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WIC API Overview

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The Windows Imaging Component (WIC) provides a Component Object Model (COM) based API for use in C and C++. The WIC API exposes a variety of image-related functionality, including:

  • Built-in codecs for the standard web image formats.
  • Built-in support for standard metadata formats.
  • Wide range of pixel format support.
  • High-color support; including 30-bit extended range, 30-bit high precision, and 48-bit high precision and wide gamut pixel formats.
  • Extensible framework for image codecs, pixel formats, and metadata formats.

This topic contains the following topics.

WIC Header Files

The WIC APIs are defined in the following header and Interface Definition Language (IDL) files:

File Description
wincodec.h Defines C and C++ versions of the primary WIC APIs.
wincodec.idl Defines the primary WIC interfaces.
wincodecsdk.h Defines C and C++ versions of the metadata WIC APIs.
wincodecsdk.idl Defines the WIC metadata interfaces.
wincodec_proxy.h Defines the WIC proxy exports.

 

To use WIC, your applications must include wincodec.h and/or wincodecsdk.h, depending on the API your application needs.

Library Files

The WIC library files:

File Description
windowscodecs.lib Import library provided by the Windows Software Development Kit (SDK).
windowscodecs.dll Stock implementation library provided by the operating system.

 

To link to WIC APIs, your application must include windowscodec.lib as an additional linker dependency.

Class Factories

The following table describes the two COM class factories the WIC APIs provide for creating WIC components.

Factory Interface Description
IWICImagingFactory Primary class factory for application development using WIC components. This factory creates components such as image decoders, encoders and streams.
IWICComponentFactory Class factory targeted for WIC component developers. Components created from this factory are primarily used in codec and metadata handler development.

 

To create either class factory, use the CoCreateInstance COM function. The following example demonstrates the creation of the WIC imaging factory.

// Initialize COM
CoInitialize(NULL);

// The factory pointer
IWICImagingFactory *pFactory = NULL;

// Create the COM imaging factory
HRESULT hr = CoCreateInstance(
    CLSID_WICImagingFactory,
    NULL,
    CLSCTX_INPROC_SERVER,
    IID_PPV_ARGS(&pFactory)
);

Imaging Components

The WIC APIs provide several types of imaging components. The following table describes some of the common WIC components. For a full list of available components, see WIC interfaces.

Component Type Description
Bitmap Represents a writable in-memory representation of an IWICBitmapSource.
Decoder Used to decode image data from a stream into a format that is useful for image processing.
Encoder Writes image data to a stream.
Stream Used to read and write data from a file, network resource, a block of memory, and so on.
Format Converter Used to convert from one pixel format to another.
Metadata Query Reader Used to read metadata of an image or image frame.
Metadata Query Writer Used to write metadata to an image or image frame.

 

See Also

References

Samples and Code Examples