gecko-dev/dom/svg/SVGMotionSMILType.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* implementation of nsISMILType for use by <animateMotion> element */
#include "SVGMotionSMILType.h"
#include "mozilla/SMILValue.h"
#include "mozilla/gfx/Point.h"
#include "gfx2DGlue.h"
#include "nsDebug.h"
#include "nsMathUtils.h"
#include "nsISupportsUtils.h"
#include "nsTArray.h"
#include <math.h>
using namespace mozilla::gfx;
namespace mozilla {
/*static*/
SVGMotionSMILType SVGMotionSMILType::sSingleton;
// Helper enum, for distinguishing between types of MotionSegment structs
enum SegmentType { eSegmentType_Translation, eSegmentType_PathPoint };
// Helper Structs: containers for params to define our MotionSegment
// (either simple translation or point-on-a-path)
struct TranslationParams { // Simple translation
float mX;
float mY;
};
struct PathPointParams { // Point along a path
// Refcounted: need to AddRef/Release. This can't be an nsRefPtr because
// this struct is used inside a union so it can't have a default constructor.
Path* MOZ_OWNING_REF mPath;
float mDistToPoint; // Distance from path start to the point on the path that
// we're interested in.
};
/**
* Helper Struct: MotionSegment
*
* Instances of this class represent the points that we move between during
* <animateMotion>. Each SMILValue will get a nsTArray of these (generally
* with at most 1 entry in the array, except for in SandwichAdd). (This
* matches our behavior in SVGTransformListSMILType.)
*
* NOTE: In general, MotionSegments are represented as points on a path
* (eSegmentType_PathPoint), so that we can easily interpolate and compute
* distance *along their path*. However, Add() outputs MotionSegments as
* simple translations (eSegmentType_Translation), because adding two points
* from a path (e.g. when accumulating a repeated animation) will generally
* take you to an arbitrary point *off* of the path.
*/
struct MotionSegment {
// Default constructor just locks us into being a Translation, and leaves
// other fields uninitialized (since client is presumably about to set them)
MotionSegment()
: mRotateType(eRotateType_Auto),
mRotateAngle(0.0),
mSegmentType(eSegmentType_Translation),
mU{} {}
// Constructor for a translation
MotionSegment(float aX, float aY, float aRotateAngle)
: mRotateType(eRotateType_Explicit),
mRotateAngle(aRotateAngle),
mSegmentType(eSegmentType_Translation) {
mU.mTranslationParams.mX = aX;
mU.mTranslationParams.mY = aY;
}
// Constructor for a point on a path (NOTE: AddRef's)
MotionSegment(Path* aPath, float aDistToPoint, RotateType aRotateType,
float aRotateAngle)
: mRotateType(aRotateType),
mRotateAngle(aRotateAngle),
mSegmentType(eSegmentType_PathPoint) {
mU.mPathPointParams.mPath = aPath;
mU.mPathPointParams.mDistToPoint = aDistToPoint;
NS_ADDREF(mU.mPathPointParams.mPath); // Retain a reference to path
}
// Copy constructor (NOTE: AddRef's if we're eSegmentType_PathPoint)
MotionSegment(const MotionSegment& aOther)
: mRotateType(aOther.mRotateType),
mRotateAngle(aOther.mRotateAngle),
mSegmentType(aOther.mSegmentType) {
if (mSegmentType == eSegmentType_Translation) {
mU.mTranslationParams = aOther.mU.mTranslationParams;
} else { // mSegmentType == eSegmentType_PathPoint
mU.mPathPointParams = aOther.mU.mPathPointParams;
NS_ADDREF(mU.mPathPointParams.mPath); // Retain a reference to path
}
}
// Destructor (releases any reference we were holding onto)
~MotionSegment() {
if (mSegmentType == eSegmentType_PathPoint) {
NS_RELEASE(mU.mPathPointParams.mPath);
}
}
// Comparison operators
bool operator==(const MotionSegment& aOther) const {
// Compare basic params
if (mSegmentType != aOther.mSegmentType ||
mRotateType != aOther.mRotateType ||
(mRotateType == eRotateType_Explicit && // Technically, angle mismatch
mRotateAngle != aOther.mRotateAngle)) { // only matters for Explicit.
return false;
}
// Compare translation params, if we're a translation.
if (mSegmentType == eSegmentType_Translation) {
return mU.mTranslationParams.mX == aOther.mU.mTranslationParams.mX &&
mU.mTranslationParams.mY == aOther.mU.mTranslationParams.mY;
}
// Else, compare path-point params, if we're a path point.
return (mU.mPathPointParams.mPath == aOther.mU.mPathPointParams.mPath) &&
(mU.mPathPointParams.mDistToPoint ==
aOther.mU.mPathPointParams.mDistToPoint);
}
bool operator!=(const MotionSegment& aOther) const {
return !(*this == aOther);
}
// Member Data
// -----------
RotateType mRotateType; // Explicit angle vs. auto vs. auto-reverse.
float mRotateAngle; // Only used if mRotateType == eRotateType_Explicit.
const SegmentType mSegmentType; // This determines how we interpret
// mU. (const for safety/sanity)
union { // Union to let us hold the params for either segment-type.
TranslationParams mTranslationParams;
PathPointParams mPathPointParams;
} mU;
};
using MotionSegmentArray = FallibleTArray<MotionSegment>;
// Helper methods to cast SMILValue.mU.mPtr to the right pointer-type
static MotionSegmentArray& ExtractMotionSegmentArray(SMILValue& aValue) {
return *static_cast<MotionSegmentArray*>(aValue.mU.mPtr);
}
static const MotionSegmentArray& ExtractMotionSegmentArray(
const SMILValue& aValue) {
return *static_cast<const MotionSegmentArray*>(aValue.mU.mPtr);
}
// nsISMILType Methods
// -------------------
void SVGMotionSMILType::Init(SMILValue& aValue) const {
MOZ_ASSERT(aValue.IsNull(), "Unexpected SMIL type");
aValue.mType = this;
aValue.mU.mPtr = new MotionSegmentArray(1);
}
void SVGMotionSMILType::Destroy(SMILValue& aValue) const {
MOZ_ASSERT(aValue.mType == this, "Unexpected SMIL type");
MotionSegmentArray* arr = static_cast<MotionSegmentArray*>(aValue.mU.mPtr);
delete arr;
aValue.mU.mPtr = nullptr;
aValue.mType = SMILNullType::Singleton();
}
nsresult SVGMotionSMILType::Assign(SMILValue& aDest,
const SMILValue& aSrc) const {
MOZ_ASSERT(aDest.mType == aSrc.mType, "Incompatible SMIL types");
MOZ_ASSERT(aDest.mType == this, "Unexpected SMIL type");
const MotionSegmentArray& srcArr = ExtractMotionSegmentArray(aSrc);
MotionSegmentArray& dstArr = ExtractMotionSegmentArray(aDest);
if (!dstArr.Assign(srcArr, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
bool SVGMotionSMILType::IsEqual(const SMILValue& aLeft,
const SMILValue& aRight) const {
MOZ_ASSERT(aLeft.mType == aRight.mType, "Incompatible SMIL types");
MOZ_ASSERT(aLeft.mType == this, "Unexpected SMIL type");
const MotionSegmentArray& leftArr = ExtractMotionSegmentArray(aLeft);
const MotionSegmentArray& rightArr = ExtractMotionSegmentArray(aRight);
// If array-lengths don't match, we're trivially non-equal.
if (leftArr.Length() != rightArr.Length()) {
return false;
}
// Array-lengths match -- check each array-entry for equality.
uint32_t length = leftArr.Length(); // == rightArr->Length(), if we get here
for (uint32_t i = 0; i < length; ++i) {
if (leftArr[i] != rightArr[i]) {
return false;
}
}
return true; // If we get here, we found no differences.
}
// Helper method for Add & CreateMatrix
inline static void GetAngleAndPointAtDistance(
Path* aPath, float aDistance, RotateType aRotateType,
float& aRotateAngle, // in & out-param.
Point& aPoint) // out-param.
{
if (aRotateType == eRotateType_Explicit) {
// Leave aRotateAngle as-is.
aPoint = aPath->ComputePointAtLength(aDistance);
} else {
Point tangent; // Unit vector tangent to the point we find.
aPoint = aPath->ComputePointAtLength(aDistance, &tangent);
float tangentAngle = atan2(tangent.y, tangent.x);
if (aRotateType == eRotateType_Auto) {
aRotateAngle = tangentAngle;
} else {
MOZ_ASSERT(aRotateType == eRotateType_AutoReverse);
aRotateAngle = M_PI + tangentAngle;
}
}
}
nsresult SVGMotionSMILType::Add(SMILValue& aDest, const SMILValue& aValueToAdd,
uint32_t aCount) const {
MOZ_ASSERT(aDest.mType == aValueToAdd.mType, "Incompatible SMIL types");
MOZ_ASSERT(aDest.mType == this, "Unexpected SMIL type");
MotionSegmentArray& dstArr = ExtractMotionSegmentArray(aDest);
const MotionSegmentArray& srcArr = ExtractMotionSegmentArray(aValueToAdd);
// We're doing a simple add here (as opposed to a sandwich add below). We
// only do this when we're accumulating a repeat result.
// NOTE: In other nsISMILTypes, we use this method with a barely-initialized
// |aDest| value to assist with "by" animation. (In this case,
// "barely-initialized" would mean dstArr.Length() would be empty.) However,
// we don't do this for <animateMotion>, because we instead use our "by"
// value to construct an equivalent "path" attribute, and we use *that* for
// our actual animation.
MOZ_ASSERT(srcArr.Length() == 1, "Invalid source segment arr to add");
MOZ_ASSERT(dstArr.Length() == 1, "Invalid dest segment arr to add to");
const MotionSegment& srcSeg = srcArr[0];
const MotionSegment& dstSeg = dstArr[0];
MOZ_ASSERT(srcSeg.mSegmentType == eSegmentType_PathPoint,
"expecting to be adding points from a motion path");
MOZ_ASSERT(dstSeg.mSegmentType == eSegmentType_PathPoint,
"expecting to be adding points from a motion path");
const PathPointParams& srcParams = srcSeg.mU.mPathPointParams;
const PathPointParams& dstParams = dstSeg.mU.mPathPointParams;
MOZ_ASSERT(srcSeg.mRotateType == dstSeg.mRotateType &&
srcSeg.mRotateAngle == dstSeg.mRotateAngle,
"unexpected angle mismatch");
MOZ_ASSERT(srcParams.mPath == dstParams.mPath, "unexpected path mismatch");
Path* path = srcParams.mPath;
// Use destination to get our rotate angle.
float rotateAngle = dstSeg.mRotateAngle;
Point dstPt;
GetAngleAndPointAtDistance(path, dstParams.mDistToPoint, dstSeg.mRotateType,
rotateAngle, dstPt);
Point srcPt = path->ComputePointAtLength(srcParams.mDistToPoint);
float newX = dstPt.x + srcPt.x * aCount;
float newY = dstPt.y + srcPt.y * aCount;
// Replace destination's current value -- a point-on-a-path -- with the
// translation that results from our addition.
dstArr.ReplaceElementAt(0, MotionSegment(newX, newY, rotateAngle));
return NS_OK;
}
nsresult SVGMotionSMILType::SandwichAdd(SMILValue& aDest,
const SMILValue& aValueToAdd) const {
MOZ_ASSERT(aDest.mType == aValueToAdd.mType, "Incompatible SMIL types");
MOZ_ASSERT(aDest.mType == this, "Unexpected SMIL type");
MotionSegmentArray& dstArr = ExtractMotionSegmentArray(aDest);
const MotionSegmentArray& srcArr = ExtractMotionSegmentArray(aValueToAdd);
// We're only expecting to be adding 1 segment on to the list
MOZ_ASSERT(srcArr.Length() == 1,
"Trying to do sandwich add of more than one value");
if (!dstArr.AppendElement(srcArr[0], fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
nsresult SVGMotionSMILType::ComputeDistance(const SMILValue& aFrom,
const SMILValue& aTo,
double& aDistance) const {
MOZ_ASSERT(aFrom.mType == aTo.mType, "Incompatible SMIL types");
MOZ_ASSERT(aFrom.mType == this, "Unexpected SMIL type");
const MotionSegmentArray& fromArr = ExtractMotionSegmentArray(aFrom);
const MotionSegmentArray& toArr = ExtractMotionSegmentArray(aTo);
// ComputeDistance is only used for calculating distances between single
// values in a values array. So we should only have one entry in each array.
MOZ_ASSERT(fromArr.Length() == 1, "Wrong number of elements in from value");
MOZ_ASSERT(toArr.Length() == 1, "Wrong number of elements in to value");
const MotionSegment& from = fromArr[0];
const MotionSegment& to = toArr[0];
MOZ_ASSERT(from.mSegmentType == to.mSegmentType,
"Mismatched MotionSegment types");
if (from.mSegmentType == eSegmentType_PathPoint) {
const PathPointParams& fromParams = from.mU.mPathPointParams;
const PathPointParams& toParams = to.mU.mPathPointParams;
MOZ_ASSERT(fromParams.mPath == toParams.mPath,
"Interpolation endpoints should be from same path");
aDistance = std::fabs(toParams.mDistToPoint - fromParams.mDistToPoint);
} else {
const TranslationParams& fromParams = from.mU.mTranslationParams;
const TranslationParams& toParams = to.mU.mTranslationParams;
float dX = toParams.mX - fromParams.mX;
float dY = toParams.mY - fromParams.mY;
aDistance = NS_hypot(dX, dY);
}
return NS_OK;
}
// Helper method for Interpolate()
static inline float InterpolateFloat(const float& aStartFlt,
const float& aEndFlt,
const double& aUnitDistance) {
return aStartFlt + aUnitDistance * (aEndFlt - aStartFlt);
}
nsresult SVGMotionSMILType::Interpolate(const SMILValue& aStartVal,
const SMILValue& aEndVal,
double aUnitDistance,
SMILValue& aResult) const {
MOZ_ASSERT(aStartVal.mType == aEndVal.mType,
"Trying to interpolate different types");
MOZ_ASSERT(aStartVal.mType == this, "Unexpected types for interpolation");
MOZ_ASSERT(aResult.mType == this, "Unexpected result type");
MOZ_ASSERT(aUnitDistance >= 0.0 && aUnitDistance <= 1.0,
"unit distance value out of bounds");
const MotionSegmentArray& startArr = ExtractMotionSegmentArray(aStartVal);
const MotionSegmentArray& endArr = ExtractMotionSegmentArray(aEndVal);
MotionSegmentArray& resultArr = ExtractMotionSegmentArray(aResult);
MOZ_ASSERT(endArr.Length() == 1,
"Invalid end-point for animateMotion interpolation");
MOZ_ASSERT(resultArr.IsEmpty(),
"Expecting result to be just-initialized w/ empty array");
const MotionSegment& endSeg = endArr[0];
MOZ_ASSERT(endSeg.mSegmentType == eSegmentType_PathPoint,
"Expecting to be interpolating along a path");
const PathPointParams& endParams = endSeg.mU.mPathPointParams;
// NOTE: Ususally, path & angle should match between start & end (since
// presumably start & end came from the same <animateMotion> element),
// unless start is empty. (as it would be for pure 'to' animation)
// Notable exception: when a to-animation layers on top of lower priority
// animation(s) -- see comment below.
Path* path = endParams.mPath;
RotateType rotateType = endSeg.mRotateType;
float rotateAngle = endSeg.mRotateAngle;
float startDist;
if (startArr.IsEmpty() ||
startArr[0].mU.mPathPointParams.mPath != endParams.mPath) {
// When a to-animation follows other lower priority animation(s),
// the endParams will contain a different path from the animation(s)
// that it layers on top of.
// Per SMIL spec, we should interpolate from the value at startArr.
// However, neither Chrome nor Safari implements to-animation that way.
// For simplicity, we use the same behavior as other browsers: override
// previous animations and start at the initial underlying value.
startDist = 0.0f;
} else {
MOZ_ASSERT(startArr.Length() <= 1,
"Invalid start-point for animateMotion interpolation");
const MotionSegment& startSeg = startArr[0];
MOZ_ASSERT(startSeg.mSegmentType == eSegmentType_PathPoint,
"Expecting to be interpolating along a path");
const PathPointParams& startParams = startSeg.mU.mPathPointParams;
MOZ_ASSERT(startSeg.mRotateType == endSeg.mRotateType &&
startSeg.mRotateAngle == endSeg.mRotateAngle,
"unexpected angle mismatch");
startDist = startParams.mDistToPoint;
}
// Get the interpolated distance along our path.
float resultDist =
InterpolateFloat(startDist, endParams.mDistToPoint, aUnitDistance);
// Construct the intermediate result segment, and put it in our outparam.
// AppendElement has guaranteed success here, since Init() allocates 1 slot.
MOZ_ALWAYS_TRUE(resultArr.AppendElement(
MotionSegment(path, resultDist, rotateType, rotateAngle), fallible));
return NS_OK;
}
/* static */ gfx::Matrix SVGMotionSMILType::CreateMatrix(
const SMILValue& aSMILVal) {
const MotionSegmentArray& arr = ExtractMotionSegmentArray(aSMILVal);
gfx::Matrix matrix;
uint32_t length = arr.Length();
for (uint32_t i = 0; i < length; i++) {
Point point; // initialized below
float rotateAngle = arr[i].mRotateAngle; // might get updated below
if (arr[i].mSegmentType == eSegmentType_Translation) {
point.x = arr[i].mU.mTranslationParams.mX;
point.y = arr[i].mU.mTranslationParams.mY;
MOZ_ASSERT(arr[i].mRotateType == eRotateType_Explicit,
"'auto'/'auto-reverse' should have been converted to "
"explicit angles when we generated this translation");
} else {
GetAngleAndPointAtDistance(arr[i].mU.mPathPointParams.mPath,
arr[i].mU.mPathPointParams.mDistToPoint,
arr[i].mRotateType, rotateAngle, point);
}
matrix.PreTranslate(point.x, point.y);
matrix.PreRotate(rotateAngle);
}
return matrix;
}
/* static */
SMILValue SVGMotionSMILType::ConstructSMILValue(Path* aPath, float aDist,
RotateType aRotateType,
float aRotateAngle) {
SMILValue smilVal(&SVGMotionSMILType::sSingleton);
MotionSegmentArray& arr = ExtractMotionSegmentArray(smilVal);
// AppendElement has guaranteed success here, since Init() allocates 1 slot.
MOZ_ALWAYS_TRUE(arr.AppendElement(
MotionSegment(aPath, aDist, aRotateType, aRotateAngle), fallible));
return smilVal;
}
} // namespace mozilla