/*
 * 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.
 */
package org.apache.pdfbox.pdfviewer;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.geom.Area;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
import java.awt.Image;
import java.io.IOException;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.common.PDMatrix;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.font.PDFont;
import org.apache.pdfbox.pdmodel.graphics.PDGraphicsState;
import org.apache.pdfbox.pdmodel.graphics.PDShading;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingResources;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType1;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType2;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType3;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType4;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType5;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType6;
import org.apache.pdfbox.pdmodel.graphics.shading.PDShadingType7;
import org.apache.pdfbox.pdmodel.graphics.shading.Type1ShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.AxialShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.RadialShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.Type4ShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.Type5ShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.Type6ShadingPaint;
import org.apache.pdfbox.pdmodel.graphics.shading.Type7ShadingPaint;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceDictionary;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceStream;
import org.apache.pdfbox.pdmodel.text.PDTextState;
import org.apache.pdfbox.util.Matrix;
import org.apache.pdfbox.util.PDFStreamEngine;
import org.apache.pdfbox.util.ResourceLoader;
import org.apache.pdfbox.util.TextPosition;
import org.apache.pdfbox.cos.COSName;


/**
 * This will paint a page in a PDF document to a graphics context.
 *
 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
 * @version $Revision: 1.22 $
 */
public class PageDrawer extends PDFStreamEngine
{

    /**
     * Log instance.
     */
    private static final Log LOG = LogFactory.getLog(PageDrawer.class);

    private Graphics2D graphics;
    
    /**
     * clipping winding rule used for the clipping path.
     */
    private int clippingWindingRule = -1;

    /**
     * Size of the page.
     */
    protected Dimension pageSize;
    /**
     * Current page to be rendered.
     */
    protected PDPage page;

    private GeneralPath linePath = new GeneralPath();

    private BasicStroke stroke = null;
    
    /**
     * Default constructor, loads properties from file.
     *
     * @throws IOException If there is an error loading properties from the file.
     */
    public PageDrawer() throws IOException
    {
        super( ResourceLoader.loadProperties(
                "org/apache/pdfbox/resources/PageDrawer.properties", true ) );
    }

    /**
     * This will draw the page to the requested context.
     *
     * @param g The graphics context to draw onto.
     * @param p The page to draw.
     * @param pageDimension The size of the page to draw.
     *
     * @throws IOException If there is an IO error while drawing the page.
     */
    public void drawPage( Graphics g, PDPage p, Dimension pageDimension ) throws IOException
    {
        graphics = (Graphics2D)g;
        page = p;
        pageSize = pageDimension;
        graphics.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
        graphics.setRenderingHint( RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON );
        // initialize the used stroke with CAP_BUTT instead of CAP_SQUARE
        graphics.setStroke(new BasicStroke(1.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER));
        // Only if there is some content, we have to process it. 
        // Otherwise we are done here and we will produce an empty page
        if ( page.getContents() != null) 
        {
            PDResources resources = page.findResources();
            processStream( page, resources, page.getContents().getStream() );
        }
        List<PDAnnotation> annotations = page.getAnnotations();
        for( int i=0; i<annotations.size(); i++ )
        {
            PDAnnotation annot = (PDAnnotation)annotations.get( i );
            PDRectangle rect = annot.getRectangle();
            String appearanceName = annot.getAppearanceStream();
            PDAppearanceDictionary appearDictionary = annot.getAppearance();
            if( appearDictionary != null )
            {
                if( appearanceName == null )
                {
                    appearanceName = "default";
                }
                Map<String, PDAppearanceStream> appearanceMap = appearDictionary.getNormalAppearance();
                if (appearanceMap != null) 
                { 
                    PDAppearanceStream appearance = 
                        (PDAppearanceStream)appearanceMap.get( appearanceName ); 
                    if( appearance != null ) 
                    { 
                        Point2D point = new Point2D.Float(rect.getLowerLeftX(), rect.getLowerLeftY());
                        Matrix matrix = appearance.getMatrix();
                        if (matrix != null) 
                        {
                            // transform the rectangle using the given matrix 
                            AffineTransform at = matrix.createAffineTransform();
                            at.transform(point, point);
                        }
                        g.translate( (int)point.getX(), -(int)point.getY() );
                        processSubStream( page, appearance.getResources(), appearance.getStream() ); 
                        g.translate( -(int)point.getX(), (int)point.getY() ); 
                    }
                }
            }
        }

    }

    /**
     * Remove all cached resources.
     */
    public void dispose()
    {
        graphics = null;
        linePath = null;
        page = null;
        pageSize = null;
    }

    /**
     * You should override this method if you want to perform an action when a
     * text is being processed.
     *
     * @param text The text to process
     */
    protected void processTextPosition( TextPosition text )
    {
        try
        {
            PDGraphicsState graphicsState = getGraphicsState();
            Composite composite;
            Paint paint;
            switch(graphicsState.getTextState().getRenderingMode()) 
            {
                case PDTextState.RENDERING_MODE_FILL_TEXT:
                    composite = graphicsState.getNonStrokeJavaComposite();
                    paint = graphicsState.getNonStrokingColor().getJavaColor();
                    if (paint == null)
                    {
                        paint = graphicsState.getNonStrokingColor().getPaint(pageSize.height);
                    }
                    break;
                case PDTextState.RENDERING_MODE_STROKE_TEXT:
                    composite = graphicsState.getStrokeJavaComposite();
                    paint = graphicsState.getStrokingColor().getJavaColor();
                    if (paint == null)
                    {
                        paint = graphicsState.getStrokingColor().getPaint(pageSize.height);
                    }
                    break;
                case PDTextState.RENDERING_MODE_NEITHER_FILL_NOR_STROKE_TEXT:
                    //basic support for text rendering mode "invisible"
                    Color nsc = graphicsState.getStrokingColor().getJavaColor();
                    float[] components = {Color.black.getRed(),Color.black.getGreen(),Color.black.getBlue()};
                    paint = new Color(nsc.getColorSpace(),components,0f);
                    composite = graphicsState.getStrokeJavaComposite();
                    break;
                default:
                    // TODO : need to implement....
                    LOG.debug("Unsupported RenderingMode "
                            + this.getGraphicsState().getTextState().getRenderingMode()
                            + " in PageDrawer.processTextPosition()."
                            + " Using RenderingMode "
                            + PDTextState.RENDERING_MODE_FILL_TEXT
                            + " instead");
                    composite = graphicsState.getNonStrokeJavaComposite();
                    paint = graphicsState.getNonStrokingColor().getJavaColor();
            }
            graphics.setComposite(composite);
            graphics.setPaint(paint);
            
            PDFont font = text.getFont();
            Matrix textPos = text.getTextPos().copy();
            float x = textPos.getXPosition();
            // the 0,0-reference has to be moved from the lower left (PDF) to the upper left (AWT-graphics)
            float y = pageSize.height - textPos.getYPosition();
            // Set translation to 0,0. We only need the scaling and shearing
            textPos.setValue(2, 0, 0);
            textPos.setValue(2, 1, 0);
            // because of the moved 0,0-reference, we have to shear in the opposite direction
            textPos.setValue(0, 1, (-1)*textPos.getValue(0, 1));
            textPos.setValue(1, 0, (-1)*textPos.getValue(1, 0));
            AffineTransform at = textPos.createAffineTransform();
            PDMatrix fontMatrix = font.getFontMatrix();
            at.scale(fontMatrix.getValue(0, 0) * 1000f, fontMatrix.getValue(1, 1) * 1000f);
            //TODO setClip() is a massive performance hot spot. Investigate optimization possibilities
            graphics.setClip(graphicsState.getCurrentClippingPath());
            // the fontSize is no longer needed as it is already part of the transformation
            // we should remove it from the parameter list in the long run
            font.drawString( text.getCharacter(), text.getCodePoints(), graphics, 1, at, x, y );
        }
        catch( IOException io )
        {
            LOG.error (io, io);
        }
    }

    /**
     * Get the graphics that we are currently drawing on.
     *
     * @return The graphics we are drawing on.
     */
    public Graphics2D getGraphics()
    {
        return graphics;
    }

    /**
     * Get the page that is currently being drawn.
     *
     * @return The page that is being drawn.
     */
    public PDPage getPage()
    {
        return page;
    }

    /**
     * Get the size of the page that is currently being drawn.
     *
     * @return The size of the page that is being drawn.
     */
    public Dimension getPageSize()
    {
        return pageSize;
    }

    /**
     * Fix the y coordinate.
     *
     * @param y The y coordinate.
     * @return The updated y coordinate.
     */
    public double fixY( double y )
    {
        return pageSize.getHeight() - y;
    }

    /**
     * Get the current line path to be drawn.
     *
     * @return The current line path to be drawn.
     */
    public GeneralPath getLinePath()
    {
        return linePath;
    }

    /**
     * Set the line path to draw.
     *
     * @param newLinePath Set the line path to draw.
     */
    public void setLinePath(GeneralPath newLinePath)
    {
        if (linePath == null || linePath.getCurrentPoint() == null)
        {
            linePath = newLinePath;
        }
        else
        {
            linePath.append(newLinePath, false);
        }
    }


    /**
     * Fill the path.
     *
     * @param windingRule The winding rule this path will use.
     * 
     * @throws IOException If there is an IO error while filling the path.
     */
    public void fillPath(int windingRule) throws IOException
    {
        graphics.setComposite(getGraphicsState().getNonStrokeJavaComposite());
        Paint nonStrokingPaint = getGraphicsState().getNonStrokingColor().getJavaColor();
        if ( nonStrokingPaint == null )
        {
            nonStrokingPaint = getGraphicsState().getNonStrokingColor().getPaint(pageSize.height);
        }
        if ( nonStrokingPaint == null )
        {
            LOG.info("ColorSpace "+getGraphicsState().getNonStrokingColor().getColorSpace().getName()
                    +" doesn't provide a non-stroking color, using white instead!");
            nonStrokingPaint = Color.WHITE;
        }
        graphics.setPaint( nonStrokingPaint );
        getLinePath().setWindingRule(windingRule);
        graphics.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF );
        graphics.setClip(getGraphicsState().getCurrentClippingPath());
        if (!(graphics.getPaint() instanceof Color))
        {
            // apply clip to path to avoid oversized device bounds in shading contexts (PDFBOX-XXXX)
            Area area = new Area(getLinePath());
            area.intersect(new Area(graphics.getClip()));
            graphics.fill(area);
        }
        else
        {
            graphics.fill( getLinePath() );
        }
        getLinePath().reset();
    }


    /**
     * This will set the current stroke.
     *
     * @param newStroke The current stroke.
     * 
     */
    public void setStroke(BasicStroke newStroke)
    {
        stroke = newStroke;
    }

    /**
     * This will return the current stroke.
     *
     * @return The current stroke.
     * 
     */
    public BasicStroke getStroke()
    {
        return stroke;
    }
    
    /**
     * Create a new stroke based on the current ctm and the current stroke.
     * 
     * @return the transformed stroke
     */
    private BasicStroke calculateStroke()
    {
        float lineWidth = transformWidth((float) getGraphicsState().getLineWidth());
        if (lineWidth < 0.25)
        {
            lineWidth = 0.25f;
        }
        BasicStroke currentStroke = null;
        if (stroke == null)
        {
            currentStroke = new BasicStroke(lineWidth);
        }
        else
        {
            float phaseStart = stroke.getDashPhase();
            float[] dashArray = stroke.getDashArray();
            if (dashArray != null)
            {
                // apply the CTM
                for (int i = 0; i < dashArray.length; ++i)
                {
                    // minimum line dash width avoids JVM crash,
                    // see PDFBOX-2373, PDFBOX-2929, PDFBOX-3204, PDFBOX-3813
                    // also avoid 0 in array like "[ 0 1000 ] 0 d", see PDFBOX-3724
                    float w = transformWidth(dashArray[i]);
                    dashArray[i] = Math.max(w, 0.062f);
                }
                phaseStart = (int)transformWidth(phaseStart);

                // empty dash array is illegal
                // avoid also infinite and NaN values (PDFBOX-3360)
                if (dashArray.length == 0 || Float.isInfinite(phaseStart) || Float.isNaN(phaseStart))
                {
                    dashArray = null;
                }
                else
                {
                    for (int i = 0; i < dashArray.length; ++i)
                    {
                        if (Float.isInfinite(dashArray[i]) || Float.isNaN(dashArray[i]))
                        {
                            dashArray = null;
                            break;
                        }
                    }
                }
            }
            currentStroke = new BasicStroke(lineWidth, stroke.getEndCap(), stroke.getLineJoin(),
                    stroke.getMiterLimit(), dashArray, phaseStart);
        }
        return currentStroke;
    }
    
    /**
     * Stroke the path.
     *
     * @throws IOException If there is an IO error while stroking the path.
     */
    public void strokePath() throws IOException
    {
        graphics.setComposite(getGraphicsState().getStrokeJavaComposite());
        Paint strokingPaint = getGraphicsState().getStrokingColor().getJavaColor();
        if ( strokingPaint == null )
        {
            strokingPaint = getGraphicsState().getStrokingColor().getPaint(pageSize.height);
        }
        if ( strokingPaint == null )
        {
            LOG.info("ColorSpace "+getGraphicsState().getStrokingColor().getColorSpace().getName()
                    +" doesn't provide a stroking color, using white instead!");
            strokingPaint = Color.WHITE;
        }
        graphics.setPaint(strokingPaint);
        graphics.setStroke(calculateStroke());
        graphics.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF );
        graphics.setClip(getGraphicsState().getCurrentClippingPath());
        GeneralPath path = getLinePath();
        graphics.draw( path );
        path.reset();
    }

    /**
     * Called when the color changed.
     * @param bStroking true for the stroking color, false for the non-stroking color
     * @throws IOException if an I/O error occurs
     */
    @Deprecated
    public void colorChanged(boolean bStroking) throws IOException
    {
        //logger().info("changing " + (bStroking ? "" : "non") + "stroking color");
    }

    //This code generalizes the code Jim Lynch wrote for AppendRectangleToPath
    /**
     * use the current transformation matrix to transform a single point.
     * @param x x-coordinate of the point to be transform
     * @param y y-coordinate of the point to be transform
     * @return the transformed coordinates as Point2D.Double
     */
    public Point2D.Double transformedPoint(double x, double y)
    {
        double[] position = {x,y}; 
        getGraphicsState().getCurrentTransformationMatrix().createAffineTransform().transform(
                position, 0, position, 0, 1);
        position[1] = fixY(position[1]);
        return new Point2D.Double(position[0],position[1]);
    }

    /**
     * Set the clipping Path.
     *
     * @param windingRule The winding rule this path will use.
     * 
     * @deprecated use {@link #setClippingWindingRule(int)} instead
     * 
     */
    public void setClippingPath(int windingRule)
    {
        setClippingWindingRule(windingRule);
    }
    
    /**
     * Set the clipping winding rule.
     *
     * @param windingRule The winding rule which will be used for clipping.
     * 
     */
    public void setClippingWindingRule(int windingRule)
    {
        clippingWindingRule = windingRule;
    }

    /**
     * Set the clipping Path.
     *
     */
    public void endPath()
    {
        if (clippingWindingRule > -1)
        {
            PDGraphicsState graphicsState = getGraphicsState();
            GeneralPath clippingPath = (GeneralPath)getLinePath().clone(); // TODO do we really need to clone this? isn't the line path reset anyway?
            clippingPath.setWindingRule(clippingWindingRule);
            // If there is already set a clipping path, we have to intersect the new with the existing one
            if (graphicsState.getCurrentClippingPath() != null) 
            {
                Area currentArea = new Area(getGraphicsState().getCurrentClippingPath());
                Area newArea = new Area(clippingPath);
                currentArea.intersect(newArea);
                graphicsState.setCurrentClippingPath(currentArea);
            }
            else 
            {
                graphicsState.setCurrentClippingPath(clippingPath);
            }
            clippingWindingRule = -1;
        }
        getLinePath().reset();
    }
    /**
     * Draw the AWT image. Called by Invoke.
     * Moved into PageDrawer so that Invoke doesn't have to reach in here for Graphics as that breaks extensibility.
     *
     * @param awtImage The image to draw.
     * @param at The transformation to use when drawing.
     * 
     */
    public void drawImage(Image awtImage, AffineTransform at)
    {
        graphics.setComposite(getGraphicsState().getStrokeJavaComposite());
        graphics.setClip(getGraphicsState().getCurrentClippingPath());
        graphics.drawImage( awtImage, at, null );
    }
    
    /**
     * Fill with Shading.  Called by SHFill operator.
     *
     * @param ShadingName  The name of the Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     * 
     * @deprecated use {@link #shFill(COSName)} instead.
     */
    public void SHFill(COSName ShadingName) throws IOException
    {
        shFill(ShadingName);
    }
    
    /**
     * Fill with Shading.  Called by SHFill operator.
     *
     * @param shadingName  The name of the Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the clipping area.
     */
    public void shFill(COSName shadingName) throws IOException
    {
        PDShadingResources shading = getResources().getShadings().get(shadingName.getName());
        LOG.debug("Shading = " + shading.toString());
        int shadingType = shading.getShadingType();
        Matrix ctm = getGraphicsState().getCurrentTransformationMatrix();
        Paint paint = null;
        switch (shadingType)
        {
            case 1:
                paint = new Type1ShadingPaint((PDShadingType1)shading, ctm, pageSize.height);
                break;
            case 2:
                paint = new AxialShadingPaint((PDShadingType2)shading, ctm, pageSize.height);
                break;
            case 3:
                paint = new RadialShadingPaint((PDShadingType3)shading, ctm, pageSize.height);
                break;
            case 4:
                paint = new Type4ShadingPaint((PDShadingType4)shading, ctm, pageSize.height);
                break;
            case 5:
                paint = new Type5ShadingPaint((PDShadingType5)shading, ctm, pageSize.height);
                break;
            case 6:
                paint = new Type6ShadingPaint((PDShadingType6)shading, ctm, pageSize.height);
                break;
            case 7:
                paint = new Type7ShadingPaint((PDShadingType7)shading, ctm, pageSize.height);
                break;
            default:
                throw new IOException("Invalid ShadingType " + shadingType + " for Shading " + shadingName);
        }
        graphics.setComposite(getGraphicsState().getNonStrokeJavaComposite());
        graphics.setPaint(paint);
        graphics.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF );
        graphics.setClip(null); // PDFBOX-2153 don't use obsolete clipping path
        graphics.fill( getGraphicsState().getCurrentClippingPath() );
    }
    /**
     * Fill with a Function-based gradient / shading.  
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_Function(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }

    /**
     * Fill with an Axial Shading.  
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_Axial(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
        
    }

    /**
     * Fill with a Radial gradient / shading.  
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_Radial(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }
    
    /**
     * Fill with a Free-form Gourad-shaded triangle mesh.
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_FreeGourad(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }
    
    /**
     * Fill with a Lattice-form Gourad-shaded triangle mesh.
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_LatticeGourad(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }
    
    /**
     * Fill with a Coons patch mesh
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_CoonsPatch(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }
    
    /**
     * Fill with a Tensor-product patch mesh.
     * If extending the class, override this and its siblings, not the public SHFill method.
     *
     * @param Shading  The Shading Dictionary to use for this fill instruction.
     *
     * @throws IOException If there is an IO error while shade-filling the path/clipping area.
     */
    protected void SHFill_TensorPatch(PDShading Shading) throws IOException
    {
        throw new IOException("Not Implemented");
    }

    private float transformWidth(float width)
    {
        Matrix ctm = getGraphicsState().getCurrentTransformationMatrix();

        if (ctm == null)
        {
            // TODO does the CTM really need to use null?
            return width;
        }

        float x = ctm.getValue(0, 0) + ctm.getValue(1, 0);
        float y = ctm.getValue(0, 1) + ctm.getValue(1, 1);
        return width * (float) Math.sqrt((x * x + y * y) * 0.5);
    }
}
