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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_d0e270523_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_d0e270665_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_d0e270678_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>
</related-links></concept>