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<concept id="GUID-824C5DB5-E568-5467-8E81-C8EFF90BA8AA" xml:lang="en"><title>Image
Compatibility Guarantees Overview</title><shortdesc>Pixel format support is generally device-dependent. This can cause
difficulties for application developers, who usually want their applications
to work across a variety of devices including those with and without hardware
acceleration. In order to allow development of more generic applications,
the Graphics Resource component guarantees a certain level of image format
compatibility across all platforms. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>Guarantees of image compatibility cover a variety of combinations of pixel
format, mutability, CPU access, usage and screen identifier. The following
table provides a description of these attributes. </p>
<table id="GUID-C5C954E8-EC80-51D8-8E2F-6E08DD34D1A4">
<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
<thead>
<row>
<entry>Attribute</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><p>Mutability </p> </entry>
<entry><p>Whether or not the image can be modified. </p> </entry>
</row>
<row>
<entry><p>Application-level CPU access </p> </entry>
<entry><p>Whether an application has direct access to the image pixel data. </p> </entry>
</row>
<row>
<entry><p>Usage </p> </entry>
<entry><p>With which rendering pipeline the image is to be used and for what
purpose (for example, DirectGDI source or OpenVG target). </p> </entry>
</row>
<row>
<entry><p>Screen identifier </p> </entry>
<entry><p>This can be the identifier of the screen which the image must be
rendered on. Alternatively, this can be -1, which indicates that the image
is screen agnostic (in other words, it can be rendered on any screen.) </p> </entry>
</row>
<row>
<entry><p>Size in pixels </p> </entry>
<entry><p>The height and width of the image in pixels. </p> </entry>
</row>
</tbody>
</tgroup>
</table>
<p>In order to allow efficient implementation on the widest possible range
of devices, the combinations of attributes that are guaranteed is limited.
For a full list of the combinations that are guaranteed, see <xref href="GUID-69E426EC-CDBB-5B19-8264-050EB93B9315.dita">Supported
Image Formats</xref>. </p>
<p>Individual devices may provide support for pixel formats and usage combinations
beyond the minimum guarantees provided by the Graphics Resource component.
Application developers can take advantage of these by querying <codeph>RSgImage::GetPixelFormats()</codeph> at
run-time. Developers must make sure that alternative methods are in place
should the features not be available on a particular device. </p>
</conbody><related-links>
<link href="GUID-12BB6113-216F-53BB-85FE-E14A6A6A2F8B.dita"><linktext>Image Compatibility
Use Cases</linktext></link>
<link href="GUID-69E426EC-CDBB-5B19-8264-050EB93B9315.dita"><linktext>Supported
Image Formats</linktext></link>
<link href="GUID-29C7FBFB-2F33-58CA-86BE-978E3187E4D6.dita"><linktext>Image Compatibility
Guarantees</linktext></link>
<link href="GUID-610C1484-112E-5442-95DC-89CF890A8310.dita"><linktext>Pixel Formats</linktext>
</link>
</related-links></concept>