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// 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"
#include "ui/gfx/vector3d_f.h"
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) {
if (progress <= 0.0)
return from;
if (progress >= 1.0)
return to;
return from * (1 - progress) + to * progress;
}
bool TransformOperation::BlendTransformOperations(
const TransformOperation* from,
const TransformOperation* to,
double progress,
gfx::Transform& 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.RotateAbout(gfx::Vector3dF(axis_x, axis_y, axis_z),
BlendDoubles(from_angle, to_angle, progress));
else {
gfx::Transform to_matrix;
if (!IsOperationIdentity(to))
to_matrix = to->matrix;
gfx::Transform 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.ApplyPerspectiveDepth(
BlendDoubles(from_perspective_depth, to_perspective_depth, progress));
break;
}
case TransformOperation::TransformOperationMatrix: {
gfx::Transform to_matrix;
if (!IsOperationIdentity(to))
to_matrix = to->matrix;
gfx::Transform 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
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