Merge topic 'context2d-fix-pdf-export-issues'

3e2f51d5 Fix context2d pdf export image flip axis
533057e9 Replace DrawPolygon with equivalent DrawQuad
4b2036a4 Enable support for VTK_POLY_LINE in pdf backend device
1f535c69 Attempt to fix pen width by computing it in world coords
Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Allison Vacanti <allison.vacanti@kitware.com>
Merge-request: !4738

IO/ExportPDF/Testing/Data/Baseline/TestPDFContextExport-rasterPDFRef.png.sha512

-baa21e41b8c62abcf33c1725bad0f21c4ca9534abedfcc004eed96393ebce80bb03b02053d51cdd136b56876254dcec6f27a608f6598143d85dd00f6b15dc93d
+fcdf54076525a02b974c6eed8fdf8cd3a6dc4b1666da0a9bdc4ed6d2a5d3370083a223d73e449661cca5b5b27e7448dfed9ba991ab4f25526ba4c8dcf1bc8b94

IO/ExportPDF/vtkPDFContextDevice2D.cxx

@@ -26,6 +26,7 @@
 #include "vtkImageFlip.h"
 #include "vtkIntArray.h"
 #include "vtkMatrix3x3.h"
+#include "vtkMatrix4x4.h"
 #include "vtkObjectFactory.h"
 #include "vtkPath.h"
 #include "vtkPen.h"
@@ -186,6 +187,58 @@ struct vtkPDFContextDevice2D::Details
   HPDF_Page Page;
 
   std::map<unsigned char, HPDF_ExtGState> AlphaGStateMap;
+
+  float computeWorldRadius(const float x1, const float y1,
+                           const float x2, const float y2,
+                           vtkMatrix4x4 *matrix, const float penWidth)
+  {
+    // Attempt to compute the radius in world space.  For this computation
+    // we make the assumption that the following expression holds true:
+    //
+    //     worldDiagonalLength       worldRadius
+    //    ---------------------  =  -------------
+    //     screenDiagonalLength      screenRadius
+    //
+    // Then we further assume that this->Matrix can take the points of our
+    // polydata bounding box and transform them into top-level pixel coords
+    // of our render window.
+    double transMat[9];
+    double *mat = matrix->GetData();
+    vtkPDFContextDevice2D::Matrix4ToMatrix3(mat, transMat);
+
+    const float boundPt1[3] = {
+      static_cast<float>(x1),
+      static_cast<float>(y1),
+      1.0f
+    };
+
+    const float boundPt2[3] = {
+      static_cast<float>(x2),
+      static_cast<float>(y2),
+      1.0f
+    };
+
+    float boundPt1Px[3];
+    float boundPt2Px[3];
+
+    vtkMatrix3x3::MultiplyPoint(transMat, boundPt1, boundPt1Px);
+    vtkMatrix3x3::MultiplyPoint(transMat, boundPt2, boundPt2Px);
+
+    // Compute the length of the bounding box diagonal in world space
+    const float wdx = boundPt1[0] - boundPt2[0];
+    const float wdy = boundPt1[1] - boundPt2[1];
+    const float worldDiag = std::sqrt(wdx * wdx + wdy * wdy);
+
+    // Do the same as above, but in screen space
+    const float sdx = boundPt1Px[0] - boundPt2Px[0];
+    const float sdy = boundPt1Px[1] - boundPt2Px[1];
+    const float screenDiag = std::sqrt(sdx * sdx + sdy * sdy);
+
+    // Pen width is twice the radius in screen space, so get that in world space
+    const float worldPenWidth = penWidth * (worldDiag / screenDiag);
+
+    return worldPenWidth * 0.5f;
+  }
 };
 
 //------------------------------------------------------------------------------
@@ -1006,6 +1059,7 @@ void vtkPDFContextDevice2D::DrawPolyData(
   vtkNew<vtkCellTypes> types;
   polyData->GetCellTypes(types);
   if (!types->IsType(VTK_LINE) &&
+      !types->IsType(VTK_POLY_LINE) &&
       !types->IsType(VTK_TRIANGLE) &&
       !types->IsType(VTK_QUAD) &&
       !types->IsType(VTK_POLYGON))
@@ -1016,8 +1070,12 @@ void vtkPDFContextDevice2D::DrawPolyData(
   double bounds[6];
   polyData->GetBounds(bounds);
 
+  float radius = this->Impl->computeWorldRadius(bounds[0], bounds[2],
+                                                bounds[1], bounds[3],
+                                                this->Matrix->GetMatrix(),
+                                                this->Pen->GetWidth());
+
   // Adjust bounds for transform, account for pen width:
-  const float radius = this->Pen->GetWidth() * 0.5f;
   bounds[0] = (bounds[0] + p[0]) * scale - radius;
   bounds[1] = (bounds[1] + p[0]) * scale + radius;
   bounds[2] = (bounds[2] + p[1]) * scale - radius;
@@ -1044,6 +1102,7 @@ void vtkPDFContextDevice2D::DrawPolyData(
     switch (cellType)
     {
       case VTK_LINE:
+      case VTK_POLY_LINE:
       case VTK_TRIANGLE:
       case VTK_QUAD:
       case VTK_POLYGON:
@@ -1085,7 +1144,7 @@ void vtkPDFContextDevice2D::DrawPolyData(
       }
     }
 
-    if (cellType == VTK_LINE)
+    if (cellType == VTK_LINE || cellType == VTK_POLY_LINE)
     {
       PolyLineToShading(verts.data(), numPoints, vertColors.data(), 4, radius,
                         shading);
@@ -1535,7 +1594,7 @@ vtkImageData *vtkPDFContextDevice2D::PrepareImageData(vtkImageData *in)
   vtkNew<vtkImageFlip> flip;
   flip->SetInputData(in);
   in->UnRegister(this);
-  flip->SetFilteredAxis(0); // x axis
+  flip->SetFilteredAxis(1); // y axis
   flip->Update();
   in = flip->GetOutput();
   in->Register(this);

Rendering/Context2D/vtkLabeledContourPolyDataItem.cxx

@@ -790,7 +790,7 @@ bool vtkLabeledContourPolyDataItem::RenderBackgrounds(vtkContext2D* painter)
     pen->SetOpacityF(bgopacity);
     brush->SetColorF(bgcolor);
     brush->SetOpacityF(bgopacity);
-    painter->DrawPolygon(this->LabelHelpers[i]->boxPoints, 5);
+    painter->DrawQuad(this->LabelHelpers[i]->boxPoints);
   }
 
   pen->SetColorF(prevPenColor);