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 copyright (c) 2009 by Jonathan Kew

 Written by 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
 */


#include "layout/LETypes.h"
#include "layout/LEFontInstance.h"
#include "layout/LESwaps.h"

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

#ifdef XETEX_MAC
#include <Carbon/Carbon.h>
#endif

#include "XeTeX_ext.h"

#include "sfnt.h"

#include <string.h>


XeTeXFontInst::XeTeXFontInst(float pointSize, LEErrorCode &status)
    : fPointSize(pointSize)
    , fUnitsPerEM(0)
    , fAscent(0)
    , fDescent(0)
    , fLeading(0)
    , fXHeight(0)
    , fItalicAngle(0)
    , fCMAPMapper(NULL)
    , fMetricsTable(NULL)
    , fNumLongMetrics(0)
    , fNumGlyphs(0)
    , fNumGlyphsInited(false)
    , fVertical(false)
    , fFilename(NULL)
    , fFirstCharCode(-1)
    , fLastCharCode(-1)
{
	// the concrete subclass is responsible to call initialize()
}

XeTeXFontInst::~XeTeXFontInst()
{
	if (fMetricsTable != NULL)
		deleteTable(fMetricsTable);

	if (fCMAPMapper != NULL)
		delete fCMAPMapper;
}

void XeTeXFontInst::initialize(LEErrorCode &status)
{
    const LETag headTag = LE_HEAD_TABLE_TAG;
    const LETag hheaTag = LE_HHEA_TABLE_TAG;
    const LETag vheaTag = LE_VHEA_TABLE_TAG;
    const LETag postTag = LE_POST_TABLE_TAG;
    const HEADTable *headTable = NULL;
    const HHEATable *dirHeadTable = NULL;
    const POSTTable *postTable = NULL;

    // dispose of any cached metrics table
    if (fMetricsTable != NULL) {
	    deleteTable(fMetricsTable);
    	fMetricsTable = NULL;
    }
    
    // read unitsPerEm from 'head' table
    headTable = (const HEADTable *) readFontTable(headTag);

    if (headTable == NULL) {
        status = LE_MISSING_FONT_TABLE_ERROR;
        goto error_exit;
    }

    fUnitsPerEM = SWAPW(headTable->unitsPerEm);
    deleteTable(headTable);

	// we use the fact that 'hhea' and 'vhea' have the same format!
    dirHeadTable = (const HHEATable *) readFontTable(fVertical ? vheaTag : hheaTag);

    if (dirHeadTable == NULL) {
        status = LE_MISSING_FONT_TABLE_ERROR;
        goto error_exit;
    }

    fAscent  = yUnitsToPoints((float)(le_int16)SWAPW(dirHeadTable->ascent));
    fDescent = yUnitsToPoints((float)(le_int16)SWAPW(dirHeadTable->descent));
    fLeading = yUnitsToPoints((float)(le_int16)SWAPW(dirHeadTable->lineGap));

    fNumLongMetrics = SWAPW(dirHeadTable->numOfLongHorMetrics);

    deleteTable(dirHeadTable);

    fCMAPMapper = findUnicodeMapper();

    if (fCMAPMapper == NULL) {
        status = LE_MISSING_FONT_TABLE_ERROR;
        goto error_exit;
    }

    postTable = (const POSTTable *) readFontTable(postTag);

    if (postTable != NULL) {
		fItalicAngle = Fix2X(SWAPL(postTable->italicAngle));
		deleteTable(postTable);
    }

    return;

error_exit:
    return;
}

void XeTeXFontInst::setLayoutDirVertical(bool vertical)
{
	fVertical = vertical;
	LEErrorCode	status = LE_NO_ERROR;
	initialize(status);
}

void XeTeXFontInst::deleteTable(const void *table) const
{
    LE_DELETE_ARRAY(table);
}

const void *XeTeXFontInst::getFontTable(LETag tableTag) const
{
    return FontTableCache::find(tableTag);
}

const void *XeTeXFontInst::getFontTable(LETag tableTag, le_uint32 *length) const
{
    return FontTableCache::find(tableTag, length);
}

const void *XeTeXFontInst::readFontTable(LETag tableTag) const
{
    le_uint32 len;

    return readTable(tableTag, &len);
}

const void *XeTeXFontInst::readFontTable(LETag tableTag, le_uint32& len) const
{
    return readTable(tableTag, &len);
}

CMAPMapper *XeTeXFontInst::findUnicodeMapper()
{
    LETag cmapTag = LE_CMAP_TABLE_TAG;
    const CMAPTable *cmap = (CMAPTable *) readFontTable(cmapTag);

    if (cmap == NULL) {
        return NULL;
    }

    return CMAPMapper::createUnicodeMapper(cmap);
}


le_uint16 XeTeXFontInst::getNumGlyphs() const
{
    if (!fNumGlyphsInited) {
        LETag maxpTag = LE_MAXP_TABLE_TAG;
        const MAXPTable *maxpTable = (MAXPTable *) readFontTable(maxpTag);

        if (maxpTable != NULL) {
			XeTeXFontInst *realThis = (XeTeXFontInst *) this;
            realThis->fNumGlyphs = SWAPW(maxpTable->numGlyphs);
            deleteTable(maxpTable);
			realThis->fNumGlyphsInited = true;
		}
    }

	return fNumGlyphs;
}

void XeTeXFontInst::getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const
{
    TTGlyphID ttGlyph = (TTGlyphID) LE_GET_GLYPH(glyph);

    if (fMetricsTable == NULL) {
    	// we use the fact that 'hmtx' and 'vmtx' have the same format
        LETag metricsTag = fVertical ? LE_VMTX_TABLE_TAG : LE_HMTX_TABLE_TAG;
        XeTeXFontInst *realThis = (XeTeXFontInst *) this;
        realThis->fMetricsTable = (const HMTXTable *) readFontTable(metricsTag);
    }

    le_uint16 index = ttGlyph;

    if (ttGlyph >= getNumGlyphs() || fMetricsTable == NULL) {
        advance.fX = advance.fY = 0;
        return;
    }

    if (ttGlyph >= fNumLongMetrics) {
        index = fNumLongMetrics - 1;
    }

    advance.fX = xUnitsToPoints(SWAPW(fMetricsTable->hMetrics[index].advanceWidth));
    advance.fY = 0;
}

le_bool XeTeXFontInst::getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const
{
    return FALSE;
}

float
XeTeXFontInst::getGlyphWidth(LEGlyphID gid)
{
	LEPoint	advance;
	getGlyphAdvance(gid, advance);
	return advance.fX;
}

void
XeTeXFontInst::getGlyphHeightDepth(LEGlyphID gid, float* ht, float* dp)
{
	GlyphBBox	bbox;
	getGlyphBounds(gid, &bbox);
	
	*ht = bbox.yMax;
	*dp = -bbox.yMin;
}

void
XeTeXFontInst::getGlyphSidebearings(LEGlyphID gid, float* lsb, float* rsb)
{
	LEPoint	adv;
	getGlyphAdvance(gid, adv);

	GlyphBBox	bbox;
	getGlyphBounds(gid, &bbox);

	*lsb = bbox.xMin;
	*rsb = adv.fX - bbox.xMax;
}

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

	LEPoint	adv;
	getGlyphAdvance(gid, adv);

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

LEGlyphID
XeTeXFontInst::mapGlyphToIndex(const char* glyphName) const
	/* default implementation, may be overridden (e.g. by Freetype-based XeTeXFontInst_ */
{
    le_uint32	len;
    const char *p = (const char*)readFontTable(LE_POST_TABLE_TAG, len);
    if (p != NULL)
		return findGlyphInPostTable(p, len, glyphName);
	else
		return 0;
}

const char*
XeTeXFontInst::getGlyphName(LEGlyphID gid, int& nameLen)
{
    le_uint32	len;
    const char *p = (const char*)readFontTable(LE_POST_TABLE_TAG, len);
    if (p != NULL) {
		return getGlyphNamePtr(p, len, gid, &nameLen);
	}
}

LEUnicode32
XeTeXFontInst::getFirstCharCode()
{
	if (fFirstCharCode == -1) {
		int ch = 0;
		while (mapCharToGlyph(ch) == 0 && ch < 0x10ffff)
			++ch;
		fFirstCharCode = ch;
	}
	return fFirstCharCode;
}

LEUnicode32
XeTeXFontInst::getLastCharCode()
{
	if (fLastCharCode == -1) {
		int ch = 0x10ffff;
		while (mapCharToGlyph(ch) == 0 && ch > 0)
			--ch;
		fLastCharCode = ch;
	}
	return fLastCharCode;
}