/*
 * 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: Java2DFontMetrics.java 1758773 2016-09-01 13:02:29Z ssteiner $ */

package org.apache.fop.render.java2d;

// Java
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.font.LineMetrics;
import java.awt.font.TextAttribute;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.util.Map;

This is a FontMetrics to be used  for AWT  rendering.
It  instanciates a font, depening on family and style
values. The java.awt.FontMetrics for this font is then
created to be used for the actual measurement.
Since layout is word by word and since it is expected that
two subsequent words often share the same style, the
Font and FontMetrics is buffered and only changed if needed.

Since FontState and FontInfo multiply all factors by
size, we assume a "standard" font of FONT_SIZE.
/**
 * This is a FontMetrics to be used  for AWT  rendering.
 * It  instanciates a font, depening on family and style
 * values. The java.awt.FontMetrics for this font is then
 * created to be used for the actual measurement.
 * Since layout is word by word and since it is expected that
 * two subsequent words often share the same style, the
 * Font and FontMetrics is buffered and only changed if needed.
 * <p>
 * Since FontState and FontInfo multiply all factors by
 * size, we assume a "standard" font of FONT_SIZE.
 */
public class Java2DFontMetrics {

    
Font size standard used for metric measurements
/**
     * Font size standard used for metric measurements
     */
    public static final int FONT_SIZE = 1;

    
This factor multiplies the calculated values to scale
to FOP internal measurements
/**
     * This factor multiplies the calculated values to scale
     * to FOP internal measurements
     */
    public static final int FONT_FACTOR = (1000 * 1000) / FONT_SIZE;

    
The width of all 256 character, if requested
/**
     * The width of all 256 character, if requested
     */
    private int[] width;

    
The typical height of a small cap latter (often derived from "x", value in mpt)
/**
     * The typical height of a small cap latter (often derived from "x", value in mpt)
     */
    private int xHeight;

    
The highest point of the font above the baseline (usually derived from "d", value in mpt)
/**
     * The highest point of the font above the baseline (usually derived from "d", value in mpt)
     */
    private int ascender;

    
The lowest point of the font under the baseline (usually derived from "p", value in mpt)
/**
     * The lowest point of the font under the baseline (usually derived from "p", value in mpt)
     */
    private int descender;

    
Buffered font.
f1 is bufferd for metric measurements during layout.
fSized is buffered for display purposes
/**
     * Buffered font.
     * f1 is bufferd for metric measurements during layout.
     * fSized is buffered for display purposes
     */
    private Font f1;    // , fSized;

    
The family type of the font last used
/**
     * The family type of the font last used
     */
    private String family = "";

    
The style of the font last used
/**
     * The style of the font last used
     */
    private int style;

    
The size of the font last used
/**
     * The size of the font last used
     */
    private float size;

    
The FontMetrics object used to calculate character width etc.
/**
     * The FontMetrics object used to calculate character width etc.
     */
    private FontMetrics fmt;

    
A LineMetrics to access high-resolution metrics information. /** A LineMetrics to access high-resolution metrics information. */
    private LineMetrics lineMetrics;

    
Temp graphics object needed to get the font metrics
/**
     * Temp graphics object needed to get the font metrics
     */
    private final Graphics2D graphics;

    
Creates a Graphics2D object for the sole purpose of getting font metrics.
Returns:
a Graphics2D object/**
     * Creates a Graphics2D object for the sole purpose of getting font metrics.
     * @return a Graphics2D object
     */
    private static Graphics2D createFontMetricsGraphics2D() {
        BufferedImage fontImage = new BufferedImage(100, 100,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics2D = fontImage.createGraphics();
        //The next line is important to get accurate font metrics!
        graphics2D.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS,
                RenderingHints.VALUE_FRACTIONALMETRICS_ON);
        return graphics2D;
    }

    
Constructs a new Font-metrics.
/**
     * Constructs a new Font-metrics.
     */
    public Java2DFontMetrics() {
        this.graphics = createFontMetricsGraphics2D();
    }

    
Determines the font's maximum ascent of the Font described by the current
FontMetrics object
Params:
family – font family (java name) to use
style – font style (java def.) to use
size – font size
Returns:
ascent in milliponts/**
     * Determines the font's maximum ascent of the Font described by the current
     * FontMetrics object
     * @param family font family (java name) to use
     * @param style font style (java def.) to use
     * @param size font size
     * @return ascent in milliponts
     */
    public int getMaxAscent(String family, int style, int size) {
        setFont(family, style, size);
        return Math.round(lineMetrics.getAscent() * FONT_FACTOR);
    }

    
Determines the font ascent of the Font described by this
FontMetrics object
Params:
family – font family (java name) to use
style – font style (java def.) to use
size – font size
Returns:
ascent in milliponts/**
     * Determines the font ascent of the Font described by this
     * FontMetrics object
     * @param family font family (java name) to use
     * @param style font style (java def.) to use
     * @param size font size
     * @return ascent in milliponts
     */
    public int getAscender(String family, int style, int size) {
        setFont(family, style, size);
        return ascender * 1000;

        // workaround for sun bug on FontMetrics.getAscent()
        // http://developer.java.sun.com/developer/bugParade/bugs/4399887.html
        /*
         * Bug 4399887 has status Closed, not a bug.  The comments on the bug
         * are:
         * The submitter is incorrectly assuming that the string he has used
         * is displaying characters which represent those with the maximum
         * ascent in the font. If (for example) the unicode character
         * \u00c1 which is the A-acute character used in many European
         * languages is placed in the bodu of the "Wrong" string it can be
         * seen that the JDK is exactly correct in its determination of the
         * ascent of the font.
         * If the bounds of a particular string are interesting then the
         * Rectangle FontMetrics.getStringBounds(..) method can be called.
         * The y value of the rectangle is the offset from the origin
         * (baseline) apparently needed by the sample test program
         *
         * xxxxx@xxxxx 2001-05-15
         */
        /* I don't think this is right.
        int realAscent = fmt.getAscent()
                         - (fmt.getDescent() + fmt.getLeading());
        return FONT_FACTOR * realAscent;
        */
    }


    
The size of a capital letter measured from the font's baseline
Params:
family – font family
style – font style
size – font size
Returns:
capital height in millipoints/**
     * The size of a capital letter measured from the font's baseline
     * @param family font family
     * @param style font style
     * @param size font size
     * @return capital height in millipoints
     */
    public int getCapHeight(String family, int style, int size) {
        // currently just gets Ascent value but maybe should use
        // getMaxAcent() at some stage
        return getAscender(family, style, size);
    }

    
Determines the font descent of the Font described by this
FontMetrics object
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
descent in milliponts/**
     * Determines the font descent of the Font described by this
     * FontMetrics object
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return descent in milliponts
     */
    public int getDescender(String family, int style, int size) {
        setFont(family, style, size);
        return descender * 1000;
    }

    
Determines the typical font height of a small cap letter
FontMetrics object
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
font height in milliponts/**
     * Determines the typical font height of a small cap letter
     * FontMetrics object
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return font height in milliponts
     */
    public int getXHeight(String family, int style, int size) {
        setFont(family, style, size);
        return xHeight * 1000;
    }

    public int getUnderlinePosition(String family, int style, int size) {
        setFont(family, style, size);
        return -Math.round(lineMetrics.getUnderlineOffset());
    }

    public int getUnderlineThickness(String family, int style, int size) {
        setFont(family, style, size);
        return Math.round(lineMetrics.getUnderlineThickness());
    }

    public int getStrikeoutPosition(String family, int style, int size) {
        setFont(family, style, size);
        return -Math.round(lineMetrics.getStrikethroughOffset());
    }

    public int getStrikeoutThickness(String family, int style, int size) {
        setFont(family, style, size);
        return Math.round(lineMetrics.getStrikethroughThickness());
    }

    
Returns width (in 1/1000ths of point size) of character at
code point i
Params:
i – the character for which to get the width
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
character width in millipoints/**
     * Returns width (in 1/1000ths of point size) of character at
     * code point i
     * @param  i the character for which to get the width
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return character width in millipoints
     */
    public int width(int i, String family, int style, int size) {
        int w;
        setFont(family, style, size);
        w = internalCharWidth(i) * 1000;
        return w;
    }

    private int internalCharWidth(int i) {
        //w = (int)(fmt.charWidth(i) * 1000); //Not accurate enough!
        char[] ch = {(char)i};
        Rectangle2D rect = fmt.getStringBounds(ch, 0, 1, this.graphics);
        return (int)Math.round(rect.getWidth() * 1000);
    }

    
Return widths (in 1/1000ths of point size) of all
characters
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
array of character widths in millipoints/**
     * Return widths (in 1/1000ths of point size) of all
     * characters
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return array of character widths in millipoints
     */
    public int[] getWidths(String family, int style, int size) {
        int i;

        if (width == null) {
            width = new int[256];
        }
        setFont(family, style, size);
        for (i = 0; i < 256; i++) {
            width[i] = 1000 * internalCharWidth(i);
        }
        return width;
    }

    private Font getBaseFont(String family, int style, float size) {
        Map atts = new java.util.HashMap();
        atts.put(TextAttribute.FAMILY, family);
        if ((style & Font.BOLD) != 0) {
            atts.put(TextAttribute.WEIGHT, TextAttribute.WEIGHT_BOLD);
        }
        if ((style & Font.ITALIC) != 0) {
            atts.put(TextAttribute.POSTURE, TextAttribute.POSTURE_OBLIQUE);
        }
        atts.put(TextAttribute.SIZE, size); //size in pt
        return new Font(atts);
    }

    
Checks whether the font  for which values are
requested is the one used immediately before or
whether it is a new one
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
true if the font was changed, false otherwise/**
     * Checks whether the font  for which values are
     * requested is the one used immediately before or
     * whether it is a new one
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return true if the font was changed, false otherwise
     */
    private boolean setFont(String family, int style, int size) {
        boolean changed = false;
        float s = size / 1000f;

        if (f1 == null) {
            f1 = getBaseFont(family, style, s);
            fmt = graphics.getFontMetrics(f1);
            changed = true;
        } else {
            if ((this.style != style) || !this.family.equals(family)
                    || this.size != s) {
                if (family.equals(this.family)) {
                    f1 = f1.deriveFont(style, s);
                } else {
                    f1 = getBaseFont(family, style, s);
                }
                fmt = graphics.getFontMetrics(f1);
                changed = true;
            }
            // else the font is unchanged from last time
        }
        if (changed) {
            //x-Height
            TextLayout layout = new TextLayout("x", f1, graphics.getFontRenderContext());
            Rectangle2D rect = layout.getBounds();
            xHeight = (int)Math.round(-rect.getY() * 1000);

            //PostScript-compatible ascent
            layout = new TextLayout("d", f1, graphics.getFontRenderContext());
            rect = layout.getBounds();
            ascender = (int)Math.round(-rect.getY() * 1000);

            //PostScript-compatible descent
            layout = new TextLayout("p", f1, graphics.getFontRenderContext());
            rect = layout.getBounds();
            descender = (int)Math.round((rect.getY() + rect.getHeight()) * -1000);

            //Alternative way to get metrics but the ascender is again wrong for our purposes
            lineMetrics = f1.getLineMetrics("", graphics.getFontRenderContext());
        }
        // save the family and style for later comparison
        this.family = family;
        this.style = style;
        this.size = s;
        return changed;
    }


    
Returns a java.awt.Font instance for the desired
family, style and size type.
This is here, so that the font-mapping
of FOP-defined fonts to java-fonts can be done
in one place and does not need to occur in
AWTFontRenderer.
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
Returns:
font with the desired characeristics./**
     * Returns a java.awt.Font instance for the desired
     * family, style and size type.
     * This is here, so that the font-mapping
     * of FOP-defined fonts to java-fonts can be done
     * in one place and does not need to occur in
     * AWTFontRenderer.
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @return font with the desired characeristics.
     */
    public java.awt.Font getFont(String family, int style, int size) {
        setFont(family, style, size);
        return f1;
        /*
         * if( setFont(family,style, size) ) fSized = null;
         * if( fSized == null ||  this.size != size ) {
         * fSized = f1.deriveFont( size / 1000f );
         * }
         * this.size = size;
         * return fSized;
         */
    }

    
Indicates whether the font contains a particular character/glyph.
Params:
family – font family (jave name) to use
style – font style (jave def.) to use
size – font size
c – the glyph to check
Returns:
true if the character is supported/**
     * Indicates whether the font contains a particular character/glyph.
     * @param family font family (jave name) to use
     * @param style font style (jave def.) to use
     * @param size font size
     * @param c the glyph to check
     * @return true if the character is supported
     */
    public boolean hasChar(String family, int style, int size, char c) {
        setFont(family, style, size);
        return f1.canDisplay(c);
    }

}