/*
 * gentexfont.c
 *
 * Copyright (c) 2003 - 2012 NVIDIA Corporation.  All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * This software is based upon texfont, with consent from Mark J. Kilgard,
 * provided under the following terms:
 *
 * Copyright (c) Mark J. Kilgard, 1997.
 *
 * This program is freely distributable without licensing fees  and is
 * provided without guarantee or warrantee expressed or  implied. This
 * program is -not- in the public domain.
 */

/* X compile line: cc -o gentexfont gentexfont.c -lX11 */

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <math.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>

#include <GLES2/gl2.h>

#include "nvtexfont.h"
#include "priv.h"

typedef struct {
  short width;
  short height;
  short xoffset;
  short yoffset;
  short advance;
  unsigned char *bitmap;
} PerGlyphInfo, *PerGlyphInfoPtr;

typedef struct {
  int min_char;
  int max_char;
  int max_ascent;
  int max_descent;
  PerGlyphInfo glyph[1];
} FontInfo, *FontInfoPtr;

Display *dpy;
FontInfoPtr fontinfo;
int format = TXF_FORMAT_BITMAP;
int gap = 3;

/* #define REPORT_GLYPHS */
#ifdef REPORT_GLYPHS
#define DEBUG_GLYPH4(msg,a,b,c,d) printf(msg,a,b,c,d)
#define DEBUG_GLYPH(msg) printf(msg)
#else
#define DEBUG_GLYPH4(msg,a,b,c,d) { /* nothing */ }
#define DEBUG_GLYPH(msg) { /* nothing */ }
#endif

#define MAX_GLYPHS_PER_GRAB 512  /* this is big enough for 2^9 glyph
                                    character sets */

static FontInfoPtr
SuckGlyphsFromServer(Display * dpy, Font font)
{
  Pixmap offscreen;
  XFontStruct *fontinfo;
  XImage *image;
  GC xgc;
  XGCValues values;
  int numchars;
  int width, height, pixwidth;
  int i, j;
  XCharStruct *charinfo = NULL;
  XChar2b character;
  unsigned char *bitmapData;
  int x, y;
  int spanLength = 0;
  int charWidth = 0, charHeight = 0, maxSpanLength;
  int grabList[MAX_GLYPHS_PER_GRAB];
  int glyphsPerGrab = MAX_GLYPHS_PER_GRAB;
  int numToGrab, thisglyph;
  FontInfoPtr myfontinfo;

  fontinfo = XQueryFont(dpy, font);
  if (!fontinfo)
    return NULL;

  numchars = fontinfo->max_char_or_byte2 - fontinfo->min_char_or_byte2 + 1;
  if (numchars < 1)
    return NULL;

  myfontinfo = (FontInfoPtr) malloc(sizeof(FontInfo) + (numchars - 1) * sizeof(PerGlyphInfo));
  if (!myfontinfo)
    return NULL;

  myfontinfo->min_char = fontinfo->min_char_or_byte2;
  myfontinfo->max_char = fontinfo->max_char_or_byte2;
  myfontinfo->max_ascent = fontinfo->max_bounds.ascent;
  myfontinfo->max_descent = fontinfo->max_bounds.descent;

  width = fontinfo->max_bounds.rbearing - fontinfo->min_bounds.lbearing;
  height = fontinfo->max_bounds.ascent + fontinfo->max_bounds.descent;

  maxSpanLength = (width + 7) / 8;
  /* Be careful determining the width of the pixmap; the X protocol allows
     pixmaps of width 2^16-1 (unsigned short size) but drawing coordinates
     max out at 2^15-1 (signed short size).  If the width is too large, we
     need to limit the glyphs per grab.  */
  if ((glyphsPerGrab * 8 * maxSpanLength) >= (1 << 15)) {
    glyphsPerGrab = (1 << 15) / (8 * maxSpanLength);
  }
  pixwidth = glyphsPerGrab * 8 * maxSpanLength;
  offscreen = XCreatePixmap(dpy, RootWindow(dpy, DefaultScreen(dpy)),
    pixwidth, height, 1);

  values.font = font;
  values.background = 0;
  values.foreground = 0;
  xgc = XCreateGC(dpy, offscreen, GCFont | GCBackground | GCForeground, &values);

  XFillRectangle(dpy, offscreen, xgc, 0, 0, 8 * maxSpanLength * glyphsPerGrab, height);
  XSetForeground(dpy, xgc, 1);

  numToGrab = 0;
  if (fontinfo->per_char == NULL) {
    charinfo = &(fontinfo->min_bounds);
    charWidth = charinfo->rbearing - charinfo->lbearing;
    charHeight = charinfo->ascent + charinfo->descent;
    spanLength = (charWidth + 7) / 8;
  }
  for (i = 0; i < numchars; i++) {
    if (fontinfo->per_char != NULL) {
      charinfo = &(fontinfo->per_char[i]);
      charWidth = charinfo->rbearing - charinfo->lbearing;
      charHeight = charinfo->ascent + charinfo->descent;
      if (charWidth == 0 || charHeight == 0) {
        /* Still must move raster pos even if empty character */
        myfontinfo->glyph[i].width = 0;
        myfontinfo->glyph[i].height = 0;
        myfontinfo->glyph[i].xoffset = 0;
        myfontinfo->glyph[i].yoffset = 0;
        myfontinfo->glyph[i].advance = charinfo->width;
        myfontinfo->glyph[i].bitmap = NULL;
        goto PossiblyDoGrab;
      }
    }
    grabList[numToGrab] = i;

    /* XXX is this right for large fonts? */
    character.byte2 = (i + fontinfo->min_char_or_byte2) & 255;
    character.byte1 = (i + fontinfo->min_char_or_byte2) >> 8;

    /* XXX we could use XDrawImageString16 which would also paint the backing

       rectangle but X server bugs in some scalable font rasterizers makes it

       more effective to do XFillRectangles to clear the pixmap and
       XDrawImage16 for the text.  */
    XDrawString16(dpy, offscreen, xgc,
      -charinfo->lbearing + 8 * maxSpanLength * numToGrab,
      charinfo->ascent, &character, 1);

    numToGrab++;

  PossiblyDoGrab:

    if (numToGrab >= glyphsPerGrab || i == numchars - 1) {
      image = XGetImage(dpy, offscreen,
        0, 0, pixwidth, height, 1, XYPixmap);
      for (j = 0; j < numToGrab; j++) {
        thisglyph = grabList[j];
        if (fontinfo->per_char != NULL) {
          charinfo = &(fontinfo->per_char[thisglyph]);
          charWidth = charinfo->rbearing - charinfo->lbearing;
          charHeight = charinfo->ascent + charinfo->descent;
          spanLength = (charWidth + 7) / 8;
        }
        bitmapData = calloc(height * spanLength, sizeof(char));
        if (!bitmapData)
          goto FreeFontAndReturn;
        DEBUG_GLYPH4("index %d, glyph %d (%d by %d)\n",
          j, thisglyph + fontinfo->min_char_or_byte2, charWidth, charHeight);
        for (y = 0; y < charHeight; y++) {
          for (x = 0; x < charWidth; x++) {
            /* XXX The algorithm used to suck across the font ensures that
               each glyph begins on a byte boundary.  In theory this would
               make it convienent to copy the glyph into a byte oriented
               bitmap.  We actually use the XGetPixel function to extract
               each pixel from the image which is not that efficient.  We
               could either do tighter packing in the pixmap or more
               efficient extraction from the image.  Oh well.  */
            if (XGetPixel(image, j * maxSpanLength * 8 + x, charHeight - 1 - y)) {
              DEBUG_GLYPH("x");
              bitmapData[y * spanLength + x / 8] |= (1 << (x & 7));
            } else {
              DEBUG_GLYPH(" ");
            }
          }
          DEBUG_GLYPH("\n");
        }
        myfontinfo->glyph[thisglyph].width = charWidth;
        myfontinfo->glyph[thisglyph].height = charHeight;
        myfontinfo->glyph[thisglyph].xoffset = charinfo->lbearing;
        myfontinfo->glyph[thisglyph].yoffset = -charinfo->descent;
        myfontinfo->glyph[thisglyph].advance = charinfo->width;
        myfontinfo->glyph[thisglyph].bitmap = bitmapData;
      }
      XDestroyImage(image);
      numToGrab = 0;
      /* do we need to clear the offscreen pixmap to get more? */
      if (i < numchars - 1) {
        XSetForeground(dpy, xgc, 0);
        XFillRectangle(dpy, offscreen, xgc, 0, 0, 8 * maxSpanLength * glyphsPerGrab, height);
        XSetForeground(dpy, xgc, 1);
      }
    }
  }
  XFreeGC(dpy, xgc);
  XFreePixmap(dpy, offscreen);
  return myfontinfo;

FreeFontAndReturn:
  XDestroyImage(image);
  XFreeGC(dpy, xgc);
  XFreePixmap(dpy, offscreen);
  for (j = i - 1; j >= 0; j--) {
    if (myfontinfo->glyph[j].bitmap)
      free(myfontinfo->glyph[j].bitmap);
  }
  free(myfontinfo);
  return NULL;
}

#if 0
static void
printGlyph(FontInfoPtr font, int c)
{
  PerGlyphInfoPtr glyph;
  unsigned char *bitmapData;
  int width, height, spanLength;
  int x, y;

  if (c < font->min_char || c > font->max_char) {
    printf("out of range glyph\n");
    return;
  }
  glyph = &font->glyph[c - font->min_char];
  bitmapData = glyph->bitmap;
  if (bitmapData) {
    width = glyph->width;
    spanLength = (width + 7) / 8;
    height = glyph->height;

    for (y = 0; y < height; y++) {
      for (x = 0; x < width; x++) {
        if (bitmapData[y * spanLength + x / 8] & (1 << (x & 7))) {
          putchar('X');
        } else {
          putchar('.');
        }
      }
      putchar('\n');
    }
  }
}
#endif

static void
getMetric(FontInfoPtr font, int c, NVTexfontGlyphInfo * tgi)
{
  PerGlyphInfoPtr glyph;
  unsigned char *bitmapData;

  tgi->c = c;
  if (c < font->min_char || c > font->max_char) {
    tgi->width = 0;
    tgi->height = 0;
    tgi->xoffset = 0;
    tgi->yoffset = 0;
    tgi->dummy = 0;
    tgi->advance = 0;
    return;
  }
  glyph = &font->glyph[c - font->min_char];
  bitmapData = glyph->bitmap;
  if (bitmapData) {
    tgi->width = glyph->width;
    tgi->height = glyph->height;
    tgi->xoffset = glyph->xoffset;
    tgi->yoffset = glyph->yoffset;
  } else {
    tgi->width = 0;
    tgi->height = 0;
    tgi->xoffset = 0;
    tgi->yoffset = 0;
  }
  tgi->dummy = 0;
  tgi->advance = glyph->advance;
}

static int
glyphCompare(const void *a, const void *b)
{
  unsigned char *c1 = (unsigned char *) a;
  unsigned char *c2 = (unsigned char *) b;
  NVTexfontGlyphInfo tgi1;
  NVTexfontGlyphInfo tgi2;

  getMetric(fontinfo, *c1, &tgi1);
  getMetric(fontinfo, *c2, &tgi2);
  return tgi2.height - tgi1.height;
}

static int
getFontel(unsigned char *bitmapData, int spanLength, int i, int j)
{
  return bitmapData[i * spanLength + j / 8] & (1 << (j & 7)) ? 255 : 0;
}

static void
placeGlyph(FontInfoPtr font, int c, unsigned char *texarea, int stride, int x, int y)
{
  PerGlyphInfoPtr glyph;
  unsigned char *bitmapData;
  int width, height, spanLength;
  int i, j;

  if (c < font->min_char || c > font->max_char) {
    printf("out of range glyph\n");
    return;
  }
  glyph = &font->glyph[c - font->min_char];
  bitmapData = glyph->bitmap;
  if (bitmapData) {
    width = glyph->width;
    spanLength = (width + 7) / 8;
    height = glyph->height;

    for (i = 0; i < height; i++) {
      for (j = 0; j < width; j++) {
        texarea[stride * (y + i) + x + j] =
          getFontel(bitmapData, spanLength, i, j);
      }
    }
  }
}

static char *
nodupstring(char *s)
{
  int len, i, p;
  char *new;

  len = strlen(s);
  new = (char *) calloc(len + 1, 1);
  p = 0;
  for (i = 0; i < len; i++) {
    if (!strchr(new, s[i])) {
      new[p] = s[i];
      p++;
    }
  }
  new = realloc(new, p + 1);
  return new;
}

int main(int argc, char **argv)
{
  int texw, texh;
  unsigned char *texarea, *texbitmap;
  FILE *file;
  int len, stride;
  int width, height;
  int px, py, maxheight;
  NVTexfontGlyphInfo tgi;
  int usageError = 0;
  char *fontname, *filename;
  XFontStruct *xfont;
  int endianness;
  int i, j;
  static unsigned char defglist[UCHAR_MAX + 2];
  unsigned char *glist = defglist;

  texw = texh = 256;

  // generating default list of supported characters
  for (j = 0, i = 0; i < UCHAR_MAX + 1; i++) {
      if (isprint(i)) {
          defglist[j++] = i;
      }
  }
  defglist[j] = 0;

  //fontname = "-adobe-courier-bold-r-normal--46-*-100-100-m-*-iso8859-1";
  fontname = "-adobe-helvetica-bold-r-normal--34-*-100-100-*-*-iso8859-1";
  filename = "helvetica.txf";

  for (i = 1; i < argc; i++) {
    if (!strcmp(argv[i], "-w")) {
      i++;
      texw = atoi(argv[i]);
    } else if (!strcmp(argv[i], "-h")) {
      i++;
      texh = atoi(argv[i]);
    } else if (!strcmp(argv[i], "-gap")) {
      i++;
      gap = atoi(argv[i]);
    } else if (!strcmp(argv[i], "-byte")) {
      format = TXF_FORMAT_BYTE;
      break;
    } else if (!strcmp(argv[i], "-bitmap")) {
      format = TXF_FORMAT_BITMAP;
    } else if (!strcmp(argv[i], "-glist")) {
      i++;
      glist = (unsigned char *) argv[i];
    } else if (!strcmp(argv[i], "-fn")) {
      i++;
      fontname = argv[i];
    } else if (!strcmp(argv[i], "-file")) {
      i++;
      filename = argv[i];
    } else {
      usageError = 1;
    }
  }

  if (usageError) {
    putchar('\n');
    printf("usage: texfontgen [options] txf-file\n");
    printf(" -w #          textureWidth (def=%d)\n", texw);
    printf(" -h #          textureHeight (def=%d)\n", texh);
    printf(" -gap #        gap between glyphs (def=%d)\n", gap);
    printf(" -bitmap       use a bitmap encoding (default)\n");
    printf(" -byte         use a byte encoding (less compact)\n");
    printf(" -glist ABC    glyph list (def=%s)\n", glist);
    printf(" -fn name      X font name (def=%s)\n", fontname);
    printf(" -file name    output file for textured font (def=%s)\n", fontname);
    putchar('\n');
    exit(1);
  }
  texarea = calloc(texw * texh, sizeof(unsigned char));
  glist = (unsigned char *) nodupstring((char *) glist);

  dpy = XOpenDisplay(NULL);
  if (!dpy) {
    printf("could not open display\n");
    exit(1);
  }
  /* find an OpenGL-capable RGB visual with depth buffer */
  xfont = XLoadQueryFont(dpy, fontname);
  if (!xfont) {
    printf("could not get load X font: %s\n", fontname);
    exit(1);
  }
  fontinfo = SuckGlyphsFromServer(dpy, xfont->fid);
  if (!fontinfo) {
    printf("could not get font glyphs\n");
    exit(1);
  }
  len = strlen((char *) glist);
  qsort(glist, len, sizeof(unsigned char), glyphCompare);

  file = fopen(filename, "wb");
  fwrite("\377txf", 1, 4, file);
  endianness = 0x12345678;
  assert(sizeof(int) == 4);  /* Ensure external file format size. */
  fwrite(&endianness, sizeof(int), 1, file);
  fwrite(&format, sizeof(int), 1, file);
  fwrite(&texw, sizeof(int), 1, file);
  fwrite(&texh, sizeof(int), 1, file);
  fwrite(&fontinfo->max_ascent, sizeof(int), 1, file);
  fwrite(&fontinfo->max_descent, sizeof(int), 1, file);
  fwrite(&len, sizeof(int), 1, file);

  px = gap;
  py = gap;
  maxheight = 0;
  for (i = 0; i < len; i++) {
    if (glist[i] != 0) {  /* If not already processed... */

      /* Try to find a character from the glist that will fit on the
         remaining space on the current row. */

      int foundWidthFit = 0;
      int c = 0;

      getMetric(fontinfo, glist[i], &tgi);
      width = tgi.width;
      height = tgi.height;
      if (height > 0 && width > 0) {
        for (j = i; j < len;) {
          if (height > 0 && width > 0) {
            if (px + width + gap < texw) {
              foundWidthFit = 1;
	      if (j != i) {
		i--;  /* Step back so i loop increment leaves us at same character. */
	      }
              break;
            }
	  }
          j++;
          getMetric(fontinfo, glist[j], &tgi);
          width = tgi.width;
          height = tgi.height;
        }

        /* If a fit was found, use that character; otherwise, advance a line
           in  the texture. */
        if (foundWidthFit) {
          if (height > maxheight) {
            maxheight = height;
          }
          c = j;
        } else {
          getMetric(fontinfo, glist[i], &tgi);
          width = tgi.width;
          height = tgi.height;

          py += maxheight + gap;
          px = gap;
          maxheight = height;
          if (py + height + gap >= texh) {
            printf("Overflowed texture space, letter %d of %d.\n", i, len);
            exit(1);
          }
          c = i;
        }

        /* Place the glyph in the texture image. */
        placeGlyph(fontinfo, glist[c], texarea, texw, px, py);

        /* Assign glyph's texture coordinate. */
        tgi.x = px;
        tgi.y = py;

	/* Advance by glyph width, remaining in the current line. */
        px += width + gap;
      } else {
	/* No texture image; assign invalid bogus texture coordinates. */
        tgi.x = -1;
        tgi.y = -1;
      }
      glist[c] = 0;     /* Mark processed; don't process again. */
      assert(sizeof(tgi) == 12);  /* Ensure external file format size. */
      fwrite(&tgi, sizeof(tgi), 1, file);
    }
  }

  switch (format) {
  case TXF_FORMAT_BYTE:
    fwrite(texarea, texw * texh, 1, file);
    break;
  case TXF_FORMAT_BITMAP:
    stride = (texw + 7) >> 3;
    texbitmap = (unsigned char *) calloc(stride * texh, 1);
    for (i = 0; i < texh; i++) {
      for (j = 0; j < texw; j++) {
        if (texarea[i * texw + j] >= 128) {
          texbitmap[i * stride + (j >> 3)] |= 1 << (j & 7);
        }
      }
    }
    fwrite(texbitmap, stride * texh, 1, file);
    free(texbitmap);
    break;
  default:
    printf("Unknown texture font format.\n");
    exit(1);
  }
  free(texarea);
  fclose(file);
  return 0;
}