xfonts.h File Reference

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Functions
void	Fake_glXUseXFont (Font font, int first, int count, int listbase)

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Function Documentation

void Fake_glXUseXFont	(	Font	font,
		int	first,
		int	count,
		int	listbase
	)

Definition at line 217 of file xfonts.c.

References fill_bitmap(), FREE, glXGetCurrentDisplay(), isvalid(), list, and MALLOC.

{
   Display *dpy;
   Window win;
   Pixmap pixmap;
   GC gc;
   XGCValues values;
   unsigned long valuemask;
   XFontStruct *fs;
   GLint swapbytes, lsbfirst, rowlength;
   GLint skiprows, skippixels, alignment;
   unsigned int max_width, max_height, max_bm_width, max_bm_height;
   GLubyte *bm;
   int i;

   dpy = glXGetCurrentDisplay();
   if (!dpy)
      return;                   /* I guess glXMakeCurrent wasn't called */
   win = RootWindow(dpy, DefaultScreen(dpy));

   fs = XQueryFont(dpy, font);
   if (!fs) {
      _mesa_error(NULL, GL_INVALID_VALUE,
                  "Couldn't get font structure information");
      return;
   }

   /* Allocate a bitmap that can fit all characters.  */
   max_width = fs->max_bounds.rbearing - fs->min_bounds.lbearing;
   max_height = fs->max_bounds.ascent + fs->max_bounds.descent;
   max_bm_width = (max_width + 7) / 8;
   max_bm_height = max_height;

   bm = (GLubyte *) MALLOC((max_bm_width * max_bm_height) * sizeof(GLubyte));
   if (!bm) {
      XFreeFontInfo(NULL, fs, 1);
      _mesa_error(NULL, GL_OUT_OF_MEMORY,
                  "Couldn't allocate bitmap in glXUseXFont()");
      return;
   }

#if 0
   /* get the page info */
   pages = fs->max_char_or_byte2 - fs->min_char_or_byte2 + 1;
   firstchar = (fs->min_byte1 << 8) + fs->min_char_or_byte2;
   lastchar = (fs->max_byte1 << 8) + fs->max_char_or_byte2;
   rows = fs->max_byte1 - fs->min_byte1 + 1;
   unsigned int first_char, last_char, pages, rows;
#endif

   /* Save the current packing mode for bitmaps.  */
   glGetIntegerv(GL_UNPACK_SWAP_BYTES, &swapbytes);
   glGetIntegerv(GL_UNPACK_LSB_FIRST, &lsbfirst);
   glGetIntegerv(GL_UNPACK_ROW_LENGTH, &rowlength);
   glGetIntegerv(GL_UNPACK_SKIP_ROWS, &skiprows);
   glGetIntegerv(GL_UNPACK_SKIP_PIXELS, &skippixels);
   glGetIntegerv(GL_UNPACK_ALIGNMENT, &alignment);

   /* Enforce a standard packing mode which is compatible with
      fill_bitmap() from above.  This is actually the default mode,
      except for the (non)alignment.  */
   glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_FALSE);
   glPixelStorei(GL_UNPACK_LSB_FIRST, GL_FALSE);
   glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
   glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
   glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

   pixmap = XCreatePixmap(dpy, win, 10, 10, 1);
   values.foreground = BlackPixel(dpy, DefaultScreen(dpy));
   values.background = WhitePixel(dpy, DefaultScreen(dpy));
   values.font = fs->fid;
   valuemask = GCForeground | GCBackground | GCFont;
   gc = XCreateGC(dpy, pixmap, valuemask, &values);
   XFreePixmap(dpy, pixmap);

#ifdef DEBUG
   if (debug_xfonts)
      dump_font_struct(fs);
#endif

   for (i = 0; i < count; i++) {
      unsigned int width, height, bm_width, bm_height;
      GLfloat x0, y0, dx, dy;
      XCharStruct *ch;
      int x, y;
      unsigned int c = first + i;
      int list = listbase + i;
      int valid;

      /* check on index validity and get the bounds */
      ch = isvalid(fs, c);
      if (!ch) {
         ch = &fs->max_bounds;
         valid = 0;
      }
      else {
         valid = 1;
      }

#ifdef DEBUG
      if (debug_xfonts) {
         char s[7];
         sprintf(s, isprint(c) ? "%c> " : "\\%03o> ", c);
         dump_char_struct(ch, s);
      }
#endif

      /* glBitmap()' parameters:
         straight from the glXUseXFont(3) manpage.  */
      width = ch->rbearing - ch->lbearing;
      height = ch->ascent + ch->descent;
      x0 = -ch->lbearing;
      y0 = ch->descent - 0;     /* XXX used to subtract 1 here */
      /* but that caused a conformace failure */
      dx = ch->width;
      dy = 0;

      /* X11's starting point.  */
      x = -ch->lbearing;
      y = ch->ascent;

      /* Round the width to a multiple of eight.  We will use this also
         for the pixmap for capturing the X11 font.  This is slightly
         inefficient, but it makes the OpenGL part real easy.  */
      bm_width = (width + 7) / 8;
      bm_height = height;

      glNewList(list, GL_COMPILE);
      if (valid && (bm_width > 0) && (bm_height > 0)) {

         MEMSET(bm, '\0', bm_width * bm_height);
         fill_bitmap(dpy, win, gc, bm_width, bm_height, x, y, c, bm);

         glBitmap(width, height, x0, y0, dx, dy, bm);
#ifdef DEBUG
         if (debug_xfonts) {
            printf("width/height = %u/%u\n", width, height);
            printf("bm_width/bm_height = %u/%u\n", bm_width, bm_height);
            dump_bitmap(bm_width, bm_height, bm);
         }
#endif
      }
      else {
         glBitmap(0, 0, 0.0, 0.0, dx, dy, NULL);
      }
      glEndList();
   }

   FREE(bm);
   XFreeFontInfo(NULL, fs, 1);
   XFreeGC(dpy, gc);

   /* Restore saved packing modes.  */
   glPixelStorei(GL_UNPACK_SWAP_BYTES, swapbytes);
   glPixelStorei(GL_UNPACK_LSB_FIRST, lsbfirst);
   glPixelStorei(GL_UNPACK_ROW_LENGTH, rowlength);
   glPixelStorei(GL_UNPACK_SKIP_ROWS, skiprows);
   glPixelStorei(GL_UNPACK_SKIP_PIXELS, skippixels);
   glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);
}

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