/* Pango
 * pangoft2topgm.c: Example program to view a UTF-8 encoding file
 *                  using Pango to render result.
 *
 * Copyright (C) 1999 Red Hat Software
 * Copyright (C) 2001 Sun Microsystems
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#define BUFSIZE 1024
#define MALLOCSIZE 1024
#define DEFAULT_FONT_FAMILY "Sans"
#define DEFAULT_FONT_SIZE 18

#include <errno.h>
#include <math.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "argcontext.h"

#include <pango/pango.h>
#include <pango/pangoft2.h>

#define _MAKE_FONT_NAME(family, size) family " " #size
#define MAKE_FONT_NAME(family, size) _MAKE_FONT_NAME(family, size)

static char *prog_name;
static PangoContext *context;

static char *tmpfile_name;
static char *outfile_name;

static gboolean opt_display = FALSE;
static int opt_dpi = 96;
static char *opt_font = MAKE_FONT_NAME (DEFAULT_FONT_FAMILY, DEFAULT_FONT_SIZE);
static gboolean opt_header = FALSE;
static char *opt_output = NULL;
static int opt_margin = 10;
static int opt_markup = FALSE;
static gboolean opt_rtl = FALSE;
static int opt_rotate = 0;
static gboolean opt_auto_dir = TRUE;
static char *opt_text = NULL;
static  gboolean opt_waterfall = FALSE;
static  int opt_width = -1;
static  int opt_indent = 0;

static void fail (const char *format, ...)  G_GNUC_PRINTF (1, 2);

static void
fail (const char *format, ...)
{
  const char *msg;
  
  va_list vap;
  va_start (vap, format);
  msg = g_strdup_vprintf (format, vap);
  g_printerr ("%s: %s\n", prog_name, msg);

  if (outfile_name && !opt_output)
    remove (outfile_name);
  
  exit (1);
}

PangoFontDescription *
get_font_description (void)
{
  PangoFontDescription *font_description = pango_font_description_from_string (opt_font);
  
  if ((pango_font_description_get_set_fields (font_description) & PANGO_FONT_MASK_FAMILY) == 0)
    pango_font_description_set_family (font_description, DEFAULT_FONT_FAMILY);

  if ((pango_font_description_get_set_fields (font_description) & PANGO_FONT_MASK_SIZE) == 0)
    pango_font_description_set_size (font_description, DEFAULT_FONT_SIZE * PANGO_SCALE);

  return font_description;
}

static PangoLayout *
make_layout(PangoContext *context,
	    const char   *text,
	    double        size)
{
  static PangoFontDescription *font_description;
  PangoDirection base_dir;
  PangoLayout *layout;

  layout = pango_layout_new (context);
  if (opt_markup)
    pango_layout_set_markup (layout, text, -1);
  else
    pango_layout_set_text (layout, text, -1);

  pango_layout_set_auto_dir (layout, opt_auto_dir);
  
  font_description = get_font_description ();
  if (size > 0)
    pango_font_description_set_size (font_description, size * PANGO_SCALE);
    
  if (opt_width > 0)
    pango_layout_set_width (layout, (opt_width * opt_dpi * PANGO_SCALE + 32) / 72);

  if (opt_indent != 0)
    pango_layout_set_indent (layout, (opt_indent * opt_dpi * PANGO_SCALE + 32) / 72);

  base_dir = pango_context_get_base_dir (context);
  pango_layout_set_alignment (layout,
			      base_dir == PANGO_DIRECTION_LTR ? PANGO_ALIGN_LEFT : PANGO_ALIGN_RIGHT);
  
  pango_layout_set_font_description (layout, font_description);

  pango_font_description_free (font_description);

  return layout;
}

static gchar *
get_options_string (void)
{
  PangoFontDescription *font_description = get_font_description ();
  gchar *font_name;
  gchar *result;

  if (opt_waterfall)
    pango_font_description_unset_fields (font_description, PANGO_FONT_MASK_SIZE);

  font_name = pango_font_description_to_string (font_description);
  result = g_strdup_printf ("%s: dpi=%d", font_name, opt_dpi);
  pango_font_description_free (font_description);
  g_free (font_name);

  return result;
}

static void
transform_point (PangoMatrix *matrix,
		 double       x_in,
		 double       y_in,
		 double      *x_out,
		 double      *y_out)
{
  *x_out = x_in * matrix->xx + y_in * matrix->xy + matrix->x0;
  *y_out = x_in * matrix->yx + y_in * matrix->yy + matrix->y0;
}

static void
output_body (PangoContext *context,
	     const char   *text,
	     FT_Bitmap    *bitmap,
	     PangoMatrix  *matrix,
	     int          *width,
	     int          *height)
{
  PangoLayout *layout;
  PangoRectangle logical_rect;
  int size, start_size, end_size, increment;
  int dy;
  
  if (opt_waterfall)
    {
      start_size = 8;
      end_size = 48;
      increment = 4;
    }
  else
    {
      start_size = end_size = -1;
      increment = 1;
    }

  *width = 0;
  *height = 0;
  dy = 0;
  
  for (size = start_size; size <= end_size; size += increment)
    {
      pango_context_set_matrix (context, matrix);
      
      layout = make_layout (context, text, size);
      pango_layout_get_extents (layout, NULL, &logical_rect);
      
      *width = MAX (*width, PANGO_PIXELS (logical_rect.width));
      *height += PANGO_PIXELS (logical_rect.height);

      if (bitmap)
	pango_ft2_render_layout (bitmap, layout, 0, dy);
      
      dy += PANGO_PIXELS (logical_rect.height);

      g_object_unref (layout);
    }
}

static void
do_output (PangoContext *context,
	   const char   *text,
	   FT_Bitmap    *bitmap,
	   int          *width,
	   int          *height)
{
  PangoLayout *layout;
  PangoRectangle logical_rect;
  PangoMatrix matrix = PANGO_MATRIX_INIT;
  int rotated_width, rotated_height;
  int x = opt_margin;
  int y = opt_margin;
  double p1x, p1y;
  double p2x, p2y;
  double p3x, p3y;
  double p4x, p4y;
  double minx, miny;
  double maxx, maxy;
  
  *width = 0;
  *height = 0;

  if (opt_header)
    {
      char *options_string = get_options_string ();
      layout = make_layout (context, options_string, 10);
      pango_layout_get_extents (layout, NULL, &logical_rect);
      
      *width = MAX (*width, PANGO_PIXELS (logical_rect.width));
      *height += PANGO_PIXELS (logical_rect.height);
      
      if (bitmap)
	pango_ft2_render_layout (bitmap, layout, x, y);
      
      y += PANGO_PIXELS (logical_rect.height);
      
      g_object_unref (layout);
      g_free (options_string);
    }

  output_body (context, text, NULL, NULL, &rotated_width, &rotated_height);

  pango_matrix_rotate (&matrix, opt_rotate);
  
  transform_point (&matrix, 0,             0,              &p1x, &p1y);
  transform_point (&matrix, rotated_width, 0,              &p2x, &p2y);
  transform_point (&matrix, rotated_width, rotated_height, &p3x, &p3y);
  transform_point (&matrix, 0,             rotated_height, &p4x, &p4y);

  minx = MIN (MIN (p1x, p2x), MIN (p3x, p4x));
  miny = MIN (MIN (p1y, p2y), MIN (p3y, p4y));

  maxx = MAX (MAX (p1x, p2x), MAX (p3x, p4x));
  maxy = MAX (MAX (p1y, p2y), MAX (p3y, p4y));

  matrix.x0 = x - minx;
  matrix.y0 = y - miny;

  if (bitmap)
    output_body (context, text, bitmap, &matrix, &rotated_width, &rotated_height);

  *width = MAX (*width, maxx - minx);
  *height += maxy - miny;

  *width += 2 * opt_margin;
  *height += 2 * opt_margin;
}

static void
show_help (ArgContext *context,
	   const char *name,
	   const char *arg,
	   gpointer    data)
{
  g_print ("%s - An example viewer for the pango ft2 extension\n"
	   "\n"
	   "Syntax:\n"
	   "    %s [options] FILE\n"
	   "\n"
	   "Options:\n",
	   prog_name, prog_name);
  arg_context_print_help (context);
  exit (0);
}

int main(int argc, char *argv[])
{
  FILE *outfile;
  char *text;
  size_t len;
  char *p;
  PangoFontMap *fontmap;
  GError *error = NULL;
  ArgContext *arg_context;
  gboolean do_convert = FALSE;
  
  static const ArgDesc args[] = {
    { "no-auto-dir","Don't set layout direction according to contents",
      ARG_NOBOOL,   &opt_auto_dir },
    { "display",    "Show output using ImageMagick",
      ARG_BOOL,     &opt_display },
    { "dpi",        "Set the dpi'",
      ARG_INT,      &opt_dpi },
    { "font",       "Set the font name",
      ARG_STRING,   &opt_font },
    { "header",     "Display the options in the output",
      ARG_BOOL,     &opt_header },
    { "help",       "Show this output",
      ARG_CALLBACK, NULL, show_help, },
    { "margin",     "Set the margin on the output in pixels",
      ARG_INT,      &opt_margin },
    { "markup",     "Interpret contents as Pango markup",
      ARG_BOOL,     &opt_markup },
    { "output",     "Name of output file",
      ARG_STRING,   &opt_output },
    { "rtl",        "Set base dir to RTL",
      ARG_BOOL,     &opt_rtl },
    { "rotate",     "Angle at which to rotate results",
      ARG_INT,      &opt_rotate },
    { "text",       "Text to display (instead of a file)",
      ARG_STRING,   &opt_text },
    { "waterfall",  "Create a waterfall display",
      ARG_BOOL,     &opt_waterfall },
    { "width",      "Width in points to which to wrap output",
      ARG_INT,      &opt_width },
    { "indent",     "Width in points to indent paragraphs",
      ARG_INT,      &opt_indent },
    { NULL }
  };

  prog_name = g_path_get_basename (argv[0]);
  
  g_type_init();

  if (g_file_test ("./pangorc", G_FILE_TEST_EXISTS))
    putenv ("PANGO_RC_FILE=./pangorc");
  
  arg_context = arg_context_new (NULL);
  arg_context_add_table (arg_context, args);

  if (!arg_context_parse (arg_context, &argc, &argv, &error))
    fail ("%s", error->message);
  
  if ((opt_text && argc != 1) ||
      (!opt_text && argc != 2))
    {
      if (opt_text && argc == 2)
	fail ("When specifying --text, no file should be given");
	
      g_printerr ("Usage: %s [options] FILE\n", prog_name);
      exit (1);
    }

  if (!opt_display && !opt_output)
    {
      g_printerr ("%s: --output not specified, assuming --display\n", prog_name);
      opt_display = TRUE;
    }

  /* Get the text
   */
  if (opt_text)
    {
      text = g_strdup (opt_text);
      len = strlen (text);
    }
  else
    {
      if (!g_file_get_contents (argv[1], &text, &len, &error))
	fail ("%s\n", error->message);
      if (!g_utf8_validate (text, len, NULL))
	fail ("Text is not valid UTF-8");
    }
  
  /* Strip trailing whitespace
   */
  p = text + len;
  while (p > text)
    {
      gunichar ch;
      p = g_utf8_prev_char (p);
      ch = g_utf8_get_char (p);
      if (!g_unichar_isspace (ch))
	break;
      else
	*p = '\0';
    }

  /* Make sure we have valid markup
   */
  if (opt_markup &&
      !pango_parse_markup (text, -1, 0, NULL, NULL, NULL, &error))
    fail ("Cannot parse input as markup: %s", error->message);

  if (opt_output)
    {
      if (!(g_str_has_suffix (opt_output, ".pgm") ||
	    g_str_has_suffix (opt_output, ".PGM")))
	do_convert = TRUE;
    }

  if (opt_output && !do_convert)
    {
      outfile = fopen (opt_output, "wb");

      if (!outfile)
	fail ("Cannot open output file %s: %s\n",
	      opt_output, g_strerror (errno));
    }
  else				/* --display */
    {
      /* This may need to be G_OS_UNIX guarded for fdopen */
      int fd = g_file_open_tmp ("pangoft2pgmXXXXXX", &tmpfile_name, &error);
      if (fd == 1)
	fail ("Cannot open temporary file: %s\n", error->message);
      outfile = fdopen (fd, "wb");
      if (!outfile)
	fail ("Cannot open temporary file: %s\n", g_strerror (errno));
    }

  fontmap = pango_ft2_font_map_new ();
  pango_ft2_font_map_set_resolution (PANGO_FT2_FONT_MAP (fontmap), opt_dpi, opt_dpi);
  context = pango_ft2_font_map_create_context (PANGO_FT2_FONT_MAP (fontmap));

  pango_context_set_language (context, pango_language_from_string ("en_US"));
  pango_context_set_base_dir (context,
			      opt_rtl ? PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR);

  /* Write contents as pgm file */
  {
      FT_Bitmap bitmap;
      guchar *buf;
      int row;
      int width, height;

      do_output (context, text, NULL, &width, &height);
      
      bitmap.width = width;
      bitmap.pitch = (bitmap.width + 3) & ~3;
      bitmap.rows = height;
      buf = bitmap.buffer = g_malloc (bitmap.pitch * bitmap.rows);
      bitmap.num_grays = 256;
      bitmap.pixel_mode = ft_pixel_mode_grays;
      memset (buf, 0x00, bitmap.pitch * bitmap.rows);

      do_output (context, text, &bitmap, &width, &height);

      /* Invert bitmap to get black text on white background */
      {
	int pix_idx;
	for (pix_idx=0; pix_idx<bitmap.pitch * bitmap.rows; pix_idx++)
	  {
	    buf[pix_idx] = 255-buf[pix_idx];
	  }
      }
      
      /* Write it as pgm to output */
      fprintf(outfile,
	      "P5\n"
	      "%d %d\n"
	      "255\n", bitmap.width, bitmap.rows);
      for (row = 0; row < bitmap.rows; row++)
	fwrite(bitmap.buffer + row * bitmap.pitch,
	       1, bitmap.width,
	       outfile);
      g_free (buf);
      if (fclose(outfile) == EOF)
	fail ("Error writing output file: %s\n", g_strerror (errno));

      /* Convert to a different format, if necessary */
      if (do_convert)
	{
	  int exit_status;
	  
	  gchar *command = g_strdup_printf ("convert %s %s",
					    tmpfile_name,
					    opt_output);
	  if (!g_spawn_command_line_sync (command, NULL, NULL, &exit_status, &error))
	    fail ("When running ImageMagick 'convert' command: %s\n",
		  error->message);

	  if (tmpfile_name)
	    {
	      remove (tmpfile_name);
	      tmpfile_name = NULL;
	    }
	  
	  if (exit_status)
	    exit (1);
	}

      if (opt_display)
	{
	  int exit_status;
	  gchar *title = get_options_string ();
	  gchar *title_quoted = g_shell_quote (title);
	  
	  gchar *command = g_strdup_printf ("display -title %s %s",
					    title_quoted,
					    opt_output ? opt_output: tmpfile_name);
	  if (!g_spawn_command_line_sync (command, NULL, NULL, &exit_status, &error))
	    fail ("When running ImageMagick 'display' command: %s\n",
		  error->message);

	  g_free (command);
	  g_free (title);
	  g_free (title_quoted);
	  
	  if (tmpfile_name)
	    remove (tmpfile_name);
	  
	  if (exit_status)
	    exit (1);
	}
    }

  return 0;
}