The shape methods

Description

Adds a circle to the target object. The arc of a circle begins at the "3 o'clock" point on the radius and progresses towards the "9 o'clock" point. The starting point and direction of the arc are affected by the user space transform in the same manner as the geometry of the object.

Arguments

radius

The radius of the circle

cx, cy

The center of the circle

Example

Description

Adds an ellipse to the target object. The arc of an ellipse begins at the "3 o'clock" point on the radius and progresses towards the "9 o'clock" point. The starting point and direction of the arc are affected by the user space transform in the same manner as the geometry of the object.

Arguments

rx, ry

The x- and y-radii of the ellipse

cx, cy

The center of the ellipse

Example

Description

Adds a line to the target object. Lines are never filled.

Arguments

x1, y1

The starting point of the line

x2, y2

The ending point of the line

Example

Description

Adds a path to the target object.

Arguments

A path string. The path string has the same syntax as the d= attribute on SVG's path element. See the SVG standard for a complete description of the syntax.

Examples

moveto, lineto, and closepath commands

simple uses of cubic Bézier commands within a path

cubic Bézier commands change their shape according to the position of the control points

simple uses of quadratic Bézier commands within a path

simple uses of arc commands within a path

Elliptical arcs: The following illustrates the four combinations of large-arc-flag and sweep-flag and the four different arcs that will be drawn based on the values of these flags.

Description

Adds a closed shape consisting of a series of connected line segments to the target object.

Arguments

The arguments to polygon and polyline can be

1. At least 4 numbers that describe the [x, y] coordinates of the points of the polygon/polyline.
2. One array containing at least 4 numbers.
3. Two arrays. The first array is a list of x-coordinates. The second array is a list of y-coordinates. Both arrays must have at least one element. If one array is shorter than the other, the shorter array is extended by duplicating its elements as necessary. The combined arrays must describe at least 2 pairs of [x,y] coordinates. For example

       x = [1, 3, 5, 7, 9]
       y = [2,4]
       canvas.polygon(x, y)
       # is equivalent to canvas.polygon(1,2, 3,4, 5,2, 7,4, 9,2)
   

It is an error to specify an odd number of coordinates. Array arguments can be any objects that can be converted to arrays by the Kernel#Array method.

Example

Description

Adds a set of connected lines segments to the target object. Typically a polyline defines an open shape.

Arguments

See polygon

Example

Description

Adds a rectangle to the target object.

Arguments

width, height

The width and height of the rectangle

x, y

The x- and y-axis coordinates of the upper-left corner

Example

Rounded rectangles

You can define a rounded rectangle by chaining the round method to rect:

obj.rect(width, height, x=0, y=0).round(rx[, ry])

The round method accepts two arguments.

rx

The x-axis radius of the ellipse used to round off the corners of the rectangle

ry

The y-axis radius of the ellipse used to round off the corners of the rectangle

If the second argument is omitted it defaults to the value of the first argument.

Example