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<concept id="GUID-59C9EF92-8207-5FA5-AA20-0DB00C211BF1" xml:lang="en"><title>Graphics

Resource Services Collection Overview</title><shortdesc>This topic provides an introduction to the Graphics Resource Services

collection. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p><b>Target audience</b>: Device creators. </p>

<note type="note">The Graphics Resource component is deprecated in Symbian^3

and will be removed in Symbian^4.</note>

<p>In ScreenPlay, a <b>graphics resource</b> is a data buffer that is suitable

for use by graphics acceleration hardware. The requirement for the data buffer

to be capable of hardware acceleration imposes certain restrictions on the

way that it is implemented and used. An <b>image</b> is a particular type

of data buffer—a two-dimensional (2D) pixel buffer. Symbian documentation

has traditionally called 2D pixel buffers bitmaps. However, they are called

images in this context in order to avoid confusion with the existing <xref href="GUID-683A1D42-2764-3EB7-BD19-9E12559199AB.dita"><apiname>CFbsBitmap</apiname></xref> class. </p>

<p>Another important concept when working with the Graphics Resource components

is <b>rendering pipeline</b>. This is a set of primitives that perform rendering

and usually (but not necessarily) implement a pipeline model. The Graphics

Resource components do not define the rendering pipeline. However, when you

create a graphics resource, particularly an image, you need to specify its

usage in terms of the rendering pipeline it is to be used with. Typical examples

of rendering pipelines are DirectGDI, OpenVG and OpenGLES. </p>

<section id="GUID-AA3EF65D-E876-44DE-8E45-0BC2850F75CA"><title>Purpose</title> <p>The

Graphics Resource collection provides the following functionality: </p> <ul>

<li id="GUID-5100C135-C881-5907-BCD3-08818EB5117D"><p> <b>The creation and

sharing of hardware acceleration-capable two-dimensional (2D) pixel buffers </b>  </p> <p>The

Graphics Resource collection provides functions to create 2D pixel buffers

of fixed size in such a way that they can be shared between several user-side

processes and the device drivers of the graphics acceleration hardware if

present. </p> <p>As mentioned above these 2D pixel buffers are called images.

They are encapsulated by the <xref href="GUID-EDC0E03F-37F6-3BEC-8FF3-D03C3CDB949C.dita"><apiname>RSgImage</apiname></xref> class. </p> </li>

<li id="GUID-ADE65736-3D6F-5FFB-B160-A4AD876D3CAD"><p> <b>Interoperability

with the composition components</b>  </p> <p>The Graphics Resource collection

provides functions to create surfaces that can be used by the <xref href="GUID-0DC3E5AA-1706-5255-ACD6-E7AB732E1095.dita">composition

components</xref>. A surface is identified by a unique ID called the surface

ID. </p> <p>Interoperability with the composition components is encapsulated

by the <xref href="GUID-FCF750E4-526C-3789-89D8-DEF02BB7A5A7.dita"><apiname>RSgImageCollection</apiname></xref> class. This class enables the

retrieval of the surface ID for passing in calls to the Surface Manager and

Surface Update Server. <xref href="GUID-FCF750E4-526C-3789-89D8-DEF02BB7A5A7.dita"><apiname>RSgImageCollection</apiname></xref> provides an alternative

view of the surface as a collection of images that are accessible through <xref href="GUID-EDC0E03F-37F6-3BEC-8FF3-D03C3CDB949C.dita"><apiname>RSgImage</apiname></xref> handles. </p> </li>

<li id="GUID-E6513288-B612-5CAB-AF58-40F0A9FF088F"><p> <b> Support for new

types of graphics resources </b>  </p> <p>The Graphics Resource collection

also provides an abstraction so that device creators can add new types of

graphics resources—for example, for handling vector data. </p> <p>Symbian

provides the <xref href="GUID-6F23F34A-A0BE-349C-ADE7-61A5AEF48018.dita"><apiname>RSgDrawable</apiname></xref> class for this purpose. Symbian

provides only one concrete type of graphics resource—the image (2D pixel buffer).

However, device creators can create additional types of resources. </p> </li>

<li id="GUID-E93EB750-03AB-578C-B2A7-E7400971AE8B"><p> <b> Extensibility and

adaptability</b>  </p> <p>The Graphics Resource collection consists of a thin

generic layer and an adaptation layer. Symbian provides a product-quality

reference implementation of the adaptation layer. Device creators can extend,

modify or replace this implementation to suit specific graphics hardware. </p> </li>

</ul> <p>In addition, the Graphics Resource collection provides a number of <xref href="GUID-29C7FBFB-2F33-58CA-86BE-978E3187E4D6.dita">image compatibility guarantees</xref>. </p> <p> <i>Note</i>:

Although the DirectGDI component depends on the Graphics Resource components,

the Graphics Resource components do not depend on DirectGDI. The Graphics

Resource components can be used in isolation from DirectGDI—for example, by

a render stage that does not use DirectGDI. </p> </section>

<section id="GUID-C5E1043E-062E-41EF-A00C-E0072CB90D0F"><title>Components</title> <p>Graphics

Resource collection consists of the following components: </p> <ul>

<li id="GUID-A99A8B07-02C6-570A-A957-26924DDAE206"><p><xref href="GUID-82B0B4B9-6BC2-5BEF-B3B0-D57AC57F8D8A.dita">Graphics

Resource Component</xref>. This is the generic layer. </p> </li>

<li id="GUID-1C4E6CF8-D331-5AF8-9CC3-B0CC825BAFC3"><p><xref href="GUID-5E46C0EE-BD7D-5C85-8083-575BB2888AA7.dita">Graphics

Resource Adaptation component</xref>. This is the adaptation layer, which

device creators can extend, modify or replace. </p> </li>

</ul> </section>

</conbody><related-links>

<link href="GUID-26E51AB0-C0FC-55EA-B747-C834E2D4FD27.dita"><linktext>Graphics

Resources Services Collection</linktext></link>

<link href="GUID-E2A886E1-39FD-517F-870E-3B1BCD49E8CD.dita"><linktext>Off-Screen

Rendering with DirectGDI Tutorial</linktext></link>