src/org/ibex/Font.java

   1 // Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
   2 package org.ibex;
   3 import org.ibex.translators.*;
   4 import org.ibex.util.*;
   5 import java.io.*;
   6 import java.util.Hashtable;
   7
   8 import org.ibex.js.JSExn;
   9
  10 // FEATURE: this could be cleaner
  11 /** encapsulates a single font (a set of Glyphs) */
  12 public class Font {
  13
  14     private Font(Stream stream, int pointsize) { this.stream = stream; this.pointsize = pointsize; }
  15
  16     private static boolean glyphRenderingTaskIsScheduled = false;
  17
  18     public final int pointsize;                 ///< the size of the font
  19     public final Stream stream;                 ///< the stream from which this font was loaded
  20     public int max_ascent;                      ///< the maximum ascent, in pixels
  21     public int max_descent;                     ///< the maximum descent, in pixels
  22     boolean latinCharsPreloaded = false;        ///< true if a request to preload ASCII 32-127 has begun
  23     Glyph[] glyphs = new Glyph[65535];          ///< the glyphs that comprise this font
  24
  25     public abstract static class Glyph {
  26         protected Glyph(Font font, char c) { this.font = font; this.c = c; }
  27         public final Font font;
  28         public final char c;
  29         public int baseline;                    ///< within the alphamask, this is the y-coordinate of the baseline
  30         public int advance;                     ///< amount to increment the x-coordinate
  31         public boolean isLoaded = false;        ///< true iff the glyph is loaded
  32         public int width = -1;                  ///< the width of the glyph
  33         public int height = -1;                 ///< the height of the glyph
  34         public byte[] data = null;              ///< the alpha channel samples for this font
  35     }
  36
  37
  38     // Statics //////////////////////////////////////////////////////////////////////
  39
  40     private static final Freetype freetype = new Freetype();
  41     static final Hashtable glyphsToBeCached = new Hashtable();
  42     static final Hashtable glyphsToBeDisplayed = new Hashtable();
  43     private static Cache fontCache = new Cache(100);
  44     public static Font getFont(Stream stream, int pointsize) {
  45         Font ret = (Font)fontCache.get(stream, new Integer(pointsize));
  46         if (ret == null) fontCache.put(stream, new Integer(pointsize), ret = new Font(stream, pointsize));
  47         return ret;
  48     }
  49
  50
  51     // Methods //////////////////////////////////////////////////////////////////////
  52
  53     /**
  54      *  Rasterize the glyphs of <code>text</code>.
  55      *
  56      *  If all the glyphs of <code>text</code> are not yet loaded,
  57      *  spawn a Task to load them and then invoke callback.  If all
  58      *  the glyphs <i>are</i> loaded, rasterize them to the
  59      *  PixelBuffer (if non-null).
  60      *
  61      *  @returns <code>(width&lt;&lt;32)|height</code> if all glyphs are loaded; else -1
  62      */
  63     public long rasterizeGlyphs(final String text, PixelBuffer pb, int textcolor,
  64                                 int x, int y, int cx1, int cy1, int cx2, int cy2,
  65                                 final Scheduler.Task callback) {
  66         boolean encounteredUnrenderedGlyph = false;
  67         int width = 0, height = 0;
  68
  69         // preload the Latin-1 charset with low priority (we'll probably want it)
  70         if (!latinCharsPreloaded) {
  71             for(int i=48; i<57; i++) glyphsToBeCached.put(glyphs[i] = Platform.createGlyph(this, (char)i),"");
  72             for(int i=32; i<47; i++) glyphsToBeCached.put(glyphs[i] = Platform.createGlyph(this, (char)i),"");
  73             for(int i=57; i<128; i++) glyphsToBeCached.put(glyphs[i] = Platform.createGlyph(this, (char)i),"");
  74             }
  75         latinCharsPreloaded = true;
  76
  77         if (!glyphRenderingTaskIsScheduled) {
  78             Scheduler.add(glyphRenderingTask);
  79             glyphRenderingTaskIsScheduled = true;
  80         }
  81
  82         for(int i=0; i<text.length(); i++) {
  83                 final char c = text.charAt(i);
  84                 Glyph g = glyphs[c];
  85                 if (g == null) {
  86                         g = Platform.createGlyph(this, c);
  87                         glyphs[c] = g;
  88                 }
  89                 if (!g.isLoaded) {
  90                         if (!glyphsToBeDisplayed.contains(g)) {
  91                                 glyphsToBeDisplayed.put(g, "");              // move glyph to the display hash
  92                                 glyphsToBeCached.remove(g);
  93                                 encounteredUnrenderedGlyph = true;
  94                         }
  95                 } else if (!encounteredUnrenderedGlyph) {
  96                         if (pb != null) pb.drawGlyph(g, x + width, y + g.font.max_ascent - g.baseline, cx1, cy1, cx2, cy2, textcolor);
  97                         width += g.advance;
  98                         height = java.lang.Math.max(height, max_ascent + max_descent);
  99                 }
 100         }
 101
 102         if (!encounteredUnrenderedGlyph) return ((((long)width) << 32) | (long)(height & 0xffffffffL));
 103
 104         if (callback != null) Scheduler.add(new Scheduler.Task() {
 105                 public void perform() throws IOException, JSExn {
 106                         // FEATURE this isn't terribly efficient... perhaps the task should go on the last glyph?
 107                         for(int i=0; i<text.length(); i++) {
 108                                 Glyph g = glyphs[text.charAt(i)];
 109                                 if (g == null || !g.isLoaded) { Scheduler.add(this); return; }
 110                         }
 111                         callback.perform();
 112                 }});
 113         return -1;
 114     }
 115
 116     // FEATURE do we really need to be caching sizes?
 117     private static Cache sizeCache = new Cache(1000);
 118     public int textwidth(String s) { return (int)((textsize(s) >>> 32) & 0xffffffff); }
 119     public int textheight(String s) { return (int)(textsize(s) & 0xffffffffL); }
 120     public long textsize(String s) {
 121         Long l = (Long)sizeCache.get(s);
 122         if (l != null) return ((Long)l).longValue();
 123         long ret = rasterizeGlyphs(s, null, 0, 0, 0, 0, 0, 0, 0, null);
 124         if (ret != -1) sizeCache.put(s, new Long(ret));
 125         return ret == -1 ? 0 : ret;
 126     }
 127
 128     static final Scheduler.Task glyphRenderingTask = new Scheduler.Task() { public void perform() {
 129         Glyph g = null;
 130         if (!glyphsToBeDisplayed.isEmpty()) {
 131             g = (Glyph)glyphsToBeDisplayed.keys().nextElement();
 132             glyphsToBeDisplayed.remove(g);
 133             Log.debug(Font.class, "glyphRenderingTask removed glyph " + g.c + " of font " /*+ g.font*/ + " from glyphsToBeDisplayed");
 134         }
 135         else if (!glyphsToBeCached.isEmpty()) {
 136             g = (Glyph)glyphsToBeCached.keys().nextElement();
 137             glyphsToBeCached.remove(g);
 138             Log.debug(Font.class, "glyphRenderingTask removed glyph " + g.c + " of font " /*+ g.font*/ + " from glyphsToBeCached");
 139         }
 140         if (g != null) {
 141             Log.debug(Glyph.class, "rendering glyph " + g);
 142             try { freetype.renderGlyph(g); } catch (IOException e) { Log.info(Freetype.class, e); }
 143             Scheduler.add(this);          // keep ourselves in the queue until there are no glyphs to render
 144             glyphRenderingTaskIsScheduled = true;
 145         }
 146         else {
 147             glyphRenderingTaskIsScheduled = false;
 148             return;
 149         }
 150     } };
 151 }