RLE (Run-Length-Encoding) Compression Routine in MFC for 256-Color Bitmaps

Environment: VC6, MFC

This is a RLE compression routine, written in MFC. I wrote this because I cannot find handy code for such a thing.

RLE compression is useful when saving a SIMPLE Windows bitmap. My implementation is rather stupid and not optimized. Therefore, if the source bitmap is complex (like the one in the demo app window shown below), you could even get a bigger bitmap file after compression.



Click here for a larger image.

The compression routine is wrapped in an MFC bitmap control class, CDVDBitmapControl, which you can put conveniently in a dialog. The usage is easy:

  1. Add a static control (say, IDC_STATIC_BITMAP) in the dialog for the bitmap control.
  2. Add an #include "DVDBitmapControl.h" in the header file of your dialog.
  3. Add a member variable (say, m_bmp) of type "CDVDBitmapControl" in your dialog class.
  4. In OnInitDialog(), add this line:
    m_bmp.SubclassDlgItem( IDC_STATIC_BITMAP, this).
  5. Call m_bmp.LoadBitmapFile(CString) to load a bitmap into the control.
  6. Call m_bmp.SaveBitmapFile(CString) to save a bitmap into an 8-bit RLE bitmap.

If you need only the compression code, you can just extract the CDVDBitmapControl::CompressInRLE8() and CDVDBitmapControl::EndOfLine() routines from "DVDBitmapControl.cpp". It is quite straightforward to use them.

I did not write the decompression part because the Windows API LoadImage() already does it.

PS: in the demo app, if the loaded bitmap is not in 256 colors, [Save] will not work.

Downloads

Download demo project - 20 Kb
Download source - 5 Kb


Comments

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • With JRebel, developers get to see their code changes immediately, fine-tune their code with incremental changes, debug, explore and deploy their code with ease (both locally and remotely), and ultimately spend more time coding instead of waiting for the dreaded application redeploy to finish. Every time a developer tests a code change it takes minutes to build and deploy the application. JRebel keeps the app server running at all times, so testing is instantaneous and interactive.

  • Live Event Date: May 6, 2014 @ 1:00 p.m. ET / 10:00 a.m. PT While you likely have very good reasons for remaining on WinXP after end of support -- an estimated 20-30% of worldwide devices still are -- the bottom line is your security risk is now significant. In the absence of security patches, attackers will certainly turn their attention to this new opportunity. Join Lumension Vice President Paul Zimski in this one-hour webcast to discuss risk and, more importantly, 5 pragmatic risk mitigation techniques …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds