Scaling Color Images Using Interpolation

ImageMan supports a version of antialiasing for color images as well which works for both shrinking or enlarging an image. Called interpolation, it allows you to create scaled down versions of color images without losing any of the color information. It also allows creating scaled up versions of these images without creating a "jaggie" effect.

Note that interpolation will work only on 24-bit images.

Interpolation is just as easy to use as antialiasing. Simply pass the proper flag to ImgCopy and it's done. Here's an example:

// In this example, the source image is a 24-bit

// color image that's 600x600 pixels.

//

// Scale the image up using interpolation:

hImage2 = ImgCopy(hImage, 1000, 1000, NULL, COPY_INTERPOLATE);

// Scale the image down using interpolation:

hImage3 = ImgCopy(hImage, 100, 100, NULL, COPY_INTERPOLATE);

Just as antialiasing can have a dramatic effect on monochrome images, interpolation can hugely affect the quality of scaled color images. You'll need to experiment with it to see exactly how it can affect your images, but we highly recommend its use when scaling any color images.