textlayout.java

JAVA基本类源代码,大家可以学习学习!

        // at offset is at the given caret.

        return textLine.caretAtOffsetIsValid(offset);
    }

    /**
     * Returns the hit for the next caret to the right (bottom); if there 
     * is no such hit, returns <code>null</code>.
     * If the hit character index is out of bounds, an 
     * {@link IllegalArgumentException} is thrown.
     * @param hit a hit on a character in this layout
     * @return a hit whose caret appears at the next position to the
     * right (bottom) of the caret of the provided hit or <code>null</code>.
     */
    public TextHitInfo getNextRightHit(TextHitInfo hit) {
        ensureCache();
        checkTextHit(hit);

        int caret = hitToCaret(hit);

        if (caret == characterCount) {
            return null;
        }

        do {
            ++caret;
        } while (!caretIsValid(caret));

        return caretToHit(caret);
    }

    /**
     * Returns the hit for the next caret to the right (bottom); if no
     * such hit, returns <code>null</code>.  The hit is to the right of 
     * the strong caret at the specified offset, as determined by the
     * specified policy.
     * The returned hit is the stronger of the two possible
     * hits, as determined by the specified policy.
     * @param offset an insertion offset in this <code>TextLayout</code>.
     * Cannot be less than 0 or greater than this <code>TextLayout</code> 
     * object's character count.
     * @param policy the policy used to select the strong caret
     * @return a hit whose caret appears at the next position to the
     * right (bottom) of the caret of the provided hit, or <code>null</code>.
     */
    public TextHitInfo getNextRightHit(int offset, CaretPolicy policy) {

        if (offset < 0 || offset > characterCount) {
            throw new IllegalArgumentException("Offset out of bounds in TextLayout.getNextRightHit()");
        }

        if (policy == null) {
            throw new IllegalArgumentException("Null CaretPolicy passed to TextLayout.getNextRightHit()");
        }

        TextHitInfo hit1 = TextHitInfo.afterOffset(offset);
        TextHitInfo hit2 = hit1.getOtherHit();

        TextHitInfo nextHit = getNextRightHit(policy.getStrongCaret(hit1, hit2, this));

        if (nextHit != null) {
            TextHitInfo otherHit = getVisualOtherHit(nextHit);
            return policy.getStrongCaret(otherHit, nextHit, this);
        }
        else {
            return null;
        }
    }

    /**
     * Returns the hit for the next caret to the right (bottom); if no
     * such hit, returns <code>null</code>.  The hit is to the right of
     * the strong caret at the specified offset, as determined by the 
     * default policy.
     * The returned hit is the stronger of the two possible
     * hits, as determined by the default policy.
     * @param offset an insertion offset in this <code>TextLayout</code>.
     * Cannot be less than 0 or greater than the <code>TextLayout</code>
     * object's character count.
     * @return a hit whose caret appears at the next position to the
     * right (bottom) of the caret of the provided hit, or <code>null</code>.
     */
    public TextHitInfo getNextRightHit(int offset) {

        return getNextRightHit(offset, DEFAULT_CARET_POLICY);
    }

    /**
     * Returns the hit for the next caret to the left (top); if no such
     * hit, returns <code>null</code>.
     * If the hit character index is out of bounds, an 
     * <code>IllegalArgumentException</code> is thrown.
     * @param hit a hit on a character in this <code>TextLayout</code>.
     * @return a hit whose caret appears at the next position to the
     * left (top) of the caret of the provided hit, or <code>null</code>.
     */
    public TextHitInfo getNextLeftHit(TextHitInfo hit) {
        ensureCache();
        checkTextHit(hit);

        int caret = hitToCaret(hit);

        if (caret == 0) {
            return null;
        }

        do {
            --caret;
        } while(!caretIsValid(caret));

        return caretToHit(caret);
    }

    /**
     * Returns the hit for the next caret to the left (top); if no
     * such hit, returns <code>null</code>.  The hit is to the left of
     * the strong caret at the specified offset, as determined by the
     * specified policy.
     * The returned hit is the stronger of the two possible
     * hits, as determined by the specified policy.
     * @param offset an insertion offset in this <code>TextLayout</code>.
     * Cannot be less than 0 or greater than this <code>TextLayout</code>
     * object's character count.
     * @param policy the policy used to select the strong caret
     * @return a hit whose caret appears at the next position to the
     * left (top) of the caret of the provided hit, or <code>null</code>.
     */
    public TextHitInfo getNextLeftHit(int offset, CaretPolicy policy) {

        if (policy == null) {
            throw new IllegalArgumentException("Null CaretPolicy passed to TextLayout.getNextLeftHit()");
        }

        if (offset < 0 || offset > characterCount) {
            throw new IllegalArgumentException("Offset out of bounds in TextLayout.getNextLeftHit()");
        }

        TextHitInfo hit1 = TextHitInfo.afterOffset(offset);
        TextHitInfo hit2 = hit1.getOtherHit();

        TextHitInfo nextHit = getNextLeftHit(policy.getStrongCaret(hit1, hit2, this));

        if (nextHit != null) {
            TextHitInfo otherHit = getVisualOtherHit(nextHit);
            return policy.getStrongCaret(otherHit, nextHit, this);
        }
        else {
            return null;
        }
    }

    /**
     * Returns the hit for the next caret to the left (top); if no
     * such hit, returns <code>null</code>.  The hit is to the left of
     * the strong caret at the specified offset, as determined by the
     * default policy.
     * The returned hit is the stronger of the two possible
     * hits, as determined by the default policy.
     * @param offset an insertion offset in this <code>TextLayout</code>.  
     * Cannot be less than 0 or greater than this <code>TextLayout</code>
     * object's character count.
     * @return a hit whose caret appears at the next position to the
     * left (top) of the caret of the provided hit, or <code>null</code>.
     */
    public TextHitInfo getNextLeftHit(int offset) {

        return getNextLeftHit(offset, DEFAULT_CARET_POLICY);
    }

    /**
     * Returns the hit on the opposite side of the specified hit's caret.
     * @param hit the specified hit
     * @return a hit that is on the opposite side of the specified hit's
     *    caret.
     */
    public TextHitInfo getVisualOtherHit(TextHitInfo hit) {

        ensureCache();
        checkTextHit(hit);

        int hitCharIndex = hit.getCharIndex();

        int charIndex;
        boolean leading;

        if (hitCharIndex == -1 || hitCharIndex == characterCount) {

            int visIndex;
            if (textLine.isDirectionLTR() == (hitCharIndex == -1)) {
                visIndex = 0;
            }
            else {
                visIndex = characterCount-1;
            }

            charIndex = textLine.visualToLogical(visIndex);

            if (textLine.isDirectionLTR() == (hitCharIndex == -1)) {
                // at left end
                leading = textLine.isCharLTR(charIndex);
            }
            else {
                // at right end
                leading = !textLine.isCharLTR(charIndex);
            }
        }
        else {

            int visIndex = textLine.logicalToVisual(hitCharIndex);

            boolean movedToRight;
            if (textLine.isCharLTR(hitCharIndex) == hit.isLeadingEdge()) {
                --visIndex;
                movedToRight = false;
            }
            else {
                ++visIndex;
                movedToRight = true;
            }

            if (visIndex > -1 && visIndex < characterCount) {
                charIndex = textLine.visualToLogical(visIndex);
                leading = movedToRight == textLine.isCharLTR(charIndex);
            }
            else {
                charIndex =
                    (movedToRight == textLine.isDirectionLTR())? characterCount : -1;
                leading = charIndex == characterCount;
            }
        }

        return leading? TextHitInfo.leading(charIndex) :
                                TextHitInfo.trailing(charIndex);
    }

    /**
     * Return an array of four floats corresponding the endpoints of the caret
     * x0, y0, x1, y1.
     *
     * This creates a line along the slope of the caret intersecting the
     * baseline at the caret
     * position, and extending from ascent above the baseline to descent below
     * it.
     */
    private double[] getCaretPath(int caret, Rectangle2D bounds,
                                  boolean clipToBounds) {

        float[] info = getCaretInfo(caret, bounds, null);

        double pos = info[0];
        double slope = info[1];

        double x0, y0, x1, y1;
        double x2 = -3141.59, y2 = -2.7; // values are there to make compiler happy

        double left = bounds.getX();
        double right = left + bounds.getWidth();
        double top = bounds.getY();
        double bottom = top + bounds.getHeight();

        boolean threePoints = false;

        if (isVerticalLine) {

            if (slope >= 0) {
                x0 = left;
                x1 = right;
            }
            else {
                x1 = left;
                x0 = right;
            }

            y0 = pos + x0 * slope;
            y1 = pos + x1 * slope;

            // y0 <= y1, always

            if (clipToBounds) {
                if (y0 < top) {
                    if (slope <= 0 || y1 <= top) {
                        y0 = y1 = top;
                    }
                    else {
                        threePoints = true;
                        y0 = top;
                        y2 = top;
                        x2 = x1 + (top-y1)/slope;
                        if (y1 > bottom) {
                            y1 = bottom;
                        }
                    }
                }
                else if (y1 > bottom) {
                    if (slope >= 0 || y0 >= bottom) {
                        y0 = y1 = bottom;
                    }
                    else {
                        threePoints = true;
                        y1 = bottom;
                        y2 = bottom;
                        x2 = x0 + (bottom-x1)/slope;
                    }
                }
            }

        }
        else {

            if (slope >= 0) {
                y0 = bottom;
                y1 = top;
            }
            else {
                y1 = bottom;
                y0 = top;
            }

            x0 = pos - y0 * slope;
            x1 = pos - y1 * slope;
            
            // x0 <= x1, always

            if (clipToBounds) {
                if (x0 < left) {
                    if (slope <= 0 || x1 <= left) {
                        x0 = x1 = left;
                    }
                    else {
                        threePoints = true;
                        x0 = left;
                        x2 = left;
                        y2 = y1 - (left-x1)/slope;
                        if (x1 > right) {
                            x1 = right;
                        }
                    }
                }
                else if (x1 > right) {
                    if (slope >= 0 || x0 >= right) {
                        x0 = x1 = right;
                    }
                    else {
                        threePoints = true;
                        x1 = right;
                        x2 = right;
                        y2 = y0 - (right-x0)/slope;
                    }
                }
            }
        }

        return threePoints?