Define cc::TransformOperations and webkit::WebTransformOperationsImpl

cc/transform_operation.cc

+// Copyright 2013 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 <cmath>
+#include <limits>
+
+#include "cc/transform_operation.h"
+
+using WebKit::WebTransformationMatrix;
+
+namespace {
+const double kAngleEpsilon = 1e-4;
+}
+
+namespace cc {
+
+bool TransformOperation::IsIdentity() const {
+  return matrix.isIdentity();
+}
+
+static bool IsOperationIdentity(const TransformOperation* operation) {
+  return !operation || operation->IsIdentity();
+}
+
+static bool ShareSameAxis(const TransformOperation* from,
+                          const TransformOperation* to,
+                          double& axis_x, double& axis_y, double& axis_z,
+                          double& angle_from) {
+  if (IsOperationIdentity(from) && IsOperationIdentity(to))
+    return false;
+
+  if (IsOperationIdentity(from) && !IsOperationIdentity(to)) {
+    axis_x = to->rotate.axis.x;
+    axis_y = to->rotate.axis.y;
+    axis_z = to->rotate.axis.z;
+    angle_from = 0;
+    return true;
+  }
+
+  if (!IsOperationIdentity(from) && IsOperationIdentity(to)) {
+    axis_x = from->rotate.axis.x;
+    axis_y = from->rotate.axis.y;
+    axis_z = from->rotate.axis.z;
+    angle_from = from->rotate.angle;
+    return true;
+  }
+
+  double length_2 = from->rotate.axis.x * from->rotate.axis.x +
+                    from->rotate.axis.y * from->rotate.axis.y +
+                    from->rotate.axis.z * from->rotate.axis.z;
+  double other_length_2 = to->rotate.axis.x * to->rotate.axis.x +
+                          to->rotate.axis.y * to->rotate.axis.y +
+                          to->rotate.axis.z * to->rotate.axis.z;
+
+  if (length_2 <= kAngleEpsilon || other_length_2 <= kAngleEpsilon)
+    return false;
+
+  double dot = to->rotate.axis.x * from->rotate.axis.x +
+               to->rotate.axis.y * from->rotate.axis.y +
+               to->rotate.axis.z * from->rotate.axis.z;
+  double error = std::fabs(1.0 - (dot * dot) / (length_2 * other_length_2));
+  bool result = error < kAngleEpsilon;
+  if (result) {
+    axis_x = to->rotate.axis.x;
+    axis_y = to->rotate.axis.y;
+    axis_z = to->rotate.axis.z;
+    // If the axes are pointing in opposite directions, we need to reverse
+    // the angle.
+    angle_from = dot > 0 ? from->rotate.angle : -from->rotate.angle;
+  }
+  return result;
+}
+
+static double BlendDoubles(double from, double to, double progress) {
+  return from * (1 - progress) + to * progress;
+}
+
+bool TransformOperation::BlendTransformOperations(
+    const TransformOperation* from,
+    const TransformOperation* to,
+    double progress,
+    WebTransformationMatrix& result) {
+  if (IsOperationIdentity(from) && IsOperationIdentity(to))
+    return true;
+
+  TransformOperation::Type interpolation_type =
+      TransformOperation::TransformOperationIdentity;
+  if (IsOperationIdentity(to))
+    interpolation_type = from->type;
+  else
+    interpolation_type = to->type;
+
+  switch (interpolation_type) {
+  case TransformOperation::TransformOperationTranslate: {
+    double from_x = IsOperationIdentity(from) ? 0 : from->translate.x;
+    double from_y = IsOperationIdentity(from) ? 0 : from->translate.y;
+    double from_z = IsOperationIdentity(from) ? 0 : from->translate.z;
+    double to_x = IsOperationIdentity(to) ? 0 : to->translate.x;
+    double to_y = IsOperationIdentity(to) ? 0 : to->translate.y;
+    double to_z = IsOperationIdentity(to) ? 0 : to->translate.z;
+    result.translate3d(BlendDoubles(from_x, to_x, progress),
+                       BlendDoubles(from_y, to_y, progress),
+                       BlendDoubles(from_z, to_z, progress));
+    break;
+  }
+  case TransformOperation::TransformOperationRotate: {
+    double axis_x = 0;
+    double axis_y = 0;
+    double axis_z = 1;
+    double from_angle = 0;
+    double to_angle = IsOperationIdentity(to) ? 0 : to->rotate.angle;
+    if (ShareSameAxis(from, to, axis_x, axis_y, axis_z, from_angle))
+      result.rotate3d(axis_x, axis_y, axis_z,
+                      BlendDoubles(from_angle, to_angle, progress));
+    else {
+      WebTransformationMatrix to_matrix;
+      if (!IsOperationIdentity(to))
+        to_matrix = to->matrix;
+      WebTransformationMatrix from_matrix;
+      if (!IsOperationIdentity(from))
+        from_matrix = from->matrix;
+      result = to_matrix;
+      if (!result.blend(from_matrix, progress))
+        return false;
+    }
+    break;
+  }
+  case TransformOperation::TransformOperationScale: {
+    double from_x = IsOperationIdentity(from) ? 1 : from->scale.x;
+    double from_y = IsOperationIdentity(from) ? 1 : from->scale.y;
+    double from_z = IsOperationIdentity(from) ? 1 : from->scale.z;
+    double to_x = IsOperationIdentity(to) ? 1 : to->scale.x;
+    double to_y = IsOperationIdentity(to) ? 1 : to->scale.y;
+    double to_z = IsOperationIdentity(to) ? 1 : to->scale.z;
+    result.scale3d(BlendDoubles(from_x, to_x, progress),
+                   BlendDoubles(from_y, to_y, progress),
+                   BlendDoubles(from_z, to_z, progress));
+    break;
+  }
+  case TransformOperation::TransformOperationSkew: {
+    double from_x = IsOperationIdentity(from) ? 0 : from->skew.x;
+    double from_y = IsOperationIdentity(from) ? 0 : from->skew.y;
+    double to_x = IsOperationIdentity(to) ? 0 : to->skew.x;
+    double to_y = IsOperationIdentity(to) ? 0 : to->skew.y;
+    result.skewX(BlendDoubles(from_x, to_x, progress));
+    result.skewY(BlendDoubles(from_y, to_y, progress));
+    break;
+  }
+  case TransformOperation::TransformOperationPerspective: {
+    double from_perspective_depth = IsOperationIdentity(from) ?
+        std::numeric_limits<double>::max() : from->perspective_depth;
+    double to_perspective_depth = IsOperationIdentity(to) ?
+        std::numeric_limits<double>::max() : to->perspective_depth;
+    result.applyPerspective(
+        BlendDoubles(from_perspective_depth, to_perspective_depth, progress));
+    break;
+  }
+  case TransformOperation::TransformOperationMatrix: {
+    WebTransformationMatrix to_matrix;
+    if (!IsOperationIdentity(to))
+      to_matrix = to->matrix;
+    WebTransformationMatrix from_matrix;
+    if (!IsOperationIdentity(from))
+      from_matrix = from->matrix;
+    result = to_matrix;
+    if (!result.blend(from_matrix, progress))
+      return false;
+    break;
+  }
+  case TransformOperation::TransformOperationIdentity:
+    // Do nothing.
+    break;
+  }
+
+  return true;
+}
+
+}  // namespace cc