diff options
Diffstat (limited to 'libjava/classpath/javax/swing/text/Utilities.java')
| -rw-r--r-- | libjava/classpath/javax/swing/text/Utilities.java | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/libjava/classpath/javax/swing/text/Utilities.java b/libjava/classpath/javax/swing/text/Utilities.java index d40408ddc3f..7830b2fca04 100644 --- a/libjava/classpath/javax/swing/text/Utilities.java +++ b/libjava/classpath/javax/swing/text/Utilities.java @@ -40,6 +40,11 @@ package javax.swing.text; import java.awt.FontMetrics; import java.awt.Graphics; +import java.awt.Point; +import java.awt.Rectangle; +import java.text.BreakIterator; + +import javax.swing.SwingConstants; /** * A set of utilities to deal with text. This is used by several other classes @@ -195,4 +200,409 @@ public class Utilities return maxWidth; } + + /** + * Provides a facility to map screen coordinates into a model location. For a + * given text fragment and start location within this fragment, this method + * determines the model location so that the resulting fragment fits best + * into the span <code>[x0, x]</code>. + * + * The parameter <code>round</code> controls which model location is returned + * if the view coordinates are on a character: If <code>round</code> is + * <code>true</code>, then the result is rounded up to the next character, so + * that the resulting fragment is the smallest fragment that is larger than + * the specified span. If <code>round</code> is <code>false</code>, then the + * resulting fragment is the largest fragment that is smaller than the + * specified span. + * + * @param s the text segment + * @param fm the font metrics to use + * @param x0 the starting screen location + * @param x the target screen location at which the requested fragment should + * end + * @param te the tab expander to use; if this is <code>null</code>, TABs are + * expanded to one space character + * @param p0 the starting model location + * @param round if <code>true</code> round up to the next location, otherwise + * round down to the current location + * + * @return the model location, so that the resulting fragment fits within the + * specified span + */ + public static final int getTabbedTextOffset(Segment s, FontMetrics fm, int x0, + int x, TabExpander te, int p0, + boolean round) + { + // At the end of the for loop, this holds the requested model location + int pos; + int currentX = x0; + + for (pos = p0; pos < s.count; pos++) + { + char nextChar = s.array[s.offset+pos]; + if (nextChar == 0) + { + if (! round) + pos--; + break; + } + if (nextChar != '\t') + currentX += fm.charWidth(nextChar); + else + { + if (te == null) + currentX += fm.charWidth(' '); + else + currentX = (int) te.nextTabStop(currentX, pos); + } + if (currentX > x) + { + if (! round) + pos--; + break; + } + } + return pos; + } + + /** + * Provides a facility to map screen coordinates into a model location. For a + * given text fragment and start location within this fragment, this method + * determines the model location so that the resulting fragment fits best + * into the span <code>[x0, x]</code>. + * + * This method rounds up to the next location, so that the resulting fragment + * will be the smallest fragment of the text, that is greater than the + * specified span. + * + * @param s the text segment + * @param fm the font metrics to use + * @param x0 the starting screen location + * @param x the target screen location at which the requested fragment should + * end + * @param te the tab expander to use; if this is <code>null</code>, TABs are + * expanded to one space character + * @param p0 the starting model location + * + * @return the model location, so that the resulting fragment fits within the + * specified span + */ + public static final int getTabbedTextOffset(Segment s, FontMetrics fm, int x0, + int x, TabExpander te, int p0) + { + return getTabbedTextOffset(s, fm, x0, x, te, p0, true); + } + + /** + * Finds the start of the next word for the given offset. + * + * @param c + * the text component + * @param offs + * the offset in the document + * @return the location in the model of the start of the next word. + * @throws BadLocationException + * if the offset is invalid. + */ + public static final int getNextWord(JTextComponent c, int offs) + throws BadLocationException + { + if (offs < 0 || offs > (c.getText().length() - 1)) + throw new BadLocationException("invalid offset specified", offs); + String text = c.getText(); + BreakIterator wb = BreakIterator.getWordInstance(); + wb.setText(text); + int last = wb.following(offs); + int current = wb.next(); + while (current != BreakIterator.DONE) + { + for (int i = last; i < current; i++) + { + // FIXME: Should use isLetter(int) and text.codePointAt(int) + // instead, but isLetter(int) isn't implemented yet + if (Character.isLetter(text.charAt(i))) + return last; + } + last = current; + current = wb.next(); + } + return BreakIterator.DONE; + } + + /** + * Finds the start of the previous word for the given offset. + * + * @param c + * the text component + * @param offs + * the offset in the document + * @return the location in the model of the start of the previous word. + * @throws BadLocationException + * if the offset is invalid. + */ + public static final int getPreviousWord(JTextComponent c, int offs) + throws BadLocationException + { + if (offs < 0 || offs > (c.getText().length() - 1)) + throw new BadLocationException("invalid offset specified", offs); + String text = c.getText(); + BreakIterator wb = BreakIterator.getWordInstance(); + wb.setText(text); + int last = wb.preceding(offs); + int current = wb.previous(); + + while (current != BreakIterator.DONE) + { + for (int i = last; i < offs; i++) + { + // FIXME: Should use isLetter(int) and text.codePointAt(int) + // instead, but isLetter(int) isn't implemented yet + if (Character.isLetter(text.charAt(i))) + return last; + } + last = current; + current = wb.previous(); + } + return 0; + } + + /** + * Finds the start of a word for the given location. + * @param c the text component + * @param offs the offset location + * @return the location of the word beginning + * @throws BadLocationException if the offset location is invalid + */ + public static final int getWordStart(JTextComponent c, int offs) + throws BadLocationException + { + if (offs < 0 || offs >= c.getText().length()) + throw new BadLocationException("invalid offset specified", offs); + + String text = c.getText(); + BreakIterator wb = BreakIterator.getWordInstance(); + wb.setText(text); + if (wb.isBoundary(offs)) + return offs; + return wb.preceding(offs); + } + + /** + * Finds the end of a word for the given location. + * @param c the text component + * @param offs the offset location + * @return the location of the word end + * @throws BadLocationException if the offset location is invalid + */ + public static final int getWordEnd(JTextComponent c, int offs) + throws BadLocationException + { + if (offs < 0 || offs >= c.getText().length()) + throw new BadLocationException("invalid offset specified", offs); + + String text = c.getText(); + BreakIterator wb = BreakIterator.getWordInstance(); + wb.setText(text); + return wb.following(offs); + } + + /** + * Get the model position of the end of the row that contains the + * specified model position. Return null if the given JTextComponent + * does not have a size. + * @param c the JTextComponent + * @param offs the model position + * @return the model position of the end of the row containing the given + * offset + * @throws BadLocationException if the offset is invalid + */ + public static final int getRowEnd(JTextComponent c, int offs) + throws BadLocationException + { + String text = c.getText(); + if (text == null) + return -1; + + // Do a binary search for the smallest position X > offs + // such that that character at positino X is not on the same + // line as the character at position offs + int high = offs + ((text.length() - 1 - offs) / 2); + int low = offs; + int oldHigh = text.length() + 1; + while (true) + { + if (c.modelToView(high).y != c.modelToView(offs).y) + { + oldHigh = high; + high = low + ((high + 1 - low) / 2); + if (oldHigh == high) + return high - 1; + } + else + { + low = high; + high += ((oldHigh - high) / 2); + if (low == high) + return low; + } + } + } + + /** + * Get the model position of the start of the row that contains the specified + * model position. Return null if the given JTextComponent does not have a + * size. + * + * @param c the JTextComponent + * @param offs the model position + * @return the model position of the start of the row containing the given + * offset + * @throws BadLocationException if the offset is invalid + */ + public static final int getRowStart(JTextComponent c, int offs) + throws BadLocationException + { + String text = c.getText(); + if (text == null) + return -1; + + // Do a binary search for the greatest position X < offs + // such that the character at position X is not on the same + // row as the character at position offs + int high = offs; + int low = 0; + int oldLow = 0; + while (true) + { + if (c.modelToView(low).y != c.modelToView(offs).y) + { + oldLow = low; + low = high - ((high + 1 - low) / 2); + if (oldLow == low) + return low + 1; + } + else + { + high = low; + low -= ((low - oldLow) / 2); + if (low == high) + return low; + } + } + } + + /** + * Determine where to break the text in the given Segment, attempting to find + * a word boundary. + * @param s the Segment that holds the text + * @param metrics the font metrics used for calculating the break point + * @param x0 starting view location representing the start of the text + * @param x the target view location + * @param e the TabExpander used for expanding tabs (if this is null tabs + * are expanded to 1 space) + * @param startOffset the offset in the Document of the start of the text + * @return the offset at which we should break the text + */ + public static final int getBreakLocation(Segment s, FontMetrics metrics, + int x0, int x, TabExpander e, + int startOffset) + { + int mark = Utilities.getTabbedTextOffset(s, metrics, x0, x, e, startOffset); + BreakIterator breaker = BreakIterator.getWordInstance(); + breaker.setText(s.toString()); + + // If mark is equal to the end of the string, just use that position + if (mark == s.count) + return mark; + + // Try to find a word boundary previous to the mark at which we + // can break the text + int preceding = breaker.preceding(mark + 1); + + if (preceding != 0) + return preceding; + else + // If preceding is 0 we couldn't find a suitable word-boundary so + // just break it on the character boundary + return mark; + } + + /** + * Returns the paragraph element in the text component <code>c</code> at + * the specified location <code>offset</code>. + * + * @param c the text component + * @param offset the offset of the paragraph element to return + * + * @return the paragraph element at <code>offset</code> + */ + public static final Element getParagraphElement(JTextComponent c, int offset) + { + Document doc = c.getDocument(); + Element par = null; + if (doc instanceof StyledDocument) + { + StyledDocument styledDoc = (StyledDocument) doc; + par = styledDoc.getParagraphElement(offset); + } + else + { + Element root = c.getDocument().getDefaultRootElement(); + int parIndex = root.getElementIndex(offset); + par = root.getElement(parIndex); + } + return par; + } + + /** + * Returns the document position that is closest above to the specified x + * coordinate in the row containing <code>offset</code>. + * + * @param c the text component + * @param offset the offset + * @param x the x coordinate + * + * @return the document position that is closest above to the specified x + * coordinate in the row containing <code>offset</code> + * + * @throws BadLocationException if <code>offset</code> is not a valid offset + */ + public static final int getPositionAbove(JTextComponent c, int offset, int x) + throws BadLocationException + { + View rootView = c.getUI().getRootView(c); + Rectangle r = c.modelToView(offset); + int offs = c.viewToModel(new Point(x, r.y)); + int pos = rootView.getNextVisualPositionFrom(c, offs, + Position.Bias.Forward, + SwingConstants.NORTH, + new Position.Bias[1]); + return pos; + } + + /** + * Returns the document position that is closest below to the specified x + * coordinate in the row containing <code>offset</code>. + * + * @param c the text component + * @param offset the offset + * @param x the x coordinate + * + * @return the document position that is closest above to the specified x + * coordinate in the row containing <code>offset</code> + * + * @throws BadLocationException if <code>offset</code> is not a valid offset + */ + public static final int getPositionBelow(JTextComponent c, int offset, int x) + throws BadLocationException + { + View rootView = c.getUI().getRootView(c); + Rectangle r = c.modelToView(offset); + int offs = c.viewToModel(new Point(x, r.y)); + int pos = rootView.getNextVisualPositionFrom(c, offs, + Position.Bias.Forward, + SwingConstants.SOUTH, + new Position.Bias[1]); + return pos; + } } |