The Image Conversion Library (ICL) is very useful for any application that needs to do some image manipulation. The ICL utilizes the ECom framework to identify the correct plugins and thus all ICL plugins are also ECom plugins.

1. IMAGING
~ Ishita

2. Agenda
 What is ICL?
 ICL Architecture
 Image Encoding
 Image Decoding
 Code Flow
 Image file Formats
 Queries

3. ICL
 Image Conversion Library
 based on active objects, to support encoding
and decoding image files
 conversion of an image in a well-defined image
format into a native Symbian OS bitmap
 conversion of a native Symbian OS bitmap into a
well-defined image format.
 image transformations (rotation, scaling, etc.)
applied to native Symbian OS bitmaps or directly
to an image in a well defined format.

4. ICL ARCHITECTURE

6. IMAGE DECODING

7. Image Decoding
 Image decoding is the process of taking an image stored
in a file or descriptor, converting it from a specified
format and writing the output to a CFbsBitmap.
 The CImageDecoder object is created specifying the
source image and decoder plugin as parameters.
 The CImageDecoder::Convert() function then decodes
the image using the methods provided by the plugin.
 The results of the conversion are then saved to a
CFbsBitmap.

8. Architectural Overview
 The ICL JPEG Decoder is implemented as ECOM plugin,
which uses the ICL framework for JPEG conversion.

9.  The key player in image decoding is the
CImageDecoder class. This API is an interface
to an extendable plug-in-based system. The
plug-in management tasks are handled by
ECOM.
 The API can be used in just three simple steps:
1. Create an image decoder object by providing
a factory method with image data.
2. Initiate the image-conversion process.
3. Wait for a request completion and handle the
conversion result.

10. Data Path
JPEG Decoder plugin (CJpegDecoder) is derived from CImageDecoderPlugin and
JPEG Decoder codec(CJpegReadCodec) is derived from CImageReadCodec

11. IMAGE ENCODING

12. Image Encoding
 Image encoding is the process of taking a bitmap stored
in a CFbsBitmap, converting it to a specified format and
writing the output to a file or descriptor.
 The CImageEncoder object is created specifying the
source image and encoder plugin as parameters.
 The CImageEncoder::Convert() function then encodes
the image using the methods provided by the plugin.
 The results of the conversion are then saved to a file or
descriptor.

13. Architectural Overview
 The JPEG Encoder is implemented as an ECOM plugin,
working under Symbian’s Image Converter Library (ICL)
Framework .

14.  The CImageEncoder API shares many usage patterns
and data structures with the CImageDecoder API.
 Its basic usage scenario is essentially the same:
1. An encoder object is to be created by using one of the
synchronous factory methods
2. Some optional encoding parameters may be adjusted
synchronously.
3. An asynchronous encoding process is initiated by calling
CImageEncoder::Convert().
4. The application waits for the request to be accomplished
and makes use of the output data in cases when no
error has been reported.

15. Data Path
JPEG Encoder plugin (CJpegEncoder) is derived from CImageEncoderPlugin and
JPEG Encoder codec(CJpegWriteCodec) is derived from CImageWriteCodec

16. Image File Formats
 JPEG : Joint Photographic Expert group
 JFIF : JPED File Inerchange Format
 Exif : Exchangeable Image File Format
 TIFF : Tagged Image File format
 RAW :Raw Image format
 PNG : Portable Network Graphics
 GIF : Graphics Interchange Format
 BMP : Windows Bitmap

17. Important Docs
Imaging JPEG Decode JPEG Encoder
For the details on Symbian ICL framework, check the SDK Documentation.