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Namespace
The namespace is really just an object where further objects and their methods and properties are attached bundling up all the functionality using a unique name.
Interface
The Interface is a contract by which the implementing class adheres. It describes a desired behavior and enforces adherence for any class that implements the interface.
Class
Classes define types of objects that will be used by the application.
Method
A function associated with a class or object.
Field
A variable associated with a class or object.
Inherited Method
A function inherited from the parent class. The present documentation scheme differentiates between a direct or indirect inheritance relationship.
Inherited Field
A variable inherited from the parent class. The present documentation scheme differentiates between a direct or indirect inheritance relationship.
Event
Events are actions that occur because of user interaction. They are normally used in combination with functions, and the function will not be executed before the event occurs.
Class nokia.maps.gfx.GraphicsImage
Class Summary
The class GraphicsImage is designed to render images within
the client application at run time. The graphics image is not rendered at
construction time for the same reason that a bitmap image is not loaded
at construction time: rendering occurs when it is really necessary.
Imagine there are 1000 map objects and the image for each object must be
rendered depending on the properties of the object, for example, because
the object contains traffic information. It would cost large amounts of
CPU time to render all the images and consume a lot of memory to keep
the image data in memory while perhaps only a few of the objects may be
visible in the current view.
The rendering of a graphics image is done by a function that is not called as soon as the image is needed. The same function can be used for multiple graphics images, therefore it is possible to implement a multi-painter, so a function that renders all markers and uses the marker properties as a source of information about how to render the markers.
It is also possible to create an instance of GraphicsImage
without a rendering function, but using a pre-created
nokia.maps.gfx.IDL or nokia.maps.gfx.Graphics context.
Examples:
// Create a few shortcuts.
var GraphicsImage = nokia.maps.gfx.GraphicsImage,
Color = nokia.maps.gfx.Color,
parseCss = Color.parseCss;
// Create a reference to the document body.
var body = document.body || document.documentElement;
// Create a new graphics image.
var image = new GraphicsImage( function( graphics, graphicsImage ) {
// This will clear the canvas and set it's size to 64 x 64 pixel
graphics.beginImage(64, 64, "MyImage");
// Let's draw a circle with a 2 pixel black border and fill it with semi
// transparent red color
graphics.set("lineWidth", 2 );
graphics.set("strokeColor", parseCss("black"));
graphics.set("fillColor", parseCss("red", 0.5));
// Create the path using a helper function.
graphics.drawEllipse(16,16, 32,32);
// Stroke and fill the path.
graphics.stroke();
graphics.fill();
});
// Add the graphics image to the body.
body.appendChild( image.createElement() );
Extends
nokia.maps.gfx.Image.
new nokia.maps.gfx.GraphicsImage
(render_fn, [context, [doc, [painter]]])
Method Summary
abstract
clone
([doc])
: nokia.maps.gfx.Image
This method clones the given image and optionally binds it to a different document.
abstract
createElement
([opacity])
: Node
This method creates a DOM node containing the given image.
abstract
getDocument
()
: Document
This method retrieves the document to which the given image is bound.
getIDL
()
: nokia.maps.gfx.IDL
This method retrieves the IDL object created by the given instance of graphics context.
abstract
prepare
(callback, [context])
: nokia.maps.gfx.Image
This method prepares the given image and calls a callback on completion or failure.
abstract
setOpacity
(element, opacity)
: nokia.maps.gfx.Image
This method changes the global opacity of an element returned by the
createElement().
Field Summary
abstract
Number
height
This property holds the height of the image in pixels.
Boolean
isGraphics
This property indicates if an image is an instace of
GraphicsImage (true) or not (false).
abstract
Number
opacity
This property holds the default opacity for the image.
abstract
Number
state
This property holds the state of the image.
abstract
Number
width
This property holds the width of the image in pixels.
Direct Inheritance
Inherited from nokia.maps.gfx.Image:
clone
createElement
getDocument
prepare
setOpacity
height
opacity
state
width
Constructor Detail
This method creates a new graphics image instance.
new nokia.maps.gfx.GraphicsImage(render_fn, [context, [doc, [painter]]])
Examples:
// Create a few shortcuts.
var GraphicsImage = nokia.maps.gfx.GraphicsImage,
Color = nokia.maps.gfx.Color,
parseCss = Color.parseCss;
// Create a reference to the document body.
var body = document.body || document.documentElement;
// Create a new graphics image.
var image = new GraphicsImage( function( graphics, graphicsImage ) {
// This will clear the canvas and set it's size to 64 x 64 pixel
graphics.beginImage(64, 64, "MyImage");
// Let's draw a circle with a 2 pixel black border and fill it with semi
// transparent red color
graphics.set("lineWidth", 2 );
graphics.set("strokeColor", parseCss("black"));
graphics.set("fillColor", parseCss("red", 0.5));
// Create the path using a helper function.
graphics.drawEllipse(16,16, 32,32);
// Stroke and fill the path.
graphics.stroke();
graphics.fill();
});
// Add the graphics image to the body.
body.appendChild( image.createElement() );
Parameters:
| {Function | nokia.maps.gfx.IDL | nokia.maps.gfx.Graphics} | render_fn |
A function to be called as soon as the image is required; the function
gets as its first argument the graphics context (an instance of
nokia.maps.gfx.Graphics) that it uses to render
the image, and as a second parameter an instance of
nokia.maps.gfx.GraphicsImage, which represents the
image to render; if the constructor is called with additional arguments,
these are forwarded as additional arguments to the rendering function;
optionally, an instance of nokia.maps.gfx.IDL or
nokia.maps.gfx.Graphics context can be supplied to
create a new graphics image instantly
|
| {Object} | [context]: |
The context in which the rendering function is to be executed; if not
specified the context (this) is bound to the given instance
of nokia.maps.gfx.GraphicsImage
|
| {Document} | [doc]: | The document to which the given graphics image is bound; if omitted, the image is bound to the current document |
| {nokia.maps.gfx.Painter} | [painter]: |
The painter to be used to paint; if not supplied, the painter currently
assigned to the static property defaultPainter of the class
nokia.maps.gfx.Painter is used; if this argument has an invalid
value, it is ignored and the defaultPainter is used
|
| {Object} | [args...]: | An arbitrary number of additional arguments to be forwarded to the rendering function |
Method Detail
getIDL
()
: nokia.maps.gfx.IDL
This method retrieves the IDL object created by the given instance of graphics context.
Returns:
| {nokia.maps.gfx.IDL} | The IDL generated by the given instance of graphics context |