--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,91 @@
+<?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-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E" xml:lang="en"><title>GDI
+Collection Overview</title><shortdesc>The Graphics Device Interface (GDI) collection is an important
+collection within the Graphics subsystem. It provides a suite of abstract
+base classes, interfaces and data structures. The suite represents and interacts
+with physical graphics hardware such as display screens, off-screen memory
+and printers. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section><title>Architectural Relationship</title> <p>The GDI collection provides
+base classes and utility functions. Every graphics component ends up using
+it. The components in this collection are closely linked and provide important
+functionality. The GDI component is a low-level component in this collection,
+BitGDI is based on this and DirectGDI is a potentially faster alternative
+to BitGDI. The Colour Palette provides coloring indexing operations. </p> </section>
+<section><title>Description</title> <p>GDI consists of a large number of diverse
+APIs that cover many different aspects of graphics including graphics device
+abstraction, color value handling, linear digital differential analysis, font
+description and information, printer devices abstraction, line breaking, text
+rendering, handling of bidirectional text, text wrapper and linked font creation. </p> <p>Graphics
+Device Interface collection includes the following components: </p> <ul>
+<li id="GUID-BA77A047-4A77-5527-9EE8-AE4302E759C9"><p><xref href="GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E.dita#GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E/GUID-25C920A3-EF7C-5E8E-B94E-531B56E36DB9">GDI</xref>  </p> </li>
+<li id="GUID-08EB75C6-0E70-5F16-9CF1-BF43AFDB3CC7"><p><xref href="GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E.dita#GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E/GUID-4CDF56F2-E278-5488-AD9D-D42EFC145A40">BitGDI</xref>  </p> </li>
+<li id="GUID-13396341-EBF4-54F4-BC5A-5223F269114C"><p><xref href="GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E.dita#GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E/GUID-81F903E9-F9BD-5141-8402-483D6E26F1F0">DirectGDI</xref>  </p> </li>
+<li id="GUID-61FA0D95-AE43-50AB-B0BF-0BE9BF9D3C95"><p><xref href="GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E.dita#GUID-C1B080D9-9C6C-520B-B73E-4EB344B1FC5E/GUID-059D5B88-E69F-5898-8D87-161B349B7C0C">Colour Palette</xref>  </p> </li>
+</ul> </section>
+<section id="GUID-25C920A3-EF7C-5E8E-B94E-531B56E36DB9"><title>GDI</title> <p>GDI
+is a low level component. Two key concepts related to GDI are Device (<xref href="GUID-500FC564-35E9-3B66-A0C2-1269371A2EA0.dita"><apiname>CGraphicsDevice</apiname></xref>)
+and Context (<xref href="GUID-DAD09DCF-3123-38B4-99E9-91FB24B92138.dita"><apiname>CGraphicsContext</apiname></xref>). Throughout the Graphics
+sub-system a graphics device provides a graphics context through which the
+device may be drawn to. The context maintains 'settings', such as the pen
+and brush colors and styles in use, and provides a rich API of drawing commands
+for creating graphical and textual output. </p> <p>Most display devices use
+bitmap graphics and the GDI provides specializations of both <xref href="GUID-500FC564-35E9-3B66-A0C2-1269371A2EA0.dita"><apiname>CGraphicsDevice</apiname></xref> and <xref href="GUID-DAD09DCF-3123-38B4-99E9-91FB24B92138.dita"><apiname>CGraphicsContext</apiname></xref> to
+act as base classes for bitmap devices: namely <xref href="GUID-2DEFEC47-F36E-3133-A08D-55F7C2534CC0.dita"><apiname>CBitmapDevice</apiname></xref> and <xref href="GUID-FC746873-0570-3900-AD89-42B205FDC0D3.dita"><apiname>CBitmapContext</apiname></xref>.
+These add, amongst other attributes, pixel awareness, blitting, scanlines
+and fading. </p> <p>The GDI defines abstract base classes for storing and
+manipulating fonts (<xref href="GUID-2A12FE3B-47F2-3016-8161-A971CA506491.dita"><apiname>CFont</apiname></xref>, <xref href="GUID-0CA79D2D-827F-3A20-A10C-1CC9C576E803.dita"><apiname>CTypefaceStore</apiname></xref>, <xref href="GUID-B68B7BC8-CFBA-32F4-A0BE-8378F0C105DA.dita"><apiname>CFontCache</apiname></xref>)
+and additional supporting classes and structures. </p> <p>The GDI defines
+the interface for mapping between device-specific pixels and real-world twips.
+A twip is a twentieth of a point and a point is 1/72 of an inch. That makes
+a twip 1/1440 of an inch, 1/567 of a centimeter or about 0.018mm. </p> <p>The
+GDI defines a base class for representing embedded pictures, <xref href="GUID-829D57CD-9659-347B-AAE9-5F0A0ECD555C.dita"><apiname>CPicture</apiname></xref>,
+and supporting classes. It also provides base classes, interfaces and structures
+for printing. </p> </section>
+<section id="GUID-4CDF56F2-E278-5488-AD9D-D42EFC145A40"><title> BitGDI</title> <p>The <xref href="GUID-EAAD1719-C02C-5705-A5C3-993E36441BE6.dita">BitGDI Component</xref> is
+used by legacy applications and the Window Server in the <xref href="GUID-F64E6551-670E-5E12-8103-DE504D3EC94F.dita">non-ScreenPlay
+variant</xref>. The BitGDI component provides the <xref href="GUID-B229156F-2344-3F46-8542-AC65882D80DE.dita"><apiname>CFbsScreenDevice</apiname></xref> and <xref href="GUID-4A501086-7EFF-376D-8901-6D9B2EB4EFF2.dita"><apiname>CFbsBitGc</apiname></xref> APIs,
+which are concrete implementations of <xref href="GUID-500FC564-35E9-3B66-A0C2-1269371A2EA0.dita"><apiname>CGraphicsDevice</apiname></xref> and <xref href="GUID-DAD09DCF-3123-38B4-99E9-91FB24B92138.dita"><apiname>CGraphicsContext</apiname></xref> for
+bitmap-based devices. This component enables: </p> <ul>
+<li id="GUID-989D5F4A-3DB5-55DA-91FE-5E70D3DFF57E"><p>hardware-independent
+access to screen attributes </p> </li>
+<li id="GUID-7E420A37-E7A9-5583-8FE0-393677696319"><p>bitmapped drawing which
+holds settings and supports drawing to bitmapped devices and screens independent
+of the display. </p> </li>
+</ul> <fig id="GUID-C75462F4-7DB3-57BF-ABDE-C500669F45C5">
+<image href="GUID-71E64F3E-40CB-560B-A482-CA92C7FD1AA2_d0e177233_href.png" placement="inline"/>
+</fig> </section>
+<section id="GUID-059D5B88-E69F-5898-8D87-161B349B7C0C"><title>Colour
+Palette</title> <p>The <xref href="GUID-E82FABA9-9CCC-548F-99DB-EF2B9036B405.dita">Colour
+Palette component</xref> provides coloring functionality. A user can specify
+the use of a particular color, as described by a <xref href="GUID-F84C7F40-6DEB-39D1-B172-CB0CC3918E27.dita"><apiname>TRgb</apiname></xref>,
+and have that color rendered on a machine’s display device as closely as possible
+to the color specified. A related functionality allows arrays of colors to
+be stored as bitmaps, and displayed at a later date in the same manner. </p> <p>Color
+palettes also provide user-definable palette support to the GDI. A palette
+is a user-defined set of colors, which is a subset of the full range of 24-bit
+colors. This allows users the advantages of having a low bpp color mode whilst
+being able to specify the colors available in that mode. Only a palette of
+16 colors enables changing the palette. Palettes are also used to allow 24-bit
+bitmaps to be stored in a more compressed form by finding the actual number
+of different colors used in the bitmap. This creates a palette that allows
+mapping of colors to a smaller index space. The pixels of the bitmaps are
+encoded using indexes to this new index space. A palette has a size which
+is set at its creation and cannot alter the number of entries in the palette.
+Each entry in a palette is a mapping between that entry's index and a <codeph>TRgb</codeph> value.
+Palette entries can be got and set at any time between the palette's creation
+and destruction. The GDI's palette support also provides functions to find
+the nearest palette color to a requested <codeph>TRgb</codeph> color. </p> </section>
+</conbody><related-links>
+<link href="GUID-E89F034F-C807-5FF9-B06B-F7CCD2441041.dita"><linktext>Graphics
+Device Interface (GDI) Collection</linktext></link>
+</related-links></concept>
\ No newline at end of file