<?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-F64E6551-670E-5E12-8103-DE504D3EC94F" xml:lang="en"><title>The

Non-ScreenPlay Graphics Architecture</title><shortdesc>ScreenPlay provides improved support for graphics hardware acceleration

and some other new features. However, it is possible to use the Symbian platform

without enabling ScreenPlay. This is called the non-ScreenPlay variant (sometimes

referred to as the <b>non-NGA</b> variant). This topic provides an introduction

to the graphics architecture when ScreenPlay is <b>not</b> enabled. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The following diagram shows the non-ScreenPlay architecture. It includes

the components in the Graphics package and some closely related components

in other packages. </p>

<fig id="GUID-060B8747-36A8-5F2A-BE82-0F637381673A">

<title>The Symbian Foundation non-ScreenPlay graphics architecture </title>

<image href="GUID-1EC68F99-C383-5D3A-BAE9-52AF530F8445_d0e228146_href.png" placement="inline"/>

</fig>

<p>The software model is as follows: </p>

<ul>

<li id="GUID-8BDB2015-C8FD-51EC-AB19-A55C55DD6D4B"><p>The Hardware Adaptation

Layer (HAL) consists of the frame buffer and basic attributes. All processes

have equal access to the frame buffer and can both read and write to it. </p> </li>

<li id="GUID-06209922-9276-5843-95ED-CCE01A96A67C"><p>The Screen Driver provides

simple pixel, scan-line and bitmap operations. The Screen Driver has the same

interface for both bitmaps and the frame buffer. Hardware manufacturers can

adapt the Screen Driver to suit the available hardware. </p> </li>

<li id="GUID-333C52F6-5B6C-5212-8286-B344749550B5"><p>The BitGDI component

provides support for higher-level geometric primitives and text. The BitGDI

component is implemented in terms of Screen Driver operations. All BitGDI

rendering operations are synchronous. </p> </li>

<li id="GUID-B542796F-47AE-5B8A-976A-446315EC6550"><p>The Window Server multiplexes

access to the screen and provides a BitGDI-like interface. </p> </li>

<li id="GUID-81912D86-0CF6-5399-84FF-904E15BA8B50"><p>The Window Server provides

Direct Screen Access (DSA) support for applications that require high frame

rates (such as video and games) to bypass the Window Server and write to the

frame buffer directly. However, some interaction with the Window Server is

needed to prevent the application from drawing over other application's data. </p> </li>

</ul>

<p>In addition, the non-ScreenPlay architecture provides support for EGL,

OpenGL and OpenVG. </p>

<p>The following diagram shows the rendering stack in the non-ScreenPlay variant. </p>

<fig id="GUID-4A245007-BE0A-5DD6-A3D5-CAD9A16E0540">

<title>The rendering stack in the non-ScreenPlay variant</title>

<image href="GUID-A51AB0B8-A13D-52D0-BEF8-435F76B30941_d0e228191_href.png" placement="inline"/>

</fig>

<p>For the equivalent ScreenPlay diagram,

see <xref href="GUID-0DC3E5AA-1706-5255-ACD6-E7AB732E1095.dita">Graphics Composition

Collection Overview</xref>. </p>

<p>Although DSA provides a solution for applications that require high frame

rates, the non-ScreenPlay architecture has limitations when used on graphics

accelerated hardware and non-uniform memory models. The architecture may require

the copying of buffers between CPU and GPU memory as shown in the following

diagram. ScreenPlay provides a solution that requires less copying of buffers

in this type of use case. </p>

<fig id="GUID-0EAF51D1-173E-52E2-8E28-C5FB7F6F9BD0">

<title> Example non-uniform memory, non-ScreenPlay hardware model </title>

<image href="GUID-AB35BA46-87DB-59F0-9342-75550AD338B7_d0e228209_href.png" placement="inline"/>

</fig>

</conbody><related-links>

<link href="GUID-D93978BE-11A3-5CE3-B110-1DEAA5AD566C.dita"><linktext>The ScreenPlay

Architecture</linktext></link>

<link href="GUID-EF62BF88-3687-505D-8BD7-EEDF36246E56.dita"><linktext>Graphics

Hardware Acceleration</linktext></link>

<link href="GUID-99BC101A-9466-59EE-B5C9-7622BAF6E6FF.dita"><linktext>Graphics

Concepts</linktext></link>