Method RenderStringInternal

Rendering/FreeType/vtkFreeTypeTools.cxx:1108–1233

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//------------------------------------------------------------------------------
bool vtkFreeTypeTools::RenderStringInternal(
  vtkTextProperty* tprop, const std::string& str, int dpi, vtkImageData* data, int textDims[2])
{
  // Check parameters
  if (!tprop || !data)
  {
    vtkErrorMacro(<< "Wrong parameters, one of them is nullptr or zero");
    return false;
  }

  if (data->GetNumberOfScalarComponents() > 4)
  {
    vtkErrorMacro("The image data must have a maximum of four components");
    return false;
  }

  if (str.empty())
  {
    data->Initialize();
    if (textDims)
    {
      textDims[0] = 0;
      textDims[1] = 0;
    }
    return true;
  }

  ImageMetaData metaData;

  // Setup the metadata cache
  if (!this->PrepareMetaData(tprop, dpi, metaData))
  {
    vtkErrorMacro(<< "Error prepare text metadata.");
    return false;
  }

  // Calculate the bounding box.
  if (!this->CalculateBoundingBox(str, metaData))
  {
    vtkErrorMacro(<< "Could not get a valid bounding box.");
    return false;
  }

  // Calculate the text dimensions:
  if (textDims)
  {
    textDims[0] = metaData.bbox[1] - metaData.bbox[0] + 1;
    textDims[1] = metaData.bbox[3] - metaData.bbox[2] + 1;
  }

  // Prepare the ImageData to receive the text
  this->PrepareImageData(data, metaData.bbox.GetData());

  // Setup the image metadata
  if (!this->PrepareImageMetaData(tprop, data, metaData))
  {
    vtkErrorMacro(<< "Error prepare image metadata.");
    return false;