netsurf/framebuffer/font_internal.c

/*
 * Copyright 2005 James Bursa <bursa@users.sourceforge.net>
 *           2008 Vincent Sanders <vince@simtec.co.uk>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <inttypes.h>
#include <string.h>
#include <assert.h>

#include "utils/nsoption.h"
#include "utils/utf8.h"
#include "desktop/gui.h"
#include "css/css.h"
#include "render/font.h"

#include "framebuffer/gui.h"
#include "framebuffer/font.h"

#include "framebuffer/GEN_font_internal.c"


#define GLYPH_LEN		16

uint8_t code_point[GLYPH_LEN];

#define SEVEN_SET	((1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | 	\
			 (1 << 4) | (1 << 5) | (1 << 6))

#define THREE_SSS	 ((1 << 0) | (1 << 1) | (1 << 2))
#define THREE_SS	 (           (1 << 1) | (1 << 2))
#define THREE_S_S	 ((1 << 0) |            (1 << 2))
#define THREE__SS	 ((1 << 0) | (1 << 1)           )
#define THREE_SS_	 (           (1 << 1) | (1 << 2))
#define THREE_S__	                        (1 << 2)
#define THREE__S_	             (1 << 1)
#define THREE___S	  (1 << 0)

uint8_t frag[16][5] = {
	{ THREE_SSS,
	  THREE_S_S,
	  THREE_S_S,
	  THREE_S_S,
	  THREE_SSS },

	{ THREE__S_,
	  THREE_SS_,
	  THREE__S_,
	  THREE__S_,
	  THREE_SSS },

	{ THREE_SS_,
	  THREE___S,
	  THREE__S_,
	  THREE_S__,
	  THREE_SSS },

	{ THREE_SS_,
	  THREE___S,
	  THREE_SS_,
	  THREE___S,
	  THREE_SS_ },

	{ THREE_S_S,
	  THREE_S_S,
	  THREE_SSS,
	  THREE___S,
	  THREE___S },

	{ THREE_SSS,
	  THREE_S__,
	  THREE_SSS,
	  THREE___S,
	  THREE_SSS },

	{ THREE__SS,
	  THREE_S__,
	  THREE_SSS,
	  THREE_S_S,
	  THREE_SSS },

	{ THREE_SSS,
	  THREE___S,
	  THREE__S_,
	  THREE__S_,
	  THREE__S_ },

	{ THREE_SSS,
	  THREE_S_S,
	  THREE_SSS,
	  THREE_S_S,
	  THREE_SSS },

	{ THREE_SSS,
	  THREE_S_S,
	  THREE_SSS,
	  THREE___S,
	  THREE___S },

	{ THREE__S_,
	  THREE_S_S,
	  THREE_SSS,
	  THREE_S_S,
	  THREE_S_S },

	{ THREE_SS_,
	  THREE_S_S,
	  THREE_SS_,
	  THREE_S_S,
	  THREE_SS_ },

	{ THREE__S_,
	  THREE_S_S,
	  THREE_S__,
	  THREE_S_S,
	  THREE__S_ },

	{ THREE_SS_,
	  THREE_S_S,
	  THREE_S_S,
	  THREE_S_S,
	  THREE_SS_ },

	{ THREE_SSS,
	  THREE_S__,
	  THREE_SS_,
	  THREE_S__,
	  THREE_SSS },

	{ THREE_SSS,
	  THREE_S__,
	  THREE_SS_,
	  THREE_S__,
	  THREE_S__ }
};

static uint8_t * get_codepoint(uint32_t id, bool italic)
{
	int shift = 0;
	int l;
	int r;

	if (!italic)
		shift = 1;

	l =       (id >> 12);
	r = 0xf & (id >>  8);

	code_point[ 0] = SEVEN_SET << shift;

	code_point[ 2] = (frag[l][0] << (4 + shift)) | (frag[r][0] << shift);
	code_point[ 3] = (frag[l][1] << (4 + shift)) | (frag[r][1] << shift);
	code_point[ 4] = (frag[l][2] << (4 + shift)) | (frag[r][2] << shift);
	code_point[ 5] = (frag[l][3] << (4 + shift)) | (frag[r][3] << shift);
	code_point[ 6] = (frag[l][4] << (4 + shift)) | (frag[r][4] << shift);

	shift = 1;

	l = 0xf & (id >>  4);
	r = 0xf & id;

	code_point[ 8] = (frag[l][0] << (4 + shift)) | (frag[r][0] << shift);
	code_point[ 9] = (frag[l][1] << (4 + shift)) | (frag[r][1] << shift);
	code_point[10] = (frag[l][2] << (4 + shift)) | (frag[r][2] << shift);
	code_point[11] = (frag[l][3] << (4 + shift)) | (frag[r][3] << shift);
	code_point[12] = (frag[l][4] << (4 + shift)) | (frag[r][4] << shift);

	code_point[14] = SEVEN_SET << shift;

	return (uint8_t *)code_point;
}


bool fb_font_init(void)
{
	return true;
}

bool fb_font_finalise(void)
{
	return true;
}

enum fb_font_style
fb_get_font_style(const plot_font_style_t *fstyle)
{
	if (fstyle->weight >= 700) {
		if ((fstyle->flags & FONTF_ITALIC) ||
				(fstyle->flags & FONTF_OBLIQUE)) {
			return FB_BOLD_ITALIC;
		} else {
			return FB_BOLD;
		}
	} else {
		if ((fstyle->flags & FONTF_ITALIC) ||
				(fstyle->flags & FONTF_OBLIQUE)) {
			return FB_ITALIC;
		} else {
			return FB_REGULAR;
		}
	}
}

const uint8_t *
fb_get_glyph(uint32_t ucs4, enum fb_font_style style)
{
	unsigned int section;
	unsigned int offset;
	uint16_t g_offset;

	switch (style) {
	case FB_BOLD_ITALIC:
		section = fb_bold_italic_section_table[ucs4 / 256];
		if (section != 0 || ucs4 / 256 == 0) {
			offset = section * 256 + (ucs4 & 0xff);
			g_offset = fb_bold_italic_sections[offset] * 16;
			if (g_offset != 0) {
				return &font_glyph_data[g_offset];
			}
		}
	case FB_BOLD:
		section = fb_bold_section_table[ucs4 / 256];
		if (section != 0 || ucs4 / 256 == 0) {
			offset = section * 256 + (ucs4 & 0xff);
			g_offset = fb_bold_sections[offset] * 16;
			if (g_offset != 0) {
				return &font_glyph_data[g_offset];
			}
		}
	case FB_ITALIC:
		section = fb_italic_section_table[ucs4 / 256];
		if (section != 0 || ucs4 / 256 == 0) {
			offset = section * 256 + (ucs4 & 0xff);
			g_offset = fb_italic_sections[offset] * 16;
			if (g_offset != 0) {
				return &font_glyph_data[g_offset];
			}
		}
	case FB_REGULAR:
		section = fb_regular_section_table[ucs4 / 256];
		if (section != 0 || ucs4 / 256 == 0) {
			offset = section * 256 + (ucs4 & 0xff);
			g_offset = fb_regular_sections[offset] * 16;
			if (g_offset != 0) {
				return &font_glyph_data[g_offset];
			}
		}
	}

	return get_codepoint(ucs4, style & FB_ITALIC);
}

static nserror utf8_to_local(const char *string,
				       size_t len,
				       char **result)
{
	return utf8_to_enc(string, "CP1252", len, result);

}

static nserror utf8_from_local(const char *string,
					size_t len,
					char **result)
{
	*result = malloc(len + 1);
	if (*result == NULL) {
		return NSERROR_NOMEM;
	}

	memcpy(*result, string, len);

	(*result)[len] = '\0';

	return NSERROR_OK;
}

static bool nsfont_width(const plot_font_style_t *fstyle,
                         const char *string, size_t length,
                         int *width)
{
        *width = FB_FONT_WIDTH * utf8_bounded_length(string, length);
	return true;
}

/**
 * Find the position in a string where an x coordinate falls.
 *
 * \param  fstyle       style for this text
 * \param  string       UTF-8 string to measure
 * \param  length       length of string
 * \param  x            x coordinate to search for
 * \param  char_offset  updated to offset in string of actual_x, [0..length]
 * \param  actual_x     updated to x coordinate of character closest to x
 * \return  true on success, false on error and error reported
 */

static bool nsfont_position_in_string(const plot_font_style_t *fstyle,
		const char *string, size_t length,
		int x, size_t *char_offset, int *actual_x)
{
        size_t nxtchr = 0;
	int x_pos = 0;

        while (nxtchr < length) {
                if (abs(x_pos - x) <= (FB_FONT_WIDTH / 2))
                        break;

                x_pos += FB_FONT_WIDTH;
                nxtchr = utf8_next(string, length, nxtchr);
        }

        *actual_x = x_pos;

        *char_offset = nxtchr;
	return true;
}



/**
 * Find where to split a string to make it fit a width.
 *
 * \param  fstyle       style for this text
 * \param  string       UTF-8 string to measure
 * \param  length       length of string, in bytes
 * \param  x            width available
 * \param  char_offset  updated to offset in string of actual_x, [1..length]
 * \param  actual_x     updated to x coordinate of character closest to x
 * \return  true on success, false on error and error reported
 *
 * On exit, char_offset indicates first character after split point.
 *
 * Note: char_offset of 0 should never be returned.
 *
 *   Returns:
 *     char_offset giving split point closest to x, where actual_x <= x
 *   else
 *     char_offset giving split point closest to x, where actual_x > x
 *
 * Returning char_offset == length means no split possible
 */

static bool nsfont_split(const plot_font_style_t *fstyle,
		const char *string, size_t length,
		int x, size_t *char_offset, int *actual_x)
{
        size_t nxtchr = 0;
        int last_space_x = 0;
        int last_space_idx = 0;

        *actual_x = 0;
        while (nxtchr < length) {

                if (string[nxtchr] == ' ') {
                        last_space_x = *actual_x;
                        last_space_idx = nxtchr;
                }

                *actual_x += FB_FONT_WIDTH;
                if (*actual_x > x && last_space_idx != 0) {
                        /* string has exceeded available width and we've
                         * found a space; return previous space */
                        *actual_x = last_space_x;
                        *char_offset = last_space_idx;
                        return true;
                }

                nxtchr = utf8_next(string, length, nxtchr);
        }

        *char_offset = nxtchr;

	return true;
}

const struct font_functions nsfont = {
	nsfont_width,
	nsfont_position_in_string,
	nsfont_split
};

static struct gui_utf8_table utf8_table = {
	.utf8_to_local = utf8_to_local,
	.local_to_utf8 = utf8_from_local,
};

struct gui_utf8_table *framebuffer_utf8_table = &utf8_table;


/*
 * Local Variables:
 * c-basic-offset:8
 * End:
 */