Symbian3/SDK/Source/GUID-30066989-4A0F-5000-9488-AA7E50E2B871.dita
author Graeme Price <GRAEME.PRICE@NOKIA.COM>
Fri, 15 Oct 2010 14:32:18 +0100
changeset 15 307f4279f433
parent 0 89d6a7a84779
permissions -rw-r--r--
Initial contribution of the Adaptation Documentation.

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<concept xml:lang="en" id="GUID-30066989-4A0F-5000-9488-AA7E50E2B871"><title>Graphics Context Settings</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>This topic provides an introduction to the graphics context settings. </p> <section><title>Drawing mode</title> <p>This is used to determine the logical operation used to put pen or brush color onto the graphics device. The usual modes are: no effect; write color; and exclusive or. Other possible logical combinations are supported. </p> </section> <section><title>Pen color, line size and style</title> <p>The pen is used for free line and shape outline drawing and also for text. The line styles include solid and various dot and dash combinations. Lines may be drawn in various sizes. </p> </section> <section><title>Brush color, style and origin</title> <p>The brush is used for filling areas drawn with the shape primitives, and also for text background fills. You can specify a color, pattern and style. The brush also has an origin point for the pattern. The way the brush fills depends on the drawing mode. A bitmap pattern may be used and then discarded. </p> </section> <section><title>Text font and a justification mode</title> <p>Font specification allows for a variety of <keyword>typeface</keyword> s and styles for sizes (bold, underline, italic, etc.). Text color (foreground) depends on the pen color and drawing mode. Text background fill depends on the brush settings. Text justification may be set for <keyword>word justification</keyword>, or full <keyword>WYSIWYG</keyword> with <keyword>character
          justification</keyword>. A font may be used and then discarded. </p> </section> <section><title>Co-ordinate origin</title> <p>All GDI operations take place within a co-ordinate system. By default the pixel in the top left corner of the screen is the origin, and has co-ordinates (0,0). The co-ordinates of the pixel in the bottom right of the screen depend on the dimensions of the display in use. </p> <p>There is a function to set the position of the origin of a graphics context: <codeph>CGraphicsContext::SetOrigin()</codeph>. All subsequent drawing operations are then done relative to this new origin. </p> </section> <section><title>Internal drawing position</title> <p>A graphics context maintains an internal drawing position relative to its origin. This can be set, without drawing, by using: </p> <ul><li id="GUID-F17EB8D8-27B4-5093-91CA-721D339BD73D"><p> <codeph>CGraphicsContext::MoveTo()</codeph>  </p> </li> <li id="GUID-FD179051-4779-56A5-B32E-306A3AAC4826"><p> <codeph>CGraphicsContext::MoveBy()</codeph>  </p> </li> </ul> <p>The internal drawing position is also changed to the last point of the line(s) drawn by the operations: </p> <ul><li id="GUID-7D7B8A79-4593-5021-847F-7625B246A62E"><p> <codeph>CGraphicsContext::DrawLine()</codeph>  </p> </li> <li id="GUID-5CC65017-4AF5-55E0-9724-70E1A9E284DF"><p> <codeph>CGraphicsContext::DrawLineTo()</codeph>  </p> </li> <li id="GUID-64CAE133-66BA-5C17-8131-EBC412D6CD76"><p> <codeph>CGraphicsContext::DrawLineBy()</codeph>  </p> </li> <li id="GUID-FD1F1049-8E24-57F5-A2E3-3E9855BAA400"><p> <codeph>CGraphicsContext::DrawPolyline()</codeph>  </p> </li> </ul> <p>The internal drawing position is used as the start point of the line drawn by: </p> <ul><li id="GUID-E750002C-94E9-56A0-9BE8-2251C67A5128"><p> <codeph>CGraphicsContext::DrawLineTo()</codeph>  </p> </li> <li id="GUID-7D2216F4-7738-5995-A057-040916422B87"><p> <codeph>CGraphicsContext::DrawLineBy()</codeph>  </p> </li> </ul> </section> </conbody><related-links><link href="GUID-55C8C429-1BEC-5A58-94EC-DA1E51F62867.dita"><linktext>Drawing
                to a Graphics Context Tutorials</linktext> </link> <link href="GUID-E3AC8F3E-9D5C-5E7D-9760-023B77C7C8A8.dita"><linktext>Drawing and Graphics Contexts</linktext> </link> </related-links></concept>