wxBitmap/wxImage: Setting resolution/dpi for saving

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wxBitmap/wxImage: Setting resolution/dpi for saving

Post by berlinermainzer » Fri Apr 07, 2006 9:36 am

Hi there,

I already searched the forum and on Google without success on this topic. My problem is as follows: I use a wxClientDC to draw some stuff onto a ScrolledWindow, which works fine. In order to save the content of the DC into a file, I use a wxBitmap and a wxImage (see code below). Saving seems to work properly, but the saved image file always (not depending on the format) has a resolution of 1 dpi, which is quite annoying when eg. printing it with some external software.
So here comes my question: Is there a way to set the resoltion to another value? I only found such a feature in wxPostScriptDC.

Thanks & Greetings

Here the code I use.

Code: Select all

  int iDCWidth = 0; int iDCHeight = 0;
  m_pwxDC->GetSize(&iDCWidth, &iDCHeight);   // m_pwxDC is the wxClientDC I use for drawing         
  m_wxSaveBitmap.Create(iDCWidth,iDCHeight);   // m_wxSaveBitmap is a wxBitmap I use for saving
  wxMemoryDC wxSaveMemDC = new wxMemoryDC();
  if (!wxSaveMemDC.Ok())
    return false;

  double dX = 0; double dY = 0;
  wxSaveMemDC.Blit(wxPoint(0,0),m_pwxDC->GetSize(), m_pwxDC, wxPoint(0,0));
  wxImage wxSaveImage = m_wxSaveBitmap.ConvertToImage();

  if (wxsFileName.empty())
    return false;

  return true;

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Re: wxBitmap/wxImage: Setting resolution/dpi for saving

Post by gunterkoenigsmann » Sat Aug 20, 2016 8:02 am

For images there is a way to set the dpi/ppi rate:

Code: Select all

    img.SetOption(wxIMAGE_OPTION_RESOLUTION,resolution * bitmapScale);
For bitmaps there is the following command:

Code: Select all

If setting these options changes anything you'll have to test, though.

...and I know that this is an old thread. But it is always good to have a googleable response for each question that might arise.

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