Graphic.Layer Class
The Layer class can hold several GraphicObjects and it provides some transformations methods to move or scale all the GraphicalObjects that it contains. This is helpful when you want for example apply the same plane transformation to some GraphicalObjects.
Constructor
Graphic.Layer
-
params
Parameters:
-
paramsObjectAll properties given to GraphicObject are available.
-
[camera]Camera optionalcamera used be the layer. if not set, a new
Camerais created. -
[spatialContainer]SpatialContainer optional -
[localContext]CanvasRenderingContext2D optionalyou can set directly the graphic canvascontext used by the layer.
-
Item Index
Methods
Methods
addChild
-
graphicObject
This method will allow you to add a child to the current Layer.
Parameters:
-
graphicObjectGraphicObjectthis parameter must be a valid GraphicObject, otherwise the method will have an undefined behavior.
draw
-
context
This method allow the user to draw on the canvas's context. If nothing has changed in the childs of the layer, then a buffered layer is printed on the canvas. Otherwise all the canvas is redraw.
Parameters:
-
contextCanvasRenderingContext2D
notifyParentChange
()
protected
This method notify the parent that a change has been done, and that it should clear his cache.
onChange
-
[child]
This method will be called when a child is changed. By using this method it will notice the current Layer to redraw the local canvas.
This method is called automatically when a child object change. You can call this method for clear internal cache.
Parameters:
-
[child]GraphicObject optionalthis object represent the child who has been changed.
rmChild
-
graphicObject
This method will allow you to remove a child from the current Layer.
Parameters:
-
graphicObjectGraphicObjectthis parameter is the GraphicObject that the method will try to find inside the child of the current layer.
rotate
-
angle
This method allow you to rotate the Graphical object around the center point of the GraphicalObject.
Parameters:
-
angleNumberrepresent the angle of rotation, it's expressed in degree.
scale
-
x -
y
this method allow you to do a scale on the GraphicObject.
Parameters:
-
xNumberthis is the x scale factor
-
yNumberthis is the y scale factor
setAttr
-
attrs
Setter availlable for updating attibuts and correctly clear the caches. You can set all attributes supported by this instance (see the GraphicObject constructor for common available properties)
Parameters:
-
attrsObjectLayer attributs. See the constructor for more details.
Example:
object.setAttr({
width: 20,
height: 20
});
object.setAttr({
pos: {
x: 0,
y: 0
}
});
skew
-
a -
b
This method allow you to do a skew transform on the GraphicObject.
Parameters:
-
aNumberthe factor of skew on the y axis
-
bNumberthe factor of skew on the x axis
translate
-
x -
y
This method allow you to translate the GraphicalObject, Internally this method modify the GraphicObject's matrix.
Parameters:
-
xNumberthis is the translation scalar of the x axis.
-
yNumberthis is the translation scalar of the y axis.
update
()
This method will allow you to update the layer and all the childs within the layer.
Properties
_needToRedraw
Boolean
private
indicate when the cache must be updated.
alpha
Number
value of opacity, between 0.0 (fully transparent) and 1.0 (opaque)
camera
Camera
camera of the layer.
Note: this property should be modified only with setAttr.
centerPoint
Object
default center of all matrix transformations.
values are exprimed depending on the size of the object. 0;0 is the up-left corner.
Sub-properties:
-
xObject -
yObject
height
Number
localContext
CanvasRenderingContext2D
All layers use a local 2D context canvas for rendering object. It is used as a cache layer, and redrawn only when needed.
Directly set the cache context can be usefull for debug.
Note: this property should be modified only with setAttr.
matrix
Matrix
matrix applied to this object before draw.
parent
Layer
parent containing this object.
spatialContainer
SpatialContainer
Note: this property should be modified only with setAttr.
width
Number
x
Number
position on X axis
y
Number
position on Y axis
zIndex
Number
zIndex, used to determine the drawing order. Hight zIndex are drawn first.