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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-824C5DB5-E568-5467-8E81-C8EFF90BA8AA" xml:lang="en"><title>Image

    13 Compatibility Guarantees Overview</title><shortdesc>Pixel format support is generally device-dependent. This can cause

    14 difficulties for application developers, who usually want their applications

    15 to work across a variety of devices including those with and without hardware

    16 acceleration. In order to allow development of more generic applications,

    17 the Graphics Resource component guarantees a certain level of image format

    18 compatibility across all platforms. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    19 <p>Guarantees of image compatibility cover a variety of combinations of pixel

    20 format, mutability, CPU access, usage and screen identifier. The following

    21 table provides a description of these attributes. </p>

    22 <table id="GUID-C5C954E8-EC80-51D8-8E2F-6E08DD34D1A4">

    23 <tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>

    24 <thead>

    25 <row>

    26 <entry>Attribute</entry>

    27 <entry>Description</entry>

    28 </row>

    29 </thead>

    30 <tbody>

    31 <row>

    32 <entry><p>Mutability </p> </entry>

    33 <entry><p>Whether or not the image can be modified. </p> </entry>

    34 </row>

    35 <row>

    36 <entry><p>Application-level CPU access </p> </entry>

    37 <entry><p>Whether an application has direct access to the image pixel data. </p> </entry>

    38 </row>

    39 <row>

    40 <entry><p>Usage </p> </entry>

    41 <entry><p>With which rendering pipeline the image is to be used and for what

    42 purpose (for example, DirectGDI source or OpenVG target). </p> </entry>

    43 </row>

    44 <row>

    45 <entry><p>Screen identifier </p> </entry>

    46 <entry><p>This can be the identifier of the screen which the image must be

    47 rendered on. Alternatively, this can be -1, which indicates that the image

    48 is screen agnostic (in other words, it can be rendered on any screen.) </p> </entry>

    49 </row>

    50 <row>

    51 <entry><p>Size in pixels </p> </entry>

    52 <entry><p>The height and width of the image in pixels. </p> </entry>

    53 </row>

    54 </tbody>

    55 </tgroup>

    56 </table>

    57 <p>In order to allow efficient implementation on the widest possible range

    58 of devices, the combinations of attributes that are guaranteed is limited.

    59 For a full list of the combinations that are guaranteed, see <xref href="GUID-69E426EC-CDBB-5B19-8264-050EB93B9315.dita">Supported

    60 Image Formats</xref>. </p>

    61 <p>Individual devices may provide support for pixel formats and usage combinations

    62 beyond the minimum guarantees provided by the Graphics Resource component.

    63 Application developers can take advantage of these by querying <codeph>RSgImage::GetPixelFormats()</codeph> at

    64 run-time. Developers must make sure that alternative methods are in place

    65 should the features not be available on a particular device. </p>

    66 </conbody><related-links>

    67 <link href="GUID-12BB6113-216F-53BB-85FE-E14A6A6A2F8B.dita"><linktext>Image Compatibility

    68 Use Cases</linktext></link>

    69 <link href="GUID-69E426EC-CDBB-5B19-8264-050EB93B9315.dita"><linktext>Supported

    70 Image Formats</linktext></link>

    71 <link href="GUID-29C7FBFB-2F33-58CA-86BE-978E3187E4D6.dita"><linktext>Image Compatibility

    72 Guarantees</linktext></link>

    73 <link href="GUID-610C1484-112E-5442-95DC-89CF890A8310.dita"><linktext>Pixel Formats</linktext>

    74 </link>

    75 </related-links></concept>