Image Transform Library Overview

This document introduces you to the Image Transform (scaling) functionality.


The CImageTransform provides function to scale the still image held in a file or descriptor.

Image Transform Library Details

The DLL that provides the functionality and the library to which your code must link is identified below.

DLL LIB Short Description



These files are used for implementing image transform operation.

Architectural Relationship

Image Transform function plays an important role for transforming the still image.


Image Transform function works in parallel to CBitmapScaler, the difference being that the CBitmapScaler works on internal bitmap objects (CFbsBitmap), whereas CImageTransform works on images stored in files and descriptors. Furthermore, the size of the destination image needs to be specified bearing in mind that the aspect ratio of the source image needs to be preserved.

Key Image Transform Classes

The key classe is:

  • CImageTransform provides the client interface to the functionality of the ImageTransform dll. This class is a single unit which can be used easily and can be instantiated without specifying any information about the source or destination images. It is free to implement a scale algorithm but not free to implement decoding or encoding process.

Using Image Transform

The Image Transform functionality is used for the following:

  • To scale only a subset of the original image which is provided by setting a clipping rectangle. This acts as if the source image outside the region does not exist causing the clipped image to be resized to the size specified.

  • This function supports standard extensions for advanced JPEG functions. For more details see JPEG Image Transform Extension Guide.

Related concepts