Fix vtkPlotBar::GetBounds logic when log scale is enabled

- address paraview/paraview#22733
- This commit fixes the logic in the
  `vtkPlotBar::GetBounds(double*, bool unscaled)` method
  to scale the bounds only if `unscaled` is false. Previously,
  it returned unscaled bounds even when `unscaled` was false and
  returned scaled bounds when `unscaled` was true.

Charts/Core/Testing/Cxx/CMakeLists.txt

@@ -57,6 +57,7 @@ vtk_add_test_cxx(vtkChartsCoreCxxTests tests
   TestChartDouble.cxx
   TestChartDoubleColors.cxx
   TestChartDoubleColorsOpaque.cxx
+  TestChartLogScaleUpdates.cxx
   TestChartMatrix.cxx
   TestChartMatrix2.cxx
   TestChartMatrix3.cxx

Charts/Core/Testing/Cxx/TestChartLogScaleUpdates.cxx

+// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include "vtkAxis.h"
+#include "vtkChartLegend.h"
+#include "vtkChartXY.h"
+#include "vtkContextView.h"
+#include "vtkFloatArray.h"
+#include "vtkPlot.h"
+#include "vtkRenderWindow.h"
+#include "vtkRenderWindowInteractor.h"
+#include "vtkTable.h"
+
+//------------------------------------------------------------------------------
+// This unit test verifies that log scale can be turned on at a later time and
+// also checks that updating other parameters after turning on log scale does
+// not reset the bounds of the axis which uses log scale.
+int TestChartLogScaleUpdates(int, char*[])
+{
+  // Set up a 2D scene, add an XY chart to it
+  vtkNew<vtkContextView> view;
+  view->GetRenderWindow()->SetSize(400, 300);
+  vtkNew<vtkChartXY> chart;
+  view->GetScene()->AddItem(chart);
+
+  // Create a table with some points in it...
+  vtkNew<vtkTable> table;
+  vtkNew<vtkFloatArray> arrX;
+  arrX->SetName("X Axis");
+  table->AddColumn(arrX);
+  vtkNew<vtkFloatArray> arrY1;
+  arrY1->SetName("y=x");
+  table->AddColumn(arrY1);
+  vtkNew<vtkFloatArray> arrY2;
+  arrY2->SetName("y=-x");
+  table->AddColumn(arrY2);
+  // Test charting with a few more points...
+  int numPoints = 10;
+  float inc = 7.5 / (numPoints - 1);
+  table->SetNumberOfRows(numPoints);
+  for (int i = 0; i < numPoints; ++i)
+  {
+    float x = 1.0e-5 + i * inc;
+    table->SetValue(i, 0, x);
+    table->SetValue(i, 1, x);
+    table->SetValue(i, 2, -x);
+  }
+  chart->SetShowLegend(true);
+  chart->GetLegend()->SetHorizontalAlignment(vtkChartLegend::CENTER);
+
+  // Add a bar plot
+  vtkPlot* bar = chart->AddPlot(vtkChart::BAR);
+  bar->SetInputData(table, 0, 1);
+  bar->SetColor(255, 0, 0, 255);
+
+  // Add a line plot
+  vtkPlot* line = chart->AddPlot(vtkChart::LINE);
+  line->SetInputData(table, 0, 2);
+  line->SetColor(255, 0, 255, 255);
+  line->SetWidth(4.0);
+
+  // Render the scene and compare the image to a reference image
+  view->GetRenderWindow()->SetMultiSamples(0);
+  view->GetInteractor()->Initialize();
+  view->Render();
+
+  // turn on log scale.
+  double xRange[2] = { 1, -1 };
+  arrX->GetRange(xRange);
+  // Initialize unscaled min/max to fit x axis data so that LogScaleActive is correctly brought
+  // up to date.
+  chart->GetAxis(vtkAxis::BOTTOM)->SetUnscaledMinimum(xRange[0]);
+  chart->GetAxis(vtkAxis::BOTTOM)->SetUnscaledMaximum(xRange[1]);
+  chart->GetAxis(vtkAxis::BOTTOM)->LogScaleOn();
+  chart->GetAxis(vtkAxis::BOTTOM)->Update();
+  chart->Update();
+  chart->RecalculateBounds();
+  view->Render();
+
+  // Change the line color to navy blue.
+  line->SetColor(0, 0, 255, 255);
+  chart->GetAxis(vtkAxis::BOTTOM)->SetCustomTickPositions(nullptr);
+  chart->RecalculateBounds();
+  view->GetInteractor()->Start();
+
+  return EXIT_SUCCESS;
+}

Charts/Core/Testing/Data/Baseline/TestChartLogScaleUpdates.png.sha512

+19a8ce4b51d64feae1faa4cc76d863fe5bb61fcb4ded1b12fb688db50102ee745f813777200163714e9a9c1c0d2b73e79a4d3163c1da96bdf8c654d044da7d08

Charts/Core/vtkPlotBar.cxx

@@ -651,7 +651,7 @@ void vtkPlotBar::GetBounds(double bounds[4], bool unscaled)
     bounds[valuesHigh] = 0.0;
   }
 
-  if (unscaled)
+  if (!unscaled)
   {
     vtkAxis* axes[2];
     axes[seriesLow / 2] = this->GetXAxis();
@@ -674,13 +674,13 @@ void vtkPlotBar::GetBounds(double bounds[4], bool unscaled)
 //------------------------------------------------------------------------------
 void vtkPlotBar::GetBounds(double bounds[4])
 {
-  this->GetBounds(bounds, false);
+  this->GetBounds(bounds, /*unscaled=*/false);
 }
 
 //------------------------------------------------------------------------------
 void vtkPlotBar::GetUnscaledInputBounds(double bounds[4])
 {
-  this->GetBounds(bounds, true);
+  this->GetBounds(bounds, /*unscaled=*/true);
 }
 
 //------------------------------------------------------------------------------

Documentation/release/dev/fix-vtkPlotBar-GetBounds.md

+# Fix vtkPlotBar::GetBounds logic when log scale is enabled
+
+The `vtkPlotBar::GetBounds(double*, bool unscaled)` now correctly returns
+unscaled bounds when `unscaled` is true and scaled bounds when `unscaled` is false.