I'm new to C++ and am trying to take a screenshot of the desktop and store it to a file. Then I want to open the image and loop through each pixel in the image and access its RGB values. I accomplished this in Python fairly easily as i found some easy-to-use libraries to accomplish this task, but in C++ i'm having trouble. I'm building a wxWidgets project and conveniently it seems wxWidgets can accomplish this. I've got the "take screenshot and save to file" down with some code I found online:
wxScreenDC screen;
wxSize size = screen.GetSize();
wxBitmap bitmap(size.GetWidth(), size.GetHeight());
wxMemoryDC memory;
memory.SelectObject(bitmap);
memory.Blit(0, 0, size.GetWidth(), size.GetHeight(), &screen, 0, 0);
bitmap.SaveFile(wxT("screenshot.bmp"), wxBITMAP_TYPE_BMP);
This works fine it seems. But I can't find any examples on how to iterate through the pixels in the image. I've found some wx classes that may be helpful like wxPixelData but no examples on how to access the pixels in an existing image. If someone could show me it would be much appreciated. Thanks
If you don't care about performance (e.g. you just do it once), you should indeed convert wxBitmap to wxImage and then use the methods of this class to access its data. If you do care about performance, you should use raw pixel data access and while this is less convenient (its API is lower level in order to allow it to be faster), there is, of course, an example of doing this in the image sample.