SkPDF: Non-outline glyphs as images

    - Cache images in PDF Canon for de-duping
    - For now, rasterize at text scale.  in the future, look at CTM and
      fRasterScale.
    - add a test that works on MacOS

BUG=chromium:705480
BUG=skia:3489
Change-Id: I4fbc42f218e5b81ea15ea6cdccc61c91e532f6d0
Reviewed-on: https://skia-review.googlesource.com/24080
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>

1 files changed, 198 insertions, 96 deletions

diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index bbc09f7ed6..7a2d51c848 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -1320,6 +1320,12 @@ static SkPath draw_text_as_path(const void* sourceText, size_t sourceByteCount,
     return path;
 }
 
+static bool has_outline_glyph(SkGlyphID gid, SkGlyphCache* cache) {
+    const SkGlyph& glyph = cache->getGlyphIDMetrics(gid);
+    const SkPath* path = cache->findPath(glyph);
+    return (path && !path->isEmpty()) || (glyph.fWidth == 0 && glyph.fHeight == 0);
+}
+
 static SkRect get_glyph_bounds_device_space(SkGlyphID gid, SkGlyphCache* cache,
                                             SkScalar xScale, SkScalar yScale,
                                             SkPoint xy, const SkMatrix& ctm) {
@@ -1338,6 +1344,46 @@ static bool contains(const SkRect& r, SkPoint p) {
           r.top()  <= p.y() && p.y() <= r.bottom();
 }
 
+static sk_sp<SkImage> image_from_mask(const SkMask& mask) {
+    if (!mask.fImage) {
+        return nullptr;
+    }
+    SkIRect bounds = mask.fBounds;
+    SkBitmap bm;
+    switch (mask.fFormat) {
+        case SkMask::kBW_Format:
+            bm.allocPixels(SkImageInfo::MakeA8(bounds.width(), bounds.height()));
+            for (int y = 0; y < bm.height(); ++y) {
+                for (int x8 = 0; x8 < bm.width(); x8 += 8) {
+                    uint8_t v = *mask.getAddr1(x8 + bounds.x(), y + bounds.y());
+                    int e = SkTMin(x8 + 8, bm.width());
+                    for (int x = x8; x < e; ++x) {
+                        *bm.getAddr8(x, y) = (v >> (x & 0x7)) & 0x1 ? 0xFF : 0x00;
+                    }
+                }
+            }
+            bm.setImmutable();
+            return SkImage::MakeFromBitmap(bm);
+        case SkMask::kA8_Format:
+            bm.installPixels(SkImageInfo::MakeA8(bounds.width(), bounds.height()),
+                             mask.fImage, mask.fRowBytes);
+            return SkMakeImageFromRasterBitmap(bm, kAlways_SkCopyPixelsMode);
+        case SkMask::kARGB32_Format:
+            bm.installPixels(SkImageInfo::MakeN32Premul(bounds.width(), bounds.height()),
+                             mask.fImage, mask.fRowBytes);
+            return SkMakeImageFromRasterBitmap(bm, kAlways_SkCopyPixelsMode);
+        case SkMask::k3D_Format:
+            SkASSERT(false);
+            return nullptr;
+        case SkMask::kLCD16_Format:
+            SkASSERT(false);
+            return nullptr;
+        default:
+            SkASSERT(false);
+            return nullptr;
+    }
+}
+
 void SkPDFDevice::internalDrawText(
         const void* sourceText, size_t sourceByteCount,
         const SkScalar pos[], SkTextBlob::GlyphPositioning positioning,
@@ -1439,113 +1485,169 @@ void SkPDFDevice::internalDrawText(
         offset.offset(alignmentFactor * advance, 0);
     }
     SkRect clipStackBounds = this->cs().bounds(size(*this));
-    ScopedContentEntry content(this, paint, true);
-    if (!content.entry()) {
-        return;
-    }
-    SkDynamicMemoryWStream* out = content.stream();
-    const SkTDArray<SkUnichar>& glyphToUnicode = metrics->fGlyphToUnicode;
-
-    out->writeText("BT\n");
-    SK_AT_SCOPE_EXIT(out->writeText("ET\n"));
-
-    const SkGlyphID maxGlyphID = SkToU16(typeface->countGlyphs() - 1);
-
-    bool multiByteGlyphs = SkPDFFont::IsMultiByte(SkPDFFont::FontType(*metrics));
-    if (clusterator.reversedChars()) {
-        out->writeText("/ReversedChars BMC\n");
-    }
-    SK_AT_SCOPE_EXIT(if (clusterator.reversedChars()) { out->writeText("EMC\n"); } );
-    GlyphPositioner glyphPositioner(out,
-                                    paint.getTextSkewX(),
-                                    multiByteGlyphs,
-                                    defaultPositioning,
-                                    offset);
-    SkPDFFont* font = nullptr;
-
-    while (Clusterator::Cluster c = clusterator.next()) {
-        int index = c.fGlyphIndex;
-        int glyphLimit = index + c.fGlyphCount;
-
-        bool actualText = false;
-        SK_AT_SCOPE_EXIT(if (actualText) { glyphPositioner.flush(); out->writeText("EMC\n"); } );
-        if (c.fUtf8Text) {  // real cluster
-            // Check if `/ActualText` needed.
-            const char* textPtr = c.fUtf8Text;
-            const char* textEnd = c.fUtf8Text + c.fTextByteLength;
-            SkUnichar unichar = SkUTF8_NextUnicharWithError(&textPtr, textEnd);
-            if (unichar < 0) {
-                return;
-            }
-            if (textPtr < textEnd ||                                  // more characters left
-                glyphLimit > index + 1 ||                             // toUnicode wouldn't work
-                unichar != map_glyph(glyphToUnicode, glyphs[index]))  // test single Unichar map
-            {
-                glyphPositioner.flush();
-                out->writeText("/Span<</ActualText <");
-                SkPDFUtils::WriteUTF16beHex(out, 0xFEFF);  // U+FEFF = BYTE ORDER MARK
-                // the BOM marks this text as UTF-16BE, not PDFDocEncoding.
-                SkPDFUtils::WriteUTF16beHex(out, unichar);  // first char
-                while (textPtr < textEnd) {
-                    unichar = SkUTF8_NextUnicharWithError(&textPtr, textEnd);
-                    if (unichar < 0) {
-                        break;
-                    }
-                    SkPDFUtils::WriteUTF16beHex(out, unichar);
-                }
-                out->writeText("> >> BDC\n");  // begin marked-content sequence
-                                               // with an associated property list.
-                actualText = true;
-            }
+    struct PositionedGlyph {
+        SkPoint fPos;
+        SkGlyphID fGlyph;
+    };
+    SkTArray<PositionedGlyph> fMissingGlyphs;
+    {
+        ScopedContentEntry content(this, paint, true);
+        if (!content.entry()) {
+            return;
         }
-        for (; index < glyphLimit; ++index) {
-            SkGlyphID gid = glyphs[index];
-            if (gid > maxGlyphID) {
-                continue;
-            }
-            if (!font || !font->hasGlyph(gid)) {
-                // Not yet specified font or need to switch font.
-                int fontIndex = this->getFontResourceIndex(typeface, gid);
-                // All preconditions for SkPDFFont::GetFontResource are met.
-                SkASSERT(fontIndex >= 0);
-                if (fontIndex < 0) {
+        SkDynamicMemoryWStream* out = content.stream();
+        const SkTDArray<SkUnichar>& glyphToUnicode = metrics->fGlyphToUnicode;
+
+        out->writeText("BT\n");
+        SK_AT_SCOPE_EXIT(out->writeText("ET\n"));
+
+        const SkGlyphID maxGlyphID = SkToU16(typeface->countGlyphs() - 1);
+
+        bool multiByteGlyphs = SkPDFFont::IsMultiByte(SkPDFFont::FontType(*metrics));
+        if (clusterator.reversedChars()) {
+            out->writeText("/ReversedChars BMC\n");
+        }
+        SK_AT_SCOPE_EXIT(if (clusterator.reversedChars()) { out->writeText("EMC\n"); } );
+        GlyphPositioner glyphPositioner(out,
+                                        paint.getTextSkewX(),
+                                        multiByteGlyphs,
+                                        defaultPositioning,
+                                        offset);
+        SkPDFFont* font = nullptr;
+
+        while (Clusterator::Cluster c = clusterator.next()) {
+            int index = c.fGlyphIndex;
+            int glyphLimit = index + c.fGlyphCount;
+
+            bool actualText = false;
+            SK_AT_SCOPE_EXIT(if (actualText) {
+                                 glyphPositioner.flush();
+                                 out->writeText("EMC\n");
+                             });
+            if (c.fUtf8Text) {  // real cluster
+                // Check if `/ActualText` needed.
+                const char* textPtr = c.fUtf8Text;
+                const char* textEnd = c.fUtf8Text + c.fTextByteLength;
+                SkUnichar unichar = SkUTF8_NextUnicharWithError(&textPtr, textEnd);
+                if (unichar < 0) {
                     return;
                 }
-                glyphPositioner.flush();
-                update_font(out, fontIndex, textSize);
-                font = fFontResources[fontIndex];
-                SkASSERT(font);  // All preconditions for SkPDFFont::GetFontResource are met.
-                if (!font) {
-                    return;
+                if (textPtr < textEnd ||                                  // more characters left
+                    glyphLimit > index + 1 ||                             // toUnicode wouldn't work
+                    unichar != map_glyph(glyphToUnicode, glyphs[index]))  // test single Unichar map
+                {
+                    glyphPositioner.flush();
+                    out->writeText("/Span<</ActualText <");
+                    SkPDFUtils::WriteUTF16beHex(out, 0xFEFF);  // U+FEFF = BYTE ORDER MARK
+                    // the BOM marks this text as UTF-16BE, not PDFDocEncoding.
+                    SkPDFUtils::WriteUTF16beHex(out, unichar);  // first char
+                    while (textPtr < textEnd) {
+                        unichar = SkUTF8_NextUnicharWithError(&textPtr, textEnd);
+                        if (unichar < 0) {
+                            break;
+                        }
+                        SkPDFUtils::WriteUTF16beHex(out, unichar);
+                    }
+                    out->writeText("> >> BDC\n");  // begin marked-content sequence
+                                                   // with an associated property list.
+                    actualText = true;
                 }
-                SkASSERT(font->multiByteGlyphs() == multiByteGlyphs);
             }
-            SkPoint xy{0, 0};
-            SkScalar advance{0};
-            if (!defaultPositioning) {
-                advance = advanceScale * glyphCache->getGlyphIDAdvance(gid).fAdvanceX;
-                xy = SkTextBlob::kFull_Positioning == positioning
-                   ? SkPoint{pos[2 * index], pos[2 * index + 1]}
-                   : SkPoint{pos[index], 0};
-                if (alignment != SkPaint::kLeft_Align) {
-                    xy.offset(alignmentFactor * advance, 0);
+            for (; index < glyphLimit; ++index) {
+                SkGlyphID gid = glyphs[index];
+                if (gid > maxGlyphID) {
+                    continue;
                 }
-                // Do a glyph-by-glyph bounds-reject if positions are absolute.
-                SkRect glyphBounds = get_glyph_bounds_device_space(
-                        gid, glyphCache.get(), textScaleX, textScaleY, xy + offset, this->ctm());
-                if (glyphBounds.isEmpty()) {
-                    if (!contains(clipStackBounds, {glyphBounds.x(), glyphBounds.y()})) {
-                        continue;
+                if (!font || !font->hasGlyph(gid)) {
+                    // Not yet specified font or need to switch font.
+                    int fontIndex = this->getFontResourceIndex(typeface, gid);
+                    // All preconditions for SkPDFFont::GetFontResource are met.
+                    SkASSERT(fontIndex >= 0);
+                    if (fontIndex < 0) {
+                        return;
+                    }
+                    glyphPositioner.flush();
+                    update_font(out, fontIndex, textSize);
+                    font = fFontResources[fontIndex];
+                    SkASSERT(font);  // All preconditions for SkPDFFont::GetFontResource are met.
+                    if (!font) {
+                        return;
+                    }
+                    SkASSERT(font->multiByteGlyphs() == multiByteGlyphs);
+                }
+                SkPoint xy = {};
+                SkScalar advance = advanceScale * glyphCache->getGlyphIDAdvance(gid).fAdvanceX;
+                if (!defaultPositioning) {
+                    xy = SkTextBlob::kFull_Positioning == positioning
+                       ? SkPoint{pos[2 * index], pos[2 * index + 1]}
+                       : SkPoint{pos[index], 0};
+                    if (alignment != SkPaint::kLeft_Align) {
+                        xy.offset(alignmentFactor * advance, 0);
+                    }
+                    // Do a glyph-by-glyph bounds-reject if positions are absolute.
+                    SkRect glyphBounds = get_glyph_bounds_device_space(
+                            gid, glyphCache.get(), textScaleX, textScaleY,
+                            xy + offset, this->ctm());
+                    if (glyphBounds.isEmpty()) {
+                        if (!contains(clipStackBounds, {glyphBounds.x(), glyphBounds.y()})) {
+                            continue;
+                        }
+                    } else {
+                        if (!clipStackBounds.intersects(glyphBounds)) {
+                            continue;  // reject glyphs as out of bounds
+                        }
+                    }
+                    if (!has_outline_glyph(gid, glyphCache.get())) {
+                        fMissingGlyphs.push_back({xy, gid});
                     }
                 } else {
-                    if (!clipStackBounds.intersects(glyphBounds)) {
-                        continue;  // reject glyphs as out of bounds
+                    if (!has_outline_glyph(gid, glyphCache.get())) {
+                        fMissingGlyphs.push_back({offset, gid});
                     }
+                    offset += SkPoint{advance, 0};
                 }
+                font->noteGlyphUsage(gid);
+
+                SkGlyphID encodedGlyph = multiByteGlyphs ? gid : font->glyphToPDFFontEncoding(gid);
+                glyphPositioner.writeGlyph(xy, advance, encodedGlyph);
+            }
+        }
+    }
+    if (fMissingGlyphs.count() > 0) {
+        // Fall back on images.
+        SkPaint scaledGlyphCachePaint;
+        scaledGlyphCachePaint.setTextSize(paint.getTextSize());
+        scaledGlyphCachePaint.setTextScaleX(paint.getTextScaleX());
+        scaledGlyphCachePaint.setTextSkewX(paint.getTextSkewX());
+        scaledGlyphCachePaint.setTypeface(sk_ref_sp(typeface));
+        SkAutoGlyphCache scaledGlyphCache(scaledGlyphCachePaint, nullptr, nullptr);
+        SkTHashMap<SkPDFCanon::BitmapGlyphKey, SkPDFCanon::BitmapGlyph>* map =
+            &this->getCanon()->fBitmapGlyphImages;
+        for (PositionedGlyph positionedGlyph : fMissingGlyphs) {
+            SkPDFCanon::BitmapGlyphKey key = {typeface->uniqueID(),
+                                              paint.getTextSize(),
+                                              paint.getTextScaleX(),
+                                              paint.getTextSkewX(),
+                                              positionedGlyph.fGlyph,
+                                              0};
+            SkImage* img = nullptr;
+            SkIPoint imgOffset = {0, 0};
+            if (SkPDFCanon::BitmapGlyph* ptr = map->find(key)) {
+                img = ptr->fImage.get();
+                imgOffset = ptr->fOffset;
+            } else {
+                (void)scaledGlyphCache->findImage(
+                        scaledGlyphCache->getGlyphIDMetrics(positionedGlyph.fGlyph));
+                SkMask mask;
+                scaledGlyphCache->getGlyphIDMetrics(positionedGlyph.fGlyph).toMask(&mask);
+                imgOffset = {mask.fBounds.x(), mask.fBounds.y()};
+                img = map->set(key, {image_from_mask(mask), imgOffset})->fImage.get();
+            }
+            if (img) {
+                SkPoint pt = positionedGlyph.fPos +
+                             SkPoint{(SkScalar)imgOffset.x(), (SkScalar)imgOffset.y()};
+                this->drawImage(img, pt.x(), pt.y(), srcPaint);
             }
-            font->noteGlyphUsage(gid);
-            SkGlyphID encodedGlyph = multiByteGlyphs ? gid : font->glyphToPDFFontEncoding(gid);
-            glyphPositioner.writeGlyph(xy, advance, encodedGlyph);
         }
     }
 }