Sketch splitting SkPicture into an interface and SkBigPicture.

src/core/SkBigPicture.cpp

Index: src/core/SkBigPicture.cpp
diff --git a/src/core/SkBigPicture.cpp b/src/core/SkBigPicture.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..62bc9c03e2c394ee6e73eda50e7d221f5e5c6c8b
--- /dev/null
+++ b/src/core/SkBigPicture.cpp
@@ -0,0 +1,220 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBBoxHierarchy.h"
+#include "SkBigPicture.h"
+#include "SkPathEffect.h"
+#include "SkRecord.h"
+#include "SkRecordDraw.h"
+
+SkBigPicture::SkBigPicture(const SkRect& cull,
+                           SkRecord* record,
+                           SnapshotArray* drawablePicts,
+                           SkBBoxHierarchy* bbh,
+                           AccelData* accelData,
+                           size_t approxBytesUsedBySubPictures)
+    : fCullRect(cull)
+    , fAnalysis(*record)
+    , fApproxBytesUsedBySubPictures(approxBytesUsedBySubPictures)
+    , fRecord(record)               // Take ownership of caller's ref.
+    , fDrawablePicts(drawablePicts) // Take ownership.
+    , fBBH(bbh)                     // Take ownership of caller's ref.
+    , fAccelData(accelData)         // Take ownership of caller's ref.
+{}
+
+void SkBigPicture::playback(SkCanvas* canvas, AbortCallback* callback) const {
+    SkASSERT(canvas);
+
+    // If the query contains the whole picture, don't bother with the BBH.
+    SkRect clipBounds = { 0, 0, 0, 0 };
+    (void)canvas->getClipBounds(&clipBounds);
+    const bool useBBH = !clipBounds.contains(this->cullRect());
+
+    SkRecordDraw(*fRecord,
+                 canvas,
+                 this->drawablePicts(),
+                 nullptr,
+                 this->drawableCount(),
+                 useBBH ? fBBH : nullptr,
+                 callback);
+}
+
+void SkBigPicture::partialPlayback(SkCanvas* canvas,
+                                   unsigned start,
+                                   unsigned stop,
+                                   const SkMatrix& initialCTM) const {
+    SkASSERT(canvas);
+    SkRecordPartialDraw(*fRecord,
+                        canvas,
+                        this->drawablePicts(),
+                        this->drawableCount(),
+                        start,
+                        stop,
+                        initialCTM);
+}
+
+SkRect SkBigPicture::cullRect()             const { return fCullRect; }
+bool   SkBigPicture::hasText()              const { return fAnalysis.fHasText; }
+bool   SkBigPicture::willPlayBackBitmaps()  const { return fAnalysis.fWillPlaybackBitmaps; }
+int    SkBigPicture::numSlowPaths()         const { return fAnalysis.fNumSlowPathsAndDashEffects; }
+int    SkBigPicture::approximateOpCount()   const { return fRecord->count(); }
+size_t SkBigPicture::approximateBytesUsed() const {
+    size_t bytes = sizeof(*this) + fRecord->bytesUsed() + fApproxBytesUsedBySubPictures;
+    if (fBBH) { bytes += fBBH->bytesUsed(); }
+    return bytes;
+}
+bool SkBigPicture::suitableForGpuRasterization(GrContext*, const char** reason) const {
+    return fAnalysis.suitableForGpuRasterization(reason);
+}
+
+int SkBigPicture::drawableCount() const {
+    return fDrawablePicts ? fDrawablePicts->count() : 0;
+}
+SkPicture const* const* SkBigPicture::drawablePicts() const {
+    return fDrawablePicts ? fDrawablePicts->begin() : nullptr;
+}
+
+
+// Some ops have a paint, some have an optional paint.  Either way, get back a pointer.
+static const SkPaint* as_ptr(const SkPaint& p) { return &p; }
+static const SkPaint* as_ptr(const SkRecords::Optional<SkPaint>& p) { return p; }
+
+struct TextHunter {
+    // Most ops never have text.  Some always do.  Subpictures know themeselves.
+    template <typename T> bool operator()(const T&) { return false; }
+    bool operator()(const SkRecords::DrawPosText&)    { return true; }
+    bool operator()(const SkRecords::DrawPosTextH&)   { return true; }
+    bool operator()(const SkRecords::DrawText&)       { return true; }
+    bool operator()(const SkRecords::DrawTextBlob&)   { return true; }
+    bool operator()(const SkRecords::DrawTextOnPath&) { return true; }
+    bool operator()(const SkRecords::DrawPicture& op) { return op.picture->hasText(); }
+};
+
+struct BitmapHunter {
+    // Helpers.  These create HasMember_bitmap and HasMember_paint.
+    SK_CREATE_MEMBER_DETECTOR(bitmap);
+    SK_CREATE_MEMBER_DETECTOR(paint);
+
+    // Main entry for visitor:
+    // If the op is a DrawPicture, recurse.
+    // If the op has a bitmap directly, return true.
+    // If the op has a paint and the paint has a bitmap, return true.
+    // Otherwise, return false.
+    bool operator()(const SkRecords::DrawPicture& op) { return op.picture->willPlayBackBitmaps(); }
+
+    template <typename T>
+    bool operator()(const T& r) { return CheckBitmap(r); }
+
+    // If the op has a bitmap, of course we're going to play back bitmaps.
+    template <typename T>
+    static SK_WHEN(HasMember_bitmap<T>, bool) CheckBitmap(const T&) { return true; }
+
+    // If not, look for one in its paint (if it has a paint).
+    template <typename T>
+    static SK_WHEN(!HasMember_bitmap<T>, bool) CheckBitmap(const T& r) { return CheckPaint(r); }
+
+    // If we have a paint, dig down into the effects looking for a bitmap.
+    template <typename T>
+    static SK_WHEN(HasMember_paint<T>, bool) CheckPaint(const T& r) {
+        const SkPaint* paint = as_ptr(r.paint);
+        if (paint) {
+            const SkShader* shader = paint->getShader();
+            if (shader &&
+                shader->asABitmap(nullptr, nullptr, nullptr) == SkShader::kDefault_BitmapType) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    // If we don't have a paint, that non-paint has no bitmap.
+    template <typename T>
+    static SK_WHEN(!HasMember_paint<T>, bool) CheckPaint(const T&) { return false; }
+};
+
+struct SkBigPicture::PathCounter {
+    SK_CREATE_MEMBER_DETECTOR(paint);
+
+    PathCounter() : fNumSlowPathsAndDashEffects(0) {}
+
+    // Recurse into nested pictures.
+    void operator()(const SkRecords::DrawPicture& op) {
+        fNumSlowPathsAndDashEffects += op.picture->numSlowPaths();
+    }
+
+    void checkPaint(const SkPaint* paint) {
+        if (paint && paint->getPathEffect()) {
+            // Initially assume it's slow.
+            fNumSlowPathsAndDashEffects++;
+        }
+    }
+
+    void operator()(const SkRecords::DrawPoints& op) {
+        this->checkPaint(&op.paint);
+        const SkPathEffect* effect = op.paint.getPathEffect();
+        if (effect) {
+            SkPathEffect::DashInfo info;
+            SkPathEffect::DashType dashType = effect->asADash(&info);
+            if (2 == op.count && SkPaint::kRound_Cap != op.paint.getStrokeCap() &&
+                SkPathEffect::kDash_DashType == dashType && 2 == info.fCount) {
+                fNumSlowPathsAndDashEffects--;
+            }
+        }
+    }
+
+    void operator()(const SkRecords::DrawPath& op) {
+        this->checkPaint(&op.paint);
+        if (op.paint.isAntiAlias() && !op.path.isConvex()) {
+            SkPaint::Style paintStyle = op.paint.getStyle();
+            const SkRect& pathBounds = op.path.getBounds();
+            if (SkPaint::kStroke_Style == paintStyle &&
+                0 == op.paint.getStrokeWidth()) {
+                // AA hairline concave path is not slow.
+            } else if (SkPaint::kFill_Style == paintStyle && pathBounds.width() < 64.f &&
+                       pathBounds.height() < 64.f && !op.path.isVolatile()) {
+                // AADF eligible concave path is not slow.
+            } else {
+                fNumSlowPathsAndDashEffects++;
+            }
+        }
+    }
+
+    template <typename T>
+    SK_WHEN(HasMember_paint<T>, void) operator()(const T& op) {
+        this->checkPaint(as_ptr(op.paint));
+    }
+
+    template <typename T>
+    SK_WHEN(!HasMember_paint<T>, void) operator()(const T& op) { /* do nothing */ }
+
+    int fNumSlowPathsAndDashEffects;
+};
+
+SkBigPicture::Analysis::Analysis(const SkRecord& record) {
+    TextHunter   text;
+    BitmapHunter bitmap;
+    PathCounter  path;
+
+    bool hasText = false, hasBitmap = false;
+    for (unsigned i = 0; i < record.count(); i++) {
+        hasText   = hasText   || record.visit<bool>(i,   text);
+        hasBitmap = hasBitmap || record.visit<bool>(i, bitmap);
+        record.visit<void>(i, path);
+    }
+
+    fHasText                    = hasText;
+    fWillPlaybackBitmaps        = hasBitmap;
+    fNumSlowPathsAndDashEffects = SkTMin<int>(path.fNumSlowPathsAndDashEffects, 255);
+}
+
+bool SkBigPicture::Analysis::suitableForGpuRasterization(const char** reason) const {
+    if (fNumSlowPathsAndDashEffects > 5) {
+        if (reason) { *reason = "Too many slow paths (either concave or dashed)."; }
+        return false;
+    }
+    return true;
+}