src/glx/xfont.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  3.1
   4  *
   5  * Copyright (C) 1999  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 /* xfonts.c -- glXUseXFont() for Mesa written by
  28  * Copyright (C) 1995 Thorsten.Ohl @ Physik.TH-Darmstadt.de
  29  */
  30
  31 /*
  32   This was take from Mesa and modified to work in the real GLX structure.
  33   It provides a fully client side implementation of glXUseXFont and is
  34   called by that routine when direct rendering is enabled.
  35 */
  36
  37 #ifdef GLX_DIRECT_RENDERING
  38
  39 #include "glxclient.h"
  40
  41 /* Some debugging info.  */
  42
  43 #ifdef DEBUG
  44 #undef _R
  45 #undef _G
  46 #undef _B
  47 #include <ctype.h>
  48
  49 int debug_xfonts = 0;
  50
  51 static void
  52 dump_char_struct(XCharStruct * ch, char *prefix)
  53 {
  54    printf("%slbearing = %d, rbearing = %d, width = %d\n",
  55           prefix, ch->lbearing, ch->rbearing, ch->width);
  56    printf("%sascent = %d, descent = %d, attributes = %u\n",
  57           prefix, ch->ascent, ch->descent, (unsigned int) ch->attributes);
  58 }
  59
  60 static void
  61 dump_font_struct(XFontStruct * font)
  62 {
  63    printf("ascent = %d, descent = %d\n", font->ascent, font->descent);
  64    printf("char_or_byte2 = (%u,%u)\n",
  65           font->min_char_or_byte2, font->max_char_or_byte2);
  66    printf("byte1 = (%u,%u)\n", font->min_byte1, font->max_byte1);
  67    printf("all_chars_exist = %s\n", font->all_chars_exist ? "True" : "False");
  68    printf("default_char = %c (\\%03o)\n",
  69           (char) (isprint(font->default_char) ? font->default_char : ' '),
  70           font->default_char);
  71    dump_char_struct(&font->min_bounds, "min> ");
  72    dump_char_struct(&font->max_bounds, "max> ");
  73 #if 0
  74    for (c = font->min_char_or_byte2; c <= font->max_char_or_byte2; c++) {
  75       char prefix[8];
  76       sprintf(prefix, "%d> ", c);
  77       dump_char_struct(&font->per_char[c], prefix);
  78    }
  79 #endif
  80 }
  81
  82 static void
  83 dump_bitmap(unsigned int width, unsigned int height, GLubyte * bitmap)
  84 {
  85    unsigned int x, y;
  86
  87    printf("    ");
  88    for (x = 0; x < 8 * width; x++)
  89       printf("%o", 7 - (x % 8));
  90    putchar('\n');
  91    for (y = 0; y < height; y++) {
  92       printf("%3o:", y);
  93       for (x = 0; x < 8 * width; x++)
  94          putchar((bitmap[width * (height - y - 1) + x / 8] & (1 << (7 - (x %
  95                                                                          8))))
  96                  ? '*' : '.');
  97       printf("   ");
  98       for (x = 0; x < width; x++)
  99          printf("0x%02x, ", bitmap[width * (height - y - 1) + x]);
 100       putchar('\n');
 101    }
 102 }
 103 #endif /* DEBUG */
 104
 105
 106 /* Implementation.  */
 107
 108 /* Fill a BITMAP with a character C from thew current font
 109    in the graphics context GC.  WIDTH is the width in bytes
 110    and HEIGHT is the height in bits.
 111
 112    Note that the generated bitmaps must be used with
 113
 114         glPixelStorei (GL_UNPACK_SWAP_BYTES, GL_FALSE);
 115         glPixelStorei (GL_UNPACK_LSB_FIRST, GL_FALSE);
 116         glPixelStorei (GL_UNPACK_ROW_LENGTH, 0);
 117         glPixelStorei (GL_UNPACK_SKIP_ROWS, 0);
 118         glPixelStorei (GL_UNPACK_SKIP_PIXELS, 0);
 119         glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
 120
 121    Possible optimizations:
 122
 123      * use only one reusable pixmap with the maximum dimensions.
 124      * draw the entire font into a single pixmap (careful with
 125        proportional fonts!).
 126 */
 127
 128
 129 /*
 130  * Generate OpenGL-compatible bitmap.
 131  */
 132 static void
 133 fill_bitmap(Display * dpy, Window win, GC gc,
 134             unsigned int width, unsigned int height,
 135             int x0, int y0, unsigned int c, GLubyte * bitmap)
 136 {
 137    XImage *image;
 138    unsigned int x, y;
 139    Pixmap pixmap;
 140    XChar2b char2b;
 141
 142    pixmap = XCreatePixmap(dpy, win, 8 * width, height, 1);
 143    XSetForeground(dpy, gc, 0);
 144    XFillRectangle(dpy, pixmap, gc, 0, 0, 8 * width, height);
 145    XSetForeground(dpy, gc, 1);
 146
 147    char2b.byte1 = (c >> 8) & 0xff;
 148    char2b.byte2 = (c & 0xff);
 149
 150    XDrawString16(dpy, pixmap, gc, x0, y0, &char2b, 1);
 151
 152    image = XGetImage(dpy, pixmap, 0, 0, 8 * width, height, 1, XYPixmap);
 153    if (image) {
 154       /* Fill the bitmap (X11 and OpenGL are upside down wrt each other).  */
 155       for (y = 0; y < height; y++)
 156          for (x = 0; x < 8 * width; x++)
 157             if (XGetPixel(image, x, y))
 158                bitmap[width * (height - y - 1) + x / 8] |=
 159                   (1 << (7 - (x % 8)));
 160       XDestroyImage(image);
 161    }
 162
 163    XFreePixmap(dpy, pixmap);
 164 }
 165
 166 /*
 167  * determine if a given glyph is valid and return the
 168  * corresponding XCharStruct.
 169  */
 170 static XCharStruct *
 171 isvalid(XFontStruct * fs, int which)
 172 {
 173    unsigned int rows, pages;
 174    int byte1 = 0, byte2 = 0;
 175    int i, valid = 1;
 176
 177    rows = fs->max_byte1 - fs->min_byte1 + 1;
 178    pages = fs->max_char_or_byte2 - fs->min_char_or_byte2 + 1;
 179
 180    if (rows == 1) {
 181       /* "linear" fonts */
 182       if ((fs->min_char_or_byte2 > which) || (fs->max_char_or_byte2 < which))
 183          valid = 0;
 184    }
 185    else {
 186       /* "matrix" fonts */
 187       byte2 = which & 0xff;
 188       byte1 = which >> 8;
 189       if ((fs->min_char_or_byte2 > byte2) ||
 190           (fs->max_char_or_byte2 < byte2) ||
 191           (fs->min_byte1 > byte1) || (fs->max_byte1 < byte1))
 192          valid = 0;
 193    }
 194
 195    if (valid) {
 196       if (fs->per_char) {
 197          if (rows == 1) {
 198             /* "linear" fonts */
 199             return (fs->per_char + (which - fs->min_char_or_byte2));
 200          }
 201          else {
 202             /* "matrix" fonts */
 203             i = ((byte1 - fs->min_byte1) * pages) +
 204                (byte2 - fs->min_char_or_byte2);
 205             return (fs->per_char + i);
 206          }
 207       }
 208       else {
 209          return (&fs->min_bounds);
 210       }
 211    }
 212    return (NULL);
 213 }
 214
 215 _X_HIDDEN void
 216 DRI_glXUseXFont(struct glx_context *CC, Font font, int first, int count, int listbase)
 217 {
 218    Display *dpy;
 219    Window win;
 220    Pixmap pixmap;
 221    GC gc;
 222    XGCValues values;
 223    unsigned long valuemask;
 224    XFontStruct *fs;
 225
 226    GLint swapbytes, lsbfirst, rowlength;
 227    GLint skiprows, skippixels, alignment;
 228
 229    unsigned int max_width, max_height, max_bm_width, max_bm_height;
 230    GLubyte *bm;
 231
 232    int i;
 233
 234    dpy = CC->currentDpy;
 235    win = CC->currentDrawable;
 236
 237    fs = XQueryFont(dpy, font);
 238    if (!fs) {
 239       __glXSetError(CC, GL_INVALID_VALUE);
 240       return;
 241    }
 242
 243    /* Allocate a bitmap that can fit all characters.  */
 244    max_width = fs->max_bounds.rbearing - fs->min_bounds.lbearing;
 245    max_height = fs->max_bounds.ascent + fs->max_bounds.descent;
 246    max_bm_width = (max_width + 7) / 8;
 247    max_bm_height = max_height;
 248
 249    bm = malloc((max_bm_width * max_bm_height) * sizeof(GLubyte));
 250    if (!bm) {
 251       XFreeFontInfo(NULL, fs, 1);
 252       __glXSetError(CC, GL_OUT_OF_MEMORY);
 253       return;
 254    }
 255
 256 #if 0
 257    /* get the page info */
 258    pages = fs->max_char_or_byte2 - fs->min_char_or_byte2 + 1;
 259    firstchar = (fs->min_byte1 << 8) + fs->min_char_or_byte2;
 260    lastchar = (fs->max_byte1 << 8) + fs->max_char_or_byte2;
 261    rows = fs->max_byte1 - fs->min_byte1 + 1;
 262    unsigned int first_char, last_char, pages, rows;
 263 #endif
 264
 265    /* Save the current packing mode for bitmaps.  */
 266    glGetIntegerv(GL_UNPACK_SWAP_BYTES, &swapbytes);
 267    glGetIntegerv(GL_UNPACK_LSB_FIRST, &lsbfirst);
 268    glGetIntegerv(GL_UNPACK_ROW_LENGTH, &rowlength);
 269    glGetIntegerv(GL_UNPACK_SKIP_ROWS, &skiprows);
 270    glGetIntegerv(GL_UNPACK_SKIP_PIXELS, &skippixels);
 271    glGetIntegerv(GL_UNPACK_ALIGNMENT, &alignment);
 272
 273    /* Enforce a standard packing mode which is compatible with
 274       fill_bitmap() from above.  This is actually the default mode,
 275       except for the (non)alignment.  */
 276    glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_FALSE);
 277    glPixelStorei(GL_UNPACK_LSB_FIRST, GL_FALSE);
 278    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 279    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
 280    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
 281    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 282
 283    pixmap = XCreatePixmap(dpy, win, 10, 10, 1);
 284    values.foreground = BlackPixel(dpy, DefaultScreen(dpy));
 285    values.background = WhitePixel(dpy, DefaultScreen(dpy));
 286    values.font = fs->fid;
 287    valuemask = GCForeground | GCBackground | GCFont;
 288    gc = XCreateGC(dpy, pixmap, valuemask, &values);
 289    XFreePixmap(dpy, pixmap);
 290
 291 #ifdef DEBUG
 292    if (debug_xfonts)
 293       dump_font_struct(fs);
 294 #endif
 295
 296    for (i = 0; i < count; i++) {
 297       unsigned int width, height, bm_width, bm_height;
 298       GLfloat x0, y0, dx, dy;
 299       XCharStruct *ch;
 300       int x, y;
 301       unsigned int c = first + i;
 302       int list = listbase + i;
 303       int valid;
 304
 305       /* check on index validity and get the bounds */
 306       ch = isvalid(fs, c);
 307       if (!ch) {
 308          ch = &fs->max_bounds;
 309          valid = 0;
 310       }
 311       else {
 312          valid = 1;
 313       }
 314
 315 #ifdef DEBUG
 316       if (debug_xfonts) {
 317          char s[7];
 318          sprintf(s, isprint(c) ? "%c> " : "\\%03o> ", c);
 319          dump_char_struct(ch, s);
 320       }
 321 #endif
 322
 323       /* glBitmap()' parameters:
 324          straight from the glXUseXFont(3) manpage.  */
 325       width = ch->rbearing - ch->lbearing;
 326       height = ch->ascent + ch->descent;
 327       x0 = -ch->lbearing;
 328       y0 = ch->descent - 1;
 329       dx = ch->width;
 330       dy = 0;
 331
 332       /* X11's starting point.  */
 333       x = -ch->lbearing;
 334       y = ch->ascent;
 335
 336       /* Round the width to a multiple of eight.  We will use this also
 337          for the pixmap for capturing the X11 font.  This is slightly
 338          inefficient, but it makes the OpenGL part real easy.  */
 339       bm_width = (width + 7) / 8;
 340       bm_height = height;
 341
 342       glNewList(list, GL_COMPILE);
 343       if (valid && (bm_width > 0) && (bm_height > 0)) {
 344
 345          memset(bm, '\0', bm_width * bm_height);
 346          fill_bitmap(dpy, win, gc, bm_width, bm_height, x, y, c, bm);
 347
 348          glBitmap(width, height, x0, y0, dx, dy, bm);
 349 #ifdef DEBUG
 350          if (debug_xfonts) {
 351             printf("width/height = %u/%u\n", width, height);
 352             printf("bm_width/bm_height = %u/%u\n", bm_width, bm_height);
 353             dump_bitmap(bm_width, bm_height, bm);
 354          }
 355 #endif
 356       }
 357       else {
 358          glBitmap(0, 0, 0.0, 0.0, dx, dy, NULL);
 359       }
 360       glEndList();
 361    }
 362
 363    free(bm);
 364    XFreeFontInfo(NULL, fs, 1);
 365    XFreeGC(dpy, gc);
 366
 367    /* Restore saved packing modes.  */
 368    glPixelStorei(GL_UNPACK_SWAP_BYTES, swapbytes);
 369    glPixelStorei(GL_UNPACK_LSB_FIRST, lsbfirst);
 370    glPixelStorei(GL_UNPACK_ROW_LENGTH, rowlength);
 371    glPixelStorei(GL_UNPACK_SKIP_ROWS, skiprows);
 372    glPixelStorei(GL_UNPACK_SKIP_PIXELS, skippixels);
 373    glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);
 374 }
 375
 376 #endif