TextLayoutUtils.java 文件源码

/**
     * Get real allocation (possibly not rectangular) of a part of layout.
     * <br>
     * It's used when rendering the text layout for filling background highlights of the view.
     *
     * @param length Total number of characters for which the allocation is computed.
     * @param alloc Allocation given by a parent view.
     * @return
     */
    public static Shape getRealAlloc(TextLayout textLayout, Rectangle2D textLayoutRect,
            TextHitInfo startHit, TextHitInfo endHit)
    {
        // Quick-fix to eliminate missing line in rendering italic "d" - more elaborate fix is needed
        textLayoutRect = new Rectangle2D.Double(textLayoutRect.getX(), textLayoutRect.getY(),
                textLayoutRect.getWidth() + 2, textLayoutRect.getHeight());
        Rectangle2D.Double zeroBasedRect = ViewUtils.shape2Bounds(textLayoutRect);
        zeroBasedRect.x = 0;
        zeroBasedRect.y = 0;
        Shape ret = textLayout.getVisualHighlightShape(startHit, endHit, zeroBasedRect);
        AffineTransform transform = AffineTransform.getTranslateInstance(
                textLayoutRect.getX(),
                textLayoutRect.getY()
        );
        ret = transform.createTransformedShape(ret);
        // The following gives bad result for some reason (works for layout but not for caret modelToView())
//        Shape ret2 = textLayout.getVisualHighlightShape(startHit.getCharIndex(), endHit.getCharIndex(), textLayoutRect);
        return ret;
    }