1.67.3 Instance variables

graphical <- active: bool

If @off, the colour of the drawing pen will be set to object<-class_variable_value: inactive_colour. The method graphical->event will simply fail if graphical<-active is @off.

graphical-area: area

The area object associated with each graphical describes a bounding-box inside which all pixels affected by the graphical are. The area is used for:

• Representing the position and size of the graphical.
• Planning redraw of the window.
• Dispatching events to graphicals below the mouse. The get method first invokes graphical->compute to update the graphical.

  Defaults: The default area of most graphicals is area(0,0,0,0).

graphical <- colour: [colour|pixmap]

The graphical<->colour attribute of a graphical describes the colour used to draw the affected pixels. It is either a colour object or @default. The latter implies the graphical<->colour attribute of the device is used.

Defaults: @default. For windows, the default colour is display<-foreground.

See also

class colour

graphical-connections: chain*

Chain of connection objects. Connections are lines relating two graphical objects. Connection are automatically updated when either of the connected graphicals is updated.

See also

topic Connections

graphical <- cursor: cursor*

Cursor displayed in this window when the graphical is in focus of events. When @nil, the cursor of the device is displayed.

Defaults: @nil.

See also

class cursor

graphical <- device: device*

The device (normally picture, dialog or figure) on which the graphical is displayed. A graphical can only be displayed on one device. The graphical<->device slot is used by graphicals to inform their device of changes, so the device can perform the appropriate redraw operations. The following is always true:

If the device of a graphical is not @nil, the graphical is
member of `Device <-graphicals` of this device and
visa-versa.

Normally, a graphical is assigned a device using device->display.

See also

- graphical-displayed
- device->display
- device-graphicals
- class device

graphical <- displayed: bool

If @off, the graphical will not be displayed even if it is member of a device. The initial value is @off. It is set to @on by device->display an @off by device->erase.

graphical->displayed is used to remove a graphical temporary from the display. See also figure->status.

Defaults: Initially @off. Set to @on by device->display.

See also

- graphical<-is_displayed
- device->display
- dialog_item->show
- graphical-device

graphical-handles: chain*

Chain of handles. Each handle defines a position to which a connection can attach. See T Connections.

Handles can be attached at the instance level and at the class level (see class->handles) or both.

Defaults: @nil (no handles at the instance level)

See also

- topic Connections
- graphical->handle
- class-handles
- class handle

graphical <- inverted: bool

If @on, graphical<->area is inverted after the graphical is painted, inverting all pixels in the bounding-box of the graphical. Note that this implies at inverted circle appears as a white circle in a black square (using white background and black foreground colours). Also note that graphicals below (i.e. hidden by this graphical) are inverted too.

Defaults: @off

See also

graphical-selected

graphical <-> name: name

The name of a graphical can be used to locate it on its device. Finding graphicals by name is a simple but very effective way. Graphicals generally do not visualise their graphical<-name.

See device<-member and device<-catch_all.

See also

- frame<-get_catch_all
- device<-get_catch_all
- device<-member

graphical <- pen: 0..

The pen attribute denotes the thickness in pixels of the drawing pen for drawing lines. It is defined at class graphical, but only applicable to classes whose images actually contain lines. If the pen is 0 (zero), lines are not displayed.

Defaults: 1

See also

graphical-texture

graphical <- request_compute: any*

When not @nil, indicates that the graphical is in inconsistent state. Used for graphical objects that require significant computation to determine their area and visual representation.

When no argument is specified with graphical->request_compute the variable will be filled with @on.

If a graphical->request_compute is invoked on a graphical, PCE's graphical kernel will invoke a graphical->compute on it if the graphical needs to be repainted or one of the dimensions of the graphical is requested. See graphical<-area, display->dispatch and graphical->compute.

See also

- graphical->compute
- graphical->request_compute

graphical <- selected: bool

Indicates whether or not the graphical is selected. The visual feedback is determined by the graphical.selection_style.

See also

- graphical.selection_style
- graphical->selected
- graphical->toggle_selected
- device<-selection
- device->selection
- graphical-inverted

graphical <- texture: texture_name

Stipple pattern used for drawing lines. Applicable to all graphicals that have line elements in them. Values:

none	Straight line
dotted	Pattern: 1 on 2 off ...
dashed	Pattern: 7 on 7 off ...
dashdot	Pattern: 7 on 3 off 1 on 7 off ...
dashdotted	Pattern: 11 on 3 off 1 on 3 off 1 on 3 off 1 on 3 off
longdash	Pattern: 15 on 7 off ...

See also

graphical-pen