Simulation Base Driver

The Simulation driver was created to simulate functions that were not supported by some CD drivers. It works jointly with the other driver (known as "client"), using its pixel, line and text functions to simulate arcs, sectors, polygons, boxes, and fillings with styles.

Important: All simulation primitives are based in the client's Pixel, Image and/or Line functions.

Use

The Simulation driver is used in several parts of the CD library.

In many drivers, the behavior of a given primitive may not be the expected. Usually this is documented in the manual. If you wish to activate the simulation of a primitive, simply call function cdSimulate with the code of the primitive to be simulated.

Behavior of Functions

Clipping

• Clipping is not implemented in the simulation base driver. The primary driver must implement its own clipping.

Attributes

• LineCap: only CD_CAPFLAT is supported.
• LineJoin: only CD_MITER is supported.
• LineStyle: If line width is greater than 1, the style is always continuous.
• Font: Selects a Truetype font file for the FreeType library to render the text.
The typeface parameter is used to find the appropriate file.

The typeface parameter can be the name of a font or the name of a font file (not including path, nor the extension ".ttf"). If a name is specified some pre-defined correspondents are tried, for instance the know font names "Courier", "Times" and "Helvetica" are mapped to "cour", "times", and "arial", their styles are added to the font file name as a suffix: "bd", "i" and "bi", to match bold, italic and bold-italic. Those files are also available in the "cd/etc" folder of the CD distribution packages. If the pre-defined names are not used, the typeface parameter is used as the file name. It can also use a manual font map added using the attribute ADDFONTMAP (see bellow).
Font files can be located in the current directory, in the directory pointed by the CDDIR environment variable, in the native system font directory, or by using the full path of the file in the typeface parameter. The ".ttf" file extension is always automatically added to the end of the file name. In Linux font files are searched using FontConfig.
The search order is: ADDFONTMAP, pre-defined names, native system, and full path.

Primitives

• Pixel: always uses the client's pixel function. When clipping simulation is active, it executes area and polygon clipping.
• Line: draws lines pixel per pixel.
• Rect: simulated using the client's Line.
• Arc: simulated using the client's Line.
• Sector: simulated using the client's Poly.
• Chord: simulated using the client's Poly
• Box: simulated using the client's Poly.
• Begin, Vertex and End: simulated using the Line or Pixel functions, depending on the interior style.
• Text: text simulation is made using TrueType font files in a transparent way for the user. Oriented text is not supported.

Exclusive Attributes

• "ADDFONTMAP": Add a font map between a type face name and a file name. It has the format "Type Face=filename", For ex: "Arial Narrow Bold=ARIALNB". "Type Face" is not case sensitive. For example:

 cdCanvasSetAttribute(canvas, "ADDFONTMAP", "MyWingDings=wingxing");

• "FREETYPEVERSION": Returns a version string with the current Freetype library being used, in the format "FreeType <major>.<minor>.<patch>".