/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id$ */

package org.apache.fop.render;

import java.awt.Color;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.util.List;
import java.util.Map;

import org.w3c.dom.Document;

import org.apache.batik.parser.AWTTransformProducer;

import org.apache.xmlgraphics.image.loader.ImageSize;
import org.apache.xmlgraphics.util.QName;
import org.apache.xmlgraphics.util.UnitConv;

import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.area.Area;
import org.apache.fop.area.Block;
import org.apache.fop.area.BlockViewport;
import org.apache.fop.area.CTM;
import org.apache.fop.area.NormalFlow;
import org.apache.fop.area.RegionReference;
import org.apache.fop.area.RegionViewport;
import org.apache.fop.area.Trait;
import org.apache.fop.area.inline.ForeignObject;
import org.apache.fop.area.inline.InlineArea;
import org.apache.fop.area.inline.InlineViewport;
import org.apache.fop.fo.Constants;
import org.apache.fop.fo.extensions.ExtensionElementMapping;
import org.apache.fop.fonts.FontMetrics;
import org.apache.fop.traits.BorderProps;


/**
 * Abstract base class for renderers like PDF and PostScript where many painting operations
 * follow similar patterns which makes it possible to share some code.
 */
public abstract class AbstractPathOrientedRenderer extends PrintRenderer {

    /**
     * @param userAgent the user agent that contains configuration details. This cannot be null.
     */
    public AbstractPathOrientedRenderer(FOUserAgent userAgent) {
        super(userAgent);
    }

    /**
     * Handle block traits.
     * The block could be any sort of block with any positioning
     * so this should render the traits such as border and background
     * in its position.
     *
     * @param block the block to render the traits
     */
    protected void handleBlockTraits(Block block) {
        float borderPaddingStart = block.getBorderAndPaddingWidthStart() / 1000f;
        float borderPaddingEnd = block.getBorderAndPaddingWidthEnd() / 1000f;
        float borderPaddingBefore = block.getBorderAndPaddingWidthBefore() / 1000f;
        float borderPaddingAfter = block.getBorderAndPaddingWidthAfter() / 1000f;

        float startx = currentIPPosition / 1000f;
        float starty = currentBPPosition / 1000f;
        float width = block.getIPD() / 1000f;
        float height = block.getBPD() / 1000f;

        int level = block.getBidiLevel();
        if ((level == -1) || ((level & 1) == 0)) {
            startx += block.getStartIndent() / 1000f;
            startx -= borderPaddingStart;
        } else {
            startx += block.getEndIndent() / 1000f;
            startx -= borderPaddingEnd;
        }

        width += borderPaddingStart;
        width += borderPaddingEnd;
        height += borderPaddingBefore;
        height += borderPaddingAfter;

        drawBackAndBorders(block, startx, starty, width, height);
    }

    /**
     * Handle the traits for a region
     * This is used to draw the traits for the given page region.
     * (See Sect. 6.4.1.2 of XSL-FO spec.)
     * @param region the RegionViewport whose region is to be drawn
     */
    protected void handleRegionTraits(RegionViewport region) {
        Rectangle2D viewArea = region.getViewArea();
        RegionReference referenceArea = region.getRegionReference();
        float startx = (float)(viewArea.getX() / 1000f);
        float starty = (float)(viewArea.getY() / 1000f);
        float width = (float)(viewArea.getWidth() / 1000f);
        float height = (float)(viewArea.getHeight() / 1000f);

        // adjust the current position according to region borders and padding
        currentBPPosition = referenceArea.getBorderAndPaddingWidthBefore();
        int level = region.getBidiLevel();
        if ((level == -1) || ((level & 1) == 0)) {
            currentIPPosition = referenceArea.getBorderAndPaddingWidthStart();
        } else {
            currentIPPosition = referenceArea.getBorderAndPaddingWidthEnd();
        }
        // draw background (traits are in the RegionViewport)
        // and borders (traits are in the RegionReference)
        drawBackAndBorders(region, referenceArea, startx, starty, width, height);
    }

    /**
     * Draw the background and borders.
     * This draws the background and border traits for an area given
     * the position.
     *
     * @param area the area to get the traits from
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     */
    protected void drawBackAndBorders(Area area,
                    float startx, float starty,
                    float width, float height) {
        drawBackAndBorders(area, area, startx, starty, width, height);
    }

    /**
     * Draw the background and borders.
     * This draws the background and border traits for an area given
     * the position.
     *
     * @param backgroundArea the area to get the background traits from
     * @param borderArea the area to get the border traits from
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     */
    protected void drawBackAndBorders(Area backgroundArea, Area borderArea,
                    float startx, float starty,
                    float width, float height) {
        // draw background then border

        BorderProps bpsBefore = (BorderProps)borderArea.getTrait(Trait.BORDER_BEFORE);
        BorderProps bpsAfter = (BorderProps)borderArea.getTrait(Trait.BORDER_AFTER);
        BorderProps bpsStart = (BorderProps)borderArea.getTrait(Trait.BORDER_START);
        BorderProps bpsEnd = (BorderProps)borderArea.getTrait(Trait.BORDER_END);

        Trait.Background backgroundTrait
            = (Trait.Background)backgroundArea.getTrait(Trait.BACKGROUND);

        drawBackground(startx, starty, width, height,
                (Trait.Background) backgroundArea.getTrait(Trait.BACKGROUND),
                bpsBefore, bpsAfter, bpsStart, bpsEnd, backgroundArea.getBidiLevel());
        // TODO what is the default bg color?   Should we serialize it?
        Color bg = Color.white;
        if (backgroundTrait != null &&  backgroundTrait.getColor() != null) {
            bg = backgroundTrait.getColor();
        }

        drawBorders(startx, starty, width, height,
                bpsBefore, bpsAfter, bpsStart, bpsEnd, backgroundArea.getBidiLevel(), bg);
    }

    /**
     * Draw the background.
     * This draws the background given the position and the traits.
     *
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     * @param back the background traits
     * @param bpsBefore the border-before traits
     * @param bpsAfter the border-after traits
     * @param bpsStart the border-start traits
     * @param bpsEnd the border-end traits
     * @param level of bidirectional embedding
     */
    protected void drawBackground(float startx, float starty, float width, float height, Trait.Background back,
            BorderProps bpsBefore, BorderProps bpsAfter,
            BorderProps bpsStart, BorderProps bpsEnd, int level) {
        BorderProps bpsTop = bpsBefore;
        BorderProps bpsBottom = bpsAfter;
        BorderProps bpsLeft;
        BorderProps bpsRight;
        if ((level == -1) || ((level & 1) == 0)) {
            bpsLeft = bpsStart;
            bpsRight = bpsEnd;
        } else {
            bpsLeft = bpsEnd;
            bpsRight = bpsStart;
        }
        drawBackground(startx, starty, width, height, back, bpsTop, bpsBottom, bpsLeft, bpsRight);
    }

    /**
     * Draw the background.
     * This draws the background given the position and the traits.
     *
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     * @param back the background traits
     * @param bpsTop the border specification on the top edge
     * @param bpsBottom the border traits associated with bottom edge
     * @param bpsLeft the border specification on the left edge
     * @param bpsRight the border specification on the right edge
     */
    protected void drawBackground(float startx, float starty, float width, float height, Trait.Background back,
            BorderProps bpsTop, BorderProps bpsBottom,
            BorderProps bpsLeft, BorderProps bpsRight) {
        if (back != null) {
            endTextObject();

            //Calculate padding rectangle
            float sx = startx;
            float sy = starty;
            float paddRectWidth = width;
            float paddRectHeight = height;
            if (bpsLeft != null) {
                sx += bpsLeft.width / 1000f;
                paddRectWidth -= bpsLeft.width / 1000f;
            }
            if (bpsTop != null) {
                sy += bpsTop.width / 1000f;
                paddRectHeight -= bpsTop.width / 1000f;
            }
            if (bpsRight != null) {
                paddRectWidth -= bpsRight.width / 1000f;
            }
            if (bpsBottom != null) {
                paddRectHeight -= bpsBottom.width / 1000f;
            }

            saveGraphicsState();

            clipBackground(sx, sy,  paddRectWidth, paddRectHeight, bpsTop, bpsBottom, bpsLeft, bpsRight);

            if (back.getColor() != null) {
                updateColor(back.getColor(), true);
                fillRect(sx, sy, paddRectWidth, paddRectHeight);
            }

            if (back.getImageInfo() != null) {
                ImageSize imageSize = back.getImageInfo().getSize();
                int targetWidth = imageSize.getWidthMpt();
                int targetHeight = imageSize.getHeightMpt();
                double multiplier = 1.0;
                if (back.getImageTargetWidth() != 0 && back.getImageTargetHeight() != 0) {
                    multiplier = Math.min(1.0 * back.getImageTargetWidth() / targetWidth,
                            1.0 * back.getImageTargetHeight() / targetHeight);
                } else if (back.getImageTargetHeight() != 0) {
                    multiplier = 1.0 * back.getImageTargetHeight() / targetHeight;
                } else if (back.getImageTargetWidth() != 0) {
                    multiplier = 1.0 * back.getImageTargetWidth() / targetWidth;
                }
                targetWidth = (int) (targetWidth * multiplier);
                targetHeight = (int) (targetHeight * multiplier);
                int horzCount = (int) ((paddRectWidth * 1000 / targetWidth) + 1.0f);
                int vertCount = (int) ((paddRectHeight * 1000 / targetHeight) + 1.0f);
                if (back.getRepeat() == EN_NOREPEAT) {
                    horzCount = 1;
                    vertCount = 1;
                } else if (back.getRepeat() == EN_REPEATX) {
                    vertCount = 1;
                } else if (back.getRepeat() == EN_REPEATY) {
                    horzCount = 1;
                }
                //change from points to millipoints
                sx *= 1000;
                sy *= 1000;
                if (horzCount == 1) {
                    sx += back.getHoriz();
                }
                if (vertCount == 1) {
                    sy += back.getVertical();
                }
                for (int x = 0; x < horzCount; x++) {
                    for (int y = 0; y < vertCount; y++) {
                        // place once
                        Rectangle2D pos;
                        // Image positions are relative to the currentIP/BP
                        pos = new Rectangle2D.Float(sx - currentIPPosition + (x * targetWidth), sy
                                - currentBPPosition + (y * targetHeight), targetWidth, targetHeight);
                        drawImage(back.getURL(), pos);
                    }
                }
            }
            restoreGraphicsState();
        }
    }

    /**
     * TODO represent border related parameters in a class
     * Clip the background to the inner border.
     * This draws the border traits given the position and the traits.
     *
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     * @param bpsBefore the border-before traits
     * @param bpsAfter the border-after traits
     * @param bpsStart the border-start traits
     * @param bpsEnd the border-end traits
     * @param innerBackgroundColor the background color of the block
     */
    protected void clipBackground(float startx, float starty,
            float width, float height,
            BorderProps bpsBefore, BorderProps bpsAfter,
            BorderProps bpsStart, BorderProps bpsEnd) {

        clipRect(startx, starty, width, height);

    }

    /**
     * Draw the borders.
     * This draws the border traits given the position and the traits.
     *
     * @param startx the start x position
     * @param starty the start y position
     * @param width the width of the area
     * @param height the height of the area
     * @param bpsBefore the border traits associated with before edge
     * @param bpsAfter the border traits associated with after edge
     * @param bpsStart the border traits associated with start edge
     * @param bpsEnd the border traits associated with end edge
     * @param level of bidirectional embedding
     * @param innerBackgroundColor the background color of the block
     */
    protected void drawBorders(float startx, float starty, float width, float height,
            BorderProps bpsBefore, BorderProps bpsAfter,
            BorderProps bpsStart, BorderProps bpsEnd, int level, Color innerBackgroundColor) {
        Rectangle2D.Float borderRect = new Rectangle2D.Float(startx, starty, width, height);
        BorderProps bpsTop = bpsBefore;
        BorderProps bpsBottom = bpsAfter;
        BorderProps bpsLeft;
        BorderProps bpsRight;
        if ((level == -1) || ((level & 1) == 0)) {
            bpsLeft = bpsStart;
            bpsRight = bpsEnd;
        } else {
            bpsLeft = bpsEnd;
            bpsRight = bpsStart;
        }
        drawBorders(borderRect, bpsTop, bpsBottom, bpsLeft, bpsRight, innerBackgroundColor);
    }

    private static final int TOP = 0;
    private static final int RIGHT = 1;
    private static final int BOTTOM = 2;
    private static final int LEFT = 3;

    /**
     * Draws borders.
     * @param borderRect the border rectangle
     * @param bpsTop the border specification on the top edge
     * @param bpsBottom the border traits associated with bottom edge
     * @param bpsLeft the border specification on the left edge
     * @param bpsRight the border specification on the right edge
     * @param innerBackgroundColor the background color of the block
     */
    protected void drawBorders(Rectangle2D.Float borderRect,
            BorderProps bpsTop, BorderProps bpsBottom, BorderProps bpsLeft, BorderProps bpsRight,
            Color innerBackgroundColor) {
        //TODO generalize each of the four conditions into using a parameterized drawBorder()
        boolean[] border = new boolean[] {
                (bpsTop != null), (bpsRight != null),
                (bpsBottom != null), (bpsLeft != null)};
        float startx = borderRect.x;
        float starty = borderRect.y;
        float width = borderRect.width;
        float height = borderRect.height;
        float[] borderWidth = new float[] {
            (border[TOP] ? bpsTop.width / 1000f : 0.0f),
            (border[RIGHT] ? bpsRight.width / 1000f : 0.0f),
            (border[BOTTOM] ? bpsBottom.width / 1000f : 0.0f),
            (border[LEFT] ? bpsLeft.width / 1000f : 0.0f)};
        float[] clipw = new float[] {
            BorderProps.getClippedWidth(bpsTop) / 1000f,
            BorderProps.getClippedWidth(bpsRight) / 1000f,
            BorderProps.getClippedWidth(bpsBottom) / 1000f,
            BorderProps.getClippedWidth(bpsLeft) / 1000f};

        starty += clipw[TOP];
        height -= clipw[TOP];
        height -= clipw[BOTTOM];
        startx += clipw[LEFT];
        width -= clipw[LEFT];
        width -= clipw[RIGHT];

        boolean[] slant = new boolean[] {
            (border[LEFT] && border[TOP]),
            (border[TOP] && border[RIGHT]),
            (border[RIGHT] && border[BOTTOM]),
            (border[BOTTOM] && border[LEFT])};
        if (bpsTop != null) {
            endTextObject();

            float sx1 = startx;
            float sx2 = (slant[TOP] ? sx1 + borderWidth[LEFT] - clipw[LEFT] : sx1);
            float ex1 = startx + width;
            float ex2 = (slant[RIGHT] ? ex1 - borderWidth[RIGHT] + clipw[RIGHT] : ex1);
            float outery = starty - clipw[TOP];
            float clipy = outery + clipw[TOP];
            float innery = outery + borderWidth[TOP];

            saveGraphicsState();
            moveTo(sx1, clipy);
            float sx1a = sx1;
            float ex1a = ex1;

            if (isCollapseOuter(bpsTop)) {
                if (isCollapseOuter(bpsLeft)) {
                    sx1a -= clipw[LEFT];
                }
                if (isCollapseOuter(bpsRight)) {
                    ex1a += clipw[RIGHT];
                }
                lineTo(sx1a, outery);
                lineTo(ex1a, outery);
            }
            lineTo(ex1, clipy);
            lineTo(ex2, innery);
            lineTo(sx2, innery);
            closePath();
            clip();
            drawBorderLine(sx1a, outery, ex1a, innery, true, true,
                    bpsTop.style, bpsTop.color);
            restoreGraphicsState();
        }
        if (bpsRight != null) {
            endTextObject();

            float sy1 = starty;
            float sy2 = (slant[RIGHT] ? sy1 + borderWidth[TOP] - clipw[TOP] : sy1);
            float ey1 = starty + height;
            float ey2 = (slant[BOTTOM] ? ey1 - borderWidth[BOTTOM] + clipw[BOTTOM] : ey1);
            float outerx = startx + width + clipw[RIGHT];
            float clipx = outerx - clipw[RIGHT];
            float innerx = outerx - borderWidth[RIGHT];

            saveGraphicsState();
            moveTo(clipx, sy1);
            float sy1a = sy1;
            float ey1a = ey1;
            if (isCollapseOuter(bpsRight)) {
                if (isCollapseOuter(bpsTop)) {
                    sy1a -= clipw[TOP];
                }
                if (isCollapseOuter(bpsBottom)) {
                    ey1a += clipw[BOTTOM];
                }
                lineTo(outerx, sy1a);
                lineTo(outerx, ey1a);
            }
            lineTo(clipx, ey1);
            lineTo(innerx, ey2);
            lineTo(innerx, sy2);
            closePath();
            clip();
            drawBorderLine(innerx, sy1a, outerx, ey1a, false, false,
                           bpsRight.style, bpsRight.color);
            restoreGraphicsState();
        }
        if (bpsBottom != null) {
            endTextObject();

            float sx1 = startx;
            float sx2 = (slant[LEFT] ? sx1 + borderWidth[LEFT] - clipw[LEFT] : sx1);
            float ex1 = startx + width;
            float ex2 = (slant[BOTTOM] ? ex1 - borderWidth[RIGHT] + clipw[RIGHT] : ex1);
            float outery = starty + height + clipw[BOTTOM];
            float clipy = outery - clipw[BOTTOM];
            float innery = outery - borderWidth[BOTTOM];

            saveGraphicsState();
            moveTo(ex1, clipy);
            float sx1a = sx1;
            float ex1a = ex1;
            if (isCollapseOuter(bpsBottom)) {
                if (isCollapseOuter(bpsLeft)) {
                    sx1a -= clipw[LEFT];
                }
                if (isCollapseOuter(bpsRight)) {
                    ex1a += clipw[RIGHT];
                }
                lineTo(ex1a, outery);
                lineTo(sx1a, outery);
            }
            lineTo(sx1, clipy);
            lineTo(sx2, innery);
            lineTo(ex2, innery);
            closePath();
            clip();
            drawBorderLine(sx1a, innery, ex1a, outery, true, false,
                           bpsBottom.style, bpsBottom.color);
            restoreGraphicsState();
        }
        if (bpsLeft != null) {
            endTextObject();

            float sy1 = starty;
            float sy2 = (slant[TOP] ? sy1 + borderWidth[TOP] - clipw[TOP] : sy1);
            float ey1 = sy1 + height;
            float ey2 = (slant[LEFT] ? ey1 - borderWidth[BOTTOM] + clipw[BOTTOM] : ey1);
            float outerx = startx - clipw[LEFT];
            float clipx = outerx + clipw[LEFT];
            float innerx = outerx + borderWidth[LEFT];

            saveGraphicsState();
            moveTo(clipx, ey1);
            float sy1a = sy1;
            float ey1a = ey1;
            if (isCollapseOuter(bpsLeft)) {
                if (isCollapseOuter(bpsTop)) {
                    sy1a -= clipw[TOP];
                }
                if (isCollapseOuter(bpsBottom)) {
                    ey1a += clipw[BOTTOM];
                }
                lineTo(outerx, ey1a);
                lineTo(outerx, sy1a);
            }
            lineTo(clipx, sy1);
            lineTo(innerx, sy2);
            lineTo(innerx, ey2);
            closePath();
            clip();
            drawBorderLine(outerx, sy1a, innerx, ey1a, false, true, bpsLeft.style, bpsLeft.color);
            restoreGraphicsState();
        }
    }

    private boolean isCollapseOuter(BorderProps bp) {
        return bp != null && bp.isCollapseOuter();
    }

    /**
     * Common method to render the background and borders for any inline area.
     * The all borders and padding are drawn outside the specified area.
     * @param area the inline area for which the background, border and padding is to be
     * rendered
     */
    protected void renderInlineAreaBackAndBorders(InlineArea area) {
        float borderPaddingStart = area.getBorderAndPaddingWidthStart() / 1000f;
        float borderPaddingEnd = area.getBorderAndPaddingWidthEnd() / 1000f;
        float borderPaddingBefore = area.getBorderAndPaddingWidthBefore() / 1000f;
        float borderPaddingAfter = area.getBorderAndPaddingWidthAfter() / 1000f;
        float bpwidth = borderPaddingStart + borderPaddingEnd;
        float bpheight = borderPaddingBefore + borderPaddingAfter;

        float height = area.getBPD() / 1000f;
        if (height != 0.0f || bpheight != 0.0f && bpwidth != 0.0f) {
            float x = currentIPPosition / 1000f;
            float y = (currentBPPosition + area.getBlockProgressionOffset()) / 1000f;
            float width = area.getIPD() / 1000f;
            drawBackAndBorders(area, x, y - borderPaddingBefore
                                , width + bpwidth
                                , height + bpheight);
        }
    }

    /** Constant for the fox:transform extension attribute */
    protected static final QName FOX_TRANSFORM
            = new QName(ExtensionElementMapping.URI, "fox:transform");

    /** {@inheritDoc} */
    protected void renderBlockViewport(BlockViewport bv, List children) {
        // clip and position viewport if necessary

        // save positions
        int saveIP = currentIPPosition;
        int saveBP = currentBPPosition;

        CTM ctm = bv.getCTM();
        int borderPaddingBefore = bv.getBorderAndPaddingWidthBefore();

        int positioning = bv.getPositioning();
        if (positioning == Block.ABSOLUTE || positioning == Block.FIXED) {

            //For FIXED, we need to break out of the current viewports to the
            //one established by the page. We save the state stack for restoration
            //after the block-container has been painted. See below.
            List breakOutList = null;
            if (positioning == Block.FIXED) {
                breakOutList = breakOutOfStateStack();
            }

            AffineTransform positionTransform = new AffineTransform();
            positionTransform.translate(bv.getXOffset(), bv.getYOffset());

            int level = bv.getBidiLevel();
            int borderPaddingStart = bv.getBorderAndPaddingWidthStart();
            int borderPaddingEnd = bv.getBorderAndPaddingWidthEnd();

            //"left/"top" (bv.getX/YOffset()) specify the position of the content rectangle
            if ((level == -1) || ((level & 1) == 0)) {
                positionTransform.translate(-borderPaddingStart, -borderPaddingBefore);
            } else {
                positionTransform.translate(-borderPaddingEnd, -borderPaddingBefore);
            }

            //Free transformation for the block-container viewport
            String transf;
            transf = bv.getForeignAttributeValue(FOX_TRANSFORM);
            if (transf != null) {
                AffineTransform freeTransform = AWTTransformProducer.createAffineTransform(transf);
                positionTransform.concatenate(freeTransform);
            }

            //Viewport position
            if (!positionTransform.isIdentity()) {
                establishTransformationMatrix(positionTransform);
            }

            //This is the content-rect
            float width = bv.getIPD() / 1000f;
            float height = bv.getBPD() / 1000f;

            //Background and borders
            float borderPaddingWidth
                = (borderPaddingStart + borderPaddingEnd) / 1000f;
            float borderPaddingHeight
                = (borderPaddingBefore + bv.getBorderAndPaddingWidthAfter()) / 1000f;
            drawBackAndBorders(bv, 0, 0, width + borderPaddingWidth, height + borderPaddingHeight);

            //Shift to content rectangle after border painting
            AffineTransform contentRectTransform = new AffineTransform();
            if ((level == -1) || ((level & 1) == 0)) {
                contentRectTransform.translate(borderPaddingStart, borderPaddingBefore);
            } else {
                contentRectTransform.translate(borderPaddingEnd, borderPaddingBefore);
            }

            if (!contentRectTransform.isIdentity()) {
                establishTransformationMatrix(contentRectTransform);
            }

            //Clipping
            if (bv.hasClip()) {
                clipRect(0f, 0f, width, height);
            }

            //Set up coordinate system for content rectangle
            AffineTransform contentTransform = ctm.toAffineTransform();
            if (!contentTransform.isIdentity()) {
                establishTransformationMatrix(contentTransform);
            }

            currentIPPosition = 0;
            currentBPPosition = 0;
            renderBlocks(bv, children);

            if (!contentTransform.isIdentity()) {
                restoreGraphicsState();
            }

            if (!contentRectTransform.isIdentity()) {
                restoreGraphicsState();
            }

            if (!positionTransform.isIdentity()) {
                restoreGraphicsState();
            }

            //For FIXED, we need to restore break out now we are done
            if (positioning == Block.FIXED) {
                if (breakOutList != null) {
                    restoreStateStackAfterBreakOut(breakOutList);
                }
            }

            currentIPPosition = saveIP;
            currentBPPosition = saveBP;
        } else {

            currentBPPosition += bv.getSpaceBefore();

            //borders and background in the old coordinate system
            handleBlockTraits(bv);

            //Advance to start of content area
            currentIPPosition += bv.getStartIndent();

            CTM tempctm = new CTM(containingIPPosition, currentBPPosition);
            ctm = tempctm.multiply(ctm);

            //Now adjust for border/padding
            currentBPPosition += borderPaddingBefore;

            Rectangle clippingRect = null;
            if (bv.hasClip()) {
                clippingRect = new Rectangle(currentIPPosition, currentBPPosition,
                        bv.getIPD(), bv.getBPD());
            }

            startVParea(ctm, clippingRect);
            currentIPPosition = 0;
            currentBPPosition = 0;
            renderBlocks(bv, children);
            endVParea();

            currentIPPosition = saveIP;
            currentBPPosition = saveBP;

            currentBPPosition += (bv.getAllocBPD());
        }
    }

    /** {@inheritDoc} */
    protected void renderReferenceArea(Block block) {
        // save position and offset
        int saveIP = currentIPPosition;
        int saveBP = currentBPPosition;

        //Establish a new coordinate system
        AffineTransform at = new AffineTransform();
        at.translate(currentIPPosition, currentBPPosition);
        at.translate(block.getXOffset(), block.getYOffset());
        at.translate(0, block.getSpaceBefore());

        if (!at.isIdentity()) {
            establishTransformationMatrix(at);
        }

        currentIPPosition = 0;
        currentBPPosition = 0;
        handleBlockTraits(block);

        List children = block.getChildAreas();
        if (children != null) {
            renderBlocks(block, children);
        }

        if (!at.isIdentity()) {
            restoreGraphicsState();
        }

        // stacked and relative blocks effect stacking
        currentIPPosition = saveIP;
        currentBPPosition = saveBP;
    }

    /** {@inheritDoc} */
    protected void renderFlow(NormalFlow flow) {
        // save position and offset
        int saveIP = currentIPPosition;
        int saveBP = currentBPPosition;

        //Establish a new coordinate system
        AffineTransform at = new AffineTransform();
        at.translate(currentIPPosition, currentBPPosition);

        if (!at.isIdentity()) {
            establishTransformationMatrix(at);
        }

        currentIPPosition = 0;
        currentBPPosition = 0;
        super.renderFlow(flow);

        if (!at.isIdentity()) {
            restoreGraphicsState();
        }

        // stacked and relative blocks effect stacking
        currentIPPosition = saveIP;
        currentBPPosition = saveBP;
    }

    /**
     * Concatenates the current transformation matrix with the given one, therefore establishing
     * a new coordinate system.
     * @param at the transformation matrix to process (coordinates in points)
     */
    protected abstract void concatenateTransformationMatrix(AffineTransform at);

    /**
     * Render an inline viewport.
     * This renders an inline viewport by clipping if necessary.
     * @param viewport the viewport to handle
     */
    public void renderInlineViewport(InlineViewport viewport) {
        int level = viewport.getBidiLevel();
        float x = currentIPPosition / 1000f;
        float y = (currentBPPosition + viewport.getBlockProgressionOffset()) / 1000f;
        float width = viewport.getIPD() / 1000f;
        float height = viewport.getBPD() / 1000f;
        // TODO: Calculate the border rect correctly.
        float borderPaddingStart = viewport.getBorderAndPaddingWidthStart() / 1000f;
        float borderPaddingEnd = viewport.getBorderAndPaddingWidthEnd() / 1000f;
        float borderPaddingBefore = viewport.getBorderAndPaddingWidthBefore() / 1000f;
        float borderPaddingAfter = viewport.getBorderAndPaddingWidthAfter() / 1000f;
        float bpwidth = borderPaddingStart + borderPaddingEnd;
        float bpheight = borderPaddingBefore + borderPaddingAfter;

        drawBackAndBorders(viewport, x, y, width + bpwidth, height + bpheight);

        if (viewport.hasClip()) {
            saveGraphicsState();
            if ((level == -1) || ((level & 1) == 0)) {
                clipRect(x + borderPaddingStart, y + borderPaddingBefore, width, height);
            } else {
                clipRect(x + borderPaddingEnd, y + borderPaddingBefore, width, height);
            }
        }
        super.renderInlineViewport(viewport);

        if (viewport.hasClip()) {
            restoreGraphicsState();
        }
    }

    /**
     * Restores the state stack after a break out.
     * @param breakOutList the state stack to restore.
     */
    protected abstract void restoreStateStackAfterBreakOut(List breakOutList);

    /**
     * Breaks out of the state stack to handle fixed block-containers.
     * @return the saved state stack to recreate later
     */
    protected abstract List breakOutOfStateStack();

    /** Saves the graphics state of the rendering engine. */
    protected abstract void saveGraphicsState();

    /** Restores the last graphics state of the rendering engine. */
    protected abstract void restoreGraphicsState();

    /** Indicates the beginning of a text object. */
    protected abstract void beginTextObject();

    /** Indicates the end of a text object. */
    protected abstract void endTextObject();

    /**
     * Paints the text decoration marks.
     * @param fm Current typeface
     * @param fontsize Current font size
     * @param inline inline area to paint the marks for
     * @param baseline position of the baseline
     * @param startx start IPD
     */
    protected void renderTextDecoration(FontMetrics fm, int fontsize, InlineArea inline,
                    int baseline, int startx) {
        boolean hasTextDeco = inline.hasUnderline()
                || inline.hasOverline()
                || inline.hasLineThrough();
        if (hasTextDeco) {
            endTextObject();
            float descender = fm.getDescender(fontsize) / 1000f;
            float capHeight = fm.getCapHeight(fontsize) / 1000f;
            float halfLineWidth = (descender / -8f) / 2f;
            float endx = (startx + inline.getIPD()) / 1000f;
            if (inline.hasUnderline()) {
                Color ct = (Color) inline.getTrait(Trait.UNDERLINE_COLOR);
                float y = baseline - descender / 2f;
                drawBorderLine(startx / 1000f, (y - halfLineWidth) / 1000f,
                        endx, (y + halfLineWidth) / 1000f,
                        true, true, Constants.EN_SOLID, ct);
            }
            if (inline.hasOverline()) {
                Color ct = (Color) inline.getTrait(Trait.OVERLINE_COLOR);
                float y = (float)(baseline - (1.1 * capHeight));
                drawBorderLine(startx / 1000f, (y - halfLineWidth) / 1000f,
                        endx, (y + halfLineWidth) / 1000f,
                        true, true, Constants.EN_SOLID, ct);
            }
            if (inline.hasLineThrough()) {
                Color ct = (Color) inline.getTrait(Trait.LINETHROUGH_COLOR);
                float y = (float)(baseline - (0.45 * capHeight));
                drawBorderLine(startx / 1000f, (y - halfLineWidth) / 1000f,
                        endx, (y + halfLineWidth) / 1000f,
                        true, true, Constants.EN_SOLID, ct);
            }
        }
    }

    /** Clip using the current path. */
    protected abstract void clip();

    /**
     * Clip using a rectangular area.
     * @param x the x coordinate (in points)
     * @param y the y coordinate (in points)
     * @param width the width of the rectangle (in points)
     * @param height the height of the rectangle (in points)
     */
    protected abstract void clipRect(float x, float y, float width, float height);

    /**
     * Moves the current point to (x, y), omitting any connecting line segment.
     * @param x x coordinate
     * @param y y coordinate
     */
    protected abstract void moveTo(float x, float y);

    /**
     * Appends a straight line segment from the current point to (x, y). The
     * new current point is (x, y).
     * @param x x coordinate
     * @param y y coordinate
     */
    protected abstract void lineTo(float x, float y);

    /**
     * Closes the current subpath by appending a straight line segment from
     * the current point to the starting point of the subpath.
     */
    protected abstract void closePath();

    /**
     * Fill a rectangular area.
     * @param x the x coordinate
     * @param y the y coordinate
     * @param width the width of the rectangle
     * @param height the height of the rectangle
     */
    protected abstract void fillRect(float x, float y, float width, float height);

    /**
     * Establishes a new foreground or fill color.
     * @param col the color to apply (null skips this operation)
     * @param fill true to set the fill color, false for the foreground color
     */
    protected abstract void updateColor(Color col, boolean fill);

    /**
     * Draw an image at the indicated location.
     * @param url the URI/URL of the image
     * @param pos the position of the image
     * @param foreignAttributes an optional Map with foreign attributes, may be null
     */
    protected abstract void drawImage(String url, Rectangle2D pos, Map foreignAttributes);

    /**
     * Draw an image at the indicated location.
     * @param url the URI/URL of the image
     * @param pos the position of the image
     */
    protected final void drawImage(String url, Rectangle2D pos) {
        drawImage(url, pos, null);
    }

    /**
     * Draw a border segment of an XSL-FO style border.
     * @param x1 starting x coordinate
     * @param y1 starting y coordinate
     * @param x2 ending x coordinate
     * @param y2 ending y coordinate
     * @param horz true for horizontal border segments, false for vertical border segments
     * @param startOrBefore true for border segments on the start or before edge,
     *                      false for end or after.
     * @param style the border style (one of Constants.EN_DASHED etc.)
     * @param col the color for the border segment
     */
    protected abstract void drawBorderLine(float x1, float y1, float x2, float y2, boolean horz,
            boolean startOrBefore, int style, Color col);

    /** {@inheritDoc} */
    public void renderForeignObject(ForeignObject fo, Rectangle2D pos) {
        endTextObject();
        Document doc = fo.getDocument();
        String ns = fo.getNameSpace();
        renderDocument(doc, ns, pos, fo.getForeignAttributes());
    }

    /**
     * Establishes a new coordinate system with the given transformation matrix.
     * The current graphics state is saved and the new coordinate system is concatenated.
     * @param at the transformation matrix
     */
    protected void establishTransformationMatrix(AffineTransform at) {
        saveGraphicsState();
        concatenateTransformationMatrix(UnitConv.mptToPt(at));
    }

}