src/glx/xfont.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /* xfonts.c -- glXUseXFont() for Mesa written by
  27  * Copyright (C) 1995 Thorsten.Ohl @ Physik.TH-Darmstadt.de
  28  */
  29
  30 /*
  31   This was take from Mesa and modified to work in the real GLX structure.
  32   It provides a fully client side implementation of glXUseXFont and is
  33   called by that routine when direct rendering is enabled.
  34 */
  35
  36 #ifdef GLX_DIRECT_RENDERING
  37
  38 #include "glxclient.h"
  39
  40 /* Some debugging info.  */
  41
  42 #ifdef DEBUG
  43 #undef _R
  44 #undef _G
  45 #undef _B
  46 #include <ctype.h>
  47
  48 int debug_xfonts = 0;
  49
  50 static void
  51 dump_char_struct(XCharStruct * ch, char *prefix)
  52 {
  53    printf("%slbearing = %d, rbearing = %d, width = %d\n",
  54           prefix, ch->lbearing, ch->rbearing, ch->width);
  55    printf("%sascent = %d, descent = %d, attributes = %u\n",
  56           prefix, ch->ascent, ch->descent, (unsigned int) ch->attributes);
  57 }
  58
  59 static void
  60 dump_font_struct(XFontStruct * font)
  61 {
  62    printf("ascent = %d, descent = %d\n", font->ascent, font->descent);
  63    printf("char_or_byte2 = (%u,%u)\n",
  64           font->min_char_or_byte2, font->max_char_or_byte2);
  65    printf("byte1 = (%u,%u)\n", font->min_byte1, font->max_byte1);
  66    printf("all_chars_exist = %s\n", font->all_chars_exist ? "True" : "False");
  67    printf("default_char = %c (\\%03o)\n",
  68           (char) (isprint(font->default_char) ? font->default_char : ' '),
  69           font->default_char);
  70    dump_char_struct(&font->min_bounds, "min> ");
  71    dump_char_struct(&font->max_bounds, "max> ");
  72 #if 0
  73    for (c = font->min_char_or_byte2; c <= font->max_char_or_byte2; c++) {
  74       char prefix[8];
  75       sprintf(prefix, "%d> ", c);
  76       dump_char_struct(&font->per_char[c], prefix);
  77    }
  78 #endif
  79 }
  80
  81 static void
  82 dump_bitmap(unsigned int width, unsigned int height, GLubyte * bitmap)
  83 {
  84    unsigned int x, y;
  85
  86    printf("    ");
  87    for (x = 0; x < 8 * width; x++)
  88       printf("%o", 7 - (x % 8));
  89    putchar('\n');
  90    for (y = 0; y < height; y++) {
  91       printf("%3o:", y);
  92       for (x = 0; x < 8 * width; x++)
  93          putchar((bitmap[width * (height - y - 1) + x / 8] & (1 << (7 - (x %
  94                                                                          8))))
  95                  ? '*' : '.');
  96       printf("   ");
  97       for (x = 0; x < width; x++)
  98          printf("0x%02x, ", bitmap[width * (height - y - 1) + x]);
  99       putchar('\n');
 100    }
 101 }
 102 #endif /* DEBUG */
 103
 104
 105 /* Implementation.  */
 106
 107 /* Fill a BITMAP with a character C from thew current font
 108    in the graphics context GC.  WIDTH is the width in bytes
 109    and HEIGHT is the height in bits.
 110
 111    Note that the generated bitmaps must be used with
 112
 113         glPixelStorei (GL_UNPACK_SWAP_BYTES, GL_FALSE);
 114         glPixelStorei (GL_UNPACK_LSB_FIRST, GL_FALSE);
 115         glPixelStorei (GL_UNPACK_ROW_LENGTH, 0);
 116         glPixelStorei (GL_UNPACK_SKIP_ROWS, 0);
 117         glPixelStorei (GL_UNPACK_SKIP_PIXELS, 0);
 118         glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
 119
 120    Possible optimizations:
 121
 122      * use only one reusable pixmap with the maximum dimensions.
 123      * draw the entire font into a single pixmap (careful with
 124        proportional fonts!).
 125 */
 126
 127
 128 /*
 129  * Generate OpenGL-compatible bitmap.
 130  */
 131 static void
 132 fill_bitmap(Display * dpy, int screen, GC gc,
 133             unsigned int width, unsigned int height,
 134             int x0, int y0, unsigned int c, GLubyte * bitmap)
 135 {
 136    XImage *image;
 137    unsigned int x, y;
 138    Pixmap pixmap;
 139    XChar2b char2b;
 140
 141    pixmap = XCreatePixmap(dpy, RootWindow(dpy, screen), 8 * width, height, 1);
 142    XSetForeground(dpy, gc, 0);
 143    XFillRectangle(dpy, pixmap, gc, 0, 0, 8 * width, height);
 144    XSetForeground(dpy, gc, 1);
 145
 146    char2b.byte1 = (c >> 8) & 0xff;
 147    char2b.byte2 = (c & 0xff);
 148
 149    XDrawString16(dpy, pixmap, gc, x0, y0, &char2b, 1);
 150
 151    image = XGetImage(dpy, pixmap, 0, 0, 8 * width, height, 1, XYPixmap);
 152    if (image) {
 153       /* Fill the bitmap (X11 and OpenGL are upside down wrt each other).  */
 154       for (y = 0; y < height; y++)
 155          for (x = 0; x < 8 * width; x++)
 156             if (XGetPixel(image, x, y))
 157                bitmap[width * (height - y - 1) + x / 8] |=
 158                   (1 << (7 - (x % 8)));
 159       XDestroyImage(image);
 160    }
 161
 162    XFreePixmap(dpy, pixmap);
 163 }
 164
 165 /*
 166  * determine if a given glyph is valid and return the
 167  * corresponding XCharStruct.
 168  */
 169 static XCharStruct *
 170 isvalid(XFontStruct * fs, int which)
 171 {
 172    unsigned int rows, pages;
 173    int byte1 = 0, byte2 = 0;
 174    int i, valid = 1;
 175
 176    rows = fs->max_byte1 - fs->min_byte1 + 1;
 177    pages = fs->max_char_or_byte2 - fs->min_char_or_byte2 + 1;
 178
 179    if (rows == 1) {
 180       /* "linear" fonts */
 181       if ((fs->min_char_or_byte2 > which) || (fs->max_char_or_byte2 < which))
 182          valid = 0;
 183    }
 184    else {
 185       /* "matrix" fonts */
 186       byte2 = which & 0xff;
 187       byte1 = which >> 8;
 188       if ((fs->min_char_or_byte2 > byte2) ||
 189           (fs->max_char_or_byte2 < byte2) ||
 190           (fs->min_byte1 > byte1) || (fs->max_byte1 < byte1))
 191          valid = 0;
 192    }
 193
 194    if (valid) {
 195       if (fs->per_char) {
 196          if (rows == 1) {
 197             /* "linear" fonts */
 198             return (fs->per_char + (which - fs->min_char_or_byte2));
 199          }
 200          else {
 201             /* "matrix" fonts */
 202             i = ((byte1 - fs->min_byte1) * pages) +
 203                (byte2 - fs->min_char_or_byte2);
 204             return (fs->per_char + i);
 205          }
 206       }
 207       else {
 208          return (&fs->min_bounds);
 209       }
 210    }
 211    return (NULL);
 212 }
 213
 214 _X_HIDDEN void
 215 DRI_glXUseXFont(struct glx_context *CC, Font font, int first, int count, int listbase)
 216 {
 217    Display *dpy;
 218    int screen;
 219    Pixmap pixmap;
 220    GC gc;
 221    XGCValues values;
 222    unsigned long valuemask;
 223    XFontStruct *fs;
 224
 225    GLint swapbytes, lsbfirst, rowlength;
 226    GLint skiprows, skippixels, alignment;
 227
 228    unsigned int max_width, max_height, max_bm_width, max_bm_height;
 229    GLubyte *bm;
 230
 231    int i;
 232
 233    dpy = CC->currentDpy;
 234    screen = CC->screen;
 235
 236    fs = XQueryFont(dpy, font);
 237    if (!fs) {
 238       __glXSetError(CC, GL_INVALID_VALUE);
 239       return;
 240    }
 241
 242    /* Allocate a bitmap that can fit all characters.  */
 243    max_width = fs->max_bounds.rbearing - fs->min_bounds.lbearing;
 244    max_height = fs->max_bounds.ascent + fs->max_bounds.descent;
 245    max_bm_width = (max_width + 7) / 8;
 246    max_bm_height = max_height;
 247
 248    bm = malloc((max_bm_width * max_bm_height) * sizeof(GLubyte));
 249    if (!bm) {
 250       XFreeFontInfo(NULL, fs, 1);
 251       __glXSetError(CC, GL_OUT_OF_MEMORY);
 252       return;
 253    }
 254
 255 #if 0
 256    /* get the page info */
 257    pages = fs->max_char_or_byte2 - fs->min_char_or_byte2 + 1;
 258    firstchar = (fs->min_byte1 << 8) + fs->min_char_or_byte2;
 259    lastchar = (fs->max_byte1 << 8) + fs->max_char_or_byte2;
 260    rows = fs->max_byte1 - fs->min_byte1 + 1;
 261    unsigned int first_char, last_char, pages, rows;
 262 #endif
 263
 264    /* Save the current packing mode for bitmaps.  */
 265    glGetIntegerv(GL_UNPACK_SWAP_BYTES, &swapbytes);
 266    glGetIntegerv(GL_UNPACK_LSB_FIRST, &lsbfirst);
 267    glGetIntegerv(GL_UNPACK_ROW_LENGTH, &rowlength);
 268    glGetIntegerv(GL_UNPACK_SKIP_ROWS, &skiprows);
 269    glGetIntegerv(GL_UNPACK_SKIP_PIXELS, &skippixels);
 270    glGetIntegerv(GL_UNPACK_ALIGNMENT, &alignment);
 271
 272    /* Enforce a standard packing mode which is compatible with
 273       fill_bitmap() from above.  This is actually the default mode,
 274       except for the (non)alignment.  */
 275    glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_FALSE);
 276    glPixelStorei(GL_UNPACK_LSB_FIRST, GL_FALSE);
 277    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 278    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
 279    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
 280    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 281
 282    pixmap = XCreatePixmap(dpy, RootWindow(dpy, screen), 10, 10, 1);
 283    values.foreground = BlackPixel(dpy, DefaultScreen(dpy));
 284    values.background = WhitePixel(dpy, DefaultScreen(dpy));
 285    values.font = fs->fid;
 286    valuemask = GCForeground | GCBackground | GCFont;
 287    gc = XCreateGC(dpy, pixmap, valuemask, &values);
 288    XFreePixmap(dpy, pixmap);
 289
 290 #ifdef DEBUG
 291    if (debug_xfonts)
 292       dump_font_struct(fs);
 293 #endif
 294
 295    for (i = 0; i < count; i++) {
 296       unsigned int width, height, bm_width, bm_height;
 297       GLfloat x0, y0, dx, dy;
 298       XCharStruct *ch;
 299       int x, y;
 300       unsigned int c = first + i;
 301       int list = listbase + i;
 302       int valid;
 303
 304       /* check on index validity and get the bounds */
 305       ch = isvalid(fs, c);
 306       if (!ch) {
 307          ch = &fs->max_bounds;
 308          valid = 0;
 309       }
 310       else {
 311          valid = 1;
 312       }
 313
 314 #ifdef DEBUG
 315       if (debug_xfonts) {
 316          char s[7];
 317          sprintf(s, isprint(c) ? "%c> " : "\\%03o> ", c);
 318          dump_char_struct(ch, s);
 319       }
 320 #endif
 321
 322       /* glBitmap()' parameters:
 323          straight from the glXUseXFont(3) manpage.  */
 324       width = ch->rbearing - ch->lbearing;
 325       height = ch->ascent + ch->descent;
 326       x0 = -ch->lbearing;
 327       y0 = ch->descent - 1;
 328       dx = ch->width;
 329       dy = 0;
 330
 331       /* X11's starting point.  */
 332       x = -ch->lbearing;
 333       y = ch->ascent;
 334
 335       /* Round the width to a multiple of eight.  We will use this also
 336          for the pixmap for capturing the X11 font.  This is slightly
 337          inefficient, but it makes the OpenGL part real easy.  */
 338       bm_width = (width + 7) / 8;
 339       bm_height = height;
 340
 341       glNewList(list, GL_COMPILE);
 342       if (valid && (bm_width > 0) && (bm_height > 0)) {
 343
 344          memset(bm, '\0', bm_width * bm_height);
 345          fill_bitmap(dpy, screen, gc, bm_width, bm_height, x, y, c, bm);
 346
 347          glBitmap(width, height, x0, y0, dx, dy, bm);
 348 #ifdef DEBUG
 349          if (debug_xfonts) {
 350             printf("width/height = %u/%u\n", width, height);
 351             printf("bm_width/bm_height = %u/%u\n", bm_width, bm_height);
 352             dump_bitmap(bm_width, bm_height, bm);
 353          }
 354 #endif
 355       }
 356       else {
 357          glBitmap(0, 0, 0.0, 0.0, dx, dy, NULL);
 358       }
 359       glEndList();
 360    }
 361
 362    free(bm);
 363    XFreeFontInfo(NULL, fs, 1);
 364    XFreeGC(dpy, gc);
 365
 366    /* Restore saved packing modes.  */
 367    glPixelStorei(GL_UNPACK_SWAP_BYTES, swapbytes);
 368    glPixelStorei(GL_UNPACK_LSB_FIRST, lsbfirst);
 369    glPixelStorei(GL_UNPACK_ROW_LENGTH, rowlength);
 370    glPixelStorei(GL_UNPACK_SKIP_ROWS, skiprows);
 371    glPixelStorei(GL_UNPACK_SKIP_PIXELS, skippixels);
 372    glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);
 373 }
 374
 375 #endif