/*
 * 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: Java2DUtil.java 1827168 2018-03-19 08:49:57Z ssteiner $ */

package org.apache.fop.render.java2d;

import java.awt.Graphics2D;
import java.awt.font.GlyphVector;
import java.util.Arrays;

import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.fonts.Font;
import org.apache.fop.fonts.FontCollection;
import org.apache.fop.fonts.FontEventAdapter;
import org.apache.fop.fonts.FontInfo;
import org.apache.fop.fonts.FontManager;
import org.apache.fop.fonts.LazyFont;
import org.apache.fop.fonts.MultiByteFont;
import org.apache.fop.fonts.Typeface;
import org.apache.fop.util.CharUtilities;

Rendering-related utilities for Java2D.
/**
 * Rendering-related utilities for Java2D.
 */
public final class Java2DUtil {

    private Java2DUtil() {
    }

    
Builds a default FontInfo object for use with output formats using the Java2D font setup. 
Params:
fontInfo – the font info object to populate
userAgent – the user agent
Returns:
the populated font information object/**
     * Builds a default {@link FontInfo} object for use with output formats using the Java2D
     * font setup.
     * @param fontInfo the font info object to populate
     * @param userAgent the user agent
     * @return the populated font information object
     */
    public static FontInfo buildDefaultJava2DBasedFontInfo(
            FontInfo fontInfo, FOUserAgent userAgent) {
        Java2DFontMetrics java2DFontMetrics = new Java2DFontMetrics();

        FontManager fontManager = userAgent.getFontManager();
        FontCollection[] fontCollections = new FontCollection[] {
                new org.apache.fop.render.java2d.Base14FontCollection(java2DFontMetrics),
                new InstalledFontCollection(java2DFontMetrics)
        };

        FontInfo fi = (fontInfo != null ? fontInfo : new FontInfo());
        fi.setEventListener(new FontEventAdapter(userAgent.getEventBroadcaster()));
        fontManager.setup(fi, fontCollections);
        return fi;
    }

    
Creates an instance of GlyphVector that correctly handle surrogate pairs and advanced font features such as GSUB/GPOS/GDEF. 
Params:
text – Text to render
g2d –  the target Graphics2D instance
font – the font instance
fontInfo – the font information
Returns:
an instance of GlyphVector/**
     * Creates an instance of {@link GlyphVector} that correctly handle surrogate pairs and advanced font features such
     * as GSUB/GPOS/GDEF.
     *
     * @param text Text to render
     * @param g2d  the target Graphics2D instance
     * @param font the font instance
     * @param fontInfo the font information
     * @return an instance of {@link GlyphVector}
     */
    public static GlyphVector createGlyphVector(String text, Graphics2D g2d, Font font, FontInfo fontInfo) {
        MultiByteFont multiByteFont = getMultiByteFont(font.getFontName(), fontInfo);

        if (multiByteFont == null) {
            return createGlyphVector(text, g2d);
        }

        return createGlyphVectorMultiByteFont(text, g2d, multiByteFont);
    }

    
Creates a GlyphVector using characters. Filters out non-bmp characters. /**
     * Creates a {@link GlyphVector} using characters. Filters out non-bmp characters.
     */
    private static GlyphVector createGlyphVector(String text, Graphics2D g2d) {
        StringBuilder sb = new StringBuilder(text.length());
        for (int cp : CharUtilities.codepointsIter(text)) {
            // If we are here we probably do not support non-BMP codepoints
            sb.appendCodePoint(cp <= 0xFFFF ? cp : Typeface.NOT_FOUND);
        }
        return g2d.getFont().createGlyphVector(g2d.getFontRenderContext(), sb.toString());
    }

    
Creates a GlyphVector using glyph indexes instead of characters. To correctly support the advanced font features we have to build the GlyphVector passing the glyph indexes instead of the characters. This because some of the chars in text might have been replaced by an internal font representation during GlyphMapping.processWordMapping. Eg 'fi' replaced with the corresponding character in the font ligatures table (GSUB). /**
     * Creates a {@link GlyphVector} using glyph indexes instead of characters. To correctly support the advanced font
     * features we have to build the GlyphVector passing the glyph indexes instead of the characters. This because some
     * of the chars in text might have been replaced by an internal font representation during
     * GlyphMapping.processWordMapping. Eg 'fi' replaced with the corresponding character in the font ligatures table
     * (GSUB).
     */
    private static GlyphVector createGlyphVectorMultiByteFont(String text, Graphics2D g2d,
            MultiByteFont multiByteFont) {
        int[] glyphCodes = new int[text.length()];
        int currentIdx = 0;

        for (int cp : CharUtilities.codepointsIter(text)) {
            // mapChar is not working here because MultiByteFont.mapChar replaces the glyph index with
            // CIDSet.mapChar when isEmbeddable == true.
            glyphCodes[currentIdx++] = multiByteFont.findGlyphIndex(cp);
        }

        // Trims glyphCodes
        if (currentIdx != text.length()) {
            glyphCodes = Arrays.copyOf(glyphCodes, currentIdx);
        }

        return g2d.getFont().createGlyphVector(g2d.getFontRenderContext(), glyphCodes);
    }

    
Returns an instance of MultiByteFont for the given font name. This method will try to unwrap containers such as CustomFontMetricsMapper and LazyFont 
Params:
fontName – font key
fontInfo – font information
Returns:
An instance of MultiByteFont or null if it/**
     * Returns an instance of {@link MultiByteFont} for the given font name. This method will try to unwrap containers
     * such as {@link CustomFontMetricsMapper} and {@link LazyFont}
     *
     * @param fontName font key
     * @param fontInfo font information
     * @return An instance of {@link MultiByteFont} or null if it
     */
    private static MultiByteFont getMultiByteFont(String fontName, FontInfo fontInfo) {
        Typeface tf = fontInfo.getFonts().get(fontName);

        if (tf instanceof CustomFontMetricsMapper) {
            tf = ((CustomFontMetricsMapper) tf).getRealFont();
        }

        if (tf instanceof LazyFont) {
            tf = ((LazyFont) tf).getRealFont();
        }

        return (tf instanceof MultiByteFont) ? (MultiByteFont) tf : null;
    }

}