiRoot.getElementCount() > 1 ) { int bidiIndex = bidiRoot.getElementIndex( startOffset ); Element bidiElem = bidiRoot.getElement( bidiIndex ); endOffset = Math.min( bidiElem.getEndOffset(), endOffset ); } } // check for tab if (v instanceof GlyphView) { Segment s = ((GlyphView)v).getText(startOffset, endOffset); char ch = s.first(); if (ch == '\t") { // if the first character is a tab, create a dedicated // view for just the tab endOffset = startOffset + 1; } else { for (ch = s.next(); ch != Segment.DONE; ch = s.next()) { if (ch == '\t") { // found a tab, don't include it in the text endOffset = startOffset + s.getIndex() - s.getBeginIndex(); break; } } } } // determine limit from LineBreakMeasurer int limitIndex = text.toIteratorIndex(endOffset); if (measurer != null) { int index = text.toIteratorIndex(startOffset); if (measurer.getPosition() != index) { measurer.setPosition(index); } limitIndex = measurer.nextOffset(spanLeft, limitIndex, requireNextWord); } int pos = text.toModelPosition(limitIndex); return pos;
public void	insertUpdate(javax.swing.text.FlowView fv, javax.swing.event.DocumentEvent e, java.awt.Rectangle alloc) Gives notification that something was inserted into the document in a location that the given flow view is responsible for. The strategy should update the appropriate changed region (which depends upon the strategy used for repair). param e the change information from the associated document param alloc the current allocation of the view inside of the insets. This value will be null if the view has not yet been displayed. see View#insertUpdate sync(fv); super.insertUpdate(fv, e, alloc);
public void	layout(javax.swing.text.FlowView fv) Does a a full layout on the given View. This causes all of the rows (child views) to be rebuilt to match the given constraints for each row. This is called by a FlowView.layout to update the child views in the flow. param v the view to reflow super.layout(fv);
protected int	layoutRow(javax.swing.text.FlowView fv, int rowIndex, int p0) Creates a row of views that will fit within the layout span of the row. This is implemented to execute the superclass functionality (which fills the row with child views or view fragments) and follow that with bidi reordering of the unidirectional view fragments. param row the row to fill in with views. This is assumed to be empty on entry. param pos The current position in the children of this views element from which to start. return the position to start the next row int p1 = super.layoutRow(fv, rowIndex, p0); View row = fv.getView(rowIndex); Document doc = fv.getDocument(); Object i18nFlag = doc.getProperty(AbstractDocument.I18NProperty); if ((i18nFlag != null) && i18nFlag.equals(Boolean.TRUE)) { int n = row.getViewCount(); if (n > 1) { AbstractDocument d = (AbstractDocument)fv.getDocument(); Element bidiRoot = d.getBidiRootElement(); byte[] levels = new byte[n]; View[] reorder = new View[n]; for( int i=0; i<n; i++ ) { View v = row.getView(i); int bidiIndex =bidiRoot.getElementIndex(v.getStartOffset()); Element bidiElem = bidiRoot.getElement( bidiIndex ); levels[i] = (byte)StyleConstants.getBidiLevel(bidiElem.getAttributes()); reorder[i] = v; } BidiUtils.reorderVisually( levels, reorder ); row.replace(0, n, reorder); } } return p1;
public void	removeUpdate(javax.swing.text.FlowView fv, javax.swing.event.DocumentEvent e, java.awt.Rectangle alloc) Gives notification that something was removed from the document in a location that the given flow view is responsible for. param e the change information from the associated document param alloc the current allocation of the view inside of the insets. see View#removeUpdate sync(fv); super.removeUpdate(fv, e, alloc);
void	sync(javax.swing.text.FlowView fv) Synchronize the strategy with its FlowView. Allows the strategy to update its state to account for changes in that portion of the model represented by the FlowView. Also allows the strategy to update the FlowView in response to these changes. View lv = getLogicalView(fv); text.setView(lv); Container container = fv.getContainer(); FontRenderContext frc = com.sun.java.swing.SwingUtilities2. getFontRenderContext(container); BreakIterator iter; Container c = fv.getContainer(); if (c != null) { iter = BreakIterator.getLineInstance(c.getLocale()); } else { iter = BreakIterator.getLineInstance(); } measurer = new LineBreakMeasurer(text, iter, frc); // If the children of the FlowView's logical view are GlyphViews, they // need to have their painters updated. int n = lv.getViewCount(); for( int i=0; i<n; i++ ) { View child = lv.getView(i); if( child instanceof GlyphView ) { int p0 = child.getStartOffset(); int p1 = child.getEndOffset(); measurer.setPosition(text.toIteratorIndex(p0)); TextLayout layout = measurer.nextLayout( Float.MAX_VALUE, text.toIteratorIndex(p1), false ); ((GlyphView)child).setGlyphPainter(new GlyphPainter2(layout)); } } // Reset measurer. measurer.setPosition(text.getBeginIndex());