Changing Colors in Bitmaps and Making Icons from Them

Environment: MFC/GDI

The day has come when I need to have a large number of identical icons with only one difference—some colors will change from icon to icon. I found the solution for making all of my icons from a single bitmap, and changing colors on the fly. So, I wrote my CCloneBitmap class. It is derived from CBitmap and is able to change colors and export 32x32 icons.

It is very simple to use. Just follow these steps:

  1. Load the bitmap using the LoadBitmap() function.
  2. Make a clone of this bitmap by calling a Clone() method.
  3. Change colors of the bitmap by calling a ChangeColor() method.
  4. You can make a 32x32 icon from this bitmap (if bitmap is 32x32).

Here is a simple example of how to use this class:

HBITMAP hBmp;
CCloneBitmap bmpClone;
HICON hIcon;
hBmp=LoadBitmap(AfxGetResourceHandle(),
     MAKEINTRESOURCE(ID_LIGHTCAR));
if(hBmp!=NULL)
{
  bmpClone.Clone(hBmp);
  DeleteObject(hBmp);
  bmpClone.ChangeColor(IRGB(0,0,0), IRGB(255,0,0));
  // change BLACK pixels to RED ones.
  hIcon=bmpClone.MakeIcon(IRGB(255,255,255));
  // make icon, using WHITE color as transparent.
}
Note: Remember to use the IRGB() macro instead of RGB().

If you have a color in the COLORREF variable, use the INVERSECOLOR() macro:

bmpClone.ChangeColor(IRGB(0,0,0), INVERSECOLOR(myColor));

Downloads

Download source - 2 Kb


Comments

  • Help with dynamic bitmap

    Posted by Legacy on 02/10/2004 12:00am

    Originally posted by: VIjay Shan

    Hi,
    I found your article to be extremely helpful, though had a couplea questions how do i use this class if i have a modified bitmap (cbitmap*). when i paste this bitmap into the clipboard it works fine but when i get a handle and pass it to the clone function and use makeicon it just gives me a black square back. whereas when i try the samething with a preproduced bitmap it works fine. Any kinda help would be appreciated.

    Vijay

    Reply
  • Great, but if you (or someone) would please....

    Posted by Legacy on 05/30/2003 12:00am

    Originally posted by: Chris

    Hello, I'm a Borland C++ Builder programmer and I'd love to use that code, I have MSVC++ and have dabbled in it... I've managed to convert most of the code, but I'm having problems, I was wondering if you could convert it into standard Windows SDK code(nothing like CDC or CBitmap used) and then post it for all programmers to use.
    Thanks and have a nice day. :)

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

Top White Papers and Webcasts

  • On-demand Event Event Date: September 10, 2014 Modern mobile applications connect systems-of-engagement (mobile apps) with systems-of-record (traditional IT) to deliver new and innovative business value. But the lifecycle for development of mobile apps is also new and different. Emerging trends in mobile development call for faster delivery of incremental features, coupled with feedback from the users of the app "in the wild." This loop of continuous delivery and continuous feedback is how the best mobile …

  • As mobile devices have pushed their way into the enterprise, they have brought cloud apps along with them. This app explosion means account passwords are multiplying, which exposes corporate data and leads to help desk calls from frustrated users. This paper will discover how IT can improve user productivity, gain visibility and control over SaaS and mobile apps, and stop password sprawl. Download this white paper to learn: How you can leverage your existing AD to manage app access. Key capabilities to …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds