Method DrawString

Rendering/ContextOpenGL2/vtkOpenGLContextDevice2D.cxx:1627–1739

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//------------------------------------------------------------------------------
void vtkOpenGLContextDevice2D::DrawString(float* point, const vtkStdString& string)
{
  vtkOpenGLGL2PSHelper* gl2ps = vtkOpenGLGL2PSHelper::GetInstance();
  if (gl2ps)
  {
    switch (gl2ps->GetActiveState())
    {
      case vtkOpenGLGL2PSHelper::Capture:
      {
        float tx = point[0];
        float ty = point[1];
        this->TransformPoint(tx, ty);
        double x[3] = { tx, ty, 0. };
        gl2ps->DrawString(string, this->TextProp, x, 0., this->Renderer);
        return;
      }
      case vtkOpenGLGL2PSHelper::Background:
        return; // Do nothing.
      case vtkOpenGLGL2PSHelper::Inactive:
        break; // Render as normal.
    }
  }

  vtkTextRenderer* tren = vtkTextRenderer::GetInstance();
  if (!tren)
  {
    vtkErrorMacro("No text renderer available. Link to vtkRenderingFreeType "
                  "to get the default implementation.");
    return;
  }

  vtkOpenGLClearErrorMacro();

  double* mv = this->ModelMatrix->GetMatrix()->Element[0];
  float xScale = mv[0];
  float yScale = mv[5];

  float p[] = { std::floor(point[0] * xScale) / xScale, std::floor(point[1] * yScale) / yScale };

  // TODO this currently ignores vtkContextScene::ScaleTiles. Not sure how to
  // get at that from here, but this is better than ignoring scaling altogether.
  // TODO Also, FreeType supports anisotropic DPI. Might be needed if the
  // tileScale isn't homogeneous, but we'll need to update the textrenderer API
  // and see if MPL/mathtext can support it.
  int tileScale[2];
  this->RenderWindow->GetTileScale(tileScale);
  int dpi = this->RenderWindow->GetDPI() * std::max(tileScale[0], tileScale[1]);

  // Cache rendered text strings
  vtkTextureImageCache<UTF8TextPropertyKey>::CacheData& cache =
    this->Storage->TextTextureCache.GetCacheData(UTF8TextPropertyKey(this->TextProp, string, dpi));
  vtkImageData* image = cache.ImageData;
  if (image->GetNumberOfPoints() == 0 && image->GetNumberOfCells() == 0)
  {
    int textDims[2];
    if (!tren->RenderString(this->TextProp, string, image, textDims, dpi))
    {
      vtkErrorMacro("Error rendering string: " << string);