KeyFrame.cpp
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/**
* @file
* @brief Source file for the Keyframe class
* @author Jonathan Thomas <jonathan@openshot.org>
*
* @ref License
*/
/* LICENSE
*
* Copyright (c) 2008-2019 OpenShot Studios, LLC
* <http://www.openshotstudios.com/>. This file is part of
* OpenShot Library (libopenshot), an open-source project dedicated to
* delivering high quality video editing and animation solutions to the
* world. For more information visit <http://www.openshot.org/>.
*
* OpenShot Library (libopenshot) is free software: you can redistribute it
* and/or modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* OpenShot Library (libopenshot) is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "../include/KeyFrame.h"
#include <algorithm>
#include <functional>
#include <utility>
using namespace std;
using namespace openshot;
namespace {
bool IsPointBeforeX(Point const & p, double const x) {
return p.co.X < x;
}
double InterpolateLinearCurve(Point const & left, Point const & right, double const target) {
double const diff_Y = right.co.Y - left.co.Y;
double const diff_X = right.co.X - left.co.X;
double const slope = diff_Y / diff_X;
return left.co.Y + slope * (target - left.co.X);
}
double InterpolateBezierCurve(Point const & left, Point const & right, double const target, double const allowed_error) {
double const X_diff = right.co.X - left.co.X;
double const Y_diff = right.co.Y - left.co.Y;
Coordinate const p0 = left.co;
Coordinate const p1 = Coordinate(p0.X + left.handle_right.X * X_diff, p0.Y + left.handle_right.Y * Y_diff);
Coordinate const p2 = Coordinate(p0.X + right.handle_left.X * X_diff, p0.Y + right.handle_left.Y * Y_diff);
Coordinate const p3 = right.co;
double t = 0.5;
double t_step = 0.25;
do {
// Bernstein polynoms
double B[4] = {1, 3, 3, 1};
double oneMinTExp = 1;
double tExp = 1;
for (int i = 0; i < 4; ++i, tExp *= t) {
B[i] *= tExp;
}
for (int i = 0; i < 4; ++i, oneMinTExp *= 1 - t) {
B[4 - i - 1] *= oneMinTExp;
}
double const x = p0.X * B[0] + p1.X * B[1] + p2.X * B[2] + p3.X * B[3];
double const y = p0.Y * B[0] + p1.Y * B[1] + p2.Y * B[2] + p3.Y * B[3];
if (fabs(target - x) < allowed_error) {
return y;
}
if (x > target) {
t -= t_step;
}
else {
t += t_step;
}
t_step /= 2;
} while (true);
}
double InterpolateBetween(Point const & left, Point const & right, double target, double allowed_error) {
assert(left.co.X < target);
assert(target <= right.co.X);
switch (right.interpolation) {
case CONSTANT: return left.co.Y;
case LINEAR: return InterpolateLinearCurve(left, right, target);
case BEZIER: return InterpolateBezierCurve(left, right, target, allowed_error);
}
}
template<typename Check>
int64_t SearchBetweenPoints(Point const & left, Point const & right, int64_t const current, Check check) {
int64_t start = left.co.X;
int64_t stop = right.co.X;
while (start < stop) {
int64_t const mid = (start + stop + 1) / 2;
double const value = InterpolateBetween(left, right, mid, 0.01);
if (check(round(value), current)) {
start = mid;
} else {
stop = mid - 1;
}
}
return start;
}
}
// Constructor which sets the default point & coordinate at X=1
Keyframe::Keyframe(double value) {
// Add initial point
AddPoint(Point(value));
}
// Add a new point on the key-frame. Each point has a primary coordinate,
// a left handle, and a right handle.
void Keyframe::AddPoint(Point p) {
// candidate is not less (greater or equal) than the new point in
// the X coordinate.
std::vector<Point>::iterator candidate =
std::lower_bound(begin(Points), end(Points), p.co.X, IsPointBeforeX);
if (candidate == end(Points)) {
// New point X is greater than all other points' X, add to
// back.
Points.push_back(p);
} else if ((*candidate).co.X == p.co.X) {
// New point is at same X coordinate as some point, overwrite
// point.
*candidate = p;
} else {
// New point needs to be inserted before candidate; thus move
// candidate and all following one to the right and insert new
// point then where candidate was.
size_t const candidate_index = candidate - begin(Points);
Points.push_back(p); // Make space; could also be a dummy point. INVALIDATES candidate!
std::move_backward(begin(Points) + candidate_index, end(Points) - 1, end(Points));
Points[candidate_index] = p;
}
}
// Add a new point on the key-frame, with some defaults set (BEZIER)
void Keyframe::AddPoint(double x, double y)
{
// Create a point
Point new_point(x, y, BEZIER);
// Add the point
AddPoint(new_point);
}
// Add a new point on the key-frame, with a specific interpolation type
void Keyframe::AddPoint(double x, double y, InterpolationType interpolate)
{
// Create a point
Point new_point(x, y, interpolate);
// Add the point
AddPoint(new_point);
}
// Get the index of a point by matching a coordinate
int64_t Keyframe::FindIndex(Point p) const {
// loop through points, and find a matching coordinate
for (std::vector<Point>::size_type x = 0; x < Points.size(); x++) {
// Get each point
Point existing_point = Points[x];
// find a match
if (p.co.X == existing_point.co.X && p.co.Y == existing_point.co.Y) {
// Remove the matching point, and break out of loop
return x;
}
}
// no matching point found
throw OutOfBoundsPoint("Invalid point requested", -1, Points.size());
}
// Determine if point already exists
bool Keyframe::Contains(Point p) const {
std::vector<Point>::const_iterator i =
std::lower_bound(begin(Points), end(Points), p.co.X, IsPointBeforeX);
return i != end(Points) && i->co.X == p.co.X;
}
// Get current point (or closest point) from the X coordinate (i.e. the frame number)
Point Keyframe::GetClosestPoint(Point p, bool useLeft) const {
if (Points.size() == 0) {
return Point(-1, -1);
}
// Finds a point with an X coordinate which is "not less" (greater
// or equal) than the queried X coordinate.
std::vector<Point>::const_iterator candidate =
std::lower_bound(begin(Points), end(Points), p.co.X, IsPointBeforeX);
if (candidate == end(Points)) {
// All points are before the queried point.
//
// Note: Behavior the same regardless of useLeft!
return Points.back();
}
if (candidate == begin(Points)) {
// First point is greater or equal to the queried point.
//
// Note: Behavior the same regardless of useLeft!
return Points.front();
}
if (useLeft) {
return *(candidate - 1);
} else {
return *candidate;
}
}
// Get current point (or closest point to the right) from the X coordinate (i.e. the frame number)
Point Keyframe::GetClosestPoint(Point p) const {
return GetClosestPoint(p, false);
}
// Get previous point (if any)
Point Keyframe::GetPreviousPoint(Point p) const {
// Lookup the index of this point
try {
int64_t index = FindIndex(p);
// If not the 1st point
if (index > 0)
return Points[index - 1];
else
return Points[0];
} catch (const OutOfBoundsPoint& e) {
// No previous point
return Point(-1, -1);
}
}
// Get max point (by Y coordinate)
Point Keyframe::GetMaxPoint() const {
Point maxPoint(-1, -1);
for (Point const & existing_point: Points) {
if (existing_point.co.Y >= maxPoint.co.Y) {
maxPoint = existing_point;
}
}
return maxPoint;
}
// Get the value at a specific index
double Keyframe::GetValue(int64_t index) const {
if (Points.empty()) {
return 0;
}
std::vector<Point>::const_iterator candidate =
std::lower_bound(begin(Points), end(Points), static_cast<double>(index), IsPointBeforeX);
if (candidate == end(Points)) {
// index is behind last point
return Points.back().co.Y;
}
if (candidate == begin(Points)) {
// index is at or before first point
return Points.front().co.Y;
}
if (candidate->co.X == index) {
// index is directly on a point
return candidate->co.Y;
}
std::vector<Point>::const_iterator predecessor = candidate - 1;
return InterpolateBetween(*predecessor, *candidate, index, 0.01);
}
// Get the rounded INT value at a specific index
int Keyframe::GetInt(int64_t index) const {
return int(round(GetValue(index)));
}
// Get the rounded INT value at a specific index
int64_t Keyframe::GetLong(int64_t index) const {
return long(round(GetValue(index)));
}
// Get the direction of the curve at a specific index (increasing or decreasing)
bool Keyframe::IsIncreasing(int index) const
{
if (index < 1 || (index + 1) >= GetLength()) {
return true;
}
std::vector<Point>::const_iterator candidate =
std::lower_bound(begin(Points), end(Points), static_cast<double>(index), IsPointBeforeX);
if (candidate == end(Points)) {
return false; // After the last point, thus constant.
}
if ((candidate->co.X == index) || (candidate == begin(Points))) {
++candidate;
}
int64_t const value = GetLong(index);
do {
if (value < round(candidate->co.Y)) {
return true;
} else if (value > round(candidate->co.Y)) {
return false;
}
++candidate;
} while (candidate != end(Points));
return false;
}
// Generate JSON string of this object
std::string Keyframe::Json() const {
// Return formatted string
return JsonValue().toStyledString();
}
// Generate Json::Value for this object
Json::Value Keyframe::JsonValue() const {
// Create root json object
Json::Value root;
root["Points"] = Json::Value(Json::arrayValue);
// loop through points
for (const auto existing_point : Points) {
root["Points"].append(existing_point.JsonValue());
}
// return JsonValue
return root;
}
// Load JSON string into this object
void Keyframe::SetJson(const std::string value) {
// Parse JSON string into JSON objects
try
{
const Json::Value root = openshot::stringToJson(value);
// Set all values that match
SetJsonValue(root);
}
catch (const std::exception& e)
{
// Error parsing JSON (or missing keys)
throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
}
}
// Load Json::Value into this object
void Keyframe::SetJsonValue(const Json::Value root) {
// Clear existing points
Points.clear();
if (!root["Points"].isNull())
// loop through points
for (const auto existing_point : root["Points"]) {
// Create Point
Point p;
// Load Json into Point
p.SetJsonValue(existing_point);
// Add Point to Keyframe
AddPoint(p);
}
}
// Get the fraction that represents how many times this value is repeated in the curve
// This is depreciated and will be removed soon.
Fraction Keyframe::GetRepeatFraction(int64_t index) const {
// Frame numbers (index) outside of the "defined" range of this
// keyframe result in a 1/1 default value.
if (index < 1 || (index + 1) >= GetLength()) {
return Fraction(1,1);
}
assert(Points.size() > 1); // Due to ! ((index + 1) >= GetLength) there are at least two points!
// First, get the value at the given frame and the closest point
// to the right.
int64_t const current_value = GetLong(index);
std::vector<Point>::const_iterator const candidate =
std::lower_bound(begin(Points), end(Points), static_cast<double>(index), IsPointBeforeX);
assert(candidate != end(Points)); // Due to the (index + 1) >= GetLength check above!
// Calculate how many of the next values are going to be the same:
int64_t next_repeats = 0;
std::vector<Point>::const_iterator i = candidate;
// If the index (frame number) is the X coordinate of the closest
// point, then look at the segment to the right; the "current"
// segement is not interesting because we're already at the last
// value of it.
if (i->co.X == index) {
++i;
}
// Skip over "constant" (when rounded) segments.
bool all_constant = true;
for (; i != end(Points); ++i) {
if (current_value != round(i->co.Y)) {
all_constant = false;
break;
}
}
if (! all_constant) {
// Found a point which defines a segment which will give a
// different value than the current value. This means we
// moved at least one segment to the right, thus we cannot be
// at the first point.
assert(i != begin(Points));
Point const left = *(i - 1);
Point const right = *i;
int64_t change_at;
if (current_value < round(i->co.Y)) {
change_at = SearchBetweenPoints(left, right, current_value, std::less_equal<double>{});
} else {
assert(current_value > round(i->co.Y));
change_at = SearchBetweenPoints(left, right, current_value, std::greater_equal<double>{});
}
next_repeats = change_at - index;
} else {
// All values to the right are the same!
next_repeats = Points.back().co.X - index;
}
// Now look to the left, to the previous values.
all_constant = true;
i = candidate;
if (i != begin(Points)) {
// The binary search below assumes i to be the left point;
// candidate is the right point of the current segment
// though. So change this if possible. If this branch is NOT
// taken, then we're at/before the first point and all is
// constant!
--i;
}
int64_t previous_repeats = 0;
// Skip over constant (when rounded) segments!
for (; i != begin(Points); --i) {
if (current_value != round(i->co.Y)) {
all_constant = false;
break;
}
}
// Special case when skipped until the first point, but the first
// point is actually different. Will not happen if index is
// before the first point!
if (current_value != round(i->co.Y)) {
assert(i != candidate);
all_constant = false;
}
if (! all_constant) {
// There are at least two points, and we're not at the end,
// thus the following is safe!
Point const left = *i;
Point const right = *(i + 1);
int64_t change_at;
if (current_value > round(left.co.Y)) {
change_at = SearchBetweenPoints(left, right, current_value, std::less<double>{});
} else {
assert(current_value < round(left.co.Y));
change_at = SearchBetweenPoints(left, right, current_value, std::greater<double>{});
}
previous_repeats = index - change_at;
} else {
// Every previous value is the same (rounded) as the current
// value.
previous_repeats = index;
}
int64_t total_repeats = previous_repeats + next_repeats;
return Fraction(previous_repeats, total_repeats);
}
// Get the change in Y value (from the previous Y value)
double Keyframe::GetDelta(int64_t index) const {
if (index < 1) return 0;
if (index == 1 && ! Points.empty()) return Points[0].co.Y;
if (index >= GetLength()) return 0;
return GetLong(index) - GetLong(index - 1);
}
// Get a point at a specific index
Point const & Keyframe::GetPoint(int64_t index) const {
// Is index a valid point?
if (index >= 0 && index < (int64_t)Points.size())
return Points[index];
else
// Invalid index
throw OutOfBoundsPoint("Invalid point requested", index, Points.size());
}
// Get the number of values (i.e. coordinates on the X axis)
int64_t Keyframe::GetLength() const {
if (Points.empty()) return 0;
if (Points.size() == 1) return 1;
return round(Points.back().co.X) + 1;
}
// Get the number of points (i.e. # of points)
int64_t Keyframe::GetCount() const {
return Points.size();
}
// Remove a point by matching a coordinate
void Keyframe::RemovePoint(Point p) {
// loop through points, and find a matching coordinate
for (std::vector<Point>::size_type x = 0; x < Points.size(); x++) {
// Get each point
Point existing_point = Points[x];
// find a match
if (p.co.X == existing_point.co.X && p.co.Y == existing_point.co.Y) {
// Remove the matching point, and break out of loop
Points.erase(Points.begin() + x);
return;
}
}
// no matching point found
throw OutOfBoundsPoint("Invalid point requested", -1, Points.size());
}
// Remove a point by index
void Keyframe::RemovePoint(int64_t index) {
// Is index a valid point?
if (index >= 0 && index < (int64_t)Points.size())
{
// Remove a specific point by index
Points.erase(Points.begin() + index);
}
else
// Invalid index
throw OutOfBoundsPoint("Invalid point requested", index, Points.size());
}
void Keyframe::UpdatePoint(int64_t index, Point p) {
// Remove matching point
RemovePoint(index);
// Add new point
AddPoint(p);
}
void Keyframe::PrintPoints() const {
cout << fixed << setprecision(4);
for (std::vector<Point>::const_iterator it = Points.begin(); it != Points.end(); it++) {
Point p = *it;
cout << p.co.X << "\t" << p.co.Y << endl;
}
}
void Keyframe::PrintValues() const {
cout << fixed << setprecision(4);
cout << "Frame Number (X)\tValue (Y)\tIs Increasing\tRepeat Numerator\tRepeat Denominator\tDelta (Y Difference)\n";
for (int64_t i = 1; i < GetLength(); ++i) {
cout << i << "\t" << GetValue(i) << "\t" << IsIncreasing(i) << "\t" ;
cout << GetRepeatFraction(i).num << "\t" << GetRepeatFraction(i).den << "\t" << GetDelta(i) << "\n";
}
}
// Scale all points by a percentage (good for evenly lengthening or shortening an openshot::Keyframe)
// 1.0 = same size, 1.05 = 5% increase, etc...
void Keyframe::ScalePoints(double scale)
{
// TODO: What if scale is small so that two points land on the
// same X coordinate?
// TODO: What if scale < 0?
// Loop through each point (skipping the 1st point)
for (std::vector<Point>::size_type point_index = 1; point_index < Points.size(); point_index++) {
// Scale X value
Points[point_index].co.X = round(Points[point_index].co.X * scale);
}
}
// Flip all the points in this openshot::Keyframe (useful for reversing an effect or transition, etc...)
void Keyframe::FlipPoints() {
for (std::vector<Point>::size_type point_index = 0, reverse_index = Points.size() - 1; point_index < reverse_index; point_index++, reverse_index--) {
// Flip the points
using std::swap;
swap(Points[point_index].co.Y, Points[reverse_index].co.Y);
// TODO: check that this has the desired effect even with
// regards to handles!
}
}
openshot::Coordinate
This class represents a Cartesian coordinate (X, Y) used in the Keyframe animation system.
Definition: Coordinate.h:55
openshot::Coordinate::X
double X
The X value of the coordinate (usually representing the frame #)
Definition: Coordinate.h:57
openshot::Coordinate::Y
double Y
The Y value of the coordinate (usually representing the value of the property being animated)
Definition: Coordinate.h:58
openshot::Fraction
This class represents a fraction.
Definition: Fraction.h:45
openshot::InvalidJSON
Exception for invalid JSON.
Definition: Exceptions.h:206
openshot::OutOfBoundsPoint
Exception for an out of bounds key-frame point.
Definition: Exceptions.h:304
openshot::Point
A Point is the basic building block of a key-frame curve.
Definition: Point.h:82
openshot::Point::handle_left
Coordinate handle_left
This is the left handle coordinate (in percentages from 0 to 1)
Definition: Point.h:85
openshot::Point::co
Coordinate co
This is the primary coordinate.
Definition: Point.h:84
openshot::Point::interpolation
InterpolationType interpolation
This is the interpolation mode.
Definition: Point.h:87
openshot::Point::handle_right
Coordinate handle_right
This is the right handle coordinate (in percentages from 0 to 1)
Definition: Point.h:86
openshot::Point::SetJsonValue
void SetJsonValue(const Json::Value root)
Load Json::Value into this object.
Definition: Point.cpp:152
openshot
This namespace is the default namespace for all code in the openshot library.
Definition: AudioBufferSource.h:39
openshot::stringToJson
const Json::Value stringToJson(const std::string value)
Definition: Json.cpp:33
openshot::InterpolationType
InterpolationType
This controls how a Keyframe uses this point to interpolate between two points.
Definition: Point.h:46
openshot::CONSTANT
@ CONSTANT
Constant curves jump from their previous position to a new one (with no interpolation).
Definition: Point.h:49
openshot::BEZIER
@ BEZIER
Bezier curves are quadratic curves, which create a smooth curve.
Definition: Point.h:47
openshot::LINEAR
@ LINEAR
Linear curves are angular, straight lines between two points.
Definition: Point.h:48