fop/src/java/org/apache/fop/svg/AbstractFOPTextPainter.java

/*
 * 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.svg;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.font.TextAttribute;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.text.AttributedCharacterIterator;
import java.text.CharacterIterator;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.batik.dom.svg.SVGOMTextElement;
import org.apache.batik.gvt.TextNode;
import org.apache.batik.gvt.TextPainter;
import org.apache.batik.gvt.renderer.StrokingTextPainter;
import org.apache.batik.gvt.text.GVTAttributedCharacterIterator;
import org.apache.batik.gvt.text.Mark;
import org.apache.batik.gvt.text.TextPaintInfo;

import org.apache.fop.afp.AFPGraphics2D;
import org.apache.fop.fonts.Font;

/**
 * Renders the attributed character iterator of a {@link TextNode}.
 * This class draws the text directly into the Graphics2D so that
 * the text is not drawn using shapes.
 * If the text is simple enough to draw then it sets the font and calls
 * drawString. If the text is complex or the cannot be translated
 * into a simple drawString the StrokingTextPainter is used instead.
 */
public abstract class AbstractFOPTextPainter implements TextPainter {

    /** the logger for this class */
    protected Log log = LogFactory.getLog(AbstractFOPTextPainter.class);

    private final FOPTextHandler nativeTextHandler;

    /**
     * Use the stroking text painter to get the bounds and shape.
     * Also used as a fallback to draw the string with strokes.
     */
    protected static final TextPainter
        PROXY_PAINTER = StrokingTextPainter.getInstance();

    /**
     * Create a new PS text painter with the given font information.
     * @param nativeTextHandler the NativeTextHandler instance used for text painting
     */
    public AbstractFOPTextPainter(FOPTextHandler nativeTextHandler) {
        this.nativeTextHandler = nativeTextHandler;
    }

    /**
     * Paints the specified attributed character iterator using the
     * specified Graphics2D and context and font context.
     *
     * @param node the TextNode to paint
     * @param g2d the Graphics2D to use
     */
    public void paint(TextNode node, Graphics2D g2d) {
        Point2D loc = node.getLocation();
        if (!isSupportedGraphics2D(g2d) || hasUnsupportedAttributes(node)) {
            if (log.isDebugEnabled()) {
                log.debug("painting text node " + node
                    + " by stroking due to unsupported attributes or an incompatible Graphics2D");
            }
            PROXY_PAINTER.paint(node, g2d);
        } else {
            if (log.isDebugEnabled()) {
                log.debug("painting text node " + node + " normally.");
            }
            paintTextRuns(node.getTextRuns(), g2d, loc);
        }
    }

    /**
     * Checks whether the Graphics2D is compatible with this text painter. Batik may
     * pass in a Graphics2D instance that paints on a special buffer image, for example
     * for filtering operations. In that case, the text painter should be bypassed.
     * @param g2d the Graphics2D instance to check
     * @return true if the Graphics2D is supported
     */
    protected abstract boolean isSupportedGraphics2D(Graphics2D g2d);

    private boolean hasUnsupportedAttributes(TextNode node) {
        Iterator iter = node.getTextRuns().iterator();
        while (iter.hasNext()) {
            StrokingTextPainter.TextRun
                    run = (StrokingTextPainter.TextRun)iter.next();
            AttributedCharacterIterator aci = run.getACI();
            boolean hasUnsupported = hasUnsupportedAttributes(aci);
            if (hasUnsupported) {
                return true;
            }
        }
        return false;
    }

    private boolean hasUnsupportedAttributes(AttributedCharacterIterator aci) {
        boolean hasUnsupported = false;

        Font font = getFont(aci);
        String text = getText(aci);
        if (hasUnsupportedGlyphs(text, font)) {
            log.trace("-> Unsupported glyphs found");
            hasUnsupported = true;
        }

        TextPaintInfo tpi = (TextPaintInfo) aci.getAttribute(
            GVTAttributedCharacterIterator.TextAttribute.PAINT_INFO);
        if ((tpi != null)
                && ((tpi.strokeStroke != null && tpi.strokePaint != null)
                    || (tpi.strikethroughStroke != null)
                    || (tpi.underlineStroke != null)
                    || (tpi.overlineStroke != null))) {
                        log.trace("-> under/overlines etc. found");
            hasUnsupported = true;
        }

        //Alpha is not supported
        Paint foreground = (Paint) aci.getAttribute(TextAttribute.FOREGROUND);
        if (foreground instanceof Color) {
            Color col = (Color)foreground;
            if (col.getAlpha() != 255) {
                log.trace("-> transparency found");
                hasUnsupported = true;
            }
        }

        Object letSpace = aci.getAttribute(
                            GVTAttributedCharacterIterator.TextAttribute.LETTER_SPACING);
        if (letSpace != null) {
            log.trace("-> letter spacing found");
            hasUnsupported = true;
        }

        Object wordSpace = aci.getAttribute(
                             GVTAttributedCharacterIterator.TextAttribute.WORD_SPACING);
        if (wordSpace != null) {
            log.trace("-> word spacing found");
            hasUnsupported = true;
        }

        Object lengthAdjust = aci.getAttribute(
                            GVTAttributedCharacterIterator.TextAttribute.LENGTH_ADJUST);
        if (lengthAdjust != null) {
            log.trace("-> length adjustments found");
            hasUnsupported = true;
        }

        Object writeMod = aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.WRITING_MODE);
        if (writeMod != null
            && !GVTAttributedCharacterIterator.TextAttribute.WRITING_MODE_LTR.equals(
                  writeMod)) {
            log.trace("-> Unsupported writing modes found");
            hasUnsupported = true;
        }

        Object vertOr = aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.VERTICAL_ORIENTATION);
        if (GVTAttributedCharacterIterator.TextAttribute.ORIENTATION_ANGLE.equals(
                  vertOr)) {
            log.trace("-> vertical orientation found");
            hasUnsupported = true;
        }

        Object rcDel = aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.TEXT_COMPOUND_DELIMITER);
        //Batik 1.6 returns null here which makes it impossible to determine whether this can
        //be painted or not, i.e. fall back to stroking. :-(
        if (rcDel != null && !(rcDel instanceof SVGOMTextElement)) {
            log.trace("-> spans found");
            hasUnsupported = true; //Filter spans
        }

        if (hasUnsupported) {
            log.trace("Unsupported attributes found in ACI, using StrokingTextPainter");
        }
        return hasUnsupported;
    }

    /**
     * Paint a list of text runs on the Graphics2D at a given location.
     * @param textRuns the list of text runs
     * @param g2d the Graphics2D to paint to
     * @param loc the current location of the "cursor"
     */
    protected void paintTextRuns(List textRuns, Graphics2D g2d, Point2D loc) {
        Point2D currentloc = loc;
        Iterator i = textRuns.iterator();
        while (i.hasNext()) {
            StrokingTextPainter.TextRun
                    run = (StrokingTextPainter.TextRun)i.next();
            currentloc = paintTextRun(run, g2d, currentloc);
        }
    }

    /**
     * Paint a single text run on the Graphics2D at a given location.
     * @param run the text run to paint
     * @param g2d the Graphics2D to paint to
     * @param loc the current location of the "cursor"
     * @return the new location of the "cursor" after painting the text run
     */
    protected Point2D paintTextRun(StrokingTextPainter.TextRun run, Graphics2D g2d, Point2D loc) {
        AttributedCharacterIterator aci = run.getACI();
        aci.first();

        updateLocationFromACI(aci, loc);
        AffineTransform at = g2d.getTransform();
        loc = at.transform(loc, null);

        // font
        Font font = getFont(aci);
        if (font != null) {
            nativeTextHandler.setOverrideFont(font);
        }

        // color
        TextPaintInfo tpi = (TextPaintInfo) aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.PAINT_INFO);
        if (tpi == null) {
            return loc;
        }
        Paint foreground = tpi.fillPaint;
        if (foreground instanceof Color) {
            Color col = (Color)foreground;
            g2d.setColor(col);
        }
        g2d.setPaint(foreground);

        // text anchor
        TextNode.Anchor anchor = (TextNode.Anchor)aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.ANCHOR_TYPE);

        // text
        String txt = getText(aci);
        float advance = getStringWidth(txt, font);
        float tx = 0;
        if (anchor != null) {
            switch (anchor.getType()) {
            case TextNode.Anchor.ANCHOR_MIDDLE:
                tx = -advance / 2;
                break;
            case TextNode.Anchor.ANCHOR_END:
                tx = -advance;
                break;
            default: //nop
            }
        }

        // draw string
        double x = loc.getX();
        double y = loc.getY();
        try {
            try {
                nativeTextHandler.drawString(g2d, txt, (float)x + tx, (float)y);
            } catch (IOException ioe) {
                if (g2d instanceof AFPGraphics2D) {
                    ((AFPGraphics2D)g2d).handleIOException(ioe);
                }
            }
        } finally {
            nativeTextHandler.setOverrideFont(null);
        }
        loc.setLocation(loc.getX() + advance, loc.getY());
        return loc;
    }

    /**
     * Extract the raw text from an ACI.
     * @param aci ACI to inspect
     * @return the extracted text
     */
    protected String getText(AttributedCharacterIterator aci) {
        StringBuffer sb = new StringBuffer(aci.getEndIndex() - aci.getBeginIndex());
        for (char c = aci.first(); c != CharacterIterator.DONE; c = aci.next()) {
            sb.append(c);
        }
        return sb.toString();
    }

    private void updateLocationFromACI(
                AttributedCharacterIterator aci,
                Point2D loc) {
        //Adjust position of span
        Float xpos = (Float)aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.X);
        Float ypos = (Float)aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.Y);
        Float dxpos = (Float)aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.DX);
        Float dypos = (Float)aci.getAttribute(
                GVTAttributedCharacterIterator.TextAttribute.DY);
        if (xpos != null) {
            loc.setLocation(xpos.doubleValue(), loc.getY());
        }
        if (ypos != null) {
            loc.setLocation(loc.getX(), ypos.doubleValue());
        }
        if (dxpos != null) {
            loc.setLocation(loc.getX() + dxpos.doubleValue(), loc.getY());
        }
        if (dypos != null) {
            loc.setLocation(loc.getX(), loc.getY() + dypos.doubleValue());
        }
    }

    private Font getFont(AttributedCharacterIterator aci) {
        Font[] fonts = ACIUtils.findFontsForBatikACI(aci, nativeTextHandler.getFontInfo());
        return fonts == null ? null : fonts[0];
    }

    private float getStringWidth(String str, Font font) {
        float wordWidth = 0;
        float whitespaceWidth = font.getWidth(font.mapChar(' '));

        for (int i = 0; i < str.length(); i++) {
            float charWidth;
            char c = str.charAt(i);
            if (!((c == ' ') || (c == '\n') || (c == '\r') || (c == '\t'))) {
                charWidth = font.getWidth(font.mapChar(c));
                if (charWidth <= 0) {
                    charWidth = whitespaceWidth;
                }
            } else {
                charWidth = whitespaceWidth;
            }
            wordWidth += charWidth;
        }
        return wordWidth / 1000f;
    }

    private boolean hasUnsupportedGlyphs(String str, Font font) {
         if (font == null) {
            return true;
         }
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (!((c == ' ') || (c == '\n') || (c == '\r') || (c == '\t'))) {
                if (!font.hasChar(c)) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * Get the outline shape of the text characters.
     * This uses the StrokingTextPainter to get the outline
     * shape since in theory it should be the same.
     *
     * @param node the text node
     * @return the outline shape of the text characters
     */
    public Shape getOutline(TextNode node) {
        return PROXY_PAINTER.getOutline(node);
    }

    /**
     * Get the bounds.
     * This uses the StrokingTextPainter to get the bounds
     * since in theory it should be the same.
     *
     * @param node the text node
     * @return the bounds of the text
     */
    public Rectangle2D getBounds2D(TextNode node) {
        /* (todo) getBounds2D() is too slow
         * because it uses the StrokingTextPainter. We should implement this
         * method ourselves. */
        return PROXY_PAINTER.getBounds2D(node);
    }

    /**
     * Get the geometry bounds.
     * This uses the StrokingTextPainter to get the bounds
     * since in theory it should be the same.
     *
     * @param node the text node
     * @return the bounds of the text
     */
    public Rectangle2D getGeometryBounds(TextNode node) {
        return PROXY_PAINTER.getGeometryBounds(node);
    }

    // Methods that have no purpose for PS

    /**
     * Get the mark.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param node the text node
     * @param pos the position
     * @param all select all
     * @return null
     */
    public Mark getMark(TextNode node, int pos, boolean all) {
        return null;
    }

    /**
     * Select at.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param x the x position
     * @param y the y position
     * @param node the text node
     * @return null
     */
    public Mark selectAt(double x, double y, TextNode node) {
        return null;
    }

    /**
     * Select to.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param x the x position
     * @param y the y position
     * @param beginMark the start mark
     * @return null
     */
    public Mark selectTo(double x, double y, Mark beginMark) {
        return null;
    }

    /**
     * Selec first.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param node the text node
     * @return null
     */
    public Mark selectFirst(TextNode node) {
        return null;
    }

    /**
     * Select last.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param node the text node
     * @return null
     */
    public Mark selectLast(TextNode node) {
        return null;
    }

    /**
     * Get selected.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param start the start mark
     * @param finish the finish mark
     * @return null
     */
    public int[] getSelected(Mark start, Mark finish) {
        return null;
    }

    /**
     * Get the highlighted shape.
     * This does nothing since the output is AFP and not interactive.
     *
     * @param beginMark the start mark
     * @param endMark the end mark
     * @return null
     */
    public Shape getHighlightShape(Mark beginMark, Mark endMark) {
        return null;
    }

}