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<!doctype HTML PUBLIC "-//IETF//DTD HTML//EN">
<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office">
<head>
<meta http-equiv="Content-Language" content="en">
<title>GDI+</title>
<link rel="stylesheet" type="text/css" href="../../style.css">
</head>
<body>
<h2>Microsoft Windows Base <em style="font-style: normal">Driver</em> Using GDI+</h2>
<p>This driver represents a base driver for all system-dependent drivers implemented in the Microsoft Windows system,
but uses a new API called GDI+. The drivers <b>Clipboard, Native Window</b>, <b>IUP</b>, <b>Image</b>, <b>Printer</b>,
<b>EMF</b> and <b>Double Buffer</b> were implemented. The driver <b>WMF</b>, and the function <font face="Courier">
<strong>cdPlay</strong></font> of the <b>Clipboard</b> and <b>EMF</b> drivers were not implemented using GDI+.</p>
<p>The main motivation for the use of GDI+ was transparency for all the primitives. Beyond that we got other features
like anti-aliasing, gradient filling, bezier lines and filled cardinal splines.</p>
<p>This driver still does not completely replace the GDI Windows base driver, because GDI+ does not have support for
XOR. Also the applications need to adapt the rendering of text that is slightly different from GDI. It is know that
GDI+ can be slower than GDI in some cases and faster in other cases, Microsoft does not make this clear.</p>
<p>So we let the programmer to choose what to use. We created the function <font face="Courier"><strong>
cdUseContextPlus</strong></font> that allows to activate or to deactivate the use of GDI+ for the available
Windows based drivers.
This function affects only the <font face="Courier"><strong>cdCreateCanvas</strong></font> function call, once created
the canvas will be always a GDI+ canvas. In fact the function affects primary the definitions
<font face="Courier"><strong>CD_NATIVEWINDOW</strong></font>,
<strong><span style="font-family: Courier">CD_IMAGE</span></strong>, <strong>
<span style="font-family: Courier">CD_PRINTER</span></strong>, <strong>
<span style="font-family: Courier">CD_EMF</span></strong>, <strong>
<span style="font-family: Courier">CD_DBUFFER</span></strong> and <strong>
<span style="font-family: Courier">CD_CLIPBOARD</span></strong>, because they are
function calls and not static defines.</p>
<p>Using GDI+ it is allowed to create more that one canvas at the same time for the same Window. And they can co-exist
with a standard GDI canvas.</p>
<p>To enable the use of GDI+ based drivers you must call the initialization function <font face="Courier"><strong>
cdInitContextPlus()</strong></font> once and link to the libraries "<strong>cdcontextplus.lib</strong>" and "<strong>gdiplus.lib</strong>".
Also the file "<strong>gdiplus.dll</strong>" must be available in your system. These files already came with Visual
C++ 7 and Windows XP. For other compilers or systems you will need to copy the ".lib" file for you libraries area, and
you will need to copy the DLL for the Windows\System (Win98/Me) or Windows\System32 (Win2000/NT4-SP6) folder. The
gdiplus files can be obtained from
<a href="http://www.microsoft.com/downloads/details.aspx?familyid=6a63ab9c-df12-4d41-933c-be590feaa05a&displaylang=en">
Microsoft</a> or from <a href="../../download/gdiplus.zip">here</a>.</p>
<p>In CDLua it is not necessary any additional initialization, but the
application must still be linked with the <strong>cdcontextplus.lib</strong>
library or a <strong>require"cdluacontextplus"</strong> can be used when
using dynamic libraries.</p>
<h3>Behavior of Functions</h3>
<h4>Control</h4>
<ul>
<li><a href="../func/other.html#cdPlay"><font face="Courier"><strong>Play</strong></font></a>:
does nothing, returns <font face="Courier">CD_ERROR</font>. </li>
</ul>
<h4>Coordinate System and Clipping</h4>
<ul>
<li><a href="../func/coordinates.html#cdUpdateYAxis"><font face="Courier">
<strong>UpdateYAxis</strong></font></a>: the orientation of axis Y is the opposite to its orientation in the CD
library. Except when using transformations.</li>
</ul>
<h4>Primitives</h4>
<ul>
<li><font face="Courier"><strong><a href="../func/marks.html#cdPixel">Pixel</a></strong></font>:
uses GDI. Excepting when the canvas is an image so it is done using GDI+.</li>
<li><font face="Courier"><a href="../func/filled.html#cdSector"><b>Sector</b></a></font>:
it also draws an arc in the same position to complete the size of the sector.</li>
<li><font face="Courier"><a href="../func/text.html#cdText"><b>Text</b></a></font>:
opaque text is simulated using a rectangle in the back.</li>
<li><a href="../func/lines.html#cdBegin"><font face="Courier"><strong>Begin</strong></font></a>:
Beyond the standard modes it accepts the additional modes: <strong><tt>CD_FILLSPLINE</tt></strong> and <strong><tt>
CD_FILLGRADIENT</tt></strong>. The C definitions of these modes are available in the <b>cdgdiplus.h</b> header.<br>
<strong><tt><br>
CD_SPLINE</tt></strong> defines the points of a curve constructed by a cardinal spline. Uses the current line style.<br>
<strong><tt>CD_FILLSPLINE</tt></strong> defines the points of a filled curve constructed by a cardinal spline. Uses
the current interior style.<br>
<strong><tt>CD_FILLGRADIENT</tt></strong> defines the points of a filled polygon. It is filled with a gradient from
colors in each vertex to a color in its center. The colors are defined by the "<strong><tt>GRADIENTCOLOR</tt></strong>"
attribute, that must be set before each <strong><tt>cdVertex</tt></strong> call and before <strong><tt>cdEnd</tt></strong>
for the center color. This will not affect the current interior style.</li>
</ul>
<h4>Attributes </h4>
<ul>
<li><a href="../func/filled.html#cdBackOpacity"><font face="Courier"><strong>
BackOpacity</strong></font></a>: only changes the transparency of the background color to 0 (transparent) or 255
(opaque).</li>
<li><a href="../func/filled.html#cdHatch"><font face="Courier"><strong>Hatch</strong></font></a>:
diagonal styles are drawn with anti-aliasing.</li>
<li><a href="../func/attributes.html#cdWriteMode"><font face="Courier">
<strong>
WriteMode</strong></font></a>: does nothing. There is no support for XOR or NOT_XOR.</li>
<li><a href="../func/filled.html#cdPattern"><font face="Courier"><strong>
Pattern</strong></font></a>: each pixel can contain transparency information.</li>
<li><font face="Courier"><strong><a href="../func/lines.html#cdLineStyle">
LineStyle</a></strong></font>: uses a custom GDI+ style when line width is 1. In World Coordinates the line style
has its scaled changed.</li>
<li><a href="../func/text.html#cdFontDim"><font face="Courier"><strong>FontDim</strong></font></a>:
the maximum width is estimated from the character "W".</li>
<li><font face="Courier"><strong><a href="../func/text.html#cdTextAlignment">
TextAlignment</a></strong></font>: is simulated. Although GDI+ has text alignment, the results
do not match the CD text alignment.</li>
<li><a href="../func/text.html#cdNativeFont"><font face="Courier"><strong>
NativeFont</strong></font></a>: also accepts <em><strong>"-d"</strong></em><strong>
</strong> to show the font-selection dialog box.</li>
<li><a href="../func/text.html#cdFont"><font face="Courier"><strong>Font</strong></font></a>:
"System" is mapped to "MS Sans Serif", "Courier" is mapped to "Courier New",
"Helvetica" is mapped to "Arial", and "Times" is mapped to "Times New Roman".
Underline and Strikeout are supported.</li>
</ul>
<h4>Colors </h4>
<ul>
<li><a href="../func/color.html#cdPalette"><font face="Courier"><strong>Palette</strong></font></a>:
works only when the canvas is a server image.</li>
<li><a href="../func/attributes.html#cdForeground"><font face="Courier">
<strong>
Foreground</strong></font></a> &
<a href="../func/attributes.html#cdBackground">
<font face="Courier"><strong>Background</strong></font></a>: accepts the transparency information encoded in the
color.</li>
</ul>
<h4>Client Images </h4>
<ul>
<li><a href="../func/client.html#cdGetImageRGB"><font face="Courier"><strong>
GetImageRGB</strong></font></a>: uses GDI. Excepting when the canvas is an image so it is done using GDI+.</li>
</ul>
<h4>Server Images </h4>
<ul>
<li><strong><a href="../func/server.html#cdGetImage">GetImage</a></strong>:
uses GDI. Excepting when the canvas is an image so it is done using GDI+.</li>
<li><strong><a href="../func/server.html#cdScrollArea">ScrollArea</a></strong>:
uses GDI. Excepting when the canvas is an image so it is done using GDI+.</li>
</ul>
<h4>Exclusive Attributes</h4>
<ul>
<li>"<span style="font-family: Courier"><strong>GDI+</strong></span>":
returns "1". So the application can detect if the driver uses the GDI+ base
driver. Other drivers that do not implement this attribute will return NULL.</li>
</ul>
<ul>
<li>"<b><font face="Courier">HDC</font></b>": returns the HDC of the Win32 canvas. It can only be retrieved (get
only). In Lua is returned as a user data. It is not NULL only in some Native Windows canvas and in the printer canvas.</li>
</ul>
<ul>
<li>"<b><font face="Courier">ANTIALIAS</font></b>": controls the use of anti-aliasing
for the text, image zoom and line
drawing primitives. Assumes values "1" (active) and "0" (inactive). Default value: "1". </li>
</ul>
<ul>
<li>"<b><font face="Courier">GRADIENTCOLOR</font></b>": necessary for the creation of the gradient fill defined by a
polygon (see details in the function <font face="Courier"><strong>cdBegin</strong></font> above). Defines the color of
each vertex and the center (%d %d %d" = r g b). It can not be retrieved (set only).</li>
</ul>
<ul>
<li>"<b><font face="Courier">IMAGETRANSP</font></b>": defines an interval of colors to be considered transparent in
client and server images (except for RGBA images). It uses two colors to define the interval ("%d %d %d %d %d %d" = r1
g1 b1 r2 g3 b3). Use NULL to remove the attribute. </li>
</ul>
<ul>
<li>"<b><font face="Courier">IMAGEFORMAT</font></b>": defines the number of bits per pixel used to create server
images. It uses 1 integer that can have the values: "32" or "24" (%d). Use NULL to remove the attribute. It is used
only in the <font face="Courier"><strong>cdCreateImage</strong></font>. When not defined, the server images use the
same format of the canvas.</li>
</ul>
<ul>
<li>"<strong><font face="Courier">IMAGEALPHA</font></strong>": allows the usage of an alpha channel for server
images if IMAGEFORMAT=32. The attribute format is a pointer to the transparency values in a sequence of chars in
the same format of alpha for client images. The attribute is used in the <strong>
<font face="Courier">cdCreateImage</font></strong> and for every <font face="Courier"><strong>
cdPutImageRect</strong></font>, the pointer must exists while the image exists. The alpha values are transfered to
the image only in <font face="Courier"><strong>cdPutImageRect</strong></font>, so they can be freely changed any time.
The data is not duplicated, only the pointer is stored. The size of the data must be the same size of the image. Use
NULL to remove the attribute. Not accessible in Lua.</li>
</ul>
<ul>
<li>"<b><font face="Courier">IMAGEPOINTS</font></b>": define 3 coordinates of a paralelogram that will be used
to warp server and client images in the subsequent calls of <font face="Courier"><strong>PutImage</strong></font>
functions. Use 6 integer values inside a string ("%d %d %d %d %d %d" = x1 y1 x2 y2 x3 y3). Use NULL to remove the
attribute. The destination rectangle of the <font face="Courier"><strong>PutImage</strong></font> functions will be
ignored. The respective specified points are the upper-left corner, the upper-right corner and the lower left corner.
In GDI+ this attribute is more complete than in GDI, because affects also client images.</li>
</ul>
<ul>
<li>"<b><font face="Courier">ROTATE</font></b>": allows the usage of 1 angle and 1 coordinate (x, y), that
define a global rotation transformation centered in the specified coordinate. Use 1 real and 2 integer values inside a
string ("%g %d %d" = angle x y). Can not be set if a transformation
is already set.</li>
</ul>
<ul>
<li><b><font face="Courier">"LINEGRADIENT": </font></b>defines a filled interior style that uses a line gradient
between two colors. It uses 2 points ("%d %d %d %d" = x1 y1 x2 y2), one for the starting point using (using the
foreground color), and another one for the end point (using the background color).</li>
</ul>
<ul>
<li><b><font face="Courier">"LINECAP": </font></b>defines addicional line cap styles. It can have the following
values: "Triangle", "NoAnchor", "SquareAnchor", "RoundAnchor", "DiamondAnchor", or "ArrowAnchor". It can not be
retrieved (set only).</li>
</ul>
</body>
</html>
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