Update PDF backend to support fallback fonts on Android.
R=edisonn@google.com, reed@google.com, vandebo@chromium.org
Review URL: https://codereview.chromium.org/24364008
git-svn-id: http://skia.googlecode.com/svn/trunk@11586 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index d13d30c..e4b07f0 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -33,6 +33,22 @@
#include "SkTypefacePriv.h"
#include "SkTSet.h"
+#ifdef SK_BUILD_FOR_ANDROID
+#include "SkTypeface_android.h"
+
+struct TypefaceFallbackData {
+ SkTypeface* typeface;
+ int lowerBounds;
+ int upperBounds;
+
+ bool operator==(const TypefaceFallbackData& b) const {
+ return typeface == b.typeface &&
+ lowerBounds == b.lowerBounds &&
+ upperBounds == b.upperBounds;
+ }
+};
+#endif
+
// Utility functions
static void emit_pdf_color(SkColor color, SkWStream* result) {
@@ -1115,6 +1131,112 @@
return;
}
+#ifdef SK_BUILD_FOR_ANDROID
+ /*
+ * In the case that we have enabled fallback fonts on Android we need to
+ * take the following steps to ensure that the PDF draws all characters,
+ * regardless of their underlying font file, correctly.
+ *
+ * 1. Convert input into GlyphID encoding if it currently is not
+ * 2. Iterate over the glyphIDs and identify the actual typeface that each
+ * glyph resolves to
+ * 3. Iterate over those typefaces and recursively call this function with
+ * only the glyphs (and their positions) that the typeface is capable of
+ * resolving.
+ */
+ if (paint.getPaintOptionsAndroid().isUsingFontFallbacks()) {
+ uint16_t* glyphIDs = NULL;
+ SkGlyphStorage tmpStorage(0);
+ size_t numGlyphs = 0;
+
+ // convert to glyphIDs
+ if (paint.getTextEncoding() == SkPaint::kGlyphID_TextEncoding) {
+ numGlyphs = len / 2;
+ glyphIDs = reinterpret_cast<uint16_t*>(const_cast<void*>(text));
+ } else {
+ numGlyphs = paint.textToGlyphs(text, len, NULL);
+ tmpStorage.reset(numGlyphs);
+ paint.textToGlyphs(text, len, tmpStorage.get());
+ glyphIDs = tmpStorage.get();
+ }
+
+ // if no typeface is provided in the paint get the default
+ SkAutoTUnref<SkTypeface> origFace(SkSafeRef(paint.getTypeface()));
+ if (NULL == origFace.get()) {
+ origFace.reset(SkTypeface::RefDefault());
+ }
+ const uint16_t origGlyphCount = origFace->countGlyphs();
+
+ // keep a list of the already visited typefaces and some data about them
+ SkTDArray<TypefaceFallbackData> visitedTypefaces;
+
+ // find all the typefaces needed to resolve this run of text
+ bool usesOriginalTypeface = false;
+ for (uint16_t x = 0; x < numGlyphs; ++x) {
+ // optimization that checks to see if original typeface can resolve the glyph
+ if (glyphIDs[x] < origGlyphCount) {
+ usesOriginalTypeface = true;
+ continue;
+ }
+
+ // find the fallback typeface that supports this glyph
+ TypefaceFallbackData data;
+ data.typeface = SkGetTypefaceForGlyphID(glyphIDs[x], origFace.get(),
+ paint.getPaintOptionsAndroid(),
+ &data.lowerBounds, &data.upperBounds);
+ // add the typeface and its data if we don't have it
+ if (data.typeface && !visitedTypefaces.contains(data)) {
+ visitedTypefaces.push(data);
+ }
+ }
+
+ // if the original font was used then add it to the list as well
+ if (usesOriginalTypeface) {
+ TypefaceFallbackData* data = visitedTypefaces.push();
+ data->typeface = origFace.get();
+ data->lowerBounds = 0;
+ data->upperBounds = origGlyphCount;
+ }
+
+ // keep a scratch glyph and pos storage
+ SkAutoTMalloc<SkScalar> posStorage(len * scalarsPerPos);
+ SkScalar* tmpPos = posStorage.get();
+ SkGlyphStorage glyphStorage(numGlyphs);
+ uint16_t* tmpGlyphIDs = glyphStorage.get();
+
+ // loop through all the valid typefaces, trim the glyphs to only those
+ // resolved by the typeface, and then draw that run of glyphs
+ for (int x = 0; x < visitedTypefaces.count(); ++x) {
+ const TypefaceFallbackData& data = visitedTypefaces[x];
+
+ int tmpGlyphCount = 0;
+ for (uint16_t y = 0; y < numGlyphs; ++y) {
+ if (glyphIDs[y] >= data.lowerBounds && glyphIDs[y] < data.upperBounds) {
+ tmpGlyphIDs[tmpGlyphCount] = glyphIDs[y] - data.lowerBounds;
+ memcpy(&(tmpPos[tmpGlyphCount * scalarsPerPos]),
+ &(pos[y * scalarsPerPos]),
+ scalarsPerPos * sizeof(SkScalar));
+ tmpGlyphCount++;
+ }
+ }
+
+ // recursively call this function with the right typeface
+ SkPaint tmpPaint = paint;
+ tmpPaint.setTypeface(data.typeface);
+ tmpPaint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+
+ // turn off fallback chaining
+ SkPaintOptionsAndroid paintOpts = tmpPaint.getPaintOptionsAndroid();
+ paintOpts.setUseFontFallbacks(false);
+ tmpPaint.setPaintOptionsAndroid(paintOpts);
+
+ this->drawPosText(d, tmpGlyphIDs, tmpGlyphCount * 2, tmpPos, constY,
+ scalarsPerPos, tmpPaint);
+ }
+ return;
+ }
+#endif
+
SkGlyphStorage storage(0);
uint16_t* glyphIDs = NULL;
size_t numGlyphs = force_glyph_encoding(paint, text, len, &storage,