Programming Reference:GraphObject Class - Revision history

Mellinger: /* OnPaint(GUI::DrawContext) */

2008-12-20T14:53:50Z

OnPaint(GUI::DrawContext)

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	==Events==		==Events==
	===OnPaint(GUI::DrawContext)===		===OnPaint(GUI::DrawContext)===
	From its <tt>OnPaint</tt> event handler, a <tt>GraphObject</tt> ~~draws~~ itself into a device context and rectangle specified in its ''DrawContext'' argument. The ''DrawContext'' consists of an OS device context handle, and a rectangle in device coordinates.		From its <tt>OnPaint</tt> event handler, a <tt>GraphObject</tt> renders itself into a device context and rectangle specified in its ''DrawContext'' argument. The ''DrawContext'' consists of an OS device context handle, and a rectangle in device coordinates.
	Implementing this function is mandatory for classes inheriting from <tt>GraphObject</tt>.		Implementing this function is mandatory for classes inheriting from <tt>GraphObject</tt>.

	===OnChange(GUI::DrawContext)===		===OnChange(GUI::DrawContext)===
	The <tt>OnChange</tt> event handler is called to notify the object that a change in size, position, or output device has occurred. E.g., if the object maintains an internal bitmap buffer that it uses to speed up paint operations, it should delete and re-create that buffer from its <tt>OnChange</tt> handler to ensure consistency with the output draw context. Objects that render themselves directly do not need to override the (empty) default handler.		The <tt>OnChange</tt> event handler is called to notify the object that a change in size, position, or output device has occurred. E.g., if the object maintains an internal bitmap buffer that it uses to speed up paint operations, it should delete and re-create that buffer from its <tt>OnChange</tt> handler to ensure consistency with the output draw context. Objects that render themselves directly do not need to override the (empty) default handler.

Mellinger: /* Synopsis */

2008-09-12T15:17:55Z

Synopsis

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	<tt>GraphObjects</tt> possess a z-order position that determines how they are drawn on top of each other.		<tt>GraphObjects</tt> possess a z-order position that determines how they are drawn on top of each other.
	You do not instantiate <tt>GraphObjects</tt> directly; rather, you create objects of classes that inherit the <tt>GraphObject</tt> interface.		You do not instantiate <tt>GraphObjects</tt> directly; rather, you create objects of classes that inherit the <tt>GraphObject</tt> interface.

			{{NamespaceRemark\|namespace=GUI\|class=GraphObject}}

	==Methods==		==Methods==

Mellinger: /* Synopsis */

2008-09-11T15:55:27Z

Synopsis

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	==Synopsis==		==Synopsis==
	The <tt>GraphObject</tt> class defines an interface for graphical objects displayed by a BCI2000 application.		The <tt>GraphObject</tt> class defines an interface for graphical objects displayed by a BCI2000 application.
	<tt>GraphObjects</tt> are tied to a [[Programming Reference~~:GUI:~~:GraphDisplay Class\|<tt>GraphDisplay</tt>]], which typically represents an application window.		<tt>GraphObjects</tt> are tied to a [[Programming Reference:GraphDisplay Class\|<tt>GraphDisplay</tt>]], which typically represents an application window.

	<tt>GraphObjects</tt> possess a z-order position that determines how they are drawn on top of each other.		<tt>GraphObjects</tt> possess a z-order position that determines how they are drawn on top of each other.

Mellinger: /* Properties */

2008-09-11T14:57:31Z

Properties

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 ==Properties==
-===GraphDisplay Display (r)===
+{{GraphObjectProperties}}
 ==Events==

Mellinger: /* GUI::Rect DisplayRect */

2008-09-11T14:56:07Z

GUI::Rect DisplayRect

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	The exact behavior of aspect ratio adjustment depends on the object's type. E.g., for bitmap images, ''AdjustBoth'' will size the image such that one image pixel corresponds to one screen pixel; ''AdjustHeight'' and ''AdjustWidth'' will adjust such that the original aspect ratio is conserved.		The exact behavior of aspect ratio adjustment depends on the object's type. E.g., for bitmap images, ''AdjustBoth'' will size the image such that one image pixel corresponds to one screen pixel; ''AdjustHeight'' and ''AdjustWidth'' will adjust such that the original aspect ratio is conserved.

	===GUI::Rect DisplayRect===		===GUI::Rect DisplayRect (rw)===
	The bounding rectangle of the space that is occupied by the object. This is given in coordinates relative to the size of the object's <tt>GraphDisplay</tt>; there, the upper left corner corresponds to (0,0), the lower right corner to (1,1).		The bounding rectangle of the space that is occupied by the object. This is given in coordinates relative to the size of the object's <tt>GraphDisplay</tt>; there, the upper left corner corresponds to (0,0), the lower right corner to (1,1).
	When a <tt>GraphObject</tt> is created, its display rectangle is empty.		When a <tt>GraphObject</tt> is created, its display rectangle is empty.

Mellinger: /* enum AspectRatioMode */

2008-09-11T14:55:51Z

enum AspectRatioMode

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	''True'' if the object is visible, ''false'' if it is hidden. Use the ''Hide()'' and ''Show()'' methods to set this property.		''True'' if the object is visible, ''false'' if it is hidden. Use the ''Hide()'' and ''Show()'' methods to set this property.

	===enum AspectRatioMode===		===enum AspectRatioMode (rw)===
	One of the following options:		One of the following options:
	;AdjustNone		;AdjustNone

Mellinger: /* Methods */

2008-09-11T14:55:33Z

Methods

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	===GraphObject(GraphDisplay, int zOrder)===		===GraphObject(GraphDisplay, int zOrder)===
	The constructor of a graph object requires a reference to a <tt>GraphDisplay</tt>, and an integer that specifies the object's z order, where lower values correspond to objects that are drawn on top of objects with larger z order values.		The constructor of a graph object requires a reference to a <tt>GraphDisplay</tt>, and an integer that specifies the object's z order, where lower values correspond to objects that are drawn on top of objects with larger z order values.
	~~===Show()===~~		{{GraphObjectMethods}}
	~~Makes the object visible. Initially, objects are created in visible state.~~
	~~===Hide()===~~
	~~Makes the object invisible.~~
	~~===Invalidate()===~~
	Invalidates the object's bounding rectangle, i.e. marks it as needing to be repainted. Typically, this function is called from a derived class, indicating that a change in object properties has occurred that requires a repaint.
	~~===Paint()===~~
	~~Asks the <tt>GraphObject</tt> to paint itself by calling its <tt>OnPaint</tt> event handler.~~
	~~===Change()===~~
	~~Notifies the <tt>GraphObject</tt> of a change in display properties by calling its <tt>OnChange</tt> event handler.~~
	~~===bool Click(GUI::Point)===~~
	~~Tests whether the specified point is inside the object's bounding rectangle, and calls its <tt>OnClick</tt> event handler if this is the case.~~

	==Properties==		==Properties==

Mellinger at 14:54, 11 September 2008

2008-09-11T14:54:02Z

New page

==Location==
<tt>src/shared/gui</tt>

==Synopsis==
The <tt>GraphObject</tt> class defines an interface for graphical objects displayed by a BCI2000 application.
<tt>GraphObjects</tt> are tied to a [[Programming Reference:GUI::GraphDisplay Class|<tt>GraphDisplay</tt>]], which typically represents an application window.

<tt>GraphObjects</tt> possess a z-order position that determines how they are drawn on top of each other.
You do not instantiate <tt>GraphObjects</tt> directly; rather, you create objects of classes that inherit the <tt>GraphObject</tt> interface.

==Methods==
===GraphObject(GraphDisplay, int zOrder)===
The constructor of a graph object requires a reference to a <tt>GraphDisplay</tt>, and an integer that specifies the object's z order, where lower values correspond to objects that are drawn on top of objects with larger z order values.
===Show()===
Makes the object visible. Initially, objects are created in visible state.
===Hide()===
Makes the object invisible.
===Invalidate()===
Invalidates the object's bounding rectangle, i.e. marks it as needing to be repainted. Typically, this function is called from a derived class, indicating that a change in object properties has occurred that requires a repaint.
===Paint()===
Asks the <tt>GraphObject</tt> to paint itself by calling its <tt>OnPaint</tt> event handler.
===Change()===
Notifies the <tt>GraphObject</tt> of a change in display properties by calling its <tt>OnChange</tt> event handler.
===bool Click(GUI::Point)===
Tests whether the specified point is inside the object's bounding rectangle, and calls its <tt>OnClick</tt> event handler if this is the case.

==Properties==
===GraphDisplay Display (r)===
The <tt>GraphDisplay</tt> object that was specified when the <tt>GraphObject</tt> was created.

===bool Visible (r)===
''True'' if the object is visible, ''false'' if it is hidden. Use the ''Hide()'' and ''Show()'' methods to set this property.

===enum AspectRatioMode===
One of the following options:
;AdjustNone
:No adjustment is made.
;AdjustWidth
:The object's width is adapted to its contents, while keeping its height constant.
;AdjustHeight
:The object's height is adapted to its contents, keeping its width constant.
;AdjustBoth
:Both the object's height and width are adjusted to its content.

The exact behavior of aspect ratio adjustment depends on the object's type. E.g., for bitmap images, ''AdjustBoth'' will size the image such that one image pixel corresponds to one screen pixel; ''AdjustHeight'' and ''AdjustWidth'' will adjust such that the original aspect ratio is conserved.

===GUI::Rect DisplayRect===
The bounding rectangle of the space that is occupied by the object. This is given in coordinates relative to the size of the object's <tt>GraphDisplay</tt>; there, the upper left corner corresponds to (0,0), the lower right corner to (1,1).
When a <tt>GraphObject</tt> is created, its display rectangle is empty.

==Events==
===OnPaint(GUI::DrawContext)===
From its <tt>OnPaint</tt> event handler, a <tt>GraphObject</tt> draws itself into a device context and rectangle specified in its ''DrawContext'' argument. The ''DrawContext'' consists of an OS device context handle, and a rectangle in device coordinates.
Implementing this function is mandatory for classes inheriting from <tt>GraphObject</tt>.
===OnChange(GUI::DrawContext)===
The <tt>OnChange</tt> event handler is called to notify the object that a change in size, position, or output device has occurred. E.g., if the object maintains an internal bitmap buffer that it uses to speed up paint operations, it should delete and re-create that buffer from its <tt>OnChange</tt> handler to ensure consistency with the output draw context. Objects that render themselves directly do not need to override the (empty) default handler.
===bool OnClick(GUI::Point)===
The <tt>OnClick</tt> event handler receives a point in normalized coordinates, and returns whether it considers itself clicked. The default handler does nothing, and returns ''true''.

==Descendants==
The <tt>GraphObject</tt> class is parent to the following class hierarchy:
<tt>
GraphObject |-> [[Programming Reference:Shape Class|Shape]] |-> [[Programming Reference:RectangularShape Class|RectangularShape]]
| |-> [[Programming Reference:EllipticShape Class|EllipticShape]]
|-> [[Programming Reference:StatusBar Class|StatusBar]]
|-> [[Programming Reference:ImageStimulus Class|ImageStimulus]]
|-> [[Programming Reference:TextField Class|TextField]]
|-> [[Programming Reference:Scene Class|Scene]]
</tt>

==See also==
[[Programming Reference:GraphDisplay Class]]

[[Category:Framework API]][[Category:Development]]