qtip2/src/position/polys.js

Introducing... qTip2. The second generation of the advanced qTip plugin for the ever popular jQuery framework.

PLUGINS.polys = {
	// POLY area coordinate calculator
	//	Special thanks to Ed Cradock for helping out with this.
	//	Uses a binary search algorithm to find suitable coordinates.
	polygon: function(baseCoords, corner) {
		var result = {
			width: 0, height: 0,
			position: {
				top: 1e10, right: 0,
				bottom: 0, left: 1e10
			},
			adjustable: FALSE
		},
		i = 0, next,
		coords = [],
		compareX = 1, compareY = 1,
		realX = 0, realY = 0,
		newWidth, newHeight;

		// First pass, sanitize coords and determine outer edges
		i = baseCoords.length; 
		while(i--) {
			next = [ parseInt(baseCoords[--i], 10), parseInt(baseCoords[i+1], 10) ];

			if(next[0] > result.position.right){ result.position.right = next[0]; }
			if(next[0] < result.position.left){ result.position.left = next[0]; }
			if(next[1] > result.position.bottom){ result.position.bottom = next[1]; }
			if(next[1] < result.position.top){ result.position.top = next[1]; }

			coords.push(next);
		}

		// Calculate height and width from outer edges
		newWidth = result.width = Math.abs(result.position.right - result.position.left);
		newHeight = result.height = Math.abs(result.position.bottom - result.position.top);

		// If it's the center corner...
		if(corner.abbrev() === 'c') {
			result.position = {
				left: result.position.left + result.width / 2,
				top: result.position.top + result.height / 2
			};
		}
		else {
			// Second pass, use a binary search algorithm to locate most suitable coordinate
			while(newWidth > 0 && newHeight > 0 && compareX > 0 && compareY > 0)
			{
				newWidth = Math.floor(newWidth / 2);
				newHeight = Math.floor(newHeight / 2);

				if(corner.x === LEFT){ compareX = newWidth; }
				else if(corner.x === RIGHT){ compareX = result.width - newWidth; }
				else{ compareX += Math.floor(newWidth / 2); }

				if(corner.y === TOP){ compareY = newHeight; }
				else if(corner.y === BOTTOM){ compareY = result.height - newHeight; }
				else{ compareY += Math.floor(newHeight / 2); }

				i = coords.length;
				while(i--)
				{
					if(coords.length < 2){ break; }

					realX = coords[i][0] - result.position.left;
					realY = coords[i][1] - result.position.top;

					if(
						corner.x === LEFT && realX >= compareX ||
						corner.x === RIGHT && realX <= compareX ||
						corner.x === CENTER && (realX < compareX || realX > result.width - compareX) ||
						corner.y === TOP && realY >= compareY ||
						corner.y === BOTTOM && realY <= compareY ||
						corner.y === CENTER && (realY < compareY || realY > result.height - compareY)) {
						coords.splice(i, 1);
					}
				}
			}
			result.position = { left: coords[0][0], top: coords[0][1] };
		}

		return result;
	},

	rect: function(ax, ay, bx, by) {
		return {
			width: Math.abs(bx - ax),
			height: Math.abs(by - ay),
			position: {
				left: Math.min(ax, bx),
				top: Math.min(ay, by)
			}
		};
	},

	_angles: {
		tc: 3 / 2, tr: 7 / 4, tl: 5 / 4,
		bc: 1 / 2, br: 1 / 4, bl: 3 / 4,
		rc: 2, lc: 1, c: 0
	},
	ellipse: function(cx, cy, rx, ry, corner) {
		var c = PLUGINS.polys._angles[ corner.abbrev() ],
			rxc = c === 0 ? 0 : rx * Math.cos( c * Math.PI ),
			rys = ry * Math.sin( c * Math.PI );

		return {
			width: rx * 2 - Math.abs(rxc),
			height: ry * 2 - Math.abs(rys),
			position: {
				left: cx + rxc,
				top: cy + rys
			},
			adjustable: FALSE
		};
	},
	circle: function(cx, cy, r, corner) {
		return PLUGINS.polys.ellipse(cx, cy, r, r, corner);
	}
};