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Graphics Exporter Component Functions By Task

This chapter describes the constants, data types, and functions in the Graphics Exporter Component.

In this section:

Constants
Data Types
Functions


Constants

The following constants are used to specify graphics exporter characteristics:

enum {
    GraphicsExporterComponentType = FOUR_CHAR_CODE('grex'),
    kBaseGraphicsExporterSubType = FOUR_CHAR_CODE('base')
};
 
enum {
    graphicsExporterIsBaseExporter = 1L << 0,
    graphicsExporterCanTranscode = 1L << 1,
    graphicsExporterUsesImageCompressor = 1L << 2
};

Data Types

The graphics exporter component type and subtype are defined as follows:

typedef ComponentInstance GraphicsExportComponent;

Functions

The graphics export functions listed in the following sections are grouped by task.

Exporting

This function is used to perform export operations.

Internal Routines

These functions are used for internal communication between the base and format-specific graphics exporter. Applications will not usually need to call them.

Finding Out About Image Formats

These functions return information about the image format supported by a graphics exporter. Format-specific exporters must implement all three of these calls.

Obtaining Graphics Exporter Settings

These functions are used for obtaining graphics exporter settings and displaying a settings dialog box.

Accessing Graphics Exporter Settings

Graphics exporters may implement some or none of these functions. To determine whether a particular setting is available, use CallComponentCanDo.

Getting and Setting Progress Procs

These functions are always implemented by the base graphics exporter.

Specifying Sources for Input Images

These functions specify the source for input images. You must specify a source before you can call GraphicsExportDoExport.

The source can be a QuickTime graphics importer component instance, a QuickDraw Picture, a GWorld or a PixMap. Or it can be a piece of compressed data described by an image description. Compressed data can be in a file, handle, pointer, or other data reference.

The application must make sure that the source is not disposed of before the graphics exporter instance is closed or given a new source.

All of these functions are implemented by the base graphics exporter. Format-specific importers should delegate all of them.

Restricting the Range of an Input Image's Source

These functions are only applicable when the input is a data reference, file, handle or pointer.

Reading Input Data

These functions are used by format-specific graphics exporters when transcoding. Applications will not normally need to call these functions.

Accessing the Input Image

These functions are used by format-specific graphics exporters. When doing a standalone export, an exporter will typically call GraphicsExportGetInputImageDescription or GraphicsExportGetInputImageDimensions and GraphicsExportGetInputImageDepth to determine the image’s bounds and depth, and then allocate an offscreen GWorld and call GraphicsExportDrawInputImage to draw portions of the image into the GWorld.

Destinations for Output Images

These functions are used to specify destinations for output images.

Writing Output Data

These functions are used by format-specific graphics exporters to write output data.



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© 2005, 2006 Apple Computer, Inc. All Rights Reserved. (Last updated: 2006-01-10)


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