textmeasurer.java

JAVA基本类源代码,大家可以学习学习!

            int gaLimit = tlcStart + fComponents[tlcIndex].getNumCharacters();
            if (gaLimit > startPos) {
                break;
            }
            else {
                tlcStart = gaLimit;
            }
        }

        // tlcStart is now the start of the tlc at tlcIndex

        int componentCount;
        {
            boolean split = false;
            int compStart = tlcStart;
            int lim=tlcIndex;
            for (boolean cont=true; cont; lim++) {
                int gaLimit = compStart + fComponents[lim].getNumCharacters();
                if (cdWsStart > Math.max(compStart, startPos) 
                            && cdWsStart < Math.min(gaLimit, limitPos)) {
                    split = true;
                }
                if (gaLimit >= limitPos) {
                    cont=false;
                }
                else {
                    compStart = gaLimit;
                }
            }
            componentCount = lim-tlcIndex;
            if (split) {
                componentCount++;
            }
        }

        TextLineComponent[] components = new TextLineComponent[componentCount];
        int newCompIndex = 0;
        int linePos = startPos;

        int breakPt = cdWsStart;

        int subsetFlag;
        if (breakPt == startPos) {
            subsetFlag = fIsDirectionLTR? TextLineComponent.LEFT_TO_RIGHT :
                                          TextLineComponent.RIGHT_TO_LEFT;
            breakPt = limitPos;
        }
        else {
            subsetFlag = TextLineComponent.UNCHANGED;
        }

        while (linePos < limitPos) {
            
            int compLength = fComponents[tlcIndex].getNumCharacters();
            int tlcLimit = tlcStart + compLength;

            int start = Math.max(linePos, tlcStart);
            int limit = Math.min(breakPt, tlcLimit);
            
            components[newCompIndex++] = fComponents[tlcIndex].getSubset(
                                                                start-tlcStart,
                                                                limit-tlcStart,
                                                                subsetFlag);
            linePos += (limit-start);
            if (linePos == breakPt) {
                breakPt = limitPos;
                subsetFlag = fIsDirectionLTR? TextLineComponent.LEFT_TO_RIGHT :
                                              TextLineComponent.RIGHT_TO_LEFT;
            }
            if (linePos == tlcLimit) {
                tlcIndex++;
                tlcStart = tlcLimit;
            }
        }

        return components;
    }

    private TextLine makeTextLineOnRange(int startPos, int limitPos) {

        int[] charsLtoV = null;
        byte[] charLevels = null;

        if (fBidi != null) {
            Bidi lineBidi = fBidi.createLineBidi(startPos, limitPos);
            charLevels = BidiUtils.getLevels(lineBidi);
	    int[] charsVtoL = BidiUtils.createVisualToLogicalMap(charLevels);
            charsLtoV = BidiUtils.createInverseMap(charsVtoL);
        }

        TextLineComponent[] components = makeComponentsOnRange(startPos, limitPos);

        return new TextLine(components, 
                            fBaselineOffsets,
                            fChars,
                            startPos,
                            limitPos,
                            charsLtoV,
                            charLevels,
                            fIsDirectionLTR);

    }
    
    private void ensureComponents(int start, int limit) {
        
        if (start < fComponentStart || limit > fComponentLimit) {
            generateComponents(start, limit);
        }
    }
    
    private void makeLayoutWindow(int localStart) {
        
        int compStart = localStart;
        int compLimit = fChars.length;
        
        // If we've already gone past the layout window, format to end of paragraph
        if (layoutCount > 0 && !haveLayoutWindow) {
            float avgLineLength = Math.max(layoutCharCount / layoutCount, 1);
            compLimit = Math.min(localStart + (int)(avgLineLength*EST_LINES), fChars.length);
        }
        
        if (localStart > 0 || compLimit < fChars.length) {
            if (charIter == null) {
                charIter = new CharArrayIterator(fChars);
            }
            else {
                charIter.reset(fChars);
            }
            if (fLineBreak == null) {
                fLineBreak = BreakIterator.getLineInstance();
            }
            fLineBreak.setText(charIter);
            if (localStart > 0) {
                if (!fLineBreak.isBoundary(localStart)) {
                    compStart = fLineBreak.preceding(localStart);
                }
            }
            if (compLimit < fChars.length) {
                if (!fLineBreak.isBoundary(compLimit)) {
                    compLimit = fLineBreak.following(compLimit);
                }
            }
        }

        ensureComponents(compStart, compLimit);
        haveLayoutWindow = true;
    }

    /**
     * Returns the index of the first character which will not fit on
     * on a line beginning at <code>start</code> and possible
     * measuring up to <code>maxAdvance</code> in graphical width.
     *
     * @param start the character index at which to start measuring.
     *  <code>start</code> is an absolute index, not relative to the
     *  start of the paragraph
     * @param maxAdvance the graphical width in which the line must fit
     * @return the index after the last character that will fit
     *  on a line beginning at <code>start</code>, which is not longer
     *  than <code>maxAdvance</code> in graphical width
     * @throws IllegalArgumentException if <code>start</code> is
     *		less than the beginning of the paragraph.
     */
    public int getLineBreakIndex(int start, float maxAdvance) {
        
        int localStart = start - fStart;

        if (!haveLayoutWindow || 
                localStart < fComponentStart || 
                localStart >= fComponentLimit) {
            makeLayoutWindow(localStart);
        }
        
        return calcLineBreak(localStart, maxAdvance) + fStart;
    }

    /**
     * Returns the graphical width of a line beginning at <code>start</code>
     * and including characters up to <code>limit</code>.
     * <code>start</code> and <code>limit</code> are absolute indices,
     * not relative to the start of the paragraph.
     *
     * @param start the character index at which to start measuring
     * @param limit the character index at which to stop measuring
     * @return the graphical width of a line beginning at <code>start</code>
     *   and including characters up to <code>limit</code>
     * @throws IndexOutOfBoundsException if <code>limit</code> is less
     *         than <code>start</code>
     * @throws IllegalArgumentException if <code>start</code> or 
     *		<code>limit</code> is not between the beginning of
     *		the paragraph and the end of the paragraph. 
     */
    public float getAdvanceBetween(int start, int limit) {
        
        int localStart = start - fStart;
        int localLimit = limit - fStart;
        
        ensureComponents(localStart, localLimit);
        TextLine line = makeTextLineOnRange(localStart, localLimit);
        return line.getMetrics().advance;
        // could cache line in case getLayout is called with same start, limit
    }

    /**
     * Returns a <code>TextLayout</code> on the given character range.
     *
     * @param start the index of the first character
     * @param limit the index after the last character.  Must be greater
     *   than <code>start</code>
     * @return a <code>TextLayout</code> for the characters beginning at
     *  <code>start</code> up to (but not including) <code>limit</code>
     * @throws IndexOutOfBoundsException if <code>limit</code> is less
     *         than <code>start</code>
     * @throws IllegalArgumentException if <code>start</code> or 
     *		<code>limit</code> is not between the beginning of
     *		the paragraph and the end of the paragraph. 
     */
    public TextLayout getLayout(int start, int limit) {
        
        int localStart = start - fStart;
        int localLimit = limit - fStart;
        
        ensureComponents(localStart, localLimit);        
        TextLine textLine = makeTextLineOnRange(localStart, localLimit);

        if (localLimit < fChars.length) {
            layoutCharCount += limit-start;
            layoutCount++;
        }
        
        return new TextLayout(textLine, 
                              fBaseline,
                              fBaselineOffsets,
                              fJustifyRatio);
    }

    private int formattedChars = 0;
    private static boolean wantStats = false;/*"true".equals(System.getProperty("collectStats"));*/
    private boolean collectStats = false;
    
    private void printStats() {
        System.out.println("formattedChars: " + formattedChars);
        //formattedChars = 0;
        collectStats = false;
    }
    
    /**
     * Updates the <code>TextMeasurer</code> after a single character has 
     * been inserted
     * into the paragraph currently represented by this
     * <code>TextMeasurer</code>.  After this call, this
     * <code>TextMeasurer</code> is equivalent to a new 
     * <code>TextMeasurer</code> created from the text;  however, it will
     * usually be more efficient to update an existing
     * <code>TextMeasurer</code> than to create a new one from scratch.
     *
     * @param newParagraph the text of the paragraph after performing
     * the insertion.  Cannot be null.
     * @param insertPos the position in the text where the character was 
     * inserted.  Must not be less than the start of 
     * <code>newParagraph</code>, and must be less than the end of
     * <code>newParagraph</code>.
     * @throws IndexOutOfBoundsException if <code>insertPos</code> is less
     *         than the start of <code>newParagraph</code> or greater than
     *         or equal to the end of <code>newParagraph</code>
     * @throws NullPointerException if <code>newParagraph</code> is   
     *         <code>null</code>
     */
    public void insertChar(AttributedCharacterIterator newParagraph, int insertPos) {

        if (collectStats) {
            printStats();
        }
        if (wantStats) {
            collectStats = true;
        }
        
        fStart = newParagraph.getBeginIndex();
        int end = newParagraph.getEndIndex();
        if (end - fStart != fChars.length+1) {
            initAll(newParagraph);
        }
        
        char[] newChars = new char[end-fStart];
        int newCharIndex = insertPos - fStart;
        System.arraycopy(fChars, 0, newChars, 0, newCharIndex);
        
        char newChar = newParagraph.setIndex(insertPos);
        newChars[newCharIndex] = newChar;
        System.arraycopy(fChars, 
                         newCharIndex, 
                         newChars, 
                         newCharIndex+1, 
                         end-insertPos-1);
        fChars = newChars;
        
        if (fBidi != null || Bidi.requiresBidi(newChars, newCharIndex, newCharIndex + 1) || 
                newParagraph.getAttribute(TextAttribute.BIDI_EMBEDDING) != null) {

            fBidi = new Bidi(newParagraph);
	    if (fBidi.isLeftToRight()) {
		fBidi = null;
	    }
        }
        
        fParagraph = StyledParagraph.insertChar(newParagraph, 
                                                fChars,
                                                insertPos,
                                                fParagraph);
        invalidateComponents();
    }
    
    /**
     * Updates the <code>TextMeasurer</code> after a single character has 
     * been deleted
     * from the paragraph currently represented by this
     * <code>TextMeasurer</code>.  After this call, this
     * <code>TextMeasurer</code> is equivalent to a new <code>TextMeasurer</code>
     * created from the text;  however, it will usually be more efficient
     * to update an existing <code>TextMeasurer</code> than to create a new one
     * from scratch.
     *
     * @param newParagraph the text of the paragraph after performing
     * the deletion.  Cannot be null.
     * @param deletePos the position in the text where the character was removed.  
     * Must not be less than
     * the start of <code>newParagraph</code>, and must not be greater than the
     * end of <code>newParagraph</code>.
     * @throws IndexOutOfBoundsException if <code>deletePos</code> is
     *         less than the start of <code>newParagraph</code> or greater
     *         than the end of <code>newParagraph</code>
     * @throws NullPointerException if <code>newParagraph</code> is
     *         <code>null</code>
     */
    public void deleteChar(AttributedCharacterIterator newParagraph, int deletePos) {

        fStart = newParagraph.getBeginIndex();
        int end = newParagraph.getEndIndex();
        if (end - fStart != fChars.length-1) {
            initAll(newParagraph);
        }
        
        char[] newChars = new char[end-fStart];
        int changedIndex = deletePos-fStart;
        
        System.arraycopy(fChars, 0, newChars, 0, deletePos-fStart);
        System.arraycopy(fChars, changedIndex+1, newChars, changedIndex, end-deletePos);
        fChars = newChars;
        
        if (fBidi != null) {
            fBidi = new Bidi(newParagraph);
	    if (fBidi.isLeftToRight()) {
		fBidi = null;
	    }
        }
        
        fParagraph = StyledParagraph.deleteChar(newParagraph, 
                                                fChars,
                                                deletePos,
                                                fParagraph);
        invalidateComponents();
    }

    /**
     * NOTE:  This method is only for LineBreakMeasurer's use.  It is package-
     * private because it returns internal data.
     */
    char[] getChars() {

        return fChars;
    }
}