Have draw(Text|PosText|PosTextH) use a single entry on the device

Handle the positioning of drawText at the canvas layer. Simplify
the code by removing similar implementations.

Change-Id: I8b711783435072f560e29fca1dd934fa2e345ed2
Reviewed-on: https://skia-review.googlesource.com/127131
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>

1 files changed, 236 insertions, 0 deletions

diff --git a/src/core/SkGlyphRun.cpp b/src/core/SkGlyphRun.cpp
new file mode 100644
index 0000000000..a25b9afa8e
--- /dev/null
+++ b/src/core/SkGlyphRun.cpp
@@ -0,0 +1,236 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkGlyphRun.h"
+
+#include <algorithm>
+#include <tuple>
+
+#include "SkDraw.h"
+#include "SkGlyphCache.h"
+#include "SkMakeUnique.h"
+#include "SkMSAN.h"
+#include "SkPaint.h"
+#include "SkPaintPriv.h"
+#include "SkStrikeCache.h"
+#include "SkUtils.h"
+
+namespace {
+
+// A faster set implementation that does not need any initialization, and reading the set items
+// is order the number of items, and not the size of the universe.
+// This implementation is based on the paper by Briggs and Torczon, "An Efficient Representation
+// for Sparse Sets"
+class GlyphSet {
+public:
+    GlyphSet(uint32_t glyphUniverseSize)
+    : fUniverseSize{glyphUniverseSize}
+    , fIndexes{skstd::make_unique_default<uint16_t[]>(2 * glyphUniverseSize)}
+    , fUniqueGlyphIDs{&fIndexes[glyphUniverseSize]} {
+        SkASSERT(glyphUniverseSize <= (1 << 16));
+        sk_msan_mark_initialized(fIndexes.get(), &fIndexes[glyphUniverseSize], "works with uninited");
+    }
+
+    uint16_t add(SkGlyphID glyphID) {
+        if (glyphID >= fUniverseSize) {
+            glyphID = kUndefGlyph;
+        }
+        auto index = fIndexes[glyphID];
+        if (index < fUniqueCount && fUniqueGlyphIDs[index] == glyphID) {
+            return index;
+        }
+
+        fUniqueGlyphIDs[fUniqueCount] = glyphID;
+        fIndexes[glyphID] = fUniqueCount;
+        fUniqueCount += 1;
+        return fUniqueCount - 1;
+    }
+
+    std::tuple<uint16_t, std::unique_ptr<SkGlyphID[]>> uniqueGlyphIDs() const {
+        auto uniqueGlyphs = skstd::make_unique_default<SkGlyphID[]>(fUniqueCount);
+        memcpy(uniqueGlyphs.get(), fUniqueGlyphIDs, fUniqueCount * sizeof(SkGlyphID));
+        return std::make_tuple(fUniqueCount, std::move(uniqueGlyphs));
+    }
+
+private:
+    static constexpr SkGlyphID  kUndefGlyph{0};
+    const uint32_t              fUniverseSize;
+    uint16_t                    fUniqueCount{0};
+    std::unique_ptr<uint16_t[]> fIndexes;
+    SkGlyphID*                  fUniqueGlyphIDs;
+ };
+
+template<typename T>
+bool is_aligned(const void* ptr) {
+    uintptr_t bits = reinterpret_cast<uintptr_t>(ptr);
+    return (bits & (alignof(T) - 1)) == 0;
+}
+
+template<typename T>
+bool is_aligned_size(size_t size) {
+    return size % sizeof(T) == 0;
+}
+
+SkTypeface::Encoding convert_encoding(SkPaint::TextEncoding encoding) {
+    switch (encoding) {
+        case  SkPaint::kUTF8_TextEncoding: return SkTypeface::kUTF8_Encoding;
+        case SkPaint::kUTF16_TextEncoding: return SkTypeface::kUTF16_Encoding;
+        case SkPaint::kUTF32_TextEncoding: return SkTypeface::kUTF32_Encoding;
+        default: return SkTypeface::kUTF32_Encoding;
+    }
+}
+
+using Core = std::tuple<size_t,   std::unique_ptr<uint16_t[]>,
+                        uint16_t, std::unique_ptr<SkGlyphID[]>>;
+
+Core make_from_glyphids(size_t glyphCount, const SkGlyphID* glyphs, SkGlyphID maxGlyphID) {
+    if (glyphCount == 0) { return Core(0, nullptr, 0, nullptr); }
+
+    GlyphSet glyphSet{maxGlyphID};
+
+    auto denseIndex = skstd::make_unique_default<uint16_t[]>(glyphCount);
+    for (size_t i = 0; i < glyphCount; i++) {
+        denseIndex[i] = glyphSet.add(glyphs[i]);
+    }
+
+    std::unique_ptr<SkGlyphID[]> uniqueGlyphIDs;
+    uint16_t uniqueCount;
+    std::tie(uniqueCount, uniqueGlyphIDs) = glyphSet.uniqueGlyphIDs();
+
+    return Core(glyphCount, std::move(denseIndex), uniqueCount, std::move(uniqueGlyphIDs));
+}
+
+Core make_from_utfn(size_t byteLength, const void* utfN, const SkTypeface& typeface,
+                    SkTypeface::Encoding encoding) {
+    auto count = SkUTFN_CountUnichars(encoding, utfN, byteLength);
+
+    if (count <= 0) {
+        return Core(0, nullptr, 0, nullptr);
+    }
+
+    auto glyphs = skstd::make_unique_default<SkGlyphID[]>(count);
+
+    // TODO: move to using cached version.
+    typeface.charsToGlyphs(utfN, encoding, glyphs.get(), count);
+
+    return make_from_glyphids(count, glyphs.get(), typeface.countGlyphs());
+}
+
+Core make_core(const SkPaint& paint, const void* bytes, size_t byteLength) {
+    auto encoding = paint.getTextEncoding();
+    auto typeface = SkPaintPriv::GetTypefaceOrDefault(paint);
+    if (encoding == SkPaint::kGlyphID_TextEncoding) {
+        return make_from_glyphids(
+                byteLength / 2, reinterpret_cast<const SkGlyphID*>(bytes), typeface->countGlyphs());
+    } else {
+        return make_from_utfn(byteLength, bytes, *typeface, convert_encoding(encoding));
+    }
+}
+
+}  // namespace
+
+SkGlyphRun SkGlyphRun::MakeFromDrawText(
+        const SkPaint& paint, const void* bytes, size_t byteLength,
+        const SkPoint origin) {
+    size_t runSize;
+    std::unique_ptr<uint16_t[]> denseIndex;
+    uint16_t uniqueSize;
+    std::unique_ptr<SkGlyphID[]> uniqueGlyphIDs;
+    std::tie(runSize, denseIndex, uniqueSize, uniqueGlyphIDs) = make_core(paint, bytes, byteLength);
+
+    if (runSize == 0) { return SkGlyphRun{}; }
+
+    auto advances = skstd::make_unique_default<SkPoint[]>(uniqueSize);
+
+    {
+        auto cache = SkStrikeCache::FindOrCreateStrikeExclusive(paint);
+        cache->getAdvances(SkSpan<SkGlyphID>{uniqueGlyphIDs.get(), uniqueSize}, advances.get());
+    }
+
+    auto positions = skstd::make_unique_default<SkPoint[]>(runSize);
+
+    SkPoint endOfLastGlyph = origin;
+
+    for (size_t i = 0; i < runSize; i++) {
+        positions[i] = endOfLastGlyph;
+        endOfLastGlyph += advances[denseIndex[i]];
+    }
+
+    if (paint.getTextAlign() != SkPaint::kLeft_Align) {
+        SkVector len = endOfLastGlyph - origin;
+        if (paint.getTextAlign() == SkPaint::kCenter_Align) {
+            len.scale(SK_ScalarHalf);
+        }
+        for (size_t i = 0; i < runSize; i++) {
+            positions[i] -= len;
+        }
+    }
+
+    return SkGlyphRun{
+        runSize, std::move(denseIndex), std::move(positions), uniqueSize, std::move(uniqueGlyphIDs)};
+}
+
+SkGlyphRun SkGlyphRun::MakeFromDrawPosTextH(
+        const SkPaint& paint, const void* bytes, size_t byteLength,
+        const SkScalar xpos[], SkScalar constY) {
+    size_t runSize;
+    std::unique_ptr<uint16_t[]> denseIndex;
+    uint16_t uniqueSize;
+    std::unique_ptr<SkGlyphID[]> uniqueGlyphIDs;
+    std::tie(runSize, denseIndex, uniqueSize, uniqueGlyphIDs) = make_core(paint, bytes, byteLength);
+
+    if (runSize == 0) { return SkGlyphRun{}; }
+
+    auto positions = skstd::make_unique_default<SkPoint[]>(runSize);
+
+    for (size_t i = 0; i < runSize; i++) {
+        positions[i] = SkPoint::Make(xpos[i], constY);
+    }
+
+    return SkGlyphRun{
+        runSize, std::move(denseIndex), std::move(positions), uniqueSize, std::move(uniqueGlyphIDs)};
+}
+
+SkGlyphRun SkGlyphRun::MakeFromDrawPosText(
+        const SkPaint& paint, const void* bytes, size_t byteLength,
+        const SkPoint pos[]) {
+    size_t runSize;
+    std::unique_ptr<uint16_t[]> denseIndex;
+    uint16_t uniqueSize;
+    std::unique_ptr<SkGlyphID[]> uniqueGlyphIDs;
+    std::tie(runSize, denseIndex, uniqueSize, uniqueGlyphIDs) = make_core(paint, bytes, byteLength);
+
+    if (runSize == 0) { return SkGlyphRun{}; }
+
+    auto positions = skstd::make_unique_default<SkPoint[]>(runSize);
+
+    memcpy(positions.get(), pos, sizeof(SkPoint) * runSize);
+
+    return SkGlyphRun{
+        runSize, std::move(denseIndex), std::move(positions), uniqueSize, std::move(uniqueGlyphIDs)};
+}
+
+std::unique_ptr<SkGlyphID[]> SkGlyphRun::copyGlyphIDs() const {
+    auto glyphs = skstd::make_unique_default<SkGlyphID[]>(fRunSize);
+
+    for (size_t i = 0; i < fRunSize; i++) {
+        glyphs[i] = fUniqueGlyphs[fDenseIndex[i]];
+    }
+
+    return glyphs;
+}
+
+SkGlyphRun::SkGlyphRun(size_t runSize,
+                       std::unique_ptr<uint16_t[]>&& denseIndex,
+                       std::unique_ptr<SkPoint[]>&& positions,
+                       uint16_t uniqueSize,
+                       std::unique_ptr<SkGlyphID[]>&& uniqueGlyphIDs)
+    : fDenseIndex{std::move(denseIndex)}
+    , fPositions{std::move(positions)}
+    , fUniqueGlyphs{std::move(uniqueGlyphIDs)}
+    , fRunSize{runSize}
+    , fUniqueSize{uniqueSize} { }