4 canvas

Highly specialized existing graphic applications (e.g. process visualization) which have to have direct access to the underlying window system can use the dialog object canvas as their individual drawing area.

The DM provides this object for the application. The DM does not consider the contents of this object; the application itself is responsible for the contents. For this reason, a canvas must not contain any child objects.

Definition

{ export | reexport } { model } canvas  { <Identifier> }
{
  <standard attributes>
  <plain attributes>
  <hierarchy attributes>
  <layout attributes>
  <object-specific attributes>
}

The DM uses the attributes listed in chapter “Attributes” in the usual manner. This object is typically used when the application has to display dynamic charts or diagrams.

Events

Children

Parent

4.1 Attributes

Attribute	RLD	PID	Properties	Short Description
.acc_label	string object	string text	S.G/D/C	overwrites the Automation Identifier for Microsoft UI Automation
.acc_text	object string	text string	S.G/D/C	overwrites the Automation Name for Microsoft UI Automation
.accelerator	identifier	accel	S,G/D/C	accelerator of object
.bgc	identifier	color	S,G/D/C	background color
.bordercolor	identifier	color	S,G/D/C	border color
.borderraster	boolean	boolean	S,G/D/-	controls computation of geometry with active grid
.borderstyle	enum	enum	S,G/D/C	defines the style, i.e. representation and characteristics of the borders (since IDM version A.06.01.a)
.borderwidth	integer	integer	S,G/D/C	borderwidth
.canvasfunc	identifier	func	S,G/D/C	canvas function
.class	class	class	-,G/-/-	class/id of object
.control	identifier	instance	-,G/-/-	control currently belonging to object
.cursor	identifier	cursor	S,G/D/C	cursor belonging to object
.cut_pending	boolean	boolean	S,G/-/-	cut operation not yet carried out
.cut_pending_changed	boolean	boolean	-,G/-/-	changing state during cut operation
.dialog	identifier	instance	-,G/-/-	dialog to which the object belongs
.document[integer]	object	document	S,G/-/-	accesses the I-th XML Document
.external	boolean	boolean	-,G/-/-	returns if the object class is an USW class
.external[integer]	class	class	-,G/-/-	returns the I-th registered USW class
.fgc	identifier	color	S,G/D/C	foreground color
.firstrecord	object	record	S,G/-/C	accesses the first record of an object
.focus	boolean	boolean	S,G/-/C	input focus on object
.font	identifier	font	S,G/D/C	object font
.function	identifier	func	S,G/D/C	function belonging to object
.groupbox	identifier	instance	-,G/-/-	object groupbox
.height	integer	integer	S,G/D/C	object height
.help	string identifier	string text	S,G/D/C	help text of object
.index	integer index	integer index	-,G/-/-	current index of object in the child list of its parent
.label	string	string	S,G/D/C	name/identifier of object
.lastrecord	object	record	S,G/-/C	accesses the last record of an object
.layoutbox	object	object	-,G/-/-	layoutbox of object
.mapped	boolean	boolean	S,G/D/-	defers the display of a visibly created object
.member[integer]	attribute	attribute	-,G/-,-	user-defined attribute [I] of object
.membercount	integer	integer	-,G/-,-	number of user-defined attributes
.menu	identifier	instance	S,G/D/C	object menu
.model	identifier	instance	S,G/D/C	model belonging to object
.notepage	object	object	-,G/-/-	notepage of object
.options[enum]	boolean	boolean	S,G/D/-	special options of object
.parent	identifier	instance	S,G/-/-	parent of object
.posraster	boolean	boolean	S,G/D/C	positions refer to grid
.real_height	integer	integer	-,G/-/-	real height of object
.real_sensitive	boolean	boolean	-,G/-/-	real selectivity of object
.real_visible	boolean	boolean	-,G/-/-	real visibility of object
.real_width	integer	integer	-,G/-/-	real width of object
.real_x	integer	integer	-,G/-/-	real distance from left (in pixel)
.real_y	integer	integer	-,G/-/-	real distance from top (in pixel)
.record[integer]	object	record	S,G/-/C	accesses the I-th record of an object
.recordcount	integer	integer	-,G/-/-	queries the number of child records
.scope	integer (1, 2, 3)	scope	-,G/-/-	queries the object type (Default, Model or instance)
.sensitive	boolean	boolean	S,G/D/C	selectivity of object
.sizeraster	boolean	boolean	S,G/D/C	size refers to grid of parent object
.statushelp	string object	string text	S,G/-/C	text to be displayed in statusbar
.toolbar	object	object	-,G/-/-	toolbar of object
.toolhelp	string object	string text	S,G/D/C	gives a short explanation of object at the cursor
.userdata	anyvalue	anyvalue	S,G/D/C	object userdata (any DM datatype)
.visible	boolean	boolean	S,G/D/C	visibility of object
.width	integer may be 0	integer	S,G/D/C	actual width of object
.window	identifier	instance	-,G/-/-	window to which object belongs
.xauto	integer (-1, 0, 1)	integer	S,G/D/C	definition type of x-coordinates
.xleft	integer	integer	S,G/D/C	x-coordinate, distance from the left
.xright	integer	integer	S,G/D/C	x-coordinate, distance from the right
.yauto	integer (-1, 0, 1)	integer	S,G/D/C	definition type of y-coordinates
.ybottom	integer	integer	S,G/D/C	y-coordinate, distance from bottom
.ytop	integer	integer	S,G/D/C	y-coordinate, distance from top

4.2 Specific Attributes

With Motif 1.1, you cannot navigate over an object with keyboard navigation, if this object is a composite widget and if this widget has no children. A program abort is also likely.

Therefore, the attribute .options[enum] which decides whether a DrawingArea-Widget (composite, i.e. it accepts children) or a DrawnButton-Widget (primitive, i.e. it does not accept children) is to be used has been made available for the object canvas.

The DrawnButton-Widget is used as default.

Applications which include their own widgets or special widgets in the canvas, have to set the option opt_accept_child.

If opt_accept_child is set to true, a DrawingArea-widget (composite) will be used for the canvas. Default is a DrawnButton-widget.

The following enum options are only evaluated if opt_accept_child is not set.

If opt_focus_frame is set to false, the location-cursor-border (keyboard focus) will not be drawn if the canvas does not have the focus. The default is true.

option_index	Meaning
opt_accept_child	canvas accepts child widgets (i.e. no focus)
opt_focus_frame	no focus frame will be drawn
opt_motif_shadow	canvas draws motif shadow frame

4.3 Example

model canvas MCanvas

{

.canvasfunc CanvasEvent;

.xauto 0;

.xleft 0;

.xright 0;

.yauto 0;

.ytop 0;

.ybottom 5;

.fgc DiaColor20;

.bgc Background;

.posraster true;

.sizeraster true;

.font DiaFont;

}

Figure 13-1: Canvas