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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-CD4B8ECA-AFE7-593C-B095-5D642EA2EC61" xml:lang="en"><title>DirectGDI
+Component Overview</title><shortdesc>This topic provides an introduction to the DirectGDI component.
+DirectGDI provides a graphics context that can be hardware accelerated, and
+allows an asynchronous interface. </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 DirectGDI framework has two parts: a generic layer, which provides
+a client API and an adaptation layer. Device creators can replace the adaptation
+layer with an implementation that takes advantage of graphics accelerated
+hardware, if it is available, or a software implementation, if it is not available.
+This section covers the generic layer. </p>
+<p>Window Server rendering is performed by one or more <xref href="GUID-3A2785D4-6185-50C3-8D7E-5D94CD2B7C98.dita">render
+stage plug-ins</xref>, which device creators can also replace. In ScreenPlay,
+the Symbian render stage plug-in uses DirectGDI rather than the older BitGDI
+component. This means that existing Window Server applications can potentially
+take advantage of hardware acceleration (and therefore run faster) without
+recompiling the code. </p>
+<p>The following diagram shows the usage of the DirectGDI component. In this
+diagram the application is a regular GUI application that draws using the
+Symbian Window Server API. </p>
+<fig id="GUID-E0731CEB-BA28-5F07-8584-16286D439433">
+<title> Usage of DirectGDI          </title>
+<image href="GUID-E401D2B1-5360-57E3-99D6-3D08730E6C09_d0e239173_href.png" placement="inline"/>
+</fig>
+<p>The Symbian DirectGDI adaptation uses the <xref href="GUID-82B0B4B9-6BC2-5BEF-B3B0-D57AC57F8D8A.dita">Graphics
+Resource component</xref>, which provides an abstraction layer for the memory
+management of pixel and non-pixel data (such as a list of VG commands). The
+Graphics Resource component supports uniform and non-uniform memory architectures,
+but is not available on all platforms. Like DirectGDI, the Graphics Resource
+component has generic and adaptation layers. When it is available, device
+creators can tailor the adaptation for a specific graphics hardware accelerator.
+The Symbian reference Graphics Resource adaptation uses surfaces. </p>
+<section id="GUID-EB8CE781-DA66-4557-87D1-88B0AF97F7B7"><title>Key concepts
+and terms</title> <p>The key elements of DirectGDI are driver, resources and
+drawing context as shown in the following diagram. </p> <fig id="GUID-13399385-2DC4-50A2-8DC7-5712BC5325A7">
+<title> DirectGDI key elements            </title>
+<image href="GUID-1A02B1FB-FDE3-565B-8E52-0F7FD3AC5188_d0e239194_href.png" placement="inline"/>
+</fig> <p> <b>Driver</b>. The driver class <xref href="GUID-0C7CD826-95FD-3DD2-9394-3A20316C9C61.dita"><apiname>CDirectGdiDriver</apiname></xref> implements
+platform-specific functionality to create and manage device-dependent drawing
+contexts and resources. It defines the Hardware Adaptation Interface (HAI)
+that must be implemented by device creators. </p> <p> <b>Drawing Context</b>. <xref href="GUID-09AFDE10-489E-3215-B821-DE7B2D31A007.dita"><apiname>CDirectGdiContext</apiname></xref> represents
+a new drawing context that is similar to <xref href="GUID-4A501086-7EFF-376D-8901-6D9B2EB4EFF2.dita"><apiname>CFbsBitGc</apiname></xref> and <xref href="GUID-B782C9A1-D7CB-3BD7-8167-27F5E3F00CB0.dita"><apiname>CWindowsGc</apiname></xref>,
+but without functions (such as read-modify-write functions like <codeph>SetFaded()</codeph>)
+that are not suitable for hardware acceleration. <xref href="GUID-09AFDE10-489E-3215-B821-DE7B2D31A007.dita"><apiname>CDirectGdiContext</apiname></xref> also
+provides new rendering operations that are not available via <xref href="GUID-4A501086-7EFF-376D-8901-6D9B2EB4EFF2.dita"><apiname>CFbsBitGc</apiname></xref>,
+such as drawing contents generated using non-native APIs. </p> <p> <b>Resources</b>.
+DirectGDI introduces two new abstractions of graphics resources: <xref href="GUID-66A0A534-7BB6-304F-9A5E-17A125DA916F.dita"><apiname>RDirectGdiDrawableSource</apiname></xref> and <xref href="GUID-8F7C2E3C-3DF6-3C76-85C0-04922A99E9D0.dita"><apiname>RDirectGdiImageTarget</apiname></xref>. These resources are created by binding them to the <xref href="GUID-6F23F34A-A0BE-349C-ADE7-61A5AEF48018.dita"><apiname>RSgDrawable</apiname></xref> or <xref href="GUID-EDC0E03F-37F6-3BEC-8FF3-D03C3CDB949C.dita"><apiname>RSgImage</apiname></xref> resource
+defined in the <xref href="GUID-82B0B4B9-6BC2-5BEF-B3B0-D57AC57F8D8A.dita">Graphics
+Resource component</xref>. </p> <p> </p> </section>
+<section id="GUID-F7EFEDD5-B145-46EB-BEF1-4FD84F6753BA"><title>Architectural
+relationships</title> <p>The DirectGDI component provides a framework that
+enables graphics hardware acceleration and interleaved rendering. This framework
+provides an API for client applications and a Hardware Adaptation Interface
+(HAI), which defines interfaces that must be implemented by device and hardware
+manufacturers in order to provide the API functionality. The framework has
+a dependency on the <xref href="GUID-82B0B4B9-6BC2-5BEF-B3B0-D57AC57F8D8A.dita">Graphics
+Resource component</xref>. </p> <p>The Graphics package provides two DirectGDI
+adaptations: </p> <ul>
+<li id="GUID-C34EF67E-127F-5464-AEA2-01F8FBD482CF"><p>a purely software adaptation
+that uses existing components to draw to the screen in a similar manner to
+BitGDI </p> </li>
+<li id="GUID-F80A29B5-E6BE-5190-8CD6-877CA0341745"><p>a hardware adaptation
+that uses OpenVG and EGL APIs. </p> </li>
+</ul> <p>The following figure shows how the DirectGDI generic layer and the
+reference adaptations interface with each other. It shows how the software
+and hardware adaptations use the same HAI. However, only one adaptation can
+be present on a phone. </p> <fig id="GUID-DCD69302-90C3-5C1B-BC62-E901EDBE133B">
+<title> DirectGDI architecture            </title>
+<image href="GUID-3E2E0C91-14B3-53AC-B797-DEE349688477_d0e239299_href.png" placement="inline"/>
+</fig> <p>For more information about the DirectGDI adaptation layer, see the <xref href="GUID-22E46647-D677-5A47-A7E0-E1E0AE736B27.dita">DirectGDI Adaptation Overview</xref>. </p> </section>
+<section id="GUID-21429397-2B36-4799-869F-5948C282B4A0"><title>DLL summary</title> <p>DirectGDI
+consists of one DLL, <filepath>directgdi.dll</filepath>. For more information,
+see <xref href="GUID-936A024F-FFBA-530E-A2C6-C835B71633F7.dita">DirectGDI Library </xref>. </p> </section>
+<section id="GUID-C8B5A833-6687-4198-A57B-81BE433DE7E7"><title>Main usage</title> <p>The
+main usage of DirectGDI is within a Window Server <xref href="GUID-3A2785D4-6185-50C3-8D7E-5D94CD2B7C98.dita">render
+stage plug-in</xref>. This enables the Window Server rendering to be hardware
+accelerated when suitable hardware is available. Currently DirectGDI is not
+available for use by applications. </p> </section>
+</conbody><related-links>
+<link href="GUID-936A024F-FFBA-530E-A2C6-C835B71633F7.dita"><linktext>DirectGDI
+Library Overview</linktext></link>
+<link href="GUID-E2A886E1-39FD-517F-870E-3B1BCD49E8CD.dita"><linktext>Off-Screen
+Rendering with                 DirectGDI Tutorial</linktext></link>
+<link href="GUID-E9C6DBBF-1910-595D-94A1-67664CF7B7A6.dita"><linktext>DirectGDI
+Interface Component</linktext></link>
+</related-links></concept>
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