Add test for typeface style round trip.

tests/TypefaceTest.cpp

Index: tests/TypefaceTest.cpp
diff --git a/tests/TypefaceTest.cpp b/tests/TypefaceTest.cpp
index 4c65fa3f9d8e08d018a3c980a669ef56c6727951..33fa887f52f615be8220649b47e477ae7053e357 100644
--- a/tests/TypefaceTest.cpp
+++ b/tests/TypefaceTest.cpp
@@ -5,11 +5,89 @@
  * found in the LICENSE file.
  */
 
+#include "SkData.h"
+#include "SkOTTable_OS_2.h"
+#include "SkSFNTHeader.h"
+#include "SkStream.h"
 #include "SkRefCnt.h"
 #include "SkTypeface.h"
 #include "SkTypefaceCache.h"
+#include "Resources.h"
 #include "Test.h"
 
+#include <memory>
+
+static void TypefaceStyle_test(skiatest::Reporter* reporter,
+                               uint16_t weight, uint16_t width, SkData* data)
+{
+    sk_sp<SkData> dataCopy;
+    SkData* dataToUse = data;
+    if (!dataToUse->unique()) {
+        dataCopy = SkData::MakeWithCopy(data->data(), data->size());
+        dataToUse = dataCopy.get();
+    }
+    SkSFNTHeader* sfntHeader = static_cast<SkSFNTHeader*>(dataToUse->writable_data());
+
+    SkSFNTHeader::TableDirectoryEntry* tableEntry =
+        SkTAfter<SkSFNTHeader::TableDirectoryEntry>(sfntHeader);
+    SkSFNTHeader::TableDirectoryEntry* os2TableEntry = nullptr;
+    int numTables = SkEndian_SwapBE16(sfntHeader->numTables);
+    for (int tableEntryIndex = 0; tableEntryIndex < numTables; ++tableEntryIndex) {
+        if (SkOTTableOS2::TAG == tableEntry[tableEntryIndex].tag) {
+            os2TableEntry = tableEntry + tableEntryIndex;
+            break;
+        }
+    }
+    SkASSERT_RELEASE(os2TableEntry);
+
+    size_t os2TableOffset = SkEndian_SwapBE32(os2TableEntry->offset);
+    SkOTTableOS2_V0* os2Table = SkTAddOffset<SkOTTableOS2_V0>(sfntHeader, os2TableOffset);
+    os2Table->usWeightClass.value = SkEndian_SwapBE16(weight);
+    using WidthType = SkOTTableOS2_V0::WidthClass::Value;
+    os2Table->usWidthClass.value = static_cast<WidthType>(SkEndian_SwapBE16(width));
+
+    sk_sp<SkTypeface> newTypeface(SkTypeface::MakeFromStream(new SkMemoryStream(dataToUse)));
+    SkASSERT_RELEASE(newTypeface);
+
+    SkFontStyle newStyle = newTypeface->fontStyle();
+
+    //printf("%d, %f\n", weight, (newStyle.weight() - (float)0x7FFF) / (float)0x7FFF);
+    //printf("%d, %f\n", width , (newStyle.width()  - (float)0x7F)   / (float)0x7F);
+    //printf("%d, %d\n", weight, newStyle.weight());
+    //printf("%d, %d\n", width , newStyle.width());
+
+    // Some back-ends (CG, GDI, DW) support OS/2 version A which uses 0 - 10 (but all differently).
+    REPORTER_ASSERT(reporter,
+                    newStyle.weight() == weight ||
+                    (weight <=   10 && newStyle.weight() == 100 * weight) ||
+                    (weight ==    4 && newStyle.weight() == 350) ||  // GDI weirdness
+                    (weight ==    5 && newStyle.weight() == 400) ||  // GDI weirdness
+                    (weight ==    0 && newStyle.weight() ==   1) ||  // DW weirdness
+                    (weight == 1000 && newStyle.weight() == 999)     // DW weirdness
+    );
+
+    // Some back-ends (GDI) don't support width, ensure these always report 'medium'.
+    REPORTER_ASSERT(reporter,
+                    newStyle.width() == width ||
+                    newStyle.width() == 5);
+}
+DEF_TEST(TypefaceStyle, reporter) {
+    std::unique_ptr<SkStreamAsset> stream(GetResourceAsStream("/fonts/Em.ttf"));
+    if (!stream) {
+        REPORT_FAILURE(reporter, "/fonts/Em.ttf", SkString("Cannot load resource"));
+        return;
+    }
+    sk_sp<SkData> data(SkData::MakeFromStream(stream.get(), stream->getLength()));
+
+    using SkFS = SkFontStyle;
+    for (int weight = SkFS::kInvisible_Weight; weight <= SkFS::kExtraBlack_Weight; ++weight) {
+        TypefaceStyle_test(reporter, weight, 5, data.get());
+    }
+    for (int width = SkFS::kUltraCondensed_Width; width <= SkFS::kUltaExpanded_Width; ++width) {
+        TypefaceStyle_test(reporter, 400, width, data.get());
+    }
+}
+
 DEF_TEST(Typeface, reporter) {
 
     sk_sp<SkTypeface> t1(SkTypeface::MakeFromName(nullptr, SkFontStyle()));