pdf: write only ToUnicode mappings needed by the font, trimming anything out of [firstChar, lastChar] interval.
R=vandebo@chromium.org
Review URL: https://codereview.chromium.org/23519006
git-svn-id: http://skia.googlecode.com/svn/trunk@11360 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pdf/SkPDFFont.cpp b/src/pdf/SkPDFFont.cpp
index 7d8c286..4184e87 100644
--- a/src/pdf/SkPDFFont.cpp
+++ b/src/pdf/SkPDFFont.cpp
@@ -342,7 +342,9 @@
} // namespace
-static void append_tounicode_header(SkDynamicMemoryWStream* cmap) {
+static void append_tounicode_header(SkDynamicMemoryWStream* cmap,
+ uint16_t firstGlyphID,
+ uint16_t lastGlyphID) {
// 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 =
@@ -365,17 +367,20 @@
// 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 =
+ // 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"
- "<0000> <FFFF>\n"
- "endcodespacerange\n";
- cmap->writeText(kTypeInfo);
+ "1 begincodespacerange\n";
+ cmap->writeText(kTypeInfoHeader);
+
+ // e.g. "<0000> <FFFF>\n"
+ SkString range;
+ range.appendf("<%04X> <%04X>\n", firstGlyphID, lastGlyphID);
+ cmap->writeText(range.c_str());
+
+ const char* kTypeInfoFooter = "endcodespacerange\n";
+ cmap->writeText(kTypeInfoFooter);
}
static void append_cmap_footer(SkDynamicMemoryWStream* cmap) {
@@ -469,11 +474,15 @@
// ( see caller in tests/ToUnicode.cpp )
void append_cmap_sections(const SkTDArray<SkUnichar>& glyphToUnicode,
const SkPDFGlyphSet* subset,
- SkDynamicMemoryWStream* cmap);
+ SkDynamicMemoryWStream* cmap,
+ uint16_t firstGlyphID,
+ uint16_t lastGlyphID);
void append_cmap_sections(const SkTDArray<SkUnichar>& glyphToUnicode,
const SkPDFGlyphSet* subset,
- SkDynamicMemoryWStream* cmap) {
+ SkDynamicMemoryWStream* cmap,
+ uint16_t firstGlyphID,
+ uint16_t lastGlyphID) {
if (glyphToUnicode.isEmpty()) {
return;
}
@@ -483,10 +492,11 @@
BFRange currentRangeEntry = {0, 0, 0};
bool rangeEmpty = true;
- const int count = glyphToUnicode.count();
+ const int limit = SkMin32(lastGlyphID + 1, glyphToUnicode.count());
- for (int i = 0; i < count + 1; ++i) {
- bool inSubset = i < count && (subset == NULL || subset->has(i));
+ for (int i = firstGlyphID; i < limit + 1; ++i) {
+ bool inSubset = i < limit &&
+ (subset == NULL || subset->has(i));
if (!rangeEmpty) {
// PDF spec requires bfrange not changing the higher byte,
// e.g. <1035> <10FF> <2222> is ok, but
@@ -494,7 +504,7 @@
bool inRange =
i == currentRangeEntry.fEnd + 1 &&
i >> 8 == currentRangeEntry.fStart >> 8 &&
- i < count &&
+ i < limit &&
glyphToUnicode[i] == currentRangeEntry.fUnicode + i -
currentRangeEntry.fStart;
if (!inSubset || !inRange) {
@@ -526,10 +536,13 @@
static SkPDFStream* generate_tounicode_cmap(
const SkTDArray<SkUnichar>& glyphToUnicode,
- const SkPDFGlyphSet* subset) {
+ const SkPDFGlyphSet* subset,
+ uint16_t firstGlyphID,
+ uint16_t lastGlyphID) {
SkDynamicMemoryWStream cmap;
- append_tounicode_header(&cmap);
- append_cmap_sections(glyphToUnicode, subset, &cmap);
+ append_tounicode_header(&cmap, firstGlyphID, lastGlyphID);
+ append_cmap_sections(glyphToUnicode, subset, &cmap,
+ firstGlyphID, lastGlyphID);
append_cmap_footer(&cmap);
SkAutoTUnref<SkMemoryStream> cmapStream(new SkMemoryStream());
cmapStream->setData(cmap.copyToData())->unref();
@@ -1015,7 +1028,8 @@
return;
}
SkAutoTUnref<SkPDFStream> pdfCmap(
- generate_tounicode_cmap(fFontInfo->fGlyphToUnicode, subset));
+ generate_tounicode_cmap(fFontInfo->fGlyphToUnicode, subset,
+ firstGlyphID(), lastGlyphID()));
addResource(pdfCmap.get());
insert("ToUnicode", new SkPDFObjRef(pdfCmap.get()))->unref();
}