FontStrikeDesc.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.font;

import java.awt.Font;
import java.awt.font.FontRenderContext;
import java.awt.geom.AffineTransform;
import static sun.awt.SunHints.*;

/*
 * This class encapsulates every thing needed that distinguishes a strike.
 * It can be used as a key to locate a FontStrike in a Hashmap/cache.
 * It is not mutatable, but contains mutatable AffineTransform objects,
 * which for performance reasons it does not keep private copies of.
 * Therefore code constructing these must pass in transforms it guarantees
 * not to mutate.
 */
public class FontStrikeDesc {

    /* Values to use as a mask that is used for faster comparison of
     * two strikes using just an int equality test.
     * The ones we don't use are listed here but commented out.
     * ie style is already built and hint "OFF" values are zero.
     * Note that this is used as a strike key and the same strike is used
     * for HRGB and HBGR, so only the orientation needed (H or V) is needed
     * to construct and distinguish a FontStrikeDesc. The rgb ordering
     * needed for rendering is stored in the graphics state.
     */
//     static final int STYLE_PLAIN       = Font.PLAIN;            // 0x0000
//     static final int STYLE_BOLD        = Font.BOLD;             // 0x0001
//     static final int STYLE_ITALIC      = Font.ITALIC;           // 0x0002
//     static final int STYLE_BOLDITALIC  = Font.BOLD|Font.ITALIC; // 0x0003
//     static final int AA_OFF            = 0x0000;
    static final int AA_ON             = 0x0010;
    static final int AA_LCD_H          = 0x0020;
    static final int AA_LCD_V          = 0x0040;
//     static final int FRAC_METRICS_OFF  = 0x0000;
    static final int FRAC_METRICS_ON   = 0x0100;
    static final int FRAC_METRICS_SP   = 0x0200;

    /* devTx is to get an inverse transform to get user space values
     * for metrics. Its not used otherwise, as the glyphTx is the important
     * one. But it does mean that a strike representing a 6pt font and identity
     * graphics transform is not equal to one for a 12 pt font and 2x scaled
     * graphics transform. Its likely to be very rare that this causes
     * duplication.
     */
    AffineTransform devTx;
    AffineTransform glyphTx; // all of ptSize, Font tx and Graphics tx.
    int style;
    int aaHint;
    int fmHint;
    private int hashCode;
    private int valuemask;

    public int hashCode() {
        /* Can cache hashcode since a strike(desc) is immutable.*/
        if (hashCode == 0) {
            hashCode = glyphTx.hashCode() + devTx.hashCode() + valuemask;
        }
        return hashCode;
    }

    public boolean equals(Object obj) {
        try {
            FontStrikeDesc desc = (FontStrikeDesc)obj;
            return (desc.valuemask == this.valuemask &&
                    desc.glyphTx.equals(this.glyphTx) &&
                    desc.devTx.equals(this.devTx));
        } catch (Exception e) {
            /* class cast or NP exceptions should not happen often, if ever,
             * and I am hoping that this is faster than an instanceof check.
             */
            return false;
        }
    }

    FontStrikeDesc() {
        // used with init
    }


    /* This maps a public text AA hint value into one of the subset of values
     * used to index strikes. For the purpose of the strike cache there are
     * only 4 values : OFF, ON, LCD_HRGB, LCD_VRGB.
     * Font and ptSize are needed to resolve the 'gasp' table. The ptSize
     * must therefore include device and font transforms.
     */
    public static int getAAHintIntVal(Object aa, Font2D font2D, int ptSize) {
        if (aa == VALUE_TEXT_ANTIALIAS_OFF ||
            aa == VALUE_TEXT_ANTIALIAS_DEFAULT) {
            return INTVAL_TEXT_ANTIALIAS_OFF;
        } else if (aa == VALUE_TEXT_ANTIALIAS_ON) {
            return INTVAL_TEXT_ANTIALIAS_ON;
        } else if (aa == VALUE_TEXT_ANTIALIAS_GASP) {
            if (font2D.useAAForPtSize(ptSize)) {
                return INTVAL_TEXT_ANTIALIAS_ON;
            } else {
                return INTVAL_TEXT_ANTIALIAS_OFF;
            }
        } else if (aa == VALUE_TEXT_ANTIALIAS_LCD_HRGB ||
                   aa == VALUE_TEXT_ANTIALIAS_LCD_HBGR) {
            return INTVAL_TEXT_ANTIALIAS_LCD_HRGB;
        } else if (aa == VALUE_TEXT_ANTIALIAS_LCD_VRGB ||
                   aa == VALUE_TEXT_ANTIALIAS_LCD_VBGR) {
            return INTVAL_TEXT_ANTIALIAS_LCD_VRGB;
        } else {
            return INTVAL_TEXT_ANTIALIAS_OFF;
        }
    }

    /* This maps a public text AA hint value into one of the subset of values
     * used to index strikes. For the purpose of the strike cache there are
     * only 4 values : OFF, ON, LCD_HRGB, LCD_VRGB.
     * Font and FontRenderContext are needed to resolve the 'gasp' table.
     * This is similar to the method above, but used by callers which have not
     * already calculated the glyph device point size.
     */
    public static int getAAHintIntVal(Font2D font2D, Font font,
                                      FontRenderContext frc) {
        Object aa = frc.getAntiAliasingHint();
        if (aa == VALUE_TEXT_ANTIALIAS_OFF ||
            aa == VALUE_TEXT_ANTIALIAS_DEFAULT) {
            return INTVAL_TEXT_ANTIALIAS_OFF;
        } else if (aa == VALUE_TEXT_ANTIALIAS_ON) {
            return INTVAL_TEXT_ANTIALIAS_ON;
        } else if (aa == VALUE_TEXT_ANTIALIAS_GASP) {
            /* FRC.isIdentity() would have been useful */
            int ptSize;
            AffineTransform tx = frc.getTransform();
            if (tx.isIdentity() && !font.isTransformed()) {
                ptSize = font.getSize();
            } else {
                /* one or both transforms is not identity */
                float size = font.getSize2D();
                if (tx.isIdentity()) {
                    tx = font.getTransform();
                    tx.scale(size, size);
                } else {
                    tx.scale(size, size);
                    if (font.isTransformed()) {
                        tx.concatenate(font.getTransform());
                    }
                }
                double shearx = tx.getShearX();
                double scaley = tx.getScaleY();
                if (shearx != 0) {
                    scaley = Math.sqrt(shearx * shearx + scaley * scaley);
                }
                ptSize = (int)(Math.abs(scaley)+0.5);
            }
            if (font2D.useAAForPtSize(ptSize)) {
                return INTVAL_TEXT_ANTIALIAS_ON;
            } else {
                return INTVAL_TEXT_ANTIALIAS_OFF;
            }
        } else if (aa == VALUE_TEXT_ANTIALIAS_LCD_HRGB ||
                   aa == VALUE_TEXT_ANTIALIAS_LCD_HBGR) {
            return INTVAL_TEXT_ANTIALIAS_LCD_HRGB;
        } else if (aa == VALUE_TEXT_ANTIALIAS_LCD_VRGB ||
                   aa == VALUE_TEXT_ANTIALIAS_LCD_VBGR) {
            return INTVAL_TEXT_ANTIALIAS_LCD_VRGB;
        } else {
            return INTVAL_TEXT_ANTIALIAS_OFF;
        }
    }

    public static int getFMHintIntVal(Object fm) {
        if (fm == VALUE_FRACTIONALMETRICS_OFF ||
            fm == VALUE_FRACTIONALMETRICS_DEFAULT) {
            return INTVAL_FRACTIONALMETRICS_OFF;
        } else {
            return INTVAL_FRACTIONALMETRICS_ON;
        }
    }

    public FontStrikeDesc(AffineTransform devAt, AffineTransform at,
                          int fStyle, int aa, int fm) {
        devTx = devAt;
        glyphTx = at; // not cloning glyphTx. Callers trusted to not mutate it.
        style = fStyle;
        aaHint = aa;
        fmHint = fm;
        valuemask = fStyle;
        switch (aa) {
           case INTVAL_TEXT_ANTIALIAS_OFF :
                break;
           case INTVAL_TEXT_ANTIALIAS_ON  :
                valuemask |= AA_ON;
                break;
           case INTVAL_TEXT_ANTIALIAS_LCD_HRGB :
           case INTVAL_TEXT_ANTIALIAS_LCD_HBGR :
                valuemask |= AA_LCD_H;
                break;
           case INTVAL_TEXT_ANTIALIAS_LCD_VRGB :
           case INTVAL_TEXT_ANTIALIAS_LCD_VBGR :
                valuemask |= AA_LCD_V;
                break;
           default: break;
        }
        if (fm == INTVAL_FRACTIONALMETRICS_ON) {
           valuemask |= FRAC_METRICS_ON;
        }
    }

    FontStrikeDesc(FontStrikeDesc desc) {
        devTx = desc.devTx;
        // Clone the TX in this case as this is called when its known
        // that "desc" is being re-used by its creator.
        glyphTx = (AffineTransform)desc.glyphTx.clone();
        style = desc.style;
        aaHint = desc.aaHint;
        fmHint = desc.fmHint;
        hashCode = desc.hashCode;
        valuemask = desc.valuemask;
    }


    public String toString() {
        return "FontStrikeDesc: Style="+style+ " AA="+aaHint+ " FM="+fmHint+
            " devTx="+devTx+ " devTx.FontTx.ptSize="+glyphTx;
    }
}