diff options
Diffstat (limited to 'gpr/source/lib/dng_sdk/dng_spline.cpp')
| -rw-r--r-- | gpr/source/lib/dng_sdk/dng_spline.cpp | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/gpr/source/lib/dng_sdk/dng_spline.cpp b/gpr/source/lib/dng_sdk/dng_spline.cpp new file mode 100644 index 0000000..cd47532 --- /dev/null +++ b/gpr/source/lib/dng_sdk/dng_spline.cpp @@ -0,0 +1,233 @@ +/*****************************************************************************/
+// Copyright 2006-2007 Adobe Systems Incorporated
+// All Rights Reserved.
+//
+// NOTICE: Adobe permits you to use, modify, and distribute this file in
+// accordance with the terms of the Adobe license agreement accompanying it.
+/*****************************************************************************/
+
+/* $Id: //mondo/dng_sdk_1_4/dng_sdk/source/dng_spline.cpp#1 $ */
+/* $DateTime: 2012/05/30 13:28:51 $ */
+/* $Change: 832332 $ */
+/* $Author: tknoll $ */
+
+/*****************************************************************************/
+
+#include "dng_spline.h"
+
+#include "dng_assertions.h"
+#include "dng_exceptions.h"
+
+/******************************************************************************/
+
+dng_spline_solver::dng_spline_solver ()
+
+ : X ()
+ , Y ()
+ , S ()
+
+ {
+
+ }
+
+/******************************************************************************/
+
+dng_spline_solver::~dng_spline_solver ()
+ {
+
+ }
+
+/******************************************************************************/
+
+void dng_spline_solver::Reset ()
+ {
+
+ X.clear ();
+ Y.clear ();
+
+ S.clear ();
+
+ }
+
+/******************************************************************************/
+
+void dng_spline_solver::Add (real64 x, real64 y)
+ {
+
+ X.push_back (x);
+ Y.push_back (y);
+
+ }
+
+/******************************************************************************/
+
+void dng_spline_solver::Solve ()
+ {
+
+ // This code computes the unique curve such that:
+ // It is C0, C1, and C2 continuous
+ // The second derivative is zero at the end points
+
+ int32 count = (int32) X.size ();
+
+ DNG_ASSERT (count >= 2, "Too few points");
+
+ int32 start = 0;
+ int32 end = count;
+
+ real64 A = X [start+1] - X [start];
+ real64 B = (Y [start+1] - Y [start]) / A;
+
+ S.resize (count);
+
+ S [start] = B;
+
+ int32 j;
+
+ // Slopes here are a weighted average of the slopes
+ // to each of the adjcent control points.
+
+ for (j = start + 2; j < end; ++j)
+ {
+
+ real64 C = X [j] - X [j-1];
+ real64 D = (Y [j] - Y [j-1]) / C;
+
+ S [j-1] = (B * C + D * A) / (A + C);
+
+ A = C;
+ B = D;
+
+ }
+
+ S [end-1] = 2.0 * B - S [end-2];
+ S [start] = 2.0 * S [start] - S [start+1];
+
+ if ((end - start) > 2)
+ {
+
+ std::vector<real64> E;
+ std::vector<real64> F;
+ std::vector<real64> G;
+
+ E.resize (count);
+ F.resize (count);
+ G.resize (count);
+
+ F [start] = 0.5;
+ E [end-1] = 0.5;
+ G [start] = 0.75 * (S [start] + S [start+1]);
+ G [end-1] = 0.75 * (S [end-2] + S [end-1]);
+
+ for (j = start+1; j < end - 1; ++j)
+ {
+
+ A = (X [j+1] - X [j-1]) * 2.0;
+
+ E [j] = (X [j+1] - X [j]) / A;
+ F [j] = (X [j] - X [j-1]) / A;
+ G [j] = 1.5 * S [j];
+
+ }
+
+ for (j = start+1; j < end; ++j)
+ {
+
+ A = 1.0 - F [j-1] * E [j];
+
+ if (j != end-1) F [j] /= A;
+
+ G [j] = (G [j] - G [j-1] * E [j]) / A;
+
+ }
+
+ for (j = end - 2; j >= start; --j)
+ G [j] = G [j] - F [j] * G [j+1];
+
+ for (j = start; j < end; ++j)
+ S [j] = G [j];
+
+ }
+
+ }
+
+/******************************************************************************/
+
+bool dng_spline_solver::IsIdentity () const
+ {
+
+ int32 count = (int32) X.size ();
+
+ if (count != 2)
+ return false;
+
+ if (X [0] != 0.0 || X [1] != 1.0 ||
+ Y [0] != 0.0 || Y [1] != 1.0)
+ return false;
+
+ return true;
+
+ }
+
+/******************************************************************************/
+
+real64 dng_spline_solver::Evaluate (real64 x) const
+ {
+
+ int32 count = (int32) X.size ();
+
+ // Check for off each end of point list.
+
+ if (x <= X [0])
+ return Y [0];
+
+ if (x >= X [count-1])
+ return Y [count-1];
+
+ // Binary search for the index.
+
+ int32 lower = 1;
+ int32 upper = count - 1;
+
+ while (upper > lower)
+ {
+
+ int32 mid = (lower + upper) >> 1;
+
+ if (x == X [mid])
+ {
+ return Y [mid];
+ }
+
+ if (x > X [mid])
+ lower = mid + 1;
+ else
+ upper = mid;
+
+ }
+
+ DNG_ASSERT (upper == lower, "Binary search error in point list");
+
+ int32 j = lower;
+
+ // X [j - 1] < x <= X [j]
+ // A is the distance between the X [j] and X [j - 1]
+ // B and C describe the fractional distance to either side. B + C = 1.
+
+ // We compute a cubic spline between the two points with slopes
+ // S[j-1] and S[j] at either end. Specifically, we compute the 1-D Bezier
+ // with control values:
+ //
+ // Y[j-1], Y[j-1] + S[j-1]*A, Y[j]-S[j]*A, Y[j]
+
+ return EvaluateSplineSegment (x,
+ X [j - 1],
+ Y [j - 1],
+ S [j - 1],
+ X [j ],
+ Y [j ],
+ S [j ]);
+
+ }
+
+/*****************************************************************************/
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