Documentation

Learn all about jCanvas

Vectors

Besides using the drawLine() method for drawing line segments on the canvas, you can also use the drawVector() method, which works differently, but produces the same result (contiguous lines).

Using the drawVector() method, each line segment is created from an angle and a length. These segments are defined using a1, l1, a2, l2, and so on.

// Draw a line that is 100px long at 45deg from the north
$('canvas').drawVector({
  strokeStyle: '#000',
  strokeWidth: 4,
  a1: 135, l1: 100
});

Defining a starting point

Additionally, you can specify a starting point for your vector using the x and y properties.

$('canvas').drawVector({
  strokeStyle: '#000',
  strokeWidth: 4,
  x: 50, y: 50,
  a1: 120, l1: 100
});

Combining vectors

Of course, you can create multiple vectors. Keep in mind that no matter where any vector is positioned, its angle is always relative to the north (or 12:00 according to any analog clock).

// Draw a bent path
$('canvas').drawVector({
  strokeStyle: '#000',
  strokeWidth: 4,
  x: 50, y: 150,
  a1: 45, l1: 100,
  a2: 135, l2: 220
});

Using line properties

Because the drawVector() method creates line segments just like the drawLine() method, the drawVector() method accepts many of the same properties as drawLine(). These properties include (but are not limited to) closed and rounded.

// Draw a closed path (making a triangle)
$('canvas').drawVector({
  strokeStyle: '#000',
  strokeWidth: 4,
  rounded: true,
  closed: true,
  x: 50, y: 150,
  a1: 45, l1: 100,
  a2: 135, l2: 220
});

Details on the usage of these properties can be found in the Lines section.

Notes

Angles are specified in degrees by default. However, if you wish you specify your angles in radians, set the inDegrees property to false.

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