path: root/Build/source/texk/web2c/xetexdir/XeTeXFontInst.cpp

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 Copyright (c) 1994-2008 by SIL International
 Copyright (c) 2009 by Jonathan Kew

 SIL Author(s): Jonathan Kew

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/*
 *   file name:  XeTeXFontInst.cpp
 *
 *   created on: 2005-10-22
 *   created by: Jonathan Kew
 *	
 *	originally based on PortableFontInstance.cpp from ICU
 */

#ifdef __cplusplus
extern "C" {
#endif
#include <w2c/config.h>
#ifdef __cplusplus
}
#endif

#include "XeTeXFontInst.h"
#include "XeTeXLayoutInterface.h"
#include "XeTeX_ext.h"

#include <string.h>
#include FT_GLYPH_H
#include FT_ADVANCES_H

FT_Library gFreeTypeLibrary = 0;

XeTeXFontInst::XeTeXFontInst(const char* pathname, int index, float pointSize, int &status)
    : fPointSize(pointSize)
    , fUnitsPerEM(0)
    , fAscent(0)
    , fDescent(0)
    , fCapHeight(0)
    , fXHeight(0)
    , fItalicAngle(0)
    , fVertical(false)
    , fFilename(NULL)
    , ftFace(0)
    , hbFont(NULL)
    , fMath(NULL)
{
	if (pathname != NULL)
		initialize(pathname, index, status);
}

XeTeXFontInst::~XeTeXFontInst()
{
	if (ftFace != 0) {
		FT_Done_Face(ftFace);
		ftFace = 0;
	}
	hb_font_destroy(hbFont);
}

/* HarfBuzz font functions */

static hb_bool_t
_get_glyph(hb_font_t*, void *font_data, hb_codepoint_t ch, hb_codepoint_t vs, hb_codepoint_t *gid, void*)
{
	FT_Face face = (FT_Face) font_data;
	*gid = 0;

	if (vs)
		*gid = FT_Face_GetCharVariantIndex (face, ch, vs);

	if (*gid == 0)
		*gid = FT_Get_Char_Index (face, ch);

	return *gid != 0;
}

static FT_Fixed
_get_glyph_advance(FT_Face face, FT_UInt gid, bool vertical)
{
	FT_Error error;
	FT_Fixed advance;
	int flags = FT_LOAD_NO_SCALE;

	if (vertical)
		flags |= FT_LOAD_VERTICAL_LAYOUT;

	error = FT_Get_Advance(face, gid, flags, &advance);
	if (error)
		advance = 0;
	else
		advance = advance;

	/* FreeType's vertical metrics grows downward */
	if (vertical)
		advance = -advance;

	return advance;
}

static hb_position_t
_get_glyph_h_advance(hb_font_t*, void *font_data, hb_codepoint_t gid, void*)
{
	return _get_glyph_advance((FT_Face) font_data, gid, false);
}

static hb_position_t
_get_glyph_v_advance(hb_font_t*, void *font_data, hb_codepoint_t gid, void*)
{
	return _get_glyph_advance((FT_Face) font_data, gid, true);
}

static hb_bool_t
_get_glyph_h_origin(hb_font_t*, void *font_data, hb_codepoint_t gid, hb_position_t *x, hb_position_t *y, void*)
{
	// horizontal origin is (0, 0)
	return true;
}

static hb_bool_t
_get_glyph_v_origin(hb_font_t*, void *font_data, hb_codepoint_t gid, hb_position_t *x, hb_position_t *y, void*)
{
	// vertical origin is (0, 0) for now
	return true;

	// TODO
	// Keep the code below for reference, for now we want to keep vertical
	// origin at (0, 0) for compatibility with pre-0.9999.
	// Reconsider this (e.g. using BASE table) when we get around overhauling
	// the text directionality model and implementing real vertical typesetting.

	FT_Face face = (FT_Face) font_data;
	FT_Error error;

	error = FT_Load_Glyph (face, gid, FT_LOAD_NO_SCALE);
	if (!error) {
		*x = face->glyph->metrics.horiBearingX -   face->glyph->metrics.vertBearingX;
		*y = face->glyph->metrics.horiBearingY - (-face->glyph->metrics.vertBearingY);
	}

	return !error;
}

static hb_position_t
_get_glyph_h_kerning(hb_font_t*, void *font_data, hb_codepoint_t gid1, hb_codepoint_t gid2, void*)
{
	FT_Face face = (FT_Face) font_data;
	FT_Error error;
	FT_Vector kerning;
	hb_position_t ret;

	error = FT_Get_Kerning (face, gid1, gid2, FT_KERNING_UNFITTED, &kerning);
	if (error)
		ret = 0;
	else
		ret = kerning.x;
	return ret;
}

static hb_position_t
_get_glyph_v_kerning(hb_font_t*, void *font_data, hb_codepoint_t gid1, hb_codepoint_t gid2, void*)
{
	/* FreeType does not support vertical kerning */
	return 0;
}

static hb_bool_t
_get_glyph_extents(hb_font_t*, void *font_data, hb_codepoint_t gid, hb_glyph_extents_t *extents, void*)
{
	FT_Face face = (FT_Face) font_data;
	FT_Error error;

	error = FT_Load_Glyph (face, gid, FT_LOAD_NO_SCALE);
	if (!error) {
		extents->x_bearing = face->glyph->metrics.horiBearingX;
		extents->y_bearing = face->glyph->metrics.horiBearingY;
		extents->width  =  face->glyph->metrics.width;
		extents->height = -face->glyph->metrics.height;
	}

	return !error;
}

static hb_bool_t
_get_glyph_contour_point(hb_font_t*, void *font_data, hb_codepoint_t gid, unsigned int point_index, hb_position_t *x, hb_position_t *y, void*)
{
	FT_Face face = (FT_Face) font_data;
	FT_Error error;
	bool ret = false;

	error = FT_Load_Glyph (face, gid, FT_LOAD_NO_SCALE);
	if (!error) {
		if (face->glyph->format == FT_GLYPH_FORMAT_OUTLINE) {
			if (point_index < (unsigned int) face->glyph->outline.n_points) {
				*x = face->glyph->outline.points[point_index].x;
				*y = face->glyph->outline.points[point_index].y;
				ret = true;
			}
		}
	}

	return ret;
}

static hb_bool_t
_get_glyph_name(hb_font_t *, void *font_data, hb_codepoint_t gid, char *name, unsigned int size, void *)
{
	FT_Face face = (FT_Face) font_data;
	bool ret = false;

	ret = !FT_Get_Glyph_Name (face, gid, name, size);
	if (ret && (size && !*name))
		ret = false;

	return ret;
}

static hb_font_funcs_t *
_get_font_funcs(void)
{
	static hb_font_funcs_t* funcs = hb_font_funcs_create();

	hb_font_funcs_set_glyph_func				(funcs, _get_glyph, NULL, NULL);
	hb_font_funcs_set_glyph_h_advance_func		(funcs, _get_glyph_h_advance, NULL, NULL);
	hb_font_funcs_set_glyph_v_advance_func		(funcs, _get_glyph_v_advance, NULL, NULL);
	hb_font_funcs_set_glyph_h_origin_func		(funcs, _get_glyph_h_origin, NULL, NULL);
	hb_font_funcs_set_glyph_v_origin_func		(funcs, _get_glyph_v_origin, NULL, NULL);
	hb_font_funcs_set_glyph_h_kerning_func		(funcs, _get_glyph_h_kerning, NULL, NULL);
	hb_font_funcs_set_glyph_v_kerning_func		(funcs, _get_glyph_v_kerning, NULL, NULL);
	hb_font_funcs_set_glyph_extents_func		(funcs, _get_glyph_extents, NULL, NULL);
	hb_font_funcs_set_glyph_contour_point_func	(funcs, _get_glyph_contour_point, NULL, NULL);
	hb_font_funcs_set_glyph_name_func			(funcs, _get_glyph_name, NULL, NULL);

	return funcs;
}

static hb_blob_t *
_get_table(hb_face_t *, hb_tag_t tag, void *user_data)
{
	FT_Face face = (FT_Face) user_data;
	FT_ULong length = 0;
	FT_Byte *table;
	FT_Error error;
	hb_blob_t* blob = NULL;

	error = FT_Load_Sfnt_Table(face, tag, 0, NULL, &length);
	if (!error) {
		table = (FT_Byte *) xmalloc(length * sizeof(char));
		if (table != NULL) {
			error = FT_Load_Sfnt_Table(face, tag, 0, (FT_Byte*)table, &length);
			if (!error) {
				blob = hb_blob_create((const char*) table, length, HB_MEMORY_MODE_WRITABLE, table, free);
			} else {
				free(table);
			}
		}
	}

    return blob;
}

void
XeTeXFontInst::initialize(const char* pathname, int index, int &status)
{
	TT_Postscript *postTable;
	TT_OS2* os2Table;
	FT_Error error;
	hb_face_t *hbFace;

	if (!gFreeTypeLibrary) {
		error = FT_Init_FreeType(&gFreeTypeLibrary);
		if (error) {
			fprintf(stderr, "FreeType initialization failed! (%d)\n", error);
			exit(1);
		}
	}

	error = FT_New_Face(gFreeTypeLibrary, (char*)pathname, index, &ftFace);
	if (error) {
        status = 1;
        return;
    }

	if (!FT_IS_SCALABLE(ftFace)) {
		status = 1;
		return;
	}

	/* for non-sfnt-packaged fonts (presumably Type 1), see if there is an AFM file we can attach */
	if (index == 0 && !FT_IS_SFNT(ftFace)) {
		char* afm = new char[strlen((const char*)pathname) + 5]; // room to append ".afm"
		strcpy(afm, (const char*)pathname);
		char* p = strrchr(afm, '.');
		if (p == NULL || strlen(p) != 4 || tolower(*(p+1)) != 'p' || tolower(*(p+2)) != 'f')
			strcat(afm, ".afm");   // append .afm if the extension didn't seem to be .pf[ab]
		else
			strcpy(p, ".afm"); 	   // else replace extension with .afm
		FT_Attach_File(ftFace, afm); // ignore error code; AFM might not exist
		delete[] afm;
	}

	char buf[20];
	if (index > 0)
		sprintf(buf, ":%d", index);
	else
		buf[0] = 0;
	fFilename = new char[strlen(pathname) + 2 + strlen(buf) + 1];
	sprintf(fFilename, "[%s%s]", pathname, buf);
	fUnitsPerEM = ftFace->units_per_EM;
	fAscent = unitsToPoints(ftFace->ascender);
	fDescent = unitsToPoints(ftFace->descender);

	postTable = (TT_Postscript *) getFontTable(ft_sfnt_post);
	if (postTable != NULL) {
		fItalicAngle = Fix2D(postTable->italicAngle);
	}

	os2Table = (TT_OS2*) getFontTable(ft_sfnt_os2);
	if (os2Table) {
		fCapHeight = unitsToPoints(os2Table->sCapHeight);
		fXHeight = unitsToPoints(os2Table->sxHeight);
	}

	// Set up HarfBuzz font
	hbFace = hb_face_create_for_tables(_get_table, ftFace, NULL);
	hb_face_set_index(hbFace, index);
	hb_face_set_upem(hbFace, fUnitsPerEM);
	hbFont = hb_font_create(hbFace);
	hb_face_destroy(hbFace);

	hb_font_set_funcs(hbFont, _get_font_funcs(), ftFace, NULL);
	hb_font_set_scale(hbFont, fUnitsPerEM, fUnitsPerEM);
	// We don’t want device tables adjustments
	hb_font_set_ppem(hbFont, 0, 0);

    return;
}

void
XeTeXFontInst::setLayoutDirVertical(bool vertical)
{
	fVertical = vertical;
}

const void *
XeTeXFontInst::getFontTable(OTTag tag) const
{
	FT_ULong tmpLength = 0;
	FT_Error error = FT_Load_Sfnt_Table(ftFace, tag, 0, NULL, &tmpLength);
	if (error)
		return NULL;

	void* table = xmalloc(tmpLength * sizeof(char));
	if (table != NULL) {
		error = FT_Load_Sfnt_Table(ftFace, tag, 0, (FT_Byte*)table, &tmpLength);
		if (error) {
			free((void *) table);
			return NULL;
		}
	}

    return table;
}

const char *
XeTeXFontInst::getMathTable()
{
	if (fMath == NULL)
		fMath = (const char*) getFontTable(MATH_TAG);
	return fMath;
}

const void *
XeTeXFontInst::getFontTable(FT_Sfnt_Tag tag) const
{
	return FT_Get_Sfnt_Table(ftFace, tag);
}

void
XeTeXFontInst::getGlyphBounds(GlyphID gid, GlyphBBox* bbox)
{
	bbox->xMin = bbox->yMin = bbox->xMax = bbox->yMax = 0.0;

	FT_Error error = FT_Load_Glyph(ftFace, gid, FT_LOAD_NO_SCALE);
	if (error)
		return;

    FT_Glyph glyph;
    error = FT_Get_Glyph(ftFace->glyph, &glyph);
	if (error == 0) {
		FT_BBox ft_bbox;
		FT_Glyph_Get_CBox(glyph, FT_GLYPH_BBOX_UNSCALED, &ft_bbox);
		bbox->xMin = unitsToPoints(ft_bbox.xMin);
		bbox->yMin = unitsToPoints(ft_bbox.yMin);
		bbox->xMax = unitsToPoints(ft_bbox.xMax);
		bbox->yMax = unitsToPoints(ft_bbox.yMax);
		FT_Done_Glyph(glyph);
	}
}

GlyphID
XeTeXFontInst::mapCharToGlyph(UChar32 ch) const
{
	return FT_Get_Char_Index(ftFace, ch);
}

uint16_t
XeTeXFontInst::getNumGlyphs() const
{
	return ftFace->num_glyphs;
}

float
XeTeXFontInst::getGlyphWidth(GlyphID gid)
{
	return unitsToPoints(_get_glyph_advance(ftFace, gid, false));
}

void
XeTeXFontInst::getGlyphHeightDepth(GlyphID gid, float* ht, float* dp)
{
	GlyphBBox bbox;
	getGlyphBounds(gid, &bbox);

	if (ht)
		*ht = bbox.yMax;
	if (dp)
		*dp = -bbox.yMin;
}

void
XeTeXFontInst::getGlyphSidebearings(GlyphID gid, float* lsb, float* rsb)
{
	float width = getGlyphWidth(gid);

	GlyphBBox bbox;
	getGlyphBounds(gid, &bbox);

	if (lsb)
		*lsb = bbox.xMin;
	if (rsb)
		*rsb = width - bbox.xMax;
}

float
XeTeXFontInst::getGlyphItalCorr(GlyphID gid)
{
	float rval = 0.0;

	float width = getGlyphWidth(gid);

	GlyphBBox bbox;
	getGlyphBounds(gid, &bbox);
	
	if (bbox.xMax > width)
		rval = bbox.xMax - width;
	
	return rval;
}

GlyphID
XeTeXFontInst::mapGlyphToIndex(const char* glyphName) const
{
	return FT_Get_Name_Index(ftFace, const_cast<char*>(glyphName));
}

const char*
XeTeXFontInst::getGlyphName(GlyphID gid, int& nameLen)
{
	if (FT_HAS_GLYPH_NAMES(ftFace)) {
		static char buffer[256];
		FT_Get_Glyph_Name(ftFace, gid, buffer, 256);
		nameLen = strlen(buffer);
		return &buffer[0];
	}
	else {
		nameLen = 0;
		return NULL;
	}
}

UChar32
XeTeXFontInst::getFirstCharCode()
{
	FT_UInt  gindex;
	return FT_Get_First_Char(ftFace, &gindex);
}

UChar32
XeTeXFontInst::getLastCharCode()
{
	FT_UInt  gindex;
	UChar32	ch = FT_Get_First_Char(ftFace, &gindex);
	UChar32	prev = ch;
	while (gindex != 0) {
		prev = ch;
		ch = FT_Get_Next_Char(ftFace, ch, &gindex);
	}
	return prev;
}