Dataset and Overlay Properties

Dataset Properties

Cadcorp SIS Desktop understands many different datasets, e.g. AutoCAD DXF or Ordnance Survey NTF.

Note: See list of datasets for more information on their properties.

Dataset properties are set and queried using the SIS_OT_DATASET constant and the

The nObject& argument must be the serial number of the dataset.

To check the serial number, access it from the _nDataset& property of an overlay or from the GetDataset, GetDatasetContainer, FindExternalDataset or TopoGetNamedSeedDataset methods.

Dataset serial numbers can change during the course of a SIS session. Therefore ensure you query serial numbers immediately before use and not stored for later access.

Overlay Properties

Overlay properties are set and queried using the SIS_OT_OVERLAY constant and the GetFlt/GetInt/GetStr/GetProperty and SetFlt/SetInt/SetStr/SetProperty methods.

The nObject& argument should be the index in the list of overlays in the current window of the required overlay.

The _nOverlay& property is the total number of overlays in the current window.

Note: Overlay indices run from zero to one less than the number of overlays.


Overlay Properties

  • Attributes: _attributes$
    The user defined attributes stored with the overlay.

  • Bitmap: _GBitmapAlphaTransparency&
    Valid values are: 0 - 255. The higher the value the greater the transparency.

  • Brush: _brush$
    The Brush to use for items if their Brush is "By Overlay", i.e. if they have no Brush of their own, or if the overlay Brush override is set.

  • Brush alpha: _brushAlpha&
    Valid values are: 0 - 255. The higher the value the greater the transparency.

  • Brush alpha override: _bBrushAlphaOverride&

  • Brush override: _bBrushOverride&
    Should the overlay Brush override any Item Brush?

  • Colour: _colour$
    The overlay colour, a space-separated RGB triple, e.g. "0 0 255" is blue, and "255 255 255" is white. When the overlay colour override is True, items will use this colour instead of their Pen colour.

  • Colour override: _bColourOverride&
    Should the overlay colour override any Item Pen colour? If this is False, then the overlay colour is ignored.
  • Dataset: _nDataset&
    The serial number of the overlay's dataset.

  • External: _bExternal&
    Is the overlay's dataset a file?

  • Font: _font$
    The font to use for items if their font is "By Overlay", i.e. if they have no font of their own, or if the overlay font override is set.

  • Font override: _bFontOverride&
    Should the overlay font override any item font?

  • Icon: _nIcon&
    The overlay icon index.

  • Maximum scale: _scalemax#
    The highest reproduction scale at which an Item on an overlay will be drawn. If you set this value to 1000, and then zoom out to 1:2000 the item will become invisible.

    This value is stored internally using a low precision byte. The value you enter will be rounded to the nearest valid value automatically.

  • Minimum scale: _scalemin#
    The lowest reproduction scale at which an Item on an overlay will be drawn. If you set this value to 100, and then zoom out to 1:50 the item will become invisible.

    This value is stored internally using a low precision byte. The value you enter will be rounded to the nearest valid value automatically.

  • Name: _name$
    The overlay name. If the overlay's dataset is a file, then this name is an alias.

  • Non-Printable: _bNonPrintable&
    Sets the overlay to be non-printable.

  • Notes: _notes$
    The overlay notes. These notes can be used to store free-form textual information about the overlay.

  • Number of themes: _nTheme&
    The number of Theme objects on the overlay.

  • Order By: _orderBy$
    For Cadcorp Base Dataset and Cadcorp Internal Datasets, supports drawing in user-defined order, which can be any expression.

  • Order By Max Scale: _orderByScalemax#
    A pre-drawing sorting step that can be skipped at small scales, where strict ordering may be expensive in terms of memory and/or processing resource and/or unnecessary.

  • Pen: _pen$
    The Pen to use for items if their Pen is "By Overlay", i.e. if they have no Pen of their own, or if the overlay Pen override is set.

  • Pen alpha: _penAlpha&
    Valid values are: 0 - 255. The higher the value the greater the transparency.

  • Pen alpha override: _bPenAlphaOverride&

  • Pen override: _bPenOverride&
    Should the overlay Pen override any item Pen?

  • Point scale override: _pointScaleOverride#
    To ensure a Symbol is displayed at the correct scale set the attribute to -1.

  • Scale: _scale#
    The overlay scale, which optionally overrides the overlay's dataset scale.

  • Scale override: _bScaleOverride&
    Should the overlay scale override the overlay's dataset scale?

  • Symbol: _shape$
    The Symbol to use for items if their Symbol is "By Overlay", i.e. if they have no Symbol of their own, or if the overlay Symbol override is set.

  • Symbol override: _bShapeOverride&
    Should the overlay Symbol override any item Symbol?

  • Sprites: _bSprites&
    A boolean value that indicates whether the overlay is a sprites overlay. If the overlay contains Items that are considered to be sprites set this value to True (-1).
    See Sprites Overlay

  • Status: _status&
    The overlay status. Valid values are:
    SIS_INVISIBLE   Items are invisible.
    SIS_VISIBLE   Items are visible.
    SIS_HITTABLE   Items are visible and can be selected.
    SIS_EDITABLE   Items are selectable and can be edited.

  • The following numbers can also be used: 0=Invisible 1=Visible 2=Hittable 3=Editable
  • Theme titles: _themes$
    A list of Themes on the overlay.