lib/network/shapes.js
/**
* Canvas shapes used by Network
*/
if (typeof CanvasRenderingContext2D !== 'undefined') {
/**
* Draw a circle shape
*
* @param {number} x
* @param {number} y
* @param {number} r
*/
CanvasRenderingContext2D.prototype.circle = function (x, y, r) {
this.beginPath();
this.arc(x, y, r, 0, 2 * Math.PI, false);
this.closePath();
};
/**
* Draw a square shape
* @param {number} x horizontal center
* @param {number} y vertical center
* @param {number} r size, width and height of the square
*/
CanvasRenderingContext2D.prototype.square = function (x, y, r) {
this.beginPath();
this.rect(x - r, y - r, r * 2, r * 2);
this.closePath();
};
/**
* Draw a triangle shape
* @param {number} x horizontal center
* @param {number} y vertical center
* @param {number} r radius, half the length of the sides of the triangle
*/
CanvasRenderingContext2D.prototype.triangle = function (x, y, r) {
// http://en.wikipedia.org/wiki/Equilateral_triangle
this.beginPath();
// the change in radius and the offset is here to center the shape
r *= 1.15;
y += 0.275 * r;
var s = r * 2;
var s2 = s / 2;
var ir = Math.sqrt(3) / 6 * s; // radius of inner circle
var h = Math.sqrt(s * s - s2 * s2); // height
this.moveTo(x, y - (h - ir));
this.lineTo(x + s2, y + ir);
this.lineTo(x - s2, y + ir);
this.lineTo(x, y - (h - ir));
this.closePath();
};
/**
* Draw a triangle shape in downward orientation
* @param {number} x horizontal center
* @param {number} y vertical center
* @param {number} r radius
*/
CanvasRenderingContext2D.prototype.triangleDown = function (x, y, r) {
// http://en.wikipedia.org/wiki/Equilateral_triangle
this.beginPath();
// the change in radius and the offset is here to center the shape
r *= 1.15;
y -= 0.275 * r;
var s = r * 2;
var s2 = s / 2;
var ir = Math.sqrt(3) / 6 * s; // radius of inner circle
var h = Math.sqrt(s * s - s2 * s2); // height
this.moveTo(x, y + (h - ir));
this.lineTo(x + s2, y - ir);
this.lineTo(x - s2, y - ir);
this.lineTo(x, y + (h - ir));
this.closePath();
};
/**
* Draw a star shape, a star with 5 points
* @param {number} x horizontal center
* @param {number} y vertical center
* @param {number} r radius, half the length of the sides of the triangle
*/
CanvasRenderingContext2D.prototype.star = function (x, y, r) {
// http://www.html5canvastutorials.com/labs/html5-canvas-star-spinner/
this.beginPath();
// the change in radius and the offset is here to center the shape
r *= 0.82;
y += 0.1 * r;
for (var n = 0; n < 10; n++) {
var radius = (n % 2 === 0) ? r * 1.3 : r * 0.5;
this.lineTo(
x + radius * Math.sin(n * 2 * Math.PI / 10),
y - radius * Math.cos(n * 2 * Math.PI / 10)
);
}
this.closePath();
};
/**
* Draw a Diamond shape
* @param {number} x horizontal center
* @param {number} y vertical center
* @param {number} r radius, half the length of the sides of the triangle
*/
CanvasRenderingContext2D.prototype.diamond = function (x, y, r) {
// http://www.html5canvastutorials.com/labs/html5-canvas-star-spinner/
this.beginPath();
this.lineTo(x, y + r);
this.lineTo(x + r, y);
this.lineTo(x, y - r);
this.lineTo(x - r, y);
this.closePath();
};
/**
* http://stackoverflow.com/questions/1255512/how-to-draw-a-rounded-rectangle-on-html-canvas
*
* @param {number} x
* @param {number} y
* @param {number} w
* @param {number} h
* @param {number} r
*/
CanvasRenderingContext2D.prototype.roundRect = function (x, y, w, h, r) {
var r2d = Math.PI / 180;
if (w - ( 2 * r ) < 0) {
r = ( w / 2 );
} //ensure that the radius isn't too large for x
if (h - ( 2 * r ) < 0) {
r = ( h / 2 );
} //ensure that the radius isn't too large for y
this.beginPath();
this.moveTo(x + r, y);
this.lineTo(x + w - r, y);
this.arc(x + w - r, y + r, r, r2d * 270, r2d * 360, false);
this.lineTo(x + w, y + h - r);
this.arc(x + w - r, y + h - r, r, 0, r2d * 90, false);
this.lineTo(x + r, y + h);
this.arc(x + r, y + h - r, r, r2d * 90, r2d * 180, false);
this.lineTo(x, y + r);
this.arc(x + r, y + r, r, r2d * 180, r2d * 270, false);
this.closePath();
};
/**
* http://stackoverflow.com/questions/2172798/how-to-draw-an-oval-in-html5-canvas
*
* Postfix '_vis' added to discern it from standard method ellipse().
*
* @param {number} x
* @param {number} y
* @param {number} w
* @param {number} h
*/
CanvasRenderingContext2D.prototype.ellipse_vis = function (x, y, w, h) {
var kappa = .5522848,
ox = (w / 2) * kappa, // control point offset horizontal
oy = (h / 2) * kappa, // control point offset vertical
xe = x + w, // x-end
ye = y + h, // y-end
xm = x + w / 2, // x-middle
ym = y + h / 2; // y-middle
this.beginPath();
this.moveTo(x, ym);
this.bezierCurveTo(x, ym - oy, xm - ox, y, xm, y);
this.bezierCurveTo(xm + ox, y, xe, ym - oy, xe, ym);
this.bezierCurveTo(xe, ym + oy, xm + ox, ye, xm, ye);
this.bezierCurveTo(xm - ox, ye, x, ym + oy, x, ym);
this.closePath();
};
/**
* http://stackoverflow.com/questions/2172798/how-to-draw-an-oval-in-html5-canvas
*
* @param {number} x
* @param {number} y
* @param {number} w
* @param {number} h
*/
CanvasRenderingContext2D.prototype.database = function (x, y, w, h) {
var f = 1 / 3;
var wEllipse = w;
var hEllipse = h * f;
var kappa = .5522848,
ox = (wEllipse / 2) * kappa, // control point offset horizontal
oy = (hEllipse / 2) * kappa, // control point offset vertical
xe = x + wEllipse, // x-end
ye = y + hEllipse, // y-end
xm = x + wEllipse / 2, // x-middle
ym = y + hEllipse / 2, // y-middle
ymb = y + (h - hEllipse / 2), // y-midlle, bottom ellipse
yeb = y + h; // y-end, bottom ellipse
this.beginPath();
this.moveTo(xe, ym);
this.bezierCurveTo(xe, ym + oy, xm + ox, ye, xm, ye);
this.bezierCurveTo(xm - ox, ye, x, ym + oy, x, ym);
this.bezierCurveTo(x, ym - oy, xm - ox, y, xm, y);
this.bezierCurveTo(xm + ox, y, xe, ym - oy, xe, ym);
this.lineTo(xe, ymb);
this.bezierCurveTo(xe, ymb + oy, xm + ox, yeb, xm, yeb);
this.bezierCurveTo(xm - ox, yeb, x, ymb + oy, x, ymb);
this.lineTo(x, ym);
};
/**
* Sets up the dashedLine functionality for drawing
* Original code came from http://stackoverflow.com/questions/4576724/dotted-stroke-in-canvas
* @author David Jordan
* @date 2012-08-08
*
* @param {number} x
* @param {number} y
* @param {number} x2
* @param {number} y2
* @param {string} pattern
*/
CanvasRenderingContext2D.prototype.dashedLine = function (x, y, x2, y2, pattern) {
this.beginPath();
this.moveTo(x, y);
var patternLength = pattern.length;
var dx = (x2 - x);
var dy = (y2 - y);
var slope = dy / dx;
var distRemaining = Math.sqrt(dx * dx + dy * dy);
var patternIndex = 0;
var draw = true;
var xStep = 0;
var dashLength = pattern[0];
while (distRemaining >= 0.1) {
dashLength = pattern[patternIndex++ % patternLength];
if (dashLength > distRemaining) {
dashLength = distRemaining;
}
xStep = Math.sqrt(dashLength * dashLength / (1 + slope * slope));
xStep = dx < 0 ? -xStep : xStep;
x += xStep;
y += slope * xStep;
if (draw === true) {this.lineTo(x,y);}
else {this.moveTo(x,y);}
distRemaining -= dashLength;
draw = !draw;
}
};
/**
* Draw a Hexagon shape with 6 sides
* @param {Number} x horizontal center
* @param {Number} y vertical center
* @param {Number} r radius
*/
CanvasRenderingContext2D.prototype.hexagon = function (x, y, r) {
this.beginPath();
var sides = 6;
var a = (Math.PI*2)/sides;
this.moveTo(x+r,y);
for (var i = 1; i < sides; i++) {
this.lineTo(x+r*Math.cos(a*i),y+r*Math.sin(a*i));
}
this.closePath();
};
}