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<concept id="GUID-E9C6DBBF-1910-595D-94A1-67664CF7B7A6" xml:lang="en"><title>DirectGDI

Interface Overview</title><shortdesc>The DirectGDI Interface component provides a Hardware Adaptation

Interface (HAI), which separates the generic and adaptation parts of the DirectGDI

functionality. This HAI defines a set of interfaces that are implemented by

device creators in order to provide the API functionality. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

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

<note type="note">DirectGDI is deprecated in Symbian^3.</note>

<p>The following diagram provides an overview of the classes in the DirectGDI

Interface component and related classes in other components. </p>

<fig id="GUID-B4E6A02D-69E7-5716-8169-9CA011A183D8">

<title>          DirectGDI Interface component classes and related classes

         </title>

<image href="GUID-4F5DCA9A-E535-54B4-B8B2-30549AC12A51_d0e239825_href.png" placement="inline"/>

</fig>

<p>The following table provides a summary of the key classes that make up

the DirectGDI Interface component. </p>

<table id="GUID-3EA14E91-1B98-5EE2-A840-B1685A338B6D">

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

<thead>

<row>

<entry>Class</entry>

<entry>Description</entry>

</row>

</thead>

<tbody>

<row>

<entry><p> <xref href="GUID-1E407D78-0FD3-30F2-BDC5-B531F34D4A27.dita"><apiname>CDirectGdiDriverInternal</apiname></xref>  </p> </entry>

<entry><p>This class represents the body part of the DirectGDI driver, which

is implemented using the handle/body idiom. The handle part is encapsulated

by the <xref href="GUID-0C7CD826-95FD-3DD2-9394-3A20316C9C61.dita"><apiname>CDirectGdiDriver</apiname></xref> class, which is part of the DirectGDI

component. <xref href="GUID-1E407D78-0FD3-30F2-BDC5-B531F34D4A27.dita"><apiname>CDirectGdiDriverInternal</apiname></xref> defines the HAI. The

DirectGDI adaptation must derive a concrete class from this class and implement

of its pure virtual functions. This concrete class must provide the initialisation,

termination and construction of the concrete drawing engine and the creation

of source and target rendering. </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-97E3E8DD-A2DA-3961-96E3-41AEAFFDD275.dita"><apiname>MDirectGdiEngine</apiname></xref>  </p> </entry>

<entry><p>This interface defines the main part of DirectGDI HAI. The DirectGDI

adaptation must provide a concrete engine class that implements this interface.

This performs the actual drawing and blitting routines that enable rendering

to a <xref href="GUID-8F7C2E3C-3DF6-3C76-85C0-04922A99E9D0.dita"><apiname>RDirectGdiImageTarget</apiname></xref> instance. The implementation

can take advantage of hardware acceleration if it is available. </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-8F7C2E3C-3DF6-3C76-85C0-04922A99E9D0.dita"><apiname>RDirectGdiImageTarget</apiname></xref>  </p> </entry>

<entry><p>This class is a handle to a DirectGDI adaptation-specific resource

which abstracts the image-based rendering target. This class allows a global

sharable image resource (<xref href="GUID-EDC0E03F-37F6-3BEC-8FF3-D03C3CDB949C.dita"><apiname>RSgImage</apiname></xref>) to be used as a target

of DirectGDI rendering. This handle class and its DirectGDI adaptation-specific

resource are non-sharable and local within the creating thread. This class

is part of the generic layer and forwards any request to the <xref href="GUID-0C7CD826-95FD-3DD2-9394-3A20316C9C61.dita"><apiname>CDirectGdiDriver</apiname></xref> singleton

for the calling thread. </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-66A0A534-7BB6-304F-9A5E-17A125DA916F.dita"><apiname>RDirectGdiDrawableSource</apiname></xref>  </p> </entry>

<entry><p>This class is a handle to a DirectGDI adaptation-specific resource

that is bound to an image or non-image resource (<xref href="GUID-6F23F34A-A0BE-349C-ADE7-61A5AEF48018.dita"><apiname>RSgDrawable</apiname></xref>).

This class allows non-image resources (global and sharable between processes)

to be used as a source from the DirectGDI rendering API. This class and its

DirectGDI adaptation-specific resource are non-sharable and are local to the

calling thread. This class is part of the generic code and forwards the creation

and deletion request to the <xref href="GUID-0C7CD826-95FD-3DD2-9394-3A20316C9C61.dita"><apiname>CDirectGdiDriver</apiname></xref> singleton

object for the calling thread. </p> </entry>

</row>

</tbody>

</tgroup>

</table>

<section id="GUID-883FAED9-386B-4CDC-A9FA-C937884F0093"><title>Sequence diagrams</title> <p>The following sequence diagrams

illustrate the behaviour of key DirectGDI classes in two separate scenarios. </p> <p><b>Context

usage </b> </p> <fig id="GUID-DC1716DF-1F1F-5935-A129-A2F81382196B">

<title>              DirectGDI context usage sequence diagram            </title>

<image href="GUID-795DA381-A997-55E6-98D0-436DC250B07E_d0e239967_href.png" placement="inline"/>

</fig> <p><b>Driver creation and deletion </b> </p> <fig id="GUID-473A67D6-56B0-593A-9F93-E47743FB6EC6">

<title>             DirectGDI driver creation and deletion sequence diagram

           </title>

<image href="GUID-4689CD4A-3835-5013-90F9-100C66F18E84_d0e239980_href.png" placement="inline"/>

</fig> </section>

</conbody><related-links>

<link href="GUID-A2E07A3C-B3A8-50B9-BD60-F1F01795FA24.dita"><linktext>DirectGDI

Component</linktext></link>

<link href="GUID-BB4F5388-32EA-5A2E-845D-E5339D2040E9.dita"><linktext>DirectGDI

Adaptation Component</linktext></link>