If everyone agrees, can someone push the following changes to the vtkScalarBarActor source code. I just did #ifndef GL_ES_VERSION_3_0 checks so it will work with WebAssembly. I just don’t have the setup to push changes right now. The only change is in the function ConfigureScalarBar. Below is the complete code for that function.
void vtkScalarBarActor::ConfigureScalarBar()
{
vtkScalarsToColors* lut = this->LookupTable;
const double* range = lut->GetRange();
this->P->NumColors =
lut->GetIndexedLookup() ? lut->GetNumberOfAnnotatedValues() : this->MaximumNumberOfColors;
this->P->NumSwatches = this->P->NumColors + (this->DrawNanAnnotation ? 1 : 0);
int numPts = 2 * (this->P->NumColors + 1) + (this->DrawNanAnnotation ? 4 : 0);
this->P->NumSwatches = this->P->NumColors + (this->DrawBelowRangeSwatch ? 1 : 0);
numPts += (this->DrawBelowRangeSwatch ? 4 : 0);
this->P->SwatchPts = vtkPoints::New();
this->P->SwatchPts->SetNumberOfPoints(numPts);
this->P->Polys = vtkCellArray::New();
this->P->Polys->AllocateEstimate(this->P->NumSwatches, 4);
this->P->SwatchColors = vtkUnsignedCharArray::New();
unsigned int nComponents = ((this->UseOpacity) ? 4 : 3);
this->P->SwatchColors->SetNumberOfComponents(nComponents);
// 1D textures are not supported in ES 2.0 or 3.0
#ifndef GL_ES_VERSION_3_0
this->P->SwatchColors->SetNumberOfTuples(this->P->NumSwatches);
#else
this->P->SwatchColors->SetNumberOfTuples(numPts);
#endif
this->ScalarBarActor->SetProperty(this->GetProperty());
this->ScalarBar->Initialize();
this->ScalarBar->SetPoints(this->P->SwatchPts);
this->ScalarBar->SetPolys(this->P->Polys);
// 1D textures are not supported in ES 2.0 or 3.0
#ifndef GL_ES_VERSION_3_0
this->ScalarBar->GetCellData()->SetScalars(this->P->SwatchColors);
#else
this->ScalarBar->GetPointData()->SetScalars(this->P->SwatchColors);
#endif
this->P->SwatchPts->Delete();
this->P->Polys->Delete();
this->P->SwatchColors->Delete();
double delta = static_cast(this->P->ScalarBarBox.Size[1]) / this->P->NumColors;
double x[3];
x[2] = 0.;
for (int i = 0; i < numPts / 2 - (this->DrawNanAnnotation ? 2 : 0) - (this->DrawBelowRangeSwatch ? 2 : 0); ++i)
{
x[this->P->TL[0]] = this->P->ScalarBarBox.Posn[this->P->TL[0]];
x[this->P->TL[1]] = this->P->ScalarBarBox.Posn[this->P->TL[1]] + i * delta;
this->P->SwatchPts->SetPoint(2 * i, x);
x[this->P->TL[0]] = this->P->ScalarBarBox.Posn[this->P->TL[0]] + this->P->ScalarBarBox.Size[0];
this->P->SwatchPts->SetPoint(2 * i + 1, x);
}
// polygons & cell colors
unsigned char* rgb;
double rgba[4];
vtkIdType ptIds[4];
for (int i = 0; i < this->P->NumColors; ++i)
{
ptIds[0] = 2 * i;
ptIds[1] = ptIds[0] + 1;
ptIds[2] = ptIds[1] + 2;
ptIds[3] = ptIds[0] + 2;
this->P->Polys->InsertNextCell(4, ptIds);
double rgbval;
if (this->LookupTable->UsingLogScale())
{
rgbval = log10(range[0]) + i * (log10(range[1]) - log10(range[0])) / this->P->NumColors;
rgbval = pow(10.0, rgbval);
}
else
{
rgbval = range[0] + (range[1] - range[0]) * (i / static_cast<double>(this->P->NumColors));
}
lut->GetColor(rgbval, rgba);
rgba[3] = lut->GetOpacity(rgbval);
// write into array directly
// 1D textures are not supported in ES 2.0 or 3.0
#ifndef GL_ES_VERSION_3_0
rgb = this->P->SwatchColors->GetPointer(nComponents * i);
rgb[0] = static_cast(rgba[0] * 255.);
rgb[1] = static_cast(rgba[1] * 255.);
rgb[2] = static_cast(rgba[2] * 255.);
if (this->P->SwatchColors->GetNumberOfComponents() > 3)
{
rgb[3] = static_cast(this->UseOpacity ? rgba[3] * 255. : 255.);
}
#else
rgb = this->P->SwatchColors->GetPointer(nComponents * (i * 2));
rgb[0] = static_cast<unsigned char>(rgba[0] * 255.);
rgb[1] = static_cast<unsigned char>(rgba[1] * 255.);
rgb[2] = static_cast<unsigned char>(rgba[2] * 255.);
if (this->P->SwatchColors->GetNumberOfComponents() > 3)
{
rgb[3] = static_cast<unsigned char>(this->UseOpacity ? rgba[3] * 255. : 255.);
}
rgb = this->P->SwatchColors->GetPointer(nComponents * (i * 2 + 1));
rgb[0] = static_cast<unsigned char>(rgba[0] * 255.);
rgb[1] = static_cast<unsigned char>(rgba[1] * 255.);
rgb[2] = static_cast<unsigned char>(rgba[2] * 255.);
if (this->P->SwatchColors->GetNumberOfComponents() > 3)
{
rgb[3] = static_cast<unsigned char>(this->UseOpacity ? rgba[3] * 255. : 255.);
}
#endif
}
// Set up a texture actor as an alternative to the 1-quad-per-color
// scalar bar polydata.
vtkPoints* texturePoints = vtkPoints::New();
texturePoints->SetNumberOfPoints(4);
this->TexturePolyData->SetPoints(texturePoints);
texturePoints->SetPoint(0, 0.0, 0.0, 0.0);
double p1[2], p2[2];
p1[0] = this->P->ScalarBarBox.Posn[0];
p1[1] = this->P->ScalarBarBox.Posn[1];
p2[0] = p1[0] + this->P->ScalarBarBox.Size[this->P->TL[0]];
p2[1] = p1[1] + this->P->ScalarBarBox.Size[this->P->TL[1]];
texturePoints->SetPoint(0, p1[0], p1[1], 0.0);
texturePoints->SetPoint(1, p2[0], p1[1], 0.0);
texturePoints->SetPoint(2, p2[0], p2[1], 0.0);
texturePoints->SetPoint(3, p1[0], p2[1], 0.0);
texturePoints->Delete();
double barWidth = this->P->ScalarBarBox.Size[this->P->TL[0]];
double barHeight = this->P->ScalarBarBox.Size[this->P->TL[1]];
vtkDataArray* tc = this->TexturePolyData->GetPointData()->GetTCoords();
tc->SetTuple2(1, barWidth / this->TextureGridWidth, 0.0);
tc->SetTuple2(2, barWidth / this->TextureGridWidth, barHeight / this->TextureGridWidth);
tc->SetTuple2(3, 0.0, barHeight / this->TextureGridWidth);
}
