diff options
author | 2011-05-09 18:13:47 +0000 | |
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committer | 2011-05-09 18:13:47 +0000 | |
commit | 6744d498fcbbbcf503ec80c4d43dd8f118a88597 (patch) | |
tree | 855c458a26e42d13ff29f9aa51266f5e151b9569 /src/pdf/SkPDFFont.cpp | |
parent | 339ac3d0a7650c98de35afbcff4ac1d5b47199c0 (diff) |
[PDF] Add a ToUnicode mapping for fonts.
This makes text in PDFs searchable and copy&paste-able.
Code from arthurhsu@chromium.org. Original review: http://codereview.appspot.com/4428082/
Review URL: http://codereview.appspot.com/4525042
git-svn-id: http://skia.googlecode.com/svn/trunk@1280 2bbb7eff-a529-9590-31e7-b0007b416f81
Diffstat (limited to 'src/pdf/SkPDFFont.cpp')
-rwxr-xr-x[-rw-r--r--] | src/pdf/SkPDFFont.cpp | 121 |
1 files changed, 117 insertions, 4 deletions
diff --git a/src/pdf/SkPDFFont.cpp b/src/pdf/SkPDFFont.cpp index acfe41e8e1..cc249ca9d3 100644..100755 --- a/src/pdf/SkPDFFont.cpp +++ b/src/pdf/SkPDFFont.cpp @@ -319,6 +319,92 @@ SkPDFArray* composeAdvanceData( } // namespace +static void append_tounicode_header(SkDynamicMemoryWStream* cmap) { + // 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. + // We specify codespacerange from 0x0000 to 0xFFFF because we convert our + // code table from unsigned short (16-bits). Codespace range just tells the + // PDF processor the valid range. It does not matter whether a complete + // mapping is provided or not. + const char* kTypeInfo = + "/CMapName /Adobe-Identity-UCS def\n" + "/CMapType 2 def\n" + "1 begincodespacerange\n" + "<0000> <FFFF>\n" + "endcodespacerange\n"; + cmap->writeText(kTypeInfo); +} + +static void append_cmap_bfchar_table(uint16_t* glyph_id, SkUnichar* unicode, + size_t count, + SkDynamicMemoryWStream* cmap) { + cmap->writeDecAsText(count); + cmap->writeText(" beginbfchar\n"); + for (size_t i = 0; i < count; ++i) { + cmap->writeText("<"); + cmap->writeHexAsText(glyph_id[i], 4); + cmap->writeText("> <"); + cmap->writeHexAsText(unicode[i], 4); + cmap->writeText(">\n"); + } + cmap->writeText("endbfchar\n"); +} + +static void append_cmap_footer(SkDynamicMemoryWStream* cmap) { + const char* kFooter = + "endcmap\n" + "CMapName currentdict /CMap defineresource pop\n" + "end\n" + "end"; + cmap->writeText(kFooter); +} + +// Generate <bfchar> table according to PDF spec 1.4 and Adobe Technote 5014. +static void append_cmap_bfchar_sections( + const SkTDArray<SkUnichar>& glyphUnicode, + SkDynamicMemoryWStream* cmap) { + // PDF spec defines that every bf* list can have at most 100 entries. + const size_t kMaxEntries = 100; + uint16_t glyphId[kMaxEntries]; + SkUnichar unicode[kMaxEntries]; + size_t index = 0; + for (int i = 0; i < glyphUnicode.count(); i++) { + if (glyphUnicode[i]) { + glyphId[index] = i; + unicode[index] = glyphUnicode[i]; + ++index; + } + if (index == kMaxEntries) { + append_cmap_bfchar_table(glyphId, unicode, index, cmap); + index = 0; + } + } + + if (index) { + append_cmap_bfchar_table(glyphId, unicode, index, cmap); + } +} + /* Font subset design: It would be nice to be able to subset fonts * (particularly type 3 fonts), but it's a lot of work and not a priority. * @@ -404,9 +490,13 @@ SkPDFFont* SkPDFFont::getFontResource(SkTypeface* typeface, uint16_t glyphID) { fontInfo = relatedFont->fFontInfo; fontDescriptor = relatedFont->fDescriptor.get(); } else { - fontInfo = SkFontHost::GetAdvancedTypefaceMetrics(fontID, SkTBitOr( - SkAdvancedTypefaceMetrics::kHAdvance_PerGlyphInfo, - SkAdvancedTypefaceMetrics::kGlyphNames_PerGlyphInfo)); + SkAdvancedTypefaceMetrics::PerGlyphInfo info; + info = SkAdvancedTypefaceMetrics::kHAdvance_PerGlyphInfo; + info = SkTBitOr<SkAdvancedTypefaceMetrics::PerGlyphInfo>( + info, SkAdvancedTypefaceMetrics::kGlyphNames_PerGlyphInfo); + info = SkTBitOr<SkAdvancedTypefaceMetrics::PerGlyphInfo>( + info, SkAdvancedTypefaceMetrics::kToUnicode_PerGlyphInfo); + fontInfo = SkFontHost::GetAdvancedTypefaceMetrics(fontID, info); SkSafeUnref(fontInfo.get()); // SkRefPtr and Get both took a reference. } @@ -497,7 +587,6 @@ SkPDFFont::SkPDFFont(class SkAdvancedTypefaceMetrics* fontInfo, } void SkPDFFont::populateType0Font() { - // TODO(vandebo) add a ToUnicode mapping. fMultiByteGlyphs = true; insert("Subtype", new SkPDFName("Type0"))->unref(); @@ -512,6 +601,26 @@ void SkPDFFont::populateType0Font() { new SkPDFFont(fFontInfo.get(), fTypeface.get(), 1, true, NULL)); descendantFonts->append(new SkPDFObjRef(fResources.top()))->unref(); insert("DescendantFonts", descendantFonts.get()); + + populateToUnicodeTable(); +} + +void SkPDFFont::populateToUnicodeTable() { + if (fFontInfo.get() == NULL || + fFontInfo->fGlyphToUnicode.begin() == NULL) { + return; + } + + SkDynamicMemoryWStream cmap; + append_tounicode_header(&cmap); + append_cmap_bfchar_sections(fFontInfo->fGlyphToUnicode, &cmap); + append_cmap_footer(&cmap); + SkRefPtr<SkMemoryStream> cmapStream = new SkMemoryStream(); + cmapStream->unref(); // SkRefPtr and new took a reference. + cmapStream->setMemoryOwned(cmap.detach(), cmap.getOffset()); + SkRefPtr<SkPDFStream> pdfCmap = new SkPDFStream(cmapStream.get()); + fResources.push(pdfCmap.get()); // Pass reference from new. + insert("ToUnicode", new SkPDFObjRef(pdfCmap.get()))->unref(); } void SkPDFFont::populateCIDFont() { @@ -522,6 +631,7 @@ void SkPDFFont::populateCIDFont() { insert("Subtype", new SkPDFName("CIDFontType0"))->unref(); } else if (fFontInfo->fType == SkAdvancedTypefaceMetrics::kTrueType_Font) { insert("Subtype", new SkPDFName("CIDFontType2"))->unref(); + insert("CIDToGIDMap", new SkPDFName("Identity"))->unref(); } else { SkASSERT(false); } @@ -697,9 +807,12 @@ void SkPDFFont::populateType3Font(int16_t glyphID) { insert("FirstChar", new SkPDFInt(fFirstGlyphID))->unref(); insert("LastChar", new SkPDFInt(fLastGlyphID))->unref(); insert("Widths", widthArray.get()); + insert("CIDToGIDMap", new SkPDFName("Identity"))->unref(); if (fFontInfo && fFontInfo->fLastGlyphID <= 255) fFontInfo = NULL; + + populateToUnicodeTable(); } bool SkPDFFont::addFontDescriptor(int16_t defaultWidth) { |