Canvas.concat takes a 16-element Float32List instead of an array.

The array should be in column-major format, in the format used by vector_math.dart.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1155193004

engine/bindings/scripts/dart_types.py

@@ -116,6 +116,7 @@ CPP_SPECIAL_CONVERSION_RULES = {
     'unrestricted float': 'float',
     # Pass these by value, not pointer.
     'Color': 'SkColor',
+    'Float32List': 'Float32List',
     'Point': 'Point',
     'Rect': 'Rect',
     'TransferMode': 'SkXfermode::Mode',
@@ -363,6 +364,7 @@ DART_TO_CPP_VALUE = {
 
     # Pass-by-value types.
     'Color': pass_by_value_format('CanvasColor'),
+    'Float32List': pass_by_value_format('Float32List'),
     'Point': pass_by_value_format('{implemented_as}'),
     'Rect': pass_by_value_format('{implemented_as}'),
     'TransferMode': pass_by_value_format('TransferMode'),

engine/core/painting/Canvas.cpp

@@ -83,14 +83,27 @@ void Canvas::skew(float sx, float sy)
     m_canvas->skew(sx, sy);
 }
 
-void Canvas::concat(const Vector<float>& matrix)
+void Canvas::concat(const Float32List& matrix4)
 {
     if (!m_canvas)
         return;
     ASSERT(m_displayList->isRecording());
-    ASSERT(matrix.size() == 9);
+    ASSERT(matrix4.data());
+
+    // TODO(mpcomplete): how can we raise an error in this case?
+    if (matrix4.num_elements() != 16)
+      return;
+
     SkMatrix sk_matrix;
-    sk_matrix.set9(matrix.data());
+    // Mappings from SkMatrix-index to input-index.
+    static const int kMappings[] = {
+      0, 4, 12,
+      1, 5, 13,
+      3, 7, 15,
+    };
+    for (intptr_t i = 0; i < 9; ++i)
+      sk_matrix[i] = matrix4.data()[kMappings[i]];
+
     m_canvas->concat(sk_matrix);
 }
 

engine/core/painting/Canvas.h

@@ -11,6 +11,7 @@
 #include "sky/engine/core/painting/Rect.h"
 #include "sky/engine/platform/graphics/DisplayList.h"
 #include "sky/engine/tonic/dart_wrappable.h"
+#include "sky/engine/tonic/float32_list.h"
 #include "sky/engine/wtf/PassRefPtr.h"
 #include "sky/engine/wtf/RefCounted.h"
 
@@ -37,7 +38,7 @@ public:
     void scale(float sx, float sy);
     void rotateDegrees(float degrees);
     void skew(float sx, float sy);
-    void concat(const Vector<float>& matrix);
+    void concat(const Float32List& matrix4);
 
     void clipRect(const Rect& rect);
 

engine/core/painting/Canvas.idl

@@ -17,7 +17,7 @@ interface Canvas {
   void scale(float sx, float sy);
   void rotateDegrees(float degrees);
   void skew(float sx, float sy);
-  void concat(float[] matrix9);
+  void concat(Float32List matrix4);
 
   void clipRect(Rect rect);
 

engine/tonic/BUILD.gn

@@ -42,6 +42,8 @@ source_set("tonic") {
     "dart_wrappable.cc",
     "dart_wrappable.h",
     "dart_wrapper_info.h",
+    "float32_list.cc",
+    "float32_list.h",
     "mojo_converter.h",
   ]
 

engine/tonic/float32_list.cc

@@ -0,0 +1,47 @@
+// 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.
+
+#include "sky/engine/config.h"
+#include "sky/engine/tonic/dart_error.h"
+#include "sky/engine/tonic/float32_list.h"
+
+namespace blink {
+
+Float32List::Float32List(Dart_Handle list)
+    : data_(nullptr), num_elements_(0), dart_handle_(list) {
+  if (Dart_IsNull(list))
+    return;
+
+  Dart_TypedData_Type type;
+  Dart_TypedDataAcquireData(
+      list, &type, reinterpret_cast<void**>(&data_), &num_elements_);
+  DCHECK(!LogIfError(list));
+  ASSERT(type == Dart_TypedData_kFloat32);
+}
+
+Float32List::Float32List(Float32List&& other)
+    : data_(other.data_),
+      num_elements_(other.num_elements_),
+      dart_handle_(other.dart_handle_) {
+  other.data_ = nullptr;
+  other.dart_handle_ = nullptr;
+}
+
+Float32List::~Float32List() {
+  if (data_)
+    Dart_TypedDataReleaseData(dart_handle_);
+}
+
+Float32List DartConverter<Float32List>::FromArgumentsWithNullCheck(
+    Dart_NativeArguments args,
+    int index,
+    Dart_Handle& exception) {
+  Dart_Handle list = Dart_GetNativeArgument(args, index);
+  DCHECK(!LogIfError(list));
+
+  Float32List result(list);
+  return result;
+}
+
+} // namespace blink

engine/tonic/float32_list.h

@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef SKY_ENGINE_TONIC_FLOAT32_LIST_H_
+#define SKY_ENGINE_TONIC_FLOAT32_LIST_H_
+
+#include "dart/runtime/include/dart_api.h"
+#include "sky/engine/tonic/dart_converter.h"
+
+namespace blink {
+
+// A simple wrapper around a Dart Float32List. It uses Dart_TypedDataAcquireData
+// to obtain a raw pointer to the data, which is released when this object is
+// destroyed.
+//
+// This is designed to be used with DartConverter only.
+class Float32List {
+ public:
+  explicit Float32List(Dart_Handle list);
+  Float32List(Float32List&& other);
+  ~Float32List();
+
+  const float* data() const { return data_; }
+  intptr_t num_elements() const { return num_elements_; }
+
+ private:
+  float* data_;
+  intptr_t num_elements_;
+  Dart_Handle dart_handle_;
+
+  Float32List(const Float32List& other) = delete;
+};
+
+template <>
+struct DartConverter<Float32List> {
+  static Float32List FromArgumentsWithNullCheck(Dart_NativeArguments args,
+                                                int index,
+                                                Dart_Handle& exception);
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_TONIC_FLOAT32_LIST_H_

examples/raw/painting.sky

@@ -8,6 +8,7 @@ div {
 <div id="canvas" />
 <script>
 import 'dart:math' as math;
+import 'dart:typed_data';
 import 'dart:sky';
 
 void main() {
@@ -29,11 +30,12 @@ void main() {
                      paint);
 
     // Scale x and y by 0.5.
-    var scaleMatrix = [
-        0.5, 0.0, 0.0,
-        0.0, 0.5, 0.0,
-        0.0, 0.0, 1.0
-    ];
+    var scaleMatrix = new Float32List.fromList([
+        0.5, 0.0, 0.0, 0.0,
+        0.0, 0.5, 0.0, 0.0,
+        0.0, 0.0, 0.0, 0.0,
+        0.0, 0.0, 0.0, 1.0,
+    ]);
     context.concat(scaleMatrix);
     paint.color = const Color.fromARGB(128, 0, 255, 0);
     context.drawCircle(0.0, 0.0, radius, paint);