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netsurf/frontends/framebuffer/font_internal.c

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/*
* 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 <stdlib.h>
#include "utils/nsoption.h"
#include "utils/utf8.h"
#include "netsurf/utf8.h"
#include "netsurf/layout.h"
#include "netsurf/plot_style.h"
#include "framebuffer/gui.h"
#include "framebuffer/font.h"
#include <font-ns-sans.h>
#define GLYPH_LEN 16
uint8_t code_point[GLYPH_LEN];
uint8_t glyph_x2[GLYPH_LEN * 4];
#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_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)
{
enum fb_font_style style = FB_REGULAR;
if (fstyle->weight >= 700)
style |= FB_BOLD;
if ((fstyle->flags & FONTF_ITALIC) || (fstyle->flags & FONTF_OBLIQUE))
style |= FB_ITALIC;
return style;
}
int
fb_get_font_size(const plot_font_style_t *fstyle)
{
int size = fstyle->size * 10 /
(((nsoption_int(font_min_size) * 3 +
nsoption_int(font_size)) / 4) * PLOT_STYLE_SCALE);
if (size > 2)
size = 2;
else if (size <= 0)
size = 1;
return size;
}
/** Lookup table to scale 4 bits to 8 bits, so e.g. 0101 --> 00110011 */
const uint8_t glyph_lut[16] = {
0x00, 0x03, 0x0c, 0x0f,
0x30, 0x33, 0x3c, 0x3f,
0xc0, 0xc3, 0xcc, 0xcf,
0xf0, 0xf3, 0xfc, 0xff
};
static const uint8_t *
glyph_scale_2(const uint8_t *glyph_data)
{
const uint8_t *glyph_max = glyph_data + GLYPH_LEN;
uint8_t *pos = glyph_x2;
do {
*pos++ = glyph_lut[*glyph_data >> 4];
*pos++ = glyph_lut[*glyph_data & 0xf];
*pos++ = glyph_lut[*glyph_data >> 4];
*pos++ = glyph_lut[*glyph_data & 0xf];
} while (++glyph_data < glyph_max);
return glyph_x2;
}
const uint8_t *
fb_get_glyph(uint32_t ucs4, enum fb_font_style style, int scale)
{
const uint8_t *glyph_data;
unsigned int section;
unsigned int offset;
uint16_t g_offset;
/* Internal font has no glyphs beyond U+FFFF and there isn't
* space to render a >4 digit codepoint; just show replacement
* character. */
if (ucs4 > 0xffff)
ucs4 = 0xfffd;
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) {
glyph_data = &font_glyph_data[g_offset];
break;
}
}
/* Fall through. */
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) {
glyph_data = &font_glyph_data[g_offset];
break;
}
}
/* Fall through. */
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) {
glyph_data = &font_glyph_data[g_offset];
break;
}
}
/* Fall through. */
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) {
glyph_data = &font_glyph_data[g_offset];
break;
}
}
/* Fall through. */
default:
glyph_data = get_codepoint(ucs4, style & FB_ITALIC);
break;
}
switch (scale) {
case 1:
break;
case 2:
glyph_data = glyph_scale_2(glyph_data);
break;
default:
assert(scale >= 1 && scale <= 2);
break;
}
return glyph_data;
}
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;
}
/* exported interface documented in framebuffer/freetype_font.h */
nserror
fb_font_width(const plot_font_style_t *fstyle,
const char *string,
size_t length,
int *width)
{
size_t nxtchr = 0;
*width = 0;
while (nxtchr < length) {
uint32_t ucs4;
ucs4 = utf8_to_ucs4(string + nxtchr, length - nxtchr);
if (codepoint_displayable(ucs4)) {
*width += FB_FONT_WIDTH;
}
nxtchr = utf8_next(string, length, nxtchr);
}
*width *= fb_get_font_size(fstyle);
return NSERROR_OK;
}
/* exported interface documented in framebuffer/freetype_font.h */
nserror
fb_font_position(const plot_font_style_t *fstyle,
const char *string,
size_t length,
int x,
size_t *char_offset,
int *actual_x)
{
const int width = fb_get_font_size(fstyle) * FB_FONT_WIDTH;
size_t nxtchr = 0;
int x_pos = 0;
while (nxtchr < length) {
uint32_t ucs4;
if (abs(x_pos - x) <= (width / 2))
break;
ucs4 = utf8_to_ucs4(string + nxtchr, length - nxtchr);
if (codepoint_displayable(ucs4)) {
x_pos += width;
}
nxtchr = utf8_next(string, length, nxtchr);
}
*actual_x = x_pos;
*char_offset = nxtchr;
return NSERROR_OK;
}
/**
* 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 nserror
fb_font_split(const plot_font_style_t *fstyle,
const char *string,
size_t length,
int x,
size_t *char_offset,
int *actual_x)
{
const int width = fb_get_font_size(fstyle) * FB_FONT_WIDTH;
size_t nxtchr = 0;
int last_space_x = 0;
int last_space_idx = 0;
*actual_x = 0;
while (nxtchr < length) {
uint32_t ucs4;
if (string[nxtchr] == ' ') {
last_space_x = *actual_x;
last_space_idx = nxtchr;
}
ucs4 = utf8_to_ucs4(string + nxtchr, length - nxtchr);
if (codepoint_displayable(ucs4)) {
*actual_x += 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 NSERROR_OK;
}
nxtchr = utf8_next(string, length, nxtchr);
}
*char_offset = nxtchr;
return NSERROR_OK;
}
static struct gui_layout_table layout_table = {
.width = fb_font_width,
.position = fb_font_position,
.split = fb_font_split,
};
struct gui_layout_table *framebuffer_layout_table = &layout_table;
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:
*/
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