1 /*
   2  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.java.swing.plaf.gtk;
  27 
  28 import java.awt.*;
  29 import java.awt.geom.AffineTransform;
  30 import javax.swing.plaf.FontUIResource;
  31 import java.util.StringTokenizer;
  32 
  33 import sun.font.FontConfigManager;
  34 import sun.font.FontUtilities;
  35 
  36 /**
  37  * @author Shannon Hickey
  38  * @author Leif Samuelsson
  39  */
  40 class PangoFonts {
  41 
  42     public static final String CHARS_DIGITS = "0123456789";
  43 
  44     /**
  45      * Calculate a default scale factor for fonts in this L&F to match
  46      * the reported resolution of the screen.
  47      * Java 2D specified a default user-space scale of 72dpi.
  48      * This is unlikely to correspond to that of the real screen.
  49      * The Xserver reports a value which may be used to adjust for this.
  50      * and Java 2D exposes it via a normalizing transform.
  51      * However many Xservers report a hard-coded 90dpi whilst others report a
  52      * calculated value based on possibly incorrect data.
  53      * That is something that must be solved at the X11 level
  54      * Note that in an X11 multi-screen environment, the default screen
  55      * is the one used by the JRE so it is safe to use it here.
  56      */
  57     private static double fontScale;
  58 
  59     static {
  60         fontScale = 1.0d;
  61         GraphicsEnvironment ge =
  62            GraphicsEnvironment.getLocalGraphicsEnvironment();
  63 
  64         if (!ge.isHeadless()) {
  65             GraphicsConfiguration gc =
  66                 ge.getDefaultScreenDevice().getDefaultConfiguration();
  67             AffineTransform at = gc.getNormalizingTransform();
  68             fontScale = at.getScaleY();
  69         }
  70     }
  71 
  72 
  73     /**
  74      * Parses a String containing a pango font description and returns
  75      * a Font object.
  76      *
  77      * @param pangoName a String describing a pango font
  78      *                  e.g. "Sans Italic 10"
  79      * @return a Font object as a FontUIResource
  80      *         or null if no suitable font could be created.
  81      */
  82     static Font lookupFont(String pangoName) {
  83         String family = "";
  84         int style = Font.PLAIN;
  85         int size = 10;
  86 
  87         StringTokenizer tok = new StringTokenizer(pangoName);
  88 
  89         while (tok.hasMoreTokens()) {
  90             String word = tok.nextToken();
  91 
  92             if (word.equalsIgnoreCase("italic")) {
  93                 style |= Font.ITALIC;
  94             } else if (word.equalsIgnoreCase("bold")) {
  95                 style |= Font.BOLD;
  96             } else if (CHARS_DIGITS.indexOf(word.charAt(0)) != -1) {
  97                 try {
  98                     size = Integer.parseInt(word);
  99                 } catch (NumberFormatException ex) {
 100                 }
 101             } else {
 102                 if (family.length() > 0) {
 103                     family += " ";
 104                 }
 105 
 106                 family += word;
 107             }
 108         }
 109 
 110         /*
 111          * Java 2D font point sizes are in a user-space scale of 72dpi.
 112          * GTK allows a user to configure a "dpi" property used to scale
 113          * the fonts used to match a user's preference.
 114          * To match the font size of GTK apps we need to obtain this DPI and
 115          * adjust as follows:
 116          * Some versions of GTK use XSETTINGS if available to dynamically
 117          * monitor user-initiated changes in the DPI to be used by GTK
 118          * apps. This value is also made available as the Xft.dpi X resource.
 119          * This is presumably a function of the font preferences API and/or
 120          * the manner in which it requests the toolkit to update the default
 121          * for the desktop. This dual approach is probably necessary since
 122          * other versions of GTK - or perhaps some apps - determine the size
 123          * to use only at start-up from that X resource.
 124          * If that resource is not set then GTK scales for the DPI resolution
 125          * reported by the Xserver using the formula
 126          * DisplayHeight(dpy, screen) / DisplayHeightMM(dpy, screen) * 25.4
 127          * (25.4mm == 1 inch).
 128          * JDK tracks the Xft.dpi XSETTINGS property directly so it can
 129          * dynamically change font size by tracking just that value.
 130          * If that resource is not available use the same fall back formula
 131          * as GTK (see calculation for fontScale).
 132          *
 133          * GTK's default setting for Xft.dpi is 96 dpi (and it seems -1
 134          * apparently also can mean that "default"). However this default
 135          * isn't used if there's no property set. The real default in the
 136          * absence of a resource is the Xserver reported dpi.
 137          * Finally this DPI is used to calculate the nearest Java 2D font
 138          * 72 dpi font size.
 139          * There are cases in which JDK behaviour may not exactly mimic
 140          * GTK native app behaviour :
 141          * 1) When a GTK app is not able to dynamically track the changes
 142          * (does not use XSETTINGS), JDK will resize but other apps will
 143          * not. This is OK as JDK is exhibiting preferred behaviour and
 144          * this is probably how all later GTK apps will behave
 145          * 2) When a GTK app does not use XSETTINGS and for some reason
 146          * the XRDB property is not present. JDK will pick up XSETTINGS
 147          * and the GTK app will use the Xserver default. Since its
 148          * impossible for JDK to know that some other GTK app is not
 149          * using XSETTINGS its impossible to account for this and in any
 150          * case for it to be a problem the values would have to be different.
 151          * It also seems unlikely to arise except when a user explicitly
 152          * deletes the X resource database entry.
 153          * There also some other issues to be aware of for the future:
 154          * GTK specifies the Xft.dpi value as server-wide which when used
 155          * on systems with 2 distinct X screens with different physical DPI
 156          * the font sizes will inevitably appear different. It would have
 157          * been a more user-friendly design to further adjust that one
 158          * setting depending on the screen resolution to achieve perceived
 159          * equivalent sizes. If such a change were ever to be made in GTK
 160          * we would need to update for that.
 161          */
 162         double dsize = size;
 163         int dpi = 96;
 164         Object value =
 165             Toolkit.getDefaultToolkit().getDesktopProperty("gnome.Xft/DPI");
 166         if (value instanceof Integer) {
 167             dpi = ((Integer)value).intValue() / 1024;
 168             if (dpi == -1) {
 169               dpi = 96;
 170             }
 171             if (dpi < 50) { /* 50 dpi is the minimum value gnome allows */
 172                 dpi = 50;
 173             }
 174             /* The Java rasteriser assumes pts are in a user space of
 175              * 72 dpi, so we need to adjust for that.
 176              */
 177             dsize = ((double)(dpi * size)/ 72.0);
 178         } else {
 179             /* If there's no property, GTK scales for the resolution
 180              * reported by the Xserver using the formula listed above.
 181              * fontScale already accounts for the 72 dpi Java 2D space.
 182              */
 183             dsize = size * fontScale;
 184         }
 185 
 186         /* Round size to nearest integer pt size */
 187         size = (int)(dsize + 0.5);
 188         if (size < 1) {
 189             size = 1;
 190         }
 191 
 192         String fcFamilyLC = family.toLowerCase();
 193         if (FontUtilities.mapFcName(fcFamilyLC) != null) {
 194             /* family is a Fc/Pango logical font which we need to expand. */
 195             Font font =  FontUtilities.getFontConfigFUIR(fcFamilyLC, style, size);
 196             font = font.deriveFont(style, (float)dsize);
 197             return new FontUIResource(font);
 198         } else {
 199             /* It's a physical font which we will create with a fallback */
 200             Font font = new Font(family, style, size);
 201             /* a roundabout way to set the font size in floating points */
 202             font = font.deriveFont(style, (float)dsize);
 203             FontUIResource fuir = new FontUIResource(font);
 204             return FontUtilities.getCompositeFontUIResource(fuir);
 205         }
 206     }
 207 
 208     /**
 209      * Parses a String containing a pango font description and returns
 210      * the (unscaled) font size as an integer.
 211      *
 212      * @param pangoName a String describing a pango font
 213      * @return the size of the font described by pangoName (e.g. if
 214      *         pangoName is "Sans Italic 10", then this method returns 10)
 215      */
 216     static int getFontSize(String pangoName) {
 217         int size = 10;
 218 
 219         StringTokenizer tok = new StringTokenizer(pangoName);
 220         while (tok.hasMoreTokens()) {
 221             String word = tok.nextToken();
 222 
 223             if (CHARS_DIGITS.indexOf(word.charAt(0)) != -1) {
 224                 try {
 225                     size = Integer.parseInt(word);
 226                 } catch (NumberFormatException ex) {
 227                 }
 228             }
 229         }
 230 
 231         return size;
 232     }
 233 }