HTML 5 Canvas Reference Manual

HTML 5 Canvas Reference Manual

• HTML Video/Audio
• HTML Document Type

Describe

HTML5 <canvas> tags are used to draw images (through scripting, usually JavaScript).

However, the,<canvas> element itself does not have the ability to draw (it is just a container for graphics)-You must use a script to accomplish the actual drawing task.

The GetContext () method returns an object that provides methods and properties for drawing on the canvas.

This manual provides complete getcontext ("2d") object properties and methods that you can use to draw text, lines, rectangles, circles, and so on on the canvas.

Browser support

Internet Explorer 9, Firefox, Opera, Chrome, and Safari support <canvas> and its properties and methods.

Note: Internet Explorer 8 and earlier versions do not support the <canvas> element.

colors, styles, and shadows

Properties	Description
FillStyle	Sets or returns the color, gradient, or pattern used to fill the drawing
Strokestyle	Sets or returns the color, gradient, or pattern used for a stroke
Shadowcolor	Sets or returns the color used for shadows
Shadowblur	Sets or returns the level of blur used for shadows
Shadowoffsetx	Sets or returns the horizontal distance of the shadow distance shape
Shadowoffsety	Sets or returns the vertical distance of the shadow distance shape

Method	Description
Createlineargradient ()	Create a linear gradient (used on canvas content)
Createpattern ()	Repeats the specified element in the specified direction
Createradialgradient ()	Create Radial/annular gradients (used on canvas content)
Addcolorstop ()	Specify the color and stop position in the gradient object

Line Style

Properties	Description
LineCap	Sets or returns the end endpoint style for a line
LineJoin	Sets or returns the type of corner created when two lines intersect
LineWidth	Sets or returns the current line width
Miterlimit	Sets or returns the maximum miter length

Rectangular

Method	Description
Rect ()	Create a rectangle
FillRect ()	Draw a "filled" rectangle
Strokerect ()	Draw Rectangle (No fill)
Clearrect ()	Clears the specified pixel within the given rectangle

Path

Method	Description
Fill ()	Fills the current drawing (path)
Stroke ()	Draw a defined path
Beginpath ()	Start a path, or reset the current path
MoveTo ()	Move a path to a specified point in the canvas without creating a line
Closepath ()	Creates a path from the current point back to the starting point
LineTo ()	Add a new point, and then create a line from that point to the last specified point in the canvas
Clip ()	Cut an area of any shape and size from the original canvas
Quadraticcurveto ()	Create a Bezier curve of two times
Beziercurveto ()	Creating three-cubic Bezier curves
Arc ()	Create Arcs/curves (for creating circular or partial circles)
ArcTo ()	Create an arc/curve between two tangents
Ispointinpath ()	Returns true if the specified point is in the current path, otherwise false

Transformation

Method	Description
Scale ()	Scale the current drawing to a larger or smaller
Rotate ()	Rotate the current drawing
Translate ()	Remap (0,0) locations on the canvas
Transform ()	Replace the current transformation matrix of the drawing
SetTransform ()	Resets the current transformation to the unit matrix. Then run transform ()

Text

Properties	Description
Font	Sets or returns the current font property of the text content
TextAlign	Sets or returns the current alignment of text content
Textbaseline	Sets or returns the current text baseline to use when drawing text

Method	Description
Filltext ()	Draw "filled" text on canvas
Stroketext ()	Draw text on the canvas (no fill)
Measuretext ()	Returns the object that contains the specified text width

Image rendering

Method	Description
DrawImage ()	Draw an image, canvas, or video to the canvas

Pixel operation

Properties	Description
Width	Returns the width of the ImageData object
Height	Returns the height of the ImageData object
Data	Returns an object that contains the image data for the specified ImageData object

Method	Description
Createimagedata ()	To create a new, blank ImageData object
Getimagedata ()	Returns a ImageData object that copies pixel data for a specified rectangle on the canvas
Putimagedata ()	Put the image data (from the specified ImageData object) back onto the canvas

Synthesis

Properties	Description
Globalalpha	Sets or returns the current alpha or transparent value of a drawing
Globalcompositeoperation	Sets or returns how the new image is drawn to an existing image

Other

Method	Description
Save ()	Save the state of the current environment
Restore ()	Returns the previously saved path state and properties
CreateEvent ()
GetContext ()
Todataurl ()

HTML 5 Canvas Reference Manual