xref: /plan9/sys/src/cmd/gs/src/write_t2.c (revision 593dc095aefb2a85c828727bbfa9da139a49bdf4)

/* Copyright (C) 1989, 2000 Aladdin Enterprises.  All rights reserved.

  This software is provided AS-IS with no warranty, either express or
  implied.

  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.

  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: write_t2.c,v 1.7 2004/12/08 21:35:13 stefan Exp $ */

/*
Functions to serialize a type 1 font so that it can then be
passed to FreeType via the FAPI FreeType bridge.
Started by Graham Asher, 9th August 2002.
*/

#include "wrfont.h"
#include "write_t2.h"
#include "ghost.h"
#include "gxfont.h"
#include "gxfont1.h"

#include <assert.h>

/*
Public structures and functions in this file are prefixed with FF_ because they are part of
the FAPI FreeType implementation.
*/

static void write_4_byte_int(unsigned char* a_output,long a_int)
	{
	a_output[0] = (unsigned char)(a_int >> 24);
	a_output[1] = (unsigned char)(a_int >> 16);
	a_output[2] = (unsigned char)(a_int >> 8);
	a_output[3] = (unsigned char)(a_int & 0xFF);
	}

static void write_type2_int(WRF_output* a_output,long a_int)
	{
	if (a_int >= -107 && a_int <= 107)
		WRF_wbyte(a_output,(unsigned char)(a_int + 139));
	else if (a_int >= -32768 && a_int <= 32767)
		{
		if (a_int >= 108 && a_int <= 1131)
			a_int += 63124;
		else if (a_int >= -1131 && a_int <= -108)
			a_int = -a_int + 64148;
		else
			WRF_wbyte(a_output,28);
		WRF_wbyte(a_output,(unsigned char)(a_int >> 8));
		WRF_wbyte(a_output,(unsigned char)(a_int & 0xFF));
		}
	else
		{
		unsigned char buffer[4];
		WRF_wbyte(a_output,29);
		write_4_byte_int(buffer,a_int);
		WRF_wtext(a_output,buffer,4);
		}
	}

static void write_type2_float(WRF_output* a_output,double a_float)
	{
	char buffer[32];
	const char* p = buffer;
	int high = true;
	char c = 0;
	sprintf(buffer,"%f",a_float);
	WRF_wbyte(a_output,30);
	for (;;)
		{
		char n = 0;
		if (*p >= '0' && *p <= '9')
			n = (char)(*p - '0');
		else if (*p == '.')
			n = 0xA;
		else if (*p == 'e' || *p == 'E')
			{
			if (p[1] == '-')
				{
				p++;
				n = 0xC;
				}
			else
				n = 0xB;
			}
		else if (*p == '-')
			n = 0xE;
		else if (*p == 0)
			n = 0xF;
		if (high)
			{
			if (*p == 0)
				WRF_wbyte(a_output,0xFF);
			else
				c = (char)(n << 4);
			}
		else
			{
			c |= n;
			WRF_wbyte(a_output,c);
			}

		if (*p == 0)
			break;

		high = !high;
		p++;
		}
	}

static void write_header(WRF_output* a_output)
	{
	WRF_wtext(a_output,(const unsigned char*)"\x1\x0\x4\x1",4);
	}

static void write_name_index(WRF_output* a_output)
	{
	/* Write a dummy name of 'x'. */
	WRF_wtext(a_output,(const unsigned char*)"\x0\x1\x1\x1\x2""x",6);
	}

static void write_word_entry(FAPI_font* a_fapi_font,WRF_output* a_output,int a_feature_id,
							 int a_feature_count,bool a_two_byte_op,int a_op,int a_divisor)
	{
	if (a_feature_count > 0)
		{
		int i;
		for (i = 0; i < a_feature_count; i++)
			{
			/* Get the value and convert it from unsigned to signed. */
			short x = a_fapi_font->get_word(a_fapi_font,a_feature_id,i);
			/* Divide by the divisor to bring it back to font units. */
			x = (short)(x / a_divisor);
			write_type2_int(a_output,x);
			}
		if (a_two_byte_op)
			WRF_wbyte(a_output,12);
		WRF_wbyte(a_output,(unsigned char)a_op);
		}
	}

static void write_delta_array_entry(FAPI_font* a_fapi_font,WRF_output* a_output,int a_feature_id,
									bool a_two_byte_op,int a_op,int a_divisor)
	{
	int i;
	/* NOTE that the feature index (a_feature_id) must be preceded by the count index for this to work. */
	int count = a_fapi_font->get_word(a_fapi_font,a_feature_id - 1,0);
	if (count > 0)
		{
		short prev_value = 0;
		for (i = 0; i < count; i++)
			{
			/* Get the value and convert it from unsigned to signed. */
			short value = a_fapi_font->get_word(a_fapi_font,a_feature_id,i);
			/* Divide by the divisor to bring it back to font units. */
			value = (short)(value / a_divisor);
			write_type2_int(a_output,value - prev_value);
			prev_value = value;
			}
		if (a_two_byte_op)
			WRF_wbyte(a_output,12);
		WRF_wbyte(a_output,(unsigned char)a_op);
		}
	}

static void write_float_entry(FAPI_font* a_fapi_font,WRF_output* a_output,int a_feature_id,int a_feature_count,bool a_two_byte_op,int a_op)
	{
	if (a_feature_count > 0)
		{
		int i;
		for (i = 0; i < a_feature_count; i++)
			{
			double x = a_fapi_font->get_float(a_fapi_font,a_feature_id,i);
			write_type2_float(a_output,x);
			}
		if (a_two_byte_op)
			WRF_wbyte(a_output,12);
		WRF_wbyte(a_output,(unsigned char)a_op);
		}
	}

static void write_font_dict_index(FAPI_font* a_fapi_font,WRF_output* a_output,
		unsigned char** a_charset_offset_ptr,
		unsigned char** a_charstrings_offset_ptr,
		unsigned char** a_private_dict_length_ptr)
	{
	unsigned char* data_start = 0;
	WRF_wtext(a_output,(const unsigned char *)"\x0\x1\x2\x0\x1\x0\x0",7); /* count = 1, offset size = 2, first offset = 1, last offset = 0 (to be filled in later). */
	if (a_output->m_pos)
		data_start = a_output->m_pos;
	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_FontBBox,4,false,5,1);
	write_float_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_FontMatrix,6,true,7);
	write_type2_int(a_output,0); /* 0 = Standard Encoding. */
	WRF_wbyte(a_output,16); /* 16 = opcode for 'encoding'. */
	*a_charset_offset_ptr = a_output->m_pos;
	WRF_wtext(a_output,(const unsigned char *)"\x1d""xxxx",5); /* placeholder for the offset to the charset, which will be a 5-byte integer. */
	WRF_wbyte(a_output,15); /* opcode for 'charset' */
	*a_charstrings_offset_ptr = a_output->m_pos;
	WRF_wtext(a_output,(const unsigned char *)"\x1d""xxxx",5); /* placeholder for the offset to the Charstrings index, which will be a 5-byte integer. */
	WRF_wbyte(a_output,17); /* opcode for 'Charstrings' */
	*a_private_dict_length_ptr = a_output->m_pos;
	WRF_wtext(a_output,(const unsigned char *)"\x1d""xxxx\x1d""yyyy",10); /* placeholder for size and offset of Private dictionary, which will be 5-byte integers. */
	WRF_wbyte(a_output,18); /* opcode for 'Private' */
	if (a_output->m_pos)
		{
		int last_offset = a_output->m_pos - data_start + 1;
		data_start[-2] = (unsigned char)(last_offset >> 8);
		data_start[-1] = (unsigned char)(last_offset & 0xFF);
		}
	}

/**
Write the character set. Return the number of characters.
For the moment this is always 1. The number cannot be obtained
via the FAPI interface, and FreeType doesn't need to know anything more
than the fact that there is at least one character.
*/
static int write_charset(WRF_output* a_output,unsigned char* a_charset_offset_ptr)
	{
	const int characters = 1;
	int i = 0;

	/* Write the offset to the start of the charset to the top dictionary. */
	if (a_output->m_pos)
		write_4_byte_int(a_charset_offset_ptr + 1,a_output->m_count);

	/*
	Write the charset. Write one less than the number of characters,
	because the first one is assumed to be .notdef. For the moment
	write all the others as .notdef (SID = 0) because we don't actually
	need the charset at the moment.
	*/
	WRF_wbyte(a_output,0); /* format = 0 */
	for (i = 1; i < characters; i++)
		{
		WRF_wbyte(a_output,0);
		WRF_wbyte(a_output,0);
		}

	return characters;
	}

/**
Write a set of empty charstrings. The only reason for the existence of the charstrings index is to tell
FreeType how many glyphs there are.
*/
static void write_charstrings_index(WRF_output* a_output,int a_characters,unsigned char* a_charstrings_offset_ptr)
	{
	/* Write the offset to the charstrings index to the top dictionary. */
	if (a_output->m_pos)
		write_4_byte_int(a_charstrings_offset_ptr + 1,a_output->m_count);

	/* Write the index. */
	WRF_wbyte(a_output,(unsigned char)(a_characters >> 8));
	WRF_wbyte(a_output,(unsigned char)(a_characters & 0xFF));
	WRF_wbyte(a_output,1); /* offset size = 1. */
	while (a_characters-- >= 0)
		WRF_wbyte(a_output,1); /* offset = 1 */
	}

static void write_subrs_index(FAPI_font* a_fapi_font,WRF_output* a_output)
	{
	unsigned char* cur_offset = 0;
	unsigned char* data_start = 0;
	int i;
	int count = a_fapi_font->get_word(a_fapi_font,FAPI_FONT_FEATURE_Subrs_count,0);
	assert(count >= 0);

	WRF_wbyte(a_output,(unsigned char)(count >> 8));
	WRF_wbyte(a_output,(unsigned char)(count & 0xFF));

	if (count == 0)
		return;

	WRF_wbyte(a_output,4); /* offset size = 4 bytes */
	WRF_wtext(a_output,(const unsigned char *)"\x0\x0\x0\x1",4); /* first offset = 1 */

	if (a_output->m_pos)
		cur_offset = a_output->m_pos;

	/* Write dummy bytes for the offsets at the end of each data item. */
	for (i = 0; i < count; i++)
		WRF_wtext(a_output,(const unsigned char *)"xxxx",4);

	if (a_output->m_pos)
		data_start = a_output->m_pos;

	for (i = 0; i < count; i++)
		{
		long buffer_size = a_output->m_limit - a_output->m_count;
		long length = a_fapi_font->get_subr(a_fapi_font,i,a_output->m_pos,(ushort)buffer_size);
		if (a_output->m_pos)
			WRF_wtext(a_output,a_output->m_pos,length);
		else
			a_output->m_count += length;
		if (cur_offset)
			{
			long pos = a_output->m_pos - data_start + 1;
			write_4_byte_int(cur_offset,pos);
			cur_offset += 4;
			}
		}
	}

static void write_private_dict(FAPI_font* a_fapi_font,WRF_output* a_output,unsigned char* a_private_dict_length_ptr)
	{
	/* Write the offset to the start of the private dictionary to the top dictionary. */
	unsigned char* start = a_output->m_pos;
	if (a_output->m_pos)
		write_4_byte_int(a_private_dict_length_ptr + 6,a_output->m_count);

	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_BlueFuzz,1,true,11,16);

	write_type2_float(a_output,a_fapi_font->get_long(a_fapi_font,FAPI_FONT_FEATURE_BlueScale,0) / 65536.0);
	WRF_wbyte(a_output,12);
	WRF_wbyte(a_output,9);

	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_BlueShift,1,true,10,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_BlueValues,false,6,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_OtherBlues,false,7,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_FamilyBlues,false,8,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_FamilyOtherBlues,false,9,16);
	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_ForceBold,1,true,14,1);
	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_StdHW,1,false,10,16);
	write_word_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_StdVW,1,false,11,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_StemSnapH,true,12,16);
	write_delta_array_entry(a_fapi_font,a_output,FAPI_FONT_FEATURE_StemSnapV,true,13,16);

	/*
	Write the default width and the nominal width. These values are not available via
	the FAPI interface so we have to get a pointer to the Type 1 font structure and
	extract them directly.
	*/
	{
	gs_font_type1* t1 = (gs_font_type1*)a_fapi_font->client_font_data;
    write_type2_float(a_output,fixed2float(t1->data.defaultWidthX));
	WRF_wbyte(a_output,20);
    write_type2_float(a_output,fixed2float(t1->data.nominalWidthX));
	WRF_wbyte(a_output,21);
	}

	/* Write the length in bytes of the private dictionary to the top dictionary. */
	if (a_output->m_pos)
		write_4_byte_int(a_private_dict_length_ptr + 1,a_output->m_pos - start);
	}

/**
Write a Type 2 font in binary format and return its length in bytes.
If a_buffer_size is less than the total length, only a_buffer_size bytes are written, but the total
length is returned correctly.
*/
long FF_serialize_type2_font(FAPI_font* a_fapi_font,unsigned char* a_buffer,long a_buffer_size)
	{
	unsigned char* charset_offset_ptr = NULL;
	unsigned char* charstrings_offset_ptr = NULL;
	unsigned char* private_dict_length_ptr = NULL;
	int characters = 0;

	WRF_output output;
	WRF_init(&output,a_buffer,a_buffer_size);

	write_header(&output);
	write_name_index(&output);
	write_font_dict_index(a_fapi_font,&output,&charset_offset_ptr,&charstrings_offset_ptr,&private_dict_length_ptr);

  	/* Write an empty string index. */
  	WRF_wtext(&output,(const unsigned char *)"\x0\x0",2);

	write_subrs_index(a_fapi_font,&output);
	characters = write_charset(&output,charset_offset_ptr);
	write_charstrings_index(&output,characters,charstrings_offset_ptr);
	write_private_dict(a_fapi_font,&output,private_dict_length_ptr);

	return output.m_count;
	}