SkPDFMakeToUnicodeCmap.cpp File Reference

#include "src/pdf/SkPDFMakeToUnicodeCmap.h"
#include "include/core/SkStream.h"
#include "include/private/base/SkTo.h"
#include "src/base/SkUTF.h"
#include "src/pdf/SkPDFGlyphUse.h"
#include "src/pdf/SkPDFUtils.h"
#include <algorithm>
#include <cstddef>
#include <vector>

Go to the source code of this file.

Functions
static void	append_tounicode_header (SkDynamicMemoryWStream *cmap, bool multibyte)
static void	append_cmap_footer (SkDynamicMemoryWStream *cmap)
static void	write_glyph (SkDynamicMemoryWStream *cmap, bool multiByte, SkGlyphID gid)
static void	append_bfchar_section (const std::vector< BFChar > &bfchar, bool multiByte, SkDynamicMemoryWStream *cmap)
static void	append_bfrange_section (const std::vector< BFRange > &bfrange, bool multiByte, SkDynamicMemoryWStream *cmap)
void	SkPDFAppendCmapSections (const SkUnichar *glyphToUnicode, const SkPDFGlyphUse *subset, SkDynamicMemoryWStream *cmap, bool multiByteGlyphs, SkGlyphID firstGlyphID, SkGlyphID lastGlyphID)
std::unique_ptr< SkStreamAsset >	SkPDFMakeToUnicodeCmap (const SkUnichar *glyphToUnicode, const SkPDFGlyphUse *subset, bool multiByteGlyphs, SkGlyphID firstGlyphID, SkGlyphID lastGlyphID)

Function Documentation

append_bfchar_section()

static void append_bfchar_section ( const std::vector< BFChar > &  bfchar, bool  multiByte, SkDynamicMemoryWStream *  cmap  )

static

Definition at line 90 of file SkPDFMakeToUnicodeCmap.cpp.

                                                                {
    // PDF spec defines that every bf* list can have at most 100 entries.
    for (size_t i = 0; i < bfchar.size(); i += 100) {
        int count = SkToInt(bfchar.size() - i);
        count = std::min(count, 100);
        cmap->writeDecAsText(count);
        cmap->writeText(" beginbfchar\n");
        for (int j = 0; j < count; ++j) {
            cmap->writeText("<");
            write_glyph(cmap, multiByte, bfchar[i + j].fGlyphId);
            cmap->writeText("> <");
            SkPDFUtils::WriteUTF16beHex(cmap, bfchar[i + j].fUnicode);
            cmap->writeText(">\n");
        }
        cmap->writeText("endbfchar\n");
    }
}

append_bfrange_section()

static void append_bfrange_section ( const std::vector< BFRange > &  bfrange, bool  multiByte, SkDynamicMemoryWStream *  cmap  )

static

Definition at line 110 of file SkPDFMakeToUnicodeCmap.cpp.

                                                                 {
    // PDF spec defines that every bf* list can have at most 100 entries.
    for (size_t i = 0; i < bfrange.size(); i += 100) {
        int count = SkToInt(bfrange.size() - i);
        count = std::min(count, 100);
        cmap->writeDecAsText(count);
        cmap->writeText(" beginbfrange\n");
        for (int j = 0; j < count; ++j) {
            cmap->writeText("<");
            write_glyph(cmap, multiByte, bfrange[i + j].fStart);
            cmap->writeText("> <");
            write_glyph(cmap, multiByte, bfrange[i + j].fEnd);
            cmap->writeText("> <");
            SkPDFUtils::WriteUTF16beHex(cmap, bfrange[i + j].fUnicode);
            cmap->writeText(">\n");
        }
        cmap->writeText("endbfrange\n");
    }
}

append_cmap_footer()

static void append_cmap_footer ( SkDynamicMemoryWStream *  cmap )

static

Definition at line 58 of file SkPDFMakeToUnicodeCmap.cpp.

                                                             {
    const char kFooter[] =
        "endcmap\n"
        "CMapName currentdict /CMap defineresource pop\n"
        "end\n"
        "end";
    cmap->writeText(kFooter);
}

append_tounicode_header()

static void append_tounicode_header ( SkDynamicMemoryWStream *  cmap, bool  multibyte  )

static

Definition at line 20 of file SkPDFMakeToUnicodeCmap.cpp.

                                                    {
    // 12 dict begin: 12 is an Adobe-suggested value. Shall not change.
    // It's there to prevent old version Adobe Readers from malfunctioning.
    const char* kHeader =
        "/CIDInit /ProcSet findresource begin\n"
        "12 dict begin\n"
        "begincmap\n";
    cmap->writeText(kHeader);
 
    // The /CIDSystemInfo must be consistent to the one in
    // SkPDFFont::populateCIDFont().
    // We can not pass over the system info object here because the format is
    // different. This is not a reference object.
    const char* kSysInfo =
        "/CIDSystemInfo\n"
        "<<  /Registry (Adobe)\n"
        "/Ordering (UCS)\n"
        "/Supplement 0\n"
        ">> def\n";
    cmap->writeText(kSysInfo);
 
    // The CMapName must be consistent to /CIDSystemInfo above.
    // /CMapType 2 means ToUnicode.
    // Codespace range just tells the PDF processor the valid range.
    const char* kTypeInfoHeader =
        "/CMapName /Adobe-Identity-UCS def\n"
        "/CMapType 2 def\n"
        "1 begincodespacerange\n";
    cmap->writeText(kTypeInfoHeader);
    if (multibyte) {
        cmap->writeText("<0000> <FFFF>\n");
    } else {
        cmap->writeText("<00> <FF>\n");
    }
    cmap->writeText("endcodespacerange\n");
}

SkPDFAppendCmapSections()

void SkPDFAppendCmapSections	(	const SkUnichar *	glyphToUnicode,
		const SkPDFGlyphUse *	subset,
		SkDynamicMemoryWStream *	cmap,
		bool	multiByteGlyphs,
		SkGlyphID	firstGlyphID,
		SkGlyphID	lastGlyphID
	)

Definition at line 158 of file SkPDFMakeToUnicodeCmap.cpp.

                                                    {
    int glyphOffset = 0;
    if (!multiByteGlyphs) {
        glyphOffset = firstGlyphID - 1;
    }
 
    std::vector<BFChar> bfcharEntries;
    std::vector<BFRange> bfrangeEntries;
 
    BFRange currentRangeEntry = {0, 0, 0};
    bool rangeEmpty = true;
    const int limit = (int)lastGlyphID + 1 - glyphOffset;
 
    for (int i = firstGlyphID - glyphOffset; i < limit + 1; ++i) {
        SkGlyphID gid = i + glyphOffset;
        bool inSubset = i < limit && (subset == nullptr || subset->has(gid));
        if (!rangeEmpty) {
            // PDF spec requires bfrange not changing the higher byte,
            // e.g. <1035> <10FF> <2222> is ok, but
            //      <1035> <1100> <2222> is no good
            bool inRange =
                i == currentRangeEntry.fEnd + 1 &&
                i >> 8 == currentRangeEntry.fStart >> 8 &&
                i < limit &&
                glyphToUnicode[gid] ==
                    currentRangeEntry.fUnicode + i - currentRangeEntry.fStart;
            if (!inSubset || !inRange) {
                if (currentRangeEntry.fEnd > currentRangeEntry.fStart) {
                    bfrangeEntries.push_back(currentRangeEntry);
                } else {
                    bfcharEntries.push_back({currentRangeEntry.fStart, currentRangeEntry.fUnicode});
                }
                rangeEmpty = true;
            }
        }
        if (inSubset) {
            currentRangeEntry.fEnd = i;
            if (rangeEmpty) {
              currentRangeEntry.fStart = i;
              currentRangeEntry.fUnicode = glyphToUnicode[gid];
              rangeEmpty = false;
            }
        }
    }
 
    // The spec requires all bfchar entries for a font must come before bfrange
    // entries.
    append_bfchar_section(bfcharEntries, multiByteGlyphs, cmap);
    append_bfrange_section(bfrangeEntries, multiByteGlyphs, cmap);
}

SkPDFMakeToUnicodeCmap()

std::unique_ptr< SkStreamAsset > SkPDFMakeToUnicodeCmap	(	const SkUnichar *	glyphToUnicode,
		const SkPDFGlyphUse *	subset,
		bool	multiByteGlyphs,
		SkGlyphID	firstGlyphID,
		SkGlyphID	lastGlyphID
	)

Definition at line 214 of file SkPDFMakeToUnicodeCmap.cpp.

                               {
    SkDynamicMemoryWStream cmap;
    append_tounicode_header(&cmap, multiByteGlyphs);
    SkPDFAppendCmapSections(glyphToUnicode, subset, &cmap, multiByteGlyphs,
                            firstGlyphID, lastGlyphID);
    append_cmap_footer(&cmap);
    return cmap.detachAsStream();
}

write_glyph()

static void write_glyph ( SkDynamicMemoryWStream *  cmap, bool  multiByte, SkGlyphID  gid  )

static

Definition at line 80 of file SkPDFMakeToUnicodeCmap.cpp.

                                       {
    if (multiByte) {
        SkPDFUtils::WriteUInt16BE(cmap, gid);
    } else {
        SkPDFUtils::WriteUInt8(cmap, SkToU8(gid));
    }
}