AcGiSubEntityTraits

acgi.h

This class is used to control the current values of the color, layer, linetype, fill type, and graphics system marker attributes for graphics primitives. 

Attribute settings are used for all graphics primitives drawn until the setting changed via one of the "set" functions in this class or the end of the current worldDraw() or viewportDraw() execution. 

For instance, you can set the color attribute to blue and all of the subsequent geometry drawn during the current worldDraw() or viewportDraw() execution appears blue until you set the current color to something else. 

Upon entry into an entity's worldDraw() or viewportDraw(), the attributes are initialized to the following: 

Currently, linetype scaling cannot be set here. 

Color 

Note If you modify a layerTableRecord and change its color or linetype during a worldDraw or viewportDraw, and it is the current AcGi layer, then you must call the AcGiSubEntityTraits::setLayer("current layer's ID") to bring the AcGi up to date. This updates any current colors or linetypes that are by layer. 

There are currently 257 color indices used in AutoCAD, two of which are special: color 0 is "color by block" and color 256 is "color by layer." Colors 1 to 6 are guaranteed. Color 7 is white unless it conflicts with the background color and then it's black. Colors 8 and 9 are mostly dark gray and light gray, respectively, but may be settable to other colors by the video driver. Colors 10 to 249 are described in the next paragraph. Colors 250 to 255 are a short ramp from dark gray to almost white. 

Starting at 10 and ending at 249, the hue changes every 10, starting at red and going through the spectrum and almost back to red again. In each of these sets of 10, the last digit determines the brightness and the pastelness of the color: -0, -2, -4, -6, and -8 are the most intense to the darkest of that color; -1, -3, -5, -7, and -9 are the most intense to the darkest of a pastel version of that color. So color 10 is bright red, 18 is dark red, 11 is pink (pastel red), and 19 is dark pale pink; color 145 is a color between cyan and turquoise, is pastel and of medium intensity. 

Layers 

The AcGi currently does not create layers. They must pre-exist in the system for the AcGi to be able to use them. 

If you modify a layerTableRecord and change its color or linetype during a worldDraw or viewportDraw and it is the current layer in use by AcGi, then you have to call the AcGiSubEntityTraits::setLayer("current layer's ID") to bring the AcGi up to date. This updates any portions of the entity with colors or linetypes that are by layer. 

The following example code gets an AcDbObjectId for a LayerTableRecord from the layer's name. 

static Acad::ErrorStatus
getLayerIdFromString(const char* pStr,AcDbobjectId& ID)
{
    //  Get a pointer to the drawing's layer table
    //
    AcDbLayerTable* pLayerTable;
    Acad::ErrorStatus err = acdbCurDwg()->getLayerTable(pLayerTable,
        AcDb::kForRead);
    if (err != Acad::eOk)
        return err;

    // Get the ID of the layer with the name in 'pStr' (even if it's
    // erased) and place it in 'id'.
    //
    err = pLayerTable->getAt(pStr, ID, Adesk::kTrue);

    pLayerTable->close();

    return err;
}

Linetypes 

The AcGi currently does not load linetypes. They must be previously loaded into the system for the AcGi to be able to use them. 

Geometry methods polylineEye() and polylineDc() cannot be automatically linetyped by the graphics system. 

If you modify a layerTableRecord and change its color or linetype during a worldDraw or viewportDraw and it is the current layer in use by AcGi, then you have to call the AcGiSubEntityTraits::setLayer("current layer's ID") to bring the AcGi up to date. This updates any portions of the entity with colors or linetypes that are by layer. 

The following example code gets an AcDbObjectId for a linetypeTableRecord from the linetype name. 

static Acad::ErrorStatus
getLinetypeIdFromString(const char* pStr, AcDbObjectId& ID)
{
    //  Get the table of currently loaded linetypes.
    //
    AcDbLinetypeTable* pLinetypeTable;
    Acad::ErrorStatus err = acdbCurDwg()->getLinetypeTable(
        pLinetypeTable, AcDb::kForRead);
    if (err != Acad::eOk)
        return err;

    // Get the ID of the linetype with the name in 'pStr'
    // (even if it's erased) and place it in 'id'.
    //
    err = pLinetypeTable->getAt(pStr, ID, Adesk::kTrue);

    pLinetypeTable->close();

    return err;
}

AcGiViewportDraw, AcGiWorldDraw, AcDbEntity, AcDbObjectId