Add spinning_square example (#2928)

Also, teach gn how to build application bundles.

.gitignore

@@ -9,7 +9,6 @@
 .checkstyle
 .gdbinit
 .landmines
-.packages
 .project
 .pub
 .pydevproject

BUILD.gn

@@ -9,6 +9,7 @@ group("flutter") {
     # TODO(abarth) Remove this specific list once Fuchsia can build everything.
     deps = [
       "//flutter/content_handler",
+      "//flutter/examples",
       "//flutter/flow",
       "//flutter/runtime",
       "//flutter/snapshotter",

build/flx.gni

@@ -0,0 +1,68 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+template("flx") {
+  if (defined(invoker.output_name)) {
+    bundle_name = invoker.output_name
+  } else {
+    bundle_name = "${target_name}.flx"
+  }
+
+  bundle_path = "$root_out_dir/$bundle_name"
+  snapshot_path = "$target_gen_dir/${target_name}_snapshot.bin"
+  depfile_path = "${snapshot_path}.d"
+
+  main_dart = invoker.main_dart
+
+  if (defined(invoker.packages)) {
+    packages_path = invoker.packages
+  } else {
+    main_dir = get_path_info(main_dart, "dir")
+    package_dir = get_path_info(main_dir, "dir")
+    packages_path = "$package_dir/.packages"
+  }
+
+  sky_snapshot_label = "//flutter/snapshotter($host_toolchain)"
+  sky_snapshot_dir = get_label_info(sky_snapshot_label, "root_out_dir")
+  sky_snapshot = "$sky_snapshot_dir/sky_snapshot"
+
+  action(target_name) {
+    depfile = depfile_path
+
+    inputs = [
+      main_dart,
+      packages_path,
+    ]
+
+    outputs = [
+      bundle_path,
+      snapshot_path,
+    ]
+
+    if (defined(invoker.sources)) {
+      sources = invoker.sources
+    }
+
+    script = "//flutter/build/package.py"
+
+    args = [
+      "--snapshotter", rebase_path(sky_snapshot),
+      "--main-dart", rebase_path(main_dart),
+      "--packages", rebase_path(packages_path),
+      "--bundle", rebase_path(bundle_path),
+      "--bundle-header", "#!mojo mojo:flutter_content_handler",
+      "--snapshot", rebase_path(snapshot_path),
+      "--depfile", rebase_path(depfile_path),
+      "--build-output", rebase_path(bundle_path, root_build_dir),
+    ]
+
+    deps = [
+      sky_snapshot_label,
+    ]
+
+    if (defined(invoker.deps)) {
+      deps += invoker.deps
+    }
+  }
+}

build/package.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import argparse
+import subprocess
+import os
+import StringIO
+import sys
+import zipfile
+
+
+def main():
+  parser = argparse.ArgumentParser(description='Package a Flutter application')
+
+  parser.add_argument('--snapshotter', type=str, required=True,
+                      help='The snapshot binary to use')
+  parser.add_argument('--main-dart', type=str, required=True,
+                      help='The main.dart file to use')
+  parser.add_argument('--packages', type=str, required=True,
+                      help='The package map to use')
+  parser.add_argument('--snapshot', type=str, required=True,
+                      help='Path to application snapshot')
+  parser.add_argument('--depfile', type=str, required=True,
+                      help='Where to output dependency information')
+  parser.add_argument('--build-output', type=str, required=True,
+                      help='The final target to use in the dependency information')
+  parser.add_argument('--bundle', type=str, required=True,
+                      help='Where to output application bundle')
+  parser.add_argument('--bundle-header', type=str, required=True,
+                      help='String to prepend to bundle')
+
+  args = parser.parse_args()
+
+  result = subprocess.call([
+    args.snapshotter,
+    '--packages=%s' % args.packages,
+    '--snapshot=%s' % args.snapshot,
+    '--depfile=%s' % args.depfile,
+    '--build-output=%s' % args.build_output,
+    args.main_dart,
+  ])
+
+  if result != 0:
+    return result
+
+  archive = StringIO.StringIO()
+  with zipfile.ZipFile(archive, 'w') as z:
+    z.write(args.snapshot, 'snapshot_blob.bin', zipfile.ZIP_DEFLATED)
+
+  with open(args.bundle, 'w') as f:
+    if args.bundle_header:
+        f.write(args.bundle_header)
+        f.write('\n')
+    f.write(archive.getvalue())
+
+
+if __name__ == '__main__':
+  sys.exit(main())

examples/BUILD.gn

@@ -0,0 +1,9 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+group("examples") {
+  deps = [
+    "spinning_square"
+  ]
+}

examples/spinning_square/.packages

@@ -0,0 +1 @@
+# spinning_square doesn't depend on any packages.

examples/spinning_square/BUILD.gn

@@ -0,0 +1,9 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//flutter/build/flx.gni")
+
+flx("spinning_square") {
+  main_dart = "lib/main.dart"
+}

examples/spinning_square/lib/main.dart

@@ -0,0 +1,59 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This example shows how to perform a simple animation using the raw interface
+// to the engine.
+
+import 'dart:math' as math;
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+void beginFrame(Duration timeStamp) {
+  // The timeStamp argument to beginFrame indicates the timing information we
+  // should use to clock our animations. It's important to use timeStamp rather
+  // than reading the system time because we want all the parts of the system to
+  // coordinate the timings of their animations. If each component read the
+  // system clock independently, the animations that we processed later would be
+  // slightly ahead of the animations we processed earlier.
+
+  // PAINT
+
+  ui.Rect paintBounds = ui.Point.origin & ui.window.size;
+  ui.PictureRecorder recorder = new ui.PictureRecorder();
+  ui.Canvas canvas = new ui.Canvas(recorder, paintBounds);
+  canvas.translate(paintBounds.width / 2.0, paintBounds.height / 2.0);
+
+  // Here we determine the rotation according to the timeStamp given to us by
+  // the engine.
+  double t = timeStamp.inMicroseconds / Duration.MICROSECONDS_PER_MILLISECOND / 1800.0;
+  canvas.rotate(math.PI * (t % 1.0));
+
+  canvas.drawRect(new ui.Rect.fromLTRB(-100.0, -100.0, 100.0, 100.0),
+                  new ui.Paint()..color = const ui.Color.fromARGB(255, 0, 255, 0));
+  ui.Picture picture = recorder.endRecording();
+
+  // COMPOSITE
+
+  final double devicePixelRatio = ui.window.devicePixelRatio;
+  Float64List deviceTransform = new Float64List(16)
+    ..[0] = devicePixelRatio
+    ..[5] = devicePixelRatio
+    ..[10] = 1.0
+    ..[15] = 1.0;
+  ui.SceneBuilder sceneBuilder = new ui.SceneBuilder()
+    ..pushTransform(deviceTransform)
+    ..addPicture(ui.Offset.zero, picture)
+    ..pop();
+  ui.window.render(sceneBuilder.build());
+
+  // After rendering the current frame of the animation, we ask the engine to
+  // schedule another frame. The engine will call beginFrame again when its time
+  // to produce the next frame.
+  ui.window.scheduleFrame();
+}
+
+void main() {
+  ui.window.onBeginFrame = beginFrame;
+  ui.window.scheduleFrame();
+}