Converting Color to Grayscale Using ATL::CImage

• Download demo - 22.08 KB
• Download source - 48.94 KB

Introduction

This is just a simple MFC application that demonstrates how you can use the ATL::CImage class to do color-to-grayscale conversion.

Background

Conversion is done by:

1. obtaining the red, green, and blue values in each pixel's color information,
2. adding together 30% of the red value, 59% of the green value, and 11% of the blue value,
3. using the sum obtained in step 2 as the new red, green, and blue values.

Using the Code

There are two implementations for doing the conversion:

• MakeGrayscale_Slow() --> simple but slow
• MakeGrayscale_Fast() --> a little complicated but fast

Points of Interest

MakeGrayscale_Slow() and MakeGrayscale_Fast() produce different grayscales for the same color image. I have no idea why this happens. Anyone who knows?

History

• 2009/11/06 - Uploaded this article