title: GDI fast scroll
body: <p>I use GDI to create some custom textwidget. I draw directly to the screen, unbuffered.</p>
  
  <p>now i'd like to implement some fast scrolling, that simply pixelshifts the respective part of the framebuffer (and only redraws the newly visible lines).</p>
  
  <p>I noticed that for example the rich text controls does it like this. If i use some GDI drawing functions to directly draw to the framebuffer, over a rich text control, and then scroll the rich text, it will also scroll my drawing along with the text. so i assume the rich text simply pixelshifts it's part of the framebuffer.</p>
  
  <p>I'd like to do the same, but don't know how to do so. </p>
  
  <p>Can someone help? (independant of programming language))</p>
  
  <p>thanks!</p>