netsurf/windows/font.c

/*
 * Copyright 2005 James Bursa <bursa@users.sourceforge.net>
 * Copyright 2008 Vincent Sanders <vince@simtec.co.uk>
 * Copyright 2009 Mark Benjamin <netsurf-browser.org.MarkBenjamin@dfgh.net>
 *
 * 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 <assert.h>
#include <windows.h>
#include "css/css.h"
#include "render/font.h"
#include "desktop/options.h"
#include "utils/utf8.h"

#include "windows/font.h"
#include "windows/gui.h"
#include "windows/plot.h"

#define NSWS_FONT_SCALE_HEIGHT 1.3
#define NSWS_FONT_SCALE_WIDTH 0.45

utf8_convert_ret utf8_to_font_encoding(const struct font_desc* font,
				       const char *string, 
				       size_t len,
				       char **result)
{
	return utf8_to_enc(string, font->encoding, len, result);
}

utf8_convert_ret utf8_to_local_encoding(const char *string, 
				       size_t len,
				       char **result)
{
	return utf8_to_enc(string, "UCS-2", len, result);
}

HFONT get_font(const plot_font_style_t *style)
{
	char *face = NULL;
	DWORD family;
	switch(style->family) {
	case PLOT_FONT_FAMILY_SERIF:
		face = strdup(option_font_serif);
		family = FF_ROMAN | DEFAULT_PITCH;
		break;
	case PLOT_FONT_FAMILY_MONOSPACE:
		face = strdup(option_font_mono);
		family = FF_MODERN | DEFAULT_PITCH;
		break;
	case PLOT_FONT_FAMILY_CURSIVE:
		face = strdup(option_font_cursive);
		family = FF_SCRIPT | DEFAULT_PITCH;
		break;
	case PLOT_FONT_FAMILY_FANTASY:
		face = strdup(option_font_fantasy);
		family = FF_DECORATIVE | DEFAULT_PITCH;
		break;
	case PLOT_FONT_FAMILY_SANS_SERIF:
	default:
		face = strdup(option_font_sans);
		family = FF_SWISS | DEFAULT_PITCH;
		break;
	}
	
	HFONT font = CreateFont((int)((((float)style->size) *
			NSWS_FONT_SCALE_HEIGHT * nsws_plot_get_scale())
			/ FONT_SIZE_SCALE), /* height */
			(int)((((float)style->size) *
			NSWS_FONT_SCALE_WIDTH * nsws_plot_get_scale())
			/ FONT_SIZE_SCALE), /* width */
			0, /* escapement*/
			0, /* orientation */
			style->weight,
			(style->flags & FONTF_ITALIC) ? TRUE : FALSE,
			FALSE, /* underline */
			FALSE, /* strike */
			DEFAULT_CHARSET, /* for locale */
			OUT_DEFAULT_PRECIS, /* general 'best match' */
			CLIP_DEFAULT_PRECIS,
			DEFAULT_QUALITY,
			family,
			face /* name of font face */
			);
	if (face != NULL)
		free(face);
	if (font == NULL) {
		if (style->family == PLOT_FONT_FAMILY_MONOSPACE)
			font = (HFONT) GetStockObject(ANSI_FIXED_FONT);
		else
			font = (HFONT) GetStockObject(ANSI_VAR_FONT);
	}
	if (font == NULL)
		font = (HFONT) GetStockObject(SYSTEM_FONT);
	return font;
}

static bool nsfont_width(const plot_font_style_t *style,
			 const char *string, size_t length,
			 int *width)
{
	HDC hdc = GetDC(NULL);
	HFONT font = get_font(style);
	HFONT fontbak = SelectObject(hdc, font);
	SIZE s;
	if (length < 8192) { /* win 95/98/ME */
		/* may well need to convert utf-8 to lpctstr */
		GetTextExtentPoint32(hdc, string,
				utf8_bounded_length(string, length), &s);
		*width = s.cx;
		font = SelectObject(hdc, fontbak);
		DeleteObject(font);
		ReleaseDC(NULL, hdc);
		return true;
	}
	font = SelectObject(hdc, fontbak);
	DeleteObject(font);
	ReleaseDC(NULL, hdc);
	return false;
}

/**
 * Find the position in a string where an x coordinate falls.
 *
 * \param  style	css_style for this text, with style->font_size.size ==
 *			CSS_FONT_SIZE_LENGTH
 * \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 *style,
		const char *string, size_t length,
		int x, size_t *char_offset, int *actual_x)
{
	HDC hdc = GetDC(NULL);
	HFONT font = get_font(style);
	HFONT fontbak = SelectObject(hdc, font);
	SIZE s;
	int offset;
	GetTextExtentExPoint(hdc, string, length, x, &offset, NULL, &s);
	*char_offset = (size_t)offset;
	nsfont_width(style, string, *char_offset, actual_x);

	font = SelectObject(hdc, fontbak);
	DeleteObject(font);
	ReleaseDC(NULL, hdc);
	
	return true;
}


/**
 * Find where to split a string to make it fit a width.
 *
 * \param  style	css_style for this text, with style->font_size.size ==
 *			CSS_FONT_SIZE_LENGTH
 * \param  string	UTF-8 string to measure
 * \param  length	length of string
 * \param  x		width available
 * \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
 *
 * On exit, [char_offset == 0 ||
 *	   string[char_offset] == ' ' ||
 *	   char_offset == length]
 */

static bool nsfont_split(const plot_font_style_t *style,
		const char *string, size_t length,
		int x, size_t *char_offset, int *actual_x)
{
	nsfont_position_in_string(style, string, length, x, char_offset, 
			actual_x);
	if (*char_offset == length) {
		printf("%s %d\n",string, (int)(*char_offset));
		return true;
	}
	while ((string[*char_offset] != ' ') && (*char_offset > 0))
		(*char_offset)--;
	nsfont_position_in_string(style, string, *char_offset, x, char_offset,
			actual_x);
	return true;
}

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