Initial Lottie loader impl (Skotty)

Coarse workflow:

* Construction

  1) build a Json tree
  2) collect asset IDs (for preComp/image layer resolution)
  3) "attach" pass
     - traverse the Json tree
     - build an SkSG dom, one fragment at a time
     - attach "animator" objects to the dom, for each animated prop
  4) done, we can throw away the Json tree

* For each animation tick

  1) iterate over active animators and poke their respective dom nodes/attributes
  2) revalidate the SkSG dom
  3) draw the SkSG dom

Note: post construction, things are super-simple - we just poke SkSG DOM attributes
with interpolated values, and everything else is handled by SkSG (invalidation,
revalidation, render).

Change-Id: I96a02be7eb4fb4cb3831f59bf2b3908ea190c0dd
Reviewed-on: https://skia-review.googlesource.com/89420
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>

4 files changed, 133 insertions, 0 deletions

diff --git a/tools/flags/SkCommandLineFlags.h b/tools/flags/SkCommandLineFlags.h
index 15f12d915b..4a22c3f4bf 100644
--- a/tools/flags/SkCommandLineFlags.h
+++ b/tools/flags/SkCommandLineFlags.h
@@ -155,6 +155,9 @@ public:
             fStrings[i].set(str);
         }
 
+        const SkString* begin() const { return fStrings.begin(); }
+        const SkString*   end() const { return fStrings.end(); }
+
     private:
         void reset() { fStrings.reset(); }
 
diff --git a/tools/viewer/SkottySlide.cpp b/tools/viewer/SkottySlide.cpp
new file mode 100644
index 0000000000..d65b7ecbc1
--- /dev/null
+++ b/tools/viewer/SkottySlide.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkottySlide.h"
+
+#include "SkAnimTimer.h"
+#include "Skotty.h"
+#include "SkStream.h"
+
+SkottySlide::SkottySlide(const SkString& name, const SkString& path)
+    : fPath(path) {
+    fName = name;
+}
+
+void SkottySlide::load(SkScalar, SkScalar) {
+    auto stream = SkStream::MakeFromFile(fPath.c_str());
+    fAnimation  = skotty::Animation::Make(stream.get());
+    fTimeBase   = 0; // force a time reset
+
+    if (fAnimation) {
+        SkDebugf("loaded Bodymovin animation v: %s, size: [%f %f], fr: %f\n",
+                 fAnimation->version().c_str(),
+                 fAnimation->size().width(),
+                 fAnimation->size().height(),
+                 fAnimation->frameRate());
+    } else {
+        SkDebugf("failed to load Bodymovin animation: %s\n", fPath.c_str());
+    }
+}
+
+void SkottySlide::unload() {
+    fAnimation.reset();
+}
+
+SkISize SkottySlide::getDimensions() const {
+    return fAnimation? fAnimation->size().toCeil() : SkISize::Make(0, 0);
+}
+
+void SkottySlide::draw(SkCanvas* canvas) {
+    if (fAnimation) {
+        fAnimation->render(canvas);
+    }
+}
+
+bool SkottySlide::animate(const SkAnimTimer& timer) {
+    if (fTimeBase == 0) {
+        // Reset the animation time.
+        fTimeBase = timer.msec();
+    }
+
+    if (fAnimation) {
+        auto t = timer.msec() - fTimeBase;
+        fAnimation->animationTick(t);
+    }
+    return true;
+}
+
+bool SkottySlide::onChar(SkUnichar c) {
+    switch (c) {
+    case 'I':
+        if (fAnimation) {
+            fShowAnimationInval = !fShowAnimationInval;
+            fAnimation->setShowInval(fShowAnimationInval);
+        }
+        break;
+    default:
+        break;
+    }
+
+    return INHERITED::onChar(c);
+}
diff --git a/tools/viewer/SkottySlide.h b/tools/viewer/SkottySlide.h
new file mode 100644
index 0000000000..9b7ae7c890
--- /dev/null
+++ b/tools/viewer/SkottySlide.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkottySlide_DEFINED
+#define SkottySlide_DEFINED
+
+#include "Slide.h"
+
+namespace skotty { class Animation; }
+
+class SkottySlide : public Slide {
+public:
+    SkottySlide(const SkString& name, const SkString& path);
+    ~SkottySlide() override = default;
+
+    void load(SkScalar winWidth, SkScalar winHeight) override;
+    void unload() override;
+
+    SkISize getDimensions() const override;
+
+    void draw(SkCanvas*) override;
+    bool animate(const SkAnimTimer&) override;
+
+    bool onChar(SkUnichar) override;
+
+private:
+    SkString                           fPath;
+    std::unique_ptr<skotty::Animation> fAnimation;
+    SkMSec                             fTimeBase  = 0;
+    bool                               fShowAnimationInval = false;
+
+    typedef Slide INHERITED;
+};
+
+#endif // SkottySlide_DEFINED
diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index 1f701e25b3..55a025c1ed 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -11,6 +11,7 @@
 #include "ImageSlide.h"
 #include "Resources.h"
 #include "SampleSlide.h"
+#include "SkottySlide.h"
 #include "SKPSlide.h"
 
 #include "GrContext.h"
@@ -68,9 +69,11 @@ static DEFINE_bool(list, false, "List samples?");
 #ifdef SK_BUILD_FOR_ANDROID
 static DEFINE_string(skps, "/data/local/tmp/skps", "Directory to read skps from.");
 static DEFINE_string(jpgs, "/data/local/tmp/resources", "Directory to read jpgs from.");
+static DEFINE_string(jsons, "/data/local/tmp/jsons", "Directory to read (Bodymovin) jsons from.");
 #else
 static DEFINE_string(skps, "skps", "Directory to read skps from.");
 static DEFINE_string(jpgs, "jpgs", "Directory to read jpgs from.");
+static DEFINE_string(jsons, "jsons", "Directory to read (Bodymovin) jsons from.");
 #endif
 
 static DEFINE_string2(backend, b, "sw", "Backend to use. Allowed values are " BACKENDS_STR ".");
@@ -480,6 +483,19 @@ void Viewer::initSlides() {
             }
         }
     }
+
+    // JSONs
+    for (const auto& json : FLAGS_jsons) {
+        SkOSFile::Iter it(json.c_str(), ".json");
+        SkString jsonName;
+        while (it.next(&jsonName)) {
+            if (SkCommandLineFlags::ShouldSkip(FLAGS_match, jsonName.c_str())) {
+                continue;
+            }
+            fSlides.push_back(sk_make_sp<SkottySlide>(jsonName, SkOSPath::Join(json.c_str(),
+                                                                               jsonName.c_str())));
+        }
+    }
 }