From 266bd45bdeeb429571324253a0a81a8f185fea34 Mon Sep 17 00:00:00 2001
From: Jonathan Thomas <Jonathan.Oomph@gmail.com>
Date: Fri, 19 Oct 2012 22:24:54 -0500
Subject: [PATCH] Added delta() to a coordinate, to track the change in unique
 value on the Y axis.  This helps in time mapping, to track how many frames
 have been skipped.

---
 include/Coordinate.h     |  1 +
 include/KeyFrame.h       |  3 +++
 src/Coordinate.cpp       |  4 ++--
 src/KeyFrame.cpp         | 29 +++++++++++++++++++++++++++--
 tests/KeyFrame_Tests.cpp |  4 ++++
 5 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/include/Coordinate.h b/include/Coordinate.h
index 0c8973fe..44b9574a 100644
--- a/include/Coordinate.h
+++ b/include/Coordinate.h
@@ -32,6 +32,7 @@ namespace openshot {
 		float Y; ///< The Y value of the coordinate
 		bool increasing; ///< Is the Y value increasing or decreasing?
 		Fraction repeated; ///< Fraction of repeated Y values (for example, 1/3 would be the first Y value of 3 repeated values)
+		float delta; ///< This difference in Y value (from the previous unique Y value)
 
 		/// The default constructor, which defaults to (0,0)
 		Coordinate();
diff --git a/include/KeyFrame.h b/include/KeyFrame.h
index 2d4bbee0..b752ed55 100644
--- a/include/KeyFrame.h
+++ b/include/KeyFrame.h
@@ -102,6 +102,9 @@ namespace openshot {
 		/// Get the fraction that represents how many times this value is repeated in the curve
 		Fraction GetRepeatFraction(int index);
 
+		/// Get the change in Y value (from the previous Y value)
+		float GetDelta(int index);
+
 		/// Get a point at a specific index
 		Point& GetPoint(int index) throw(OutOfBoundsPoint);
 
diff --git a/src/Coordinate.cpp b/src/Coordinate.cpp
index 6d494cde..aaa26e74 100644
--- a/src/Coordinate.cpp
+++ b/src/Coordinate.cpp
@@ -11,10 +11,10 @@ using namespace openshot;
 
 // Default constructor for a coordinate, which defaults the X and Y to zero (0,0)
 Coordinate::Coordinate() :
-	X(0), Y(0), increasing(true), repeated(1,1) {
+	X(0), Y(0), increasing(true), repeated(1,1), delta(0.0) {
 }
 
 // Constructor which also allows the user to set the X and Y
 Coordinate::Coordinate(float x, float y) :
-	X(x), Y(y), increasing(true), repeated(1,1) {
+	X(x), Y(y), increasing(true), repeated(1,1), delta(0.0)  {
 }
diff --git a/src/KeyFrame.cpp b/src/KeyFrame.cpp
index da7d5426..e3cfa7e5 100644
--- a/src/KeyFrame.cpp
+++ b/src/KeyFrame.cpp
@@ -234,6 +234,28 @@ Fraction Keyframe::GetRepeatFraction(int index)
 		return Fraction(1,1);
 }
 
+// Get the change in Y value (from the previous Y value)
+float Keyframe::GetDelta(int index)
+{
+	// Check if it needs to be processed
+	if (needs_update)
+		Process();
+
+	// Is index a valid point?
+	if (index >= 0 && index < Values.size())
+		// Return value
+		return Values[index].delta;
+	else if (index < 0 && Values.size() > 0)
+		// Return the minimum value
+		return Values[0].delta;
+	else if (index >= Values.size() && Values.size() > 0)
+		// return the maximum value
+		return Values[Values.size() - 1].delta;
+	else
+		// return a blank coordinate (0,0)
+		return 0.0;
+}
+
 // Get a point at a specific index
 Point& Keyframe::GetPoint(int index) throw(OutOfBoundsPoint) {
 	// Is index a valid point?
@@ -312,11 +334,11 @@ void Keyframe::PrintValues() {
 	if (needs_update)
 		Process();
 
-	cout << " PRINT ALL VALUES " << endl;
+	cout << "Frame Number (X)\tValue (Y)\tIs Increasing\tRepeat Numerator\tRepeat Denominator\tDelta (Y Difference)" << endl;
 
 	for (vector<Coordinate>::iterator it = Values.begin() + 1; it != Values.end(); it++) {
 		Coordinate c = *it;
-		cout << int(round(c.X)) << "\t" << int(round(c.Y)) << "\t" << c.increasing << "\t" << c.repeated.num << "\t" << c.repeated.den << endl;
+		cout << int(round(c.X)) << "\t" << int(round(c.Y)) << "\t" << c.increasing << "\t" << c.repeated.num << "\t" << c.repeated.den << "\t" << c.delta << endl;
 	}
 }
 
@@ -412,6 +434,9 @@ void Keyframe::Process() {
 		(*it).repeated.num = repeat_count;
 		(*it).repeated.den = repeat_count + additional_repeats;
 
+		// Set delta (i.e. different from previous unique Y value)
+		(*it).delta = current_value - last_value;
+
 		// track the last value
 		last_value = current_value;
 	}
diff --git a/tests/KeyFrame_Tests.cpp b/tests/KeyFrame_Tests.cpp
index 3a751490..69272f1e 100644
--- a/tests/KeyFrame_Tests.cpp
+++ b/tests/KeyFrame_Tests.cpp
@@ -176,19 +176,23 @@ TEST(Keyframe_Check_Direction_and_Repeat_Fractions)
 	CHECK_EQUAL(kf.IsIncreasing(1), false);
 	CHECK_EQUAL(kf.GetRepeatFraction(1).num, 1);
 	CHECK_EQUAL(kf.GetRepeatFraction(1).den, 10);
+	CHECK_EQUAL(kf.GetDelta(1), 500);
 
 	CHECK_EQUAL(kf.GetInt(24), 497);
 	CHECK_EQUAL(kf.IsIncreasing(24), false);
 	CHECK_EQUAL(kf.GetRepeatFraction(24).num, 2);
 	CHECK_EQUAL(kf.GetRepeatFraction(24).den, 4);
+	CHECK_EQUAL(kf.GetDelta(24), 0);
 
 	CHECK_EQUAL(kf.GetInt(390), 101);
 	CHECK_EQUAL(kf.IsIncreasing(390), false);
 	CHECK_EQUAL(kf.GetRepeatFraction(390).num, 8);
 	CHECK_EQUAL(kf.GetRepeatFraction(390).den, 8);
+	CHECK_EQUAL(kf.GetDelta(390), 0);
 
 	CHECK_EQUAL(kf.GetInt(391), 100);
 	CHECK_EQUAL(kf.IsIncreasing(391), true);
 	CHECK_EQUAL(kf.GetRepeatFraction(391).num, 1);
 	CHECK_EQUAL(kf.GetRepeatFraction(391).den, 12);
+	CHECK_EQUAL(kf.GetDelta(391), -1);
 }