Image Display Library Overview

This document introduces you to the Image Display functionality.

Purpose

This function provides an interface to encode image into CFbsBitmap object which can be easily displayed on the screen.

Image Display Library Details

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

DLL LIB Short Description

imagedisplay.dll

imagedisplay.lib

These files are used for implementing image display operation.

Architectural Relationship

Image Display function plays an important role for displaying the still image.

Furthermore, the CImageDisplay also incorporates a function ExifMetadata in its plugin to access Exif metadata and display it. For more details see Exif support in CImageDisplay.

Description

This functionality is similar to CImageDecoder, but CImageDisplay provides some more features which is listed in Using Image Display.

The client application states where the source image is to be taken from. The image can be read either from a descriptor, or a file. The only other mandatory parameter supplied by the client is the size (in pixels) of the destination image. Additional (optional) parameters can be specified such as the designation of a clipping region for pan/zoom, but these are not necessarily supported by all ImageDisplay plugins.

Key Image Display Classes

The key class is:

  • CImageDisplay provides a convenient interface to convert encoded images into internal Symbian platform bitmap objects ready to be displayed on the screen. As part of decoding process scaling and rotation can be done.

Using Image Display

The Image Display functionality is used for the following:

  • To encode image into CFbsBitmap object.

  • Scaling and rotation are provided in the decoding process.

  • Progressive decoding is possible; for example, an unscaled (or roughly scaled) image may be displayed temporarily during the scaling process. This feature can be used to improve perceived responsiveness.