<!doctype HTML PUBLIC "-//IETF//DTD HTML//EN"> <html> <head> <meta http-equiv="Content-Language" content="en-us"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>Canvas Initialization</title> <link rel="stylesheet" type="text/css" href="../../style.css"> </head> <body> <h2 align="center">Canvas Initialization</h2> <pre class="function"><span class="mainFunction">cdCanvas *<a name="cdCreateCanvas">cdCreateCanvas(cdContext* ctx, void *data)</a>; [in C]</span> cd.CreateCanvas(ctx: number, data: string or userdata) -> (canvas: cdCanvas) [in Lua]</pre> <p>Creates a CD canvas for a virtual visualization surface (VVS). A VVS may be the canvas of a user-interface window, the page of a document sent to a printer, an offscreen image, the clipboard, a metafile, and so on. To create the canvas, it is necessary to specify the driver in which each canvas is implemented. </p> <p>The driver is set by the <b>driver</b> variable with additional information provided in the <tt> <b>data</b></tt> parameter. Even though it is possible to create more than one canvas with the same <tt> <b>driver/data</b></tt> pair, this is not recommended, and its behavior is not specified. Each canvas maintains its own features. </p> <p>In case of failure, a <b>NULL</b> value is returned. The following predefined drivers are available:</p> <p><b>Window-Base Drivers</b></p> <ul> <li><a href="../drv/iup.html"><b>CD_IUP</b></a> = IUP Canvas (<b>cdiup.h</b>).</li> <li><a href="../drv/native.html"><b>CD_NATIVEWINDOW</b></a> = Native Window (<b>cdnative.h</b>).</li> </ul> <p><b>Device-Based Drivers</b></p> <ul> <li><a href="../drv/clipbd.html"><b>CD_CLIPBOARD</b></a> = Clipboard (<b>cdclipbd.h</b>).</li> <li><a href="../drv/printer.html"><b>CD_PRINTER</b></a> = Printer (<b>cdprint.h</b>).<br> <a href="../drv/picture.html"><strong>CD_PICTURE</strong></a> = Picture in memory (<strong>cdpicture.h</strong>).</li> </ul> <p><b>Image-Based Drivers</b> </p> <ul> <li><a href="../drv/image.html"><b>CD_IMAGE</b></a> = Server-Image Drawing (<b>cdimage.h</b>).</li> <li><a href="../drv/irgb.html"><b>CD_IMAGERGB</b></a> = Client-Image Drawing (<b>cdirgb.h</b>).</li> <li><a href="../drv/dbuf.html"><b>CD_DBUFFER</b></a> = Offscreen Drawing (<b>cddbuf.h</b>).</li> <li><b><a href="../drv/dbufrgb.html">CD_DBUFFERRGB</a></b> = Client Offscreen Drawing (<b>cddbuf.h</b>).</li> </ul> <p><b>File-Based Drivers</b> </p> <ul> <li><a href="../drv/pdf.html"><b>CD_PDF</b></a> = Adobe Portable Document Format (<b>cdpdf.h</b>).</li> <li><a href="../drv/ps.html"><b>CD_PS</b></a> = PostScript File (<b>cdps.h</b>).</li> <li><a href="../drv/svg.html"><b>CD_SVG</b></a> = Scalable Vector Graphics (<b>cdsvg.h</b>).</li> <li><a href="../drv/mf.html"><b>CD_METAFILE</b></a> = Internal CD Metafile (<b>cdmf.h</b>).</li> <li><a href="../drv/debug.html"><b>CD_DEBUG</b></a> = Internal CD Debug Log (<b>cddebug.h</b>).<br> </li> <li><a href="../drv/cgm.html"><b>CD_CGM</b></a> = Computer Graphics Metafile ISO (<b>cdcgm.h</b>).</li> <li><a href="../drv/dgn.html"><b>CD_DGN</b></a> = MicroStation Design File (<b>cddgn.h</b>).</li> <li><a href="../drv/dxf.html"><b>CD_DXF</b></a> = AutoCad Drawing Interchange File (<b>cddxf.h</b>).<br> </li> <li><a href="../drv/emf.html"><b>CD_EMF</b></a> = Microsoft Windows Enhanced Metafile (<b>cdemf.h</b>). Works only in MS Windows systems.</li> <li><a href="../drv/wmf.html"><b>CD_WMF</b></a> = Microsoft Windows Metafile (<b>cdwmf.h</b>). Works only in MS Windows systems.</li> </ul> <pre class="function"><span class="mainFunction">cdCanvas* <a name="cdCreateCanvasf">cdCreateCanvasf(cdContext *ctx, const char* format, ...)</a>; [in C] </span><font> </font>[There is no equivalent in Lua]</pre> <p>Same as <strong><font>cdCreateCanvas</font></strong>, used in the case that the parameter <b> <font>data</font></b> is a string composed by several parameters. This function can be used with parameters equivalent to the <b><font>printf</font></b> function from the default C library.</p> <pre class="function"><span class="mainFunction">void <a name="cdKillCanvas">cdKillCanvas(cdCanvas *canvas)</a>; [in C]</span> cd.KillCanvas(canvas: cdCanvas) [in Lua]</pre> <p>Destroys a previously created canvas. If this function is not called in Lua, the garbage collector will call it.</p> <pre class="function"><span class="mainFunction">int <a name="cdCanvasActivate">cdCanvasActivate</a>(cdCanvas *canvas); [in C]</span> canvas:Activate(canvas: cdCanvas) -> (status: number) [in Lua]</pre> <p>Activates a canvas for drawing. This is used only for a few drivers. Native Window and IUP drivers will update the canvas size if the window size has changed. Double Buffer driver will recreate the image buffer if the window canvas size has changed. In these cases the function MUST be called, for other drivers is useless. Returns CD_ERROR or CD_OK.</p> <pre class="function"><span class="mainFunction">void <a name="cdCanvasDeactivate">cdCanvasDeactivate</a>(cdCanvas* canvas); [in C]</span> canvas:Deactivate(canvas: cdCanvas) [in Lua]</pre> <p>Called when the application has finished drawing in the canvas. It is optional, but if used for the Native Window driver in Windows when the handle can not be retained, the drawing can only be done again after a <strong> cdCanvasActivate</strong>. On some drivers will simply call <a href="control.html#cdFlush">Flush</a>.</p> <pre class="function"><span class="mainFunction">int <a name="cdUseContextPlus">cdUseContextPlus</a>(int use); [in C]</span> cd.UseContextPlus(use: boolean) -> (old_use: boolean) [in Lua]</pre> <p>Activates or deactivates the use of an external context for the next calls of the <font face="Courier"><b> <a href="../func/init.html#cdCreateCanvas">cdCreateCanvas</a></b></font> function.</p> <pre class="function"><span class="mainFunction">void <a name="cdInitContextPlus">cdInitContextPlus</a>(void); [in C] </span> cd.InitContextPlus() [in Lua]</pre> <p>Initializes the context driver to use another context replacing the standard drivers. This functions is only available when a library containing a "ContextPlus" context driver is used. See the <a href="../drv/cairo.html">Cairo</a>, <a href="../drv/gdiplus.html">GDI+</a> and <a href="../drv/xrender.html">XRender</a> base drivers.</p> <p>In Lua, when using require"cdluacontextplus" this function will be automatically called.</p> <hr> <pre class="function"><span class="mainFunction">cdContext* cdCanvasGetContext(cdCanvas *canvas); [in C]</span> canvas:GetContext(canvas: cdCanvas) -> (ctx: number) [in Lua]</pre> <p>Returns the context of a given canvas, which can be compared with the predefined contexts, such as "CD_PS".</p> <pre class="function"><span class="mainFunction">int cdContextCaps(cdContext* ctx); [in C]</span> cd.ContextCaps(ctx: number) -> (caps: number) [in Lua]</pre> <p>Returns the resources available for that context. To verify if a given resource is available, perform a binary AND ('&.html with the following values:</p> <p><font>CD_CAP_FLUSH<br> CD_CAP_CLEAR <br> CD_CAP_PLAY <br> CD_CAP_YAXIS</font> - The Y axis has the same orientation as the CD axis.<br> <font>CD_CAP_CLIPAREA <br> CD_CAP_CLIPPOLY</font> - Usually is not implemented.<br> <font>CD_CAP_MARK</font> - Marks are implemented directly in the driver (they are usually simulated).<br> <font>CD_CAP_RECT</font> - Rectangles are implemented directly in the driver (they are usually simulated).<br> <font>CD_CAP_VECTORTEXT</font> - Vector text is implemented directly in the driver (it is usually simulated).<br> <font>CD_CAP_IMAGERGB <br> CD_CAP_IMAGERGBA</font> - If this is not implemented, but <font>cdGetImageRGB</font> is, then it is simulated using <font>cdGetImageRGB</font> and <font>cdPutImageRGB</font>.<br> <font>CD_CAP_IMAGEMAP <br> CD_CAP_GETIMAGERGB <br> CD_CAP_IMAGESRV</font> - Usually is only implemented in contexts of window graphics systems (Native Window and IUP).<br> <font>CD_CAP_BACKGROUND <br> CD_CAP_BACKOPACITY <br> CD_CAP_WRITEMODE <br> CD_CAP_LINESTYLE <br> CD_CAP_LINEWITH <br> CD_CAP_WD</font> - Functions of world coordinates are implemented directly in the driver (they are usually simulated).<br> <font>CD_CAP_HATCH <br> CD_CAP_STIPPLE <br> CD_CAP_PATTERN <br> CD_CAP_FONT <br> CD_CAP_FONTDIM</font> - If not defined, the function is implemented using an internal heuristics of the library.<br> <font>CD_CAP_TEXTSIZE</font> - If not defined, the function is implemented using an internal heuristics of the library.<br> <font>CD_CAP_TEXTORIENTATION</font> - Usually is not implemented.<br> <font>CD_CAP_PALETTE</font> - Usually is only implemented in contexts of window graphics systems (Native Window and IUP).</p> <pre class="function"><span class="mainFunction">int cdCanvasSimulate(cdCanvas* canvas, int mode); [in C]</span> canvas:Simulate(mode: number) -> (old_mode: number) [in Lua]</pre> <p>Activates the simulation of one or more primitives. It is ignored for the canvas in the ImageRGB context, because in this case everything is already simulated. It also has no effect for primitives that are usually simulated. It returns the previous simulation, but does not include primitives that are usually simulated. The simulation can be activated at any moment. For instance, if a line simulation is required only for a situation, the simulation can be activated for the line to be drawn, and then deactivated.</p> <p>If simulation is activated the driver transformation matrix is disabled.</p> <p>See in the Simulation sub-driver the information on how each simulation is performed.</p> <p>To activate a given simulation, perform a binary OR ('|.html using one or more of the following values (in Lua, the values must be added '+.html:</p> <p><font>CD_SIM_NONE</font> - Deactivates all kinds of simulation.<br> <font>CD_SIM_LINE <br> CD_SIM_RECT <br> CD_SIM_BOX <br> CD_SIM_ARC <br> CD_SIM_SECTOR <br> CD_SIM_CHORD <br> CD_SIM_POLYLINE <br> CD_SIM_POLYGON <br> CD_SIM_TEXT <br> CD_SIM_ALL</font> - Activates all simulation options. <br> <font>CD_SIM_LINES</font> - Combination of <font>CD_SIM_LINE, CD_SIM_RECT, CD_SIM_ARC</font> and <font>CD_SIM_POLYLINE</font>.<br> <font>CD_SIM_FILLS</font> - Combination of <font>CD_SIM_BOX, CD_SIM_SECTOR, CD_SIM_</font>CHORD and <font>CD_SIM_POLYGON</font>.<br> </p> <h3>Extras</h3> <pre class="function">int <strong><span style="font-size: 110%"><a name="cdlua_open">cdlua_open</a></span></strong>(lua_State* L); [for Lua 5]</pre> <p>Initializes the CDLua binding. In Lua 5 the binding is lua state safe, this means that several states can be initialized any time.</p> <pre class="function">int <strong><span style="font-size: 110%"><a name="cdlua_close">cdlua_close</a></span></strong>(lua_State* L); [for Lua 5]</pre> <p>Releases the memory allocated by the CDLua binding.</p> <pre class="function">cdCanvas* <strong><span style="font-size: 110%"><a name="cdlua_getcanvas">cdlua_checkcanvas</a></span></strong>(lua_State* L, int pos); [for Lua 5]</pre> <p>Returns the canvas in the Lua stack at position pos. The function will call lua_error if there is not a valid canvas in the stack at the given position.</p> <pre class="function">void <strong><span style="font-size: 110%">cdlua_pushcanvas</span></strong>(lua_State* L, cdCanvas* canvas);</pre> <p>Pushes the given canvas into the stack.</p> </body> </html>