--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Toolbox/AffineTransform2D.cpp	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,271 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program 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
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "AffineTransform2D.h"
+
+#include "ImageGeometry.h"
+
+#include <Logging.h>
+#include <OrthancException.h>
+
+namespace OrthancStone
+{
+  AffineTransform2D::AffineTransform2D() :
+    matrix_(LinearAlgebra::IdentityMatrix(3))
+  {
+  }
+
+  
+  AffineTransform2D::AffineTransform2D(const Matrix& m)
+  {
+    if (m.size1() != 3 ||
+        m.size2() != 3)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_IncompatibleImageSize);
+    }
+
+    if (!LinearAlgebra::IsCloseToZero(m(2, 0)) ||
+        !LinearAlgebra::IsCloseToZero(m(2, 1)) ||
+        LinearAlgebra::IsCloseToZero(m(2, 2)))
+    {
+      LOG(ERROR) << "Cannot setup an AffineTransform2D with perspective effects";
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
+    }
+
+    matrix_ = m / m(2, 2);
+  }
+    
+
+  void AffineTransform2D::Apply(double& x /* inout */,
+                                double& y /* inout */) const
+  {
+    Vector p;
+    LinearAlgebra::AssignVector(p, x, y, 1);
+
+    Vector q = LinearAlgebra::Product(matrix_, p);
+
+    if (!LinearAlgebra::IsNear(q[2], 1.0))
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+    }
+    else
+    {
+      x = q[0];
+      y = q[1];
+    }
+  }
+
+
+  void AffineTransform2D::Apply(Orthanc::ImageAccessor& target,
+                                const Orthanc::ImageAccessor& source,
+                                ImageInterpolation interpolation,
+                                bool clear) const
+  {
+    assert(LinearAlgebra::IsNear(matrix_(2, 0), 0) &&
+           LinearAlgebra::IsNear(matrix_(2, 1), 0) &&
+           LinearAlgebra::IsNear(matrix_(2, 2), 1));
+
+    ApplyAffineTransform(target, source,
+                         matrix_(0, 0), matrix_(0, 1), matrix_(0, 2),
+                         matrix_(1, 0), matrix_(1, 1), matrix_(1, 2),
+                         interpolation, clear);
+  }
+
+
+  void AffineTransform2D::ConvertToOpenGLMatrix(float target[16],
+                                                unsigned int canvasWidth,
+                                                unsigned int canvasHeight) const
+  {
+    const AffineTransform2D t = AffineTransform2D::Combine(
+      CreateOpenGLClipspace(canvasWidth, canvasHeight), *this);
+    
+    const Matrix source = t.GetHomogeneousMatrix();
+  
+    if (source.size1() != 3 ||
+        source.size2() != 3)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+    }
+
+    // "z" must be in the [-1,1] range, otherwise the texture does not show up
+    float z = 0;
+
+    // Embed the 3x3 affine transform of the 2D plane into a 4x4
+    // matrix (3D) for OpenGL. The matrix must be transposed.
+
+    target[0] = static_cast<float>(source(0, 0)); 
+    target[1] = static_cast<float>(source(1, 0)); 
+    target[2] = 0; 
+    target[3] = static_cast<float>(source(2, 0));
+    target[4] = static_cast<float>(source(0, 1)); 
+    target[5] = static_cast<float>(source(1, 1));
+    target[6] = 0;
+    target[7] = static_cast<float>(source(2, 1));
+    target[8] = 0; 
+    target[9] = 0; 
+    target[10] = -1; 
+    target[11] = 0;
+    target[12] = static_cast<float>(source(0, 2)); 
+    target[13] = static_cast<float>(source(1, 2));
+    target[14] = -z;
+    target[15] = static_cast<float>(source(2, 2));
+  }
+
+
+  double AffineTransform2D::ComputeZoom() const
+  {
+    // Compute the length of the (0,0)-(1,1) diagonal (whose
+    // length is sqrt(2)) instead of the (0,0)-(1,0) unit segment,
+    // in order to cope with possible anisotropic zooming
+        
+    double x1 = 0;
+    double y1 = 0;
+    Apply(x1, y1);
+
+    double x2 = 1;
+    double y2 = 1;
+    Apply(x2, y2);
+
+    double dx = x2 - x1;
+    double dy = y2 - y1;
+
+    double zoom = sqrt(dx * dx + dy * dy) / sqrt(2.0);
+
+    if (LinearAlgebra::IsCloseToZero(zoom))
+    {
+      return 1;  // Default value if transform is ill-conditioned 
+    }
+    else
+    {
+      return zoom;
+    }
+  }    
+
+
+  AffineTransform2D AffineTransform2D::Invert(const AffineTransform2D& a)
+  {
+    AffineTransform2D t;
+    LinearAlgebra::InvertMatrix(t.matrix_, a.matrix_);
+    return t;
+  }
+
+
+  AffineTransform2D AffineTransform2D::Combine(const AffineTransform2D& a,
+                                               const AffineTransform2D& b)
+  {
+    return AffineTransform2D(LinearAlgebra::Product(a.GetHomogeneousMatrix(),
+                                                    b.GetHomogeneousMatrix()));
+  }
+  
+      
+  AffineTransform2D AffineTransform2D::Combine(const AffineTransform2D& a,
+                                               const AffineTransform2D& b,
+                                               const AffineTransform2D& c)
+  {
+    return AffineTransform2D(LinearAlgebra::Product(a.GetHomogeneousMatrix(),
+                                                    b.GetHomogeneousMatrix(),
+                                                    c.GetHomogeneousMatrix()));
+  }
+  
+      
+  AffineTransform2D AffineTransform2D::Combine(const AffineTransform2D& a,
+                                               const AffineTransform2D& b,
+                                               const AffineTransform2D& c,
+                                               const AffineTransform2D& d)
+  {
+    return AffineTransform2D(LinearAlgebra::Product(a.GetHomogeneousMatrix(),
+                                                    b.GetHomogeneousMatrix(),
+                                                    c.GetHomogeneousMatrix(),
+                                                    d.GetHomogeneousMatrix()));
+  }
+  
+  AffineTransform2D AffineTransform2D::Combine(const AffineTransform2D& a,
+                                               const AffineTransform2D& b,
+                                               const AffineTransform2D& c,
+                                               const AffineTransform2D& d,
+                                               const AffineTransform2D& e)
+  {
+    return AffineTransform2D(LinearAlgebra::Product(a.GetHomogeneousMatrix(),
+                                                    b.GetHomogeneousMatrix(),
+                                                    c.GetHomogeneousMatrix(),
+                                                    d.GetHomogeneousMatrix(),
+                                                    e.GetHomogeneousMatrix()));
+  }
+
+  AffineTransform2D AffineTransform2D::CreateOffset(double dx,
+                                                    double dy)
+  {
+    AffineTransform2D t;
+    t.matrix_(0, 2) = dx;
+    t.matrix_(1, 2) = dy;
+      
+    return t;
+  }
+  
+
+  AffineTransform2D AffineTransform2D::CreateScaling(double sx,
+                                                     double sy)
+  {
+    AffineTransform2D t;
+    t.matrix_(0, 0) = sx;
+    t.matrix_(1, 1) = sy;
+      
+    return t;
+  }
+  
+
+  AffineTransform2D AffineTransform2D::CreateRotation(double angle)
+  {
+    double cosine = cos(angle);
+    double sine = sin(angle);
+      
+    AffineTransform2D t;
+    t.matrix_(0, 0) = cosine;
+    t.matrix_(0, 1) = -sine;
+    t.matrix_(1, 0) = sine;
+    t.matrix_(1, 1) = cosine;
+
+    return t;
+  }
+
+  AffineTransform2D AffineTransform2D::CreateRotation(double angle, // CW rotation
+                                                      double cx,    // rotation center
+                                                      double cy)    // rotation center
+  {
+    return Combine(
+          CreateOffset(cx, cy),
+          CreateRotation(angle),
+          CreateOffset(-cx, -cy)
+          );
+  }
+
+  AffineTransform2D AffineTransform2D::CreateOpenGLClipspace(unsigned int canvasWidth,
+                                                             unsigned int canvasHeight)
+  {
+    AffineTransform2D t;
+    t.matrix_(0, 0) = 2.0 / static_cast<double>(canvasWidth);
+    t.matrix_(0, 2) = -1.0;
+    t.matrix_(1, 1) = -2.0 / static_cast<double>(canvasHeight);
+    t.matrix_(1, 2) = 1.0;
+    
+    return t;
+  }
+}