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constructions.js
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/* TODO(csilvers): fix these lint errors (http://eslint.org/docs/rules): */
/* eslint-disable brace-style, comma-dangle, indent, max-len, no-redeclare, no-undef, no-var, space-before-function-paren */
/* To fix, remove an entry above, run ka-lint, and fix errors. */
define(function(require) {
var kmatrix = require("./kmatrix.js");
$.extend(KhanUtil, {
drawHintLine: function(pt1, pt2, ticks) {
var graphie = KhanUtil.currentGraph;
var length = KhanUtil.eDist(pt1, pt2);
var midpoint = [(pt1[0] + pt2[0]) / 2, (pt1[1] + pt2[1]) / 2];
var angle = Math.atan2(pt2[1] - pt1[1], pt2[0] - pt1[0]);
var transform = function(point) {
var matrix = kmatrix.makeMatrix([
[Math.cos(angle), -Math.sin(angle), midpoint[0]],
[Math.sin(angle), Math.cos(angle), midpoint[1]],
[0, 0, 1]
]);
var vector = kmatrix.makeMatrix([[point[0]], [point[1]], [1]]);
var prod = kmatrix.matrixMult(matrix, vector);
return [prod[0], prod[1]];
};
var hintLine = graphie.raphael.set();
hintLine.push(graphie.line(transform([-length / 2, 0]),
transform([length / 2, 0]), {
stroke: KhanUtil.BLUE,
strokeWidth: 1,
strokeDasharray: "- "
}));
graphie.style({
stroke: KhanUtil.BLUE,
strokeWidth: 1
}, function() {
if (ticks === 1) {
hintLine.push(graphie.line(
transform(graphie.unscaleVector([0, 6])),
transform(graphie.unscaleVector([0, -6]))));
} else if (ticks === 2) {
hintLine.push(graphie.line(
transform(graphie.unscaleVector([-3, 6])),
transform(graphie.unscaleVector([-3, -6]))));
hintLine.push(graphie.line(
transform(graphie.unscaleVector([3, 6])),
transform(graphie.unscaleVector([3, -6]))));
} else if (ticks === 3) {
hintLine.push(graphie.line(
transform(graphie.unscaleVector([-6, 6])),
transform(graphie.unscaleVector([-6, -6]))));
hintLine.push(graphie.line(
transform(graphie.unscaleVector([0, 6])),
transform(graphie.unscaleVector([0, -6]))));
hintLine.push(graphie.line(
transform(graphie.unscaleVector([6, 6])),
transform(graphie.unscaleVector([6, -6]))));
}
});
return hintLine;
},
construction: {},
// Useful for diagnostics: type "KhanUtil.showSnapPts()" in the console
showSnapPts: function() {
var graphie = KhanUtil.currentGraph;
var set = graphie.raphael.set();
_.each(KhanUtil.construction.interPoints, function(pt) {
set.push(graphie.circle(pt, 0.1, {
stroke: KhanUtil.PINK,
fill: KhanUtil.PINK
}));
});
_.each(KhanUtil.construction.snapPoints, function(pt) {
set.push(graphie.circle(pt.coord, 0.1, {
stroke: KhanUtil.RED,
fill: KhanUtil.RED
}));
});
_.delay(function() { set.remove(); }, 500);
},
// initialize the construction object, giving it a reference to the
// graphie it should refer to (so that the KhanUtil.currentGraph
// pointer can change without screwing everything up)
addConstruction: function(graphieId) {
var graphie = $("#" + graphieId).data("graphie");
var construction = KhanUtil.construction = {
tools: [], // a list of all compasses/straightedges on the graph
tool: {}, // the latest tool added
snapPoints: [], // "special" points all other points should snap to
interPoints: [], // "special" points all other points should snap to
snapLines: [] // points should also snap to lines
};
// add a compass tool to the graph
// the compass has the following fields:
// center: movable point
// radius: int
// circ: graphie circle
// perim: invisible mouse target for dragging/changing radius
construction.addCompass = function() {
var start = [Math.random() * 4 - 2, Math.random() * 4 - 2];
var startRadius = Math.random() + 1.5;
construction.tool = {
interType: "circle",
center: graphie.addMovablePoint({
graph: graphie,
coord: start,
normalStyle: {
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}
}),
radius: startRadius,
circ: graphie.circle(start, startRadius, {
stroke: KhanUtil.BLUE,
strokeDasharray: "- ",
fill: KhanUtil.ORANGE,
fillOpacity: 0
}),
perim: graphie.mouselayer.circle(
graphie.scalePoint(start)[0],
graphie.scalePoint(start)[1],
graphie.scaleVector(startRadius)[0]).attr({
"stroke-width": 20,
"opacity": 0.0
})
};
var t = construction.tool;
$(t.center.mouseTarget.getMouseTarget()).bind(
"vmouseover vmouseout", function(event) {
if (t.center.highlight) {
t.circ.animate({
stroke: KhanUtil.ORANGE,
"fill-opacity": 0.05
}, 50);
} else {
t.circ.animate({
stroke: KhanUtil.BLUE,
"fill-opacity": 0
}, 50);
}
});
// add this tool to the graph's set
construction.tools.push(t);
// add new points that all other points should snap to
construction.snapPoints.push(t.center);
t.center.onMove = function(x, y) {
t.circ.toFront();
t.perim.toFront();
t.center.visibleShape.toFront();
t.center.mouseTarget.toFront();
t.circ.attr({
cx: graphie.scalePoint(x)[0],
cy: graphie.scalePoint(y)[1]
});
t.perim.attr({
cx: graphie.scalePoint(x)[0],
cy: graphie.scalePoint(y)[1]
});
};
t.center.onMoveEnd = function(x, y) {
_.each(construction.snapLines, function(line) {
var distIntersect = KhanUtil.lDist(t.center.coord, line);
if (distIntersect[0] < 0.25) {
t.center.onMove(distIntersect[1][0],
distIntersect[1][1]);
t.center.setCoord(distIntersect[1]);
}
});
// keep track of all the possible snap points,
// and snap to the closest one
var myPossibleSnaps = [];
_.each(construction.snapPoints, function(point) {
if (KhanUtil.eDist(t.center.coord, point.coord) < 0.25 &&
t.center.coord !== point.coord) {
myPossibleSnaps.push(point.coord);
}
});
// before checking to see if we've moved onto an
// intersection of lines/circles, update these
// intersections
construction.updateIntersections();
_.each(construction.interPoints, function(point) {
if (KhanUtil.eDist(t.center.coord, point) < 0.3 &&
t.center.coord !== point) {
myPossibleSnaps.push(point);
}
});
// Now, snap to closest possible snap Point
var mySnapPoint = [];
var mySnapDist = null;
_.each(myPossibleSnaps, function(sCoord) {
if (mySnapDist == null ||
KhanUtil.eDist(sCoord, t.center.coord) <
mySnapDist) {
mySnapPoint = sCoord;
mySnapDist = KhanUtil.eDist(sCoord, t.center.coord);
}
});
if (mySnapPoint.length > 0) {
t.center.onMove(mySnapPoint[0], mySnapPoint[1]);
t.center.setCoord(mySnapPoint);
}
};
// XXX(joel/emily)
// t.center.mouseTarget.dblclick(function() {
// construction.removeTool(t, true);
// });
$(t.perim[0]).css("cursor", "move");
$(t.perim[0]).bind(
"vmouseover vmouseout vmousedown", function(event) {
if (event.type === "vmouseover") {
t.highlight = true;
if (!KhanUtil.dragging) {
t.circ.animate({
stroke: KhanUtil.ORANGE,
"fill-opacity": 0.05
}, 50);
t.center.visibleShape.animate({
stroke: KhanUtil.ORANGE,
fill: KhanUtil.ORANGE
}, 50);
}
} else if (event.type === "vmouseout") {
t.highlight = false;
if (!t.dragging) {
t.circ.animate({
stroke: KhanUtil.BLUE,
"fill-opacity": 0
}, 50);
t.center.visibleShape.animate({
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}, 50);
}
} else if (event.type === "vmousedown" &&
(event.which === 1 || event.which === 0)) {
event.preventDefault();
var data = t;
data.circ.toFront();
data.perim.toFront();
data.center.visibleShape.toFront();
data.center.mouseTarget.toFront();
$(document).bind("vmousemove vmouseup", function(event) {
event.preventDefault();
data.dragging = true;
KhanUtil.dragging = true;
if (event.type === "vmousemove") {
var mouseX = event.pageX -
$(graphie.raphael.canvas.parentNode).offset().left;
var mouseY = event.pageY -
$(graphie.raphael.canvas.parentNode).offset().top;
data.radius = KhanUtil.eDist(data.center.coord,
graphie.unscalePoint([mouseX, mouseY]));
data.perim.attr({
r: graphie.scaleVector(data.radius)[0]
});
data.circ.attr({
rx: graphie.scaleVector(data.radius)[0],
ry: graphie.scaleVector(data.radius)[1]
});
} else if (event.type === "vmouseup") {
$(document).unbind("vmousemove vmouseup");
data.dragging = false;
KhanUtil.dragging = false;
construction.updateIntersections();
}
});
}
});
construction.updateIntersections();
};
construction.mark = function() {
var x = -1;
var y = Math.random() * 2;
construction.tool = {
interType: "line",
center: graphie.addMovablePoint({
graph: graphie,
coordX: x,
coordY: y,
normalStyle: {
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}
})
};
// this is a bit confusing: "graph: graphie" refers
// to the movableLineSegment's graph field, whereas
// "construction.tool.etc" refers to the KhanUtil.construction
// object being built in this util
construction.tool.line1 = graphie.addMovableLineSegment({
graph: graphie,
pointA: [x + 0.2, y + 0.2],
pointZ: [x - 0.2, y - 0.2],
normalStyle: {
stroke: KhanUtil.BLUE,
"stroke-width": 2
},
highlightStyle: {
stroke: KhanUtil.ORANGE,
"stroke-width": 3
},
movePointsWithLine: true
});
construction.tool.line2 = graphie.addMovableLineSegment({
graph: graphie,
pointA: [x + 0.2, y - 0.2],
pointZ: [x - 0.2, y + 0.2],
normalStyle: {
stroke: KhanUtil.BLUE,
"stroke-width": 2
},
highlightStyle: {
stroke: KhanUtil.ORANGE,
"stroke-width": 3
},
movePointsWithLine: true
});
$(construction.tool.center.mouseTarget.getMouseTarget()).bind(
"vmouseover vmouseout", construction.tool, function(event) {
if (event.data.center.highlight) {
event.data.line1.visibleLine.animate({
stroke: KhanUtil.ORANGE
}, 50);
event.data.line2.visibleLine.animate({
stroke: KhanUtil.ORANGE
}, 50);
} else {
event.data.line1.visibleLine.animate({
stroke: KhanUtil.BLUE
}, 50);
event.data.line2.visibleShape.animate({
stroke: KhanUtil.BLUE
}, 50);
}
});
// add new tool object to graph's collection
construction.tools.push(construction.tool);
// keep track of all the points/lines that points should snap to
construction.snapPoints.push(construction.tool.center);
var t = construction.tool;
t.center.onMoveEnd = function(dX, dY) {
t.line1.visibleLine.toFront();
t.line1.mouseTarget.toFront();
t.line2.visibleLine.toFront();
t.line2.mouseTarget.toFront();
t.center.visibleShape.toFront();
t.center.mouseTarget.toFront();
//t.first.onMoveEnd(t.first.coord[0], t.first.coord[1]);
//t.second.onMoveEnd(t.second.coord[0], t.second.coord[1]);
};
$(t.center.mouseTarget.getMouseTarget()).bind("dblclick", function() {
construction.removeTool(t, true);
});
construction.updateIntersections();
};
// add a straightedge object
// the straightedge object has the following fields
// first, second: movable endpoints
// edge: movable line segment
// extend determines whether the line extends off
// screen (default) or is a line segment
// if fixed is true then the line cannot be dragged
// by selecting the line (as opposed to the end points)
construction.addStraightedge = function(extend, fixed) {
extend = extend == null ? true : extend;
fixed = fixed == null ? false : fixed;
construction.tool = {
interType: "line",
first: graphie.addMovablePoint({
graph: graphie,
coordX: -1, coordY: Math.random() * 2,
normalStyle: {
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}
}),
second: graphie.addMovablePoint({
graph: graphie,
coordX: 1, coordY: Math.random() * 2,
normalStyle: {
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}
})
};
// this is a bit confusing: "graph: graphie" refers
// to the movableLineSegment's graph field, whereas
// "construction.tool.etc" refers to the KhanUtil.construction
// object being built in this util
construction.tool.edge = graphie.addMovableLineSegment({
graph: graphie,
pointA: construction.tool.first,
pointZ: construction.tool.second,
normalStyle: {
stroke: KhanUtil.BLUE,
"stroke-width": 2
},
highlightStyle: {
stroke: KhanUtil.ORANGE,
"stroke-width": 3
},
extendLine: extend,
constraints: {
fixed: fixed
},
movePointsWithLine: true
});
$(construction.tool.first.mouseTarget.getMouseTarget()).bind(
"vmouseover vmouseout", construction.tool, function(event) {
if (event.data.first.highlight) {
event.data.edge.visibleLine.animate({
stroke: KhanUtil.ORANGE
}, 50);
event.data.second.visibleShape.animate({
stroke: KhanUtil.ORANGE,
fill: KhanUtil.ORANGE
}, 50);
} else {
event.data.edge.visibleLine.animate({
stroke: KhanUtil.BLUE
}, 50);
event.data.second.visibleShape.animate({
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}, 50);
}
});
$(construction.tool.second.mouseTarget.getMouseTarget()).bind(
"vmouseover vmouseout", construction.tool, function(event) {
if (event.data.second.highlight) {
event.data.edge.visibleLine.animate({
stroke: KhanUtil.ORANGE
}, 50);
event.data.first.visibleShape.animate({
stroke: KhanUtil.ORANGE,
fill: KhanUtil.ORANGE
}, 50);
} else {
event.data.edge.visibleLine.animate({
stroke: KhanUtil.BLUE
}, 50);
event.data.first.visibleShape.animate({
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}, 50);
}
});
$(construction.tool.edge.mouseTarget.getMouseTarget()).bind(
"vmouseover vmouseout", construction.tool, function(event) {
if (event.data.edge.highlight) {
event.data.first.visibleShape.animate({
stroke: KhanUtil.ORANGE,
fill: KhanUtil.ORANGE
}, 50);
event.data.second.visibleShape.animate({
stroke: KhanUtil.ORANGE,
fill: KhanUtil.ORANGE
}, 50);
} else {
event.data.first.visibleShape.animate({
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}, 50);
event.data.second.visibleShape.animate({
stroke: KhanUtil.BLUE,
fill: KhanUtil.BLUE
}, 50);
}
});
// add new tool object to graph's collection
construction.tools.push(construction.tool);
// keep track of all the points/lines that points
// should snap to
construction.snapPoints.push(construction.tool.first);
construction.snapPoints.push(construction.tool.second);
construction.snapLines.push(construction.tool.edge);
var t = construction.tool;
//t.edge.toBack();
t.edge.onMoveEnd = function(dX, dY) {
t.edge.visibleLine.toFront();
t.edge.mouseTarget.toFront();
t.first.visibleShape.toFront();
t.first.mouseTarget.toFront();
t.second.visibleShape.toFront();
t.second.mouseTarget.toFront();
t.first.onMoveEnd(t.first.coord[0], t.first.coord[1]);
t.second.onMoveEnd(t.second.coord[0], t.second.coord[1]);
};
var endpointMoveEnd = function(x, y, end) {
_.each(construction.snapLines, function(line) {
var distIntersect = KhanUtil.lDist(end.coord, line);
if (distIntersect[0] < 0.25) {
end.setCoord(distIntersect[1]);
end.updateLineEnds();
}
});
// keep track of all the possible snap points,
// and snap to the closest one
var myPossibleSnaps = [];
_.each(construction.snapPoints, function(point) {
if (KhanUtil.eDist(end.coord, point.coord) < 0.25 &&
end.coord !== point.coord) {
myPossibleSnaps.push(point.coord);
}
});
// before checking to see if we've moved onto an
// intersection of lines/circles, update these
// intersections
construction.updateIntersections();
_.each(construction.interPoints, function(point) {
if (KhanUtil.eDist(end.coord, point) < 0.3 &&
end.coord !== point) {
myPossibleSnaps.push(point);
}
});
// Now, snap to closest possible snap Point
var mySnapPoint = [];
var mySnapDist = null;
_.each(myPossibleSnaps, function(sCoord) {
if (mySnapDist == null ||
KhanUtil.eDist(sCoord, end.coord) < mySnapDist) {
mySnapPoint = sCoord;
mySnapDist = KhanUtil.eDist(sCoord, end.coord);
}
});
if (mySnapPoint.length > 0) {
end.setCoord(mySnapPoint);
end.updateLineEnds();
}
t.edge.visibleLine.toFront();
t.edge.mouseTarget.toFront();
t.first.visibleShape.toFront();
t.first.mouseTarget.toFront();
t.second.visibleShape.toFront();
t.second.mouseTarget.toFront();
};
t.first.onMoveEnd = function(x, y) {
endpointMoveEnd(x, y, t.first);
};
t.second.onMoveEnd = function(x, y) {
endpointMoveEnd(x, y, t.second);
};
$(t.first.mouseTarget.getMouseTarget()).bind("dblclick", function() {
construction.removeTool(t, true);
});
$(t.second.mouseTarget.getMouseTarget()).bind("dblclick", function() {
construction.removeTool(t, true);
});
$(t.edge.mouseTarget.getMouseTarget()).bind("dblclick", function() {
construction.removeTool(t, true);
});
construction.updateIntersections();
};
construction.removeTool = function(tool, updateTools) {
_.each(_.keys(tool), function(key) {
if (key === "center" || key === "perimeter" ||
key === "first" || key === "second") {
tool[key].visibleShape.remove();
tool[key].visible = false;
$(tool[key].mouseTarget.getMouseTarget()).remove();
} else if (key === "circ") {
tool[key].remove();
} else if (key === "edge") {
tool[key].remove();
}
});
if (updateTools) {
construction.tools.splice(_.indexOf(construction.tools, tool), 1);
}
};
// remove ALL the tools
construction.removeAllTools = function() {
var staticTools = [];
_.each(construction.tools, function(tool) {
if (tool.dummy) {
staticTools.push(tool);
} else {
construction.removeTool(tool, false);
}
});
construction.tools = staticTools;
construction.snapPoints =
construction.snapPoints.filter(function(point) {
return point.dummy;
});
construction.interPoints = [];
construction.snapLines =
construction.snapLines.filter(function(line) {
return line.dummy;
});
};
// detect intersections between existing circles,
// lines, so that new points can snap to these intersections
construction.updateIntersections = function() {
construction.interPoints = [];
_.each(construction.tools, function(tool1) {
_.each(construction.tools, function(tool2) {
if (tool1 !== tool2) {
// two lines
if (tool1.interType === "line" &&
tool2.interType === "line") {
construction.interPoints.push(
findIntersection([tool1.first.coord,
tool1.second.coord],
[tool2.first.coord, tool2.second.coord])
.slice(0, 2));
}
// a line and a circle
else if (tool1.interType === "line" &&
tool2.interType === "circle") {
var m = (tool1.second.coord[1] -
tool1.first.coord[1]) /
(tool1.second.coord[0] -
tool1.first.coord[0]);
var yint = tool1.first.coord[1] -
m * tool1.first.coord[0];
// solve for x-values of intersections
// (x - cX)^2 + (y - cY)^2 = radius
var cX = tool2.center.coord[0];
var cY = tool2.center.coord[1];
var rad = tool2.radius;
// baby why you gotta play me like that
var a = 1 + Math.pow(m, 2);
var b = (-2 * cX + 2 * m * yint - 2 * cY * m);
var c = (Math.pow(yint, 2) - 2 * yint * cY +
Math.pow(cY, 2) + Math.pow(cX, 2) -
Math.pow(rad, 2));
var x1 = (-b + Math.sqrt(Math.pow(b, 2) -
4 * a * c)) / (2 * a);
var x2 = (-b - Math.sqrt(Math.pow(b, 2) -
4 * a * c)) / (2 * a);
if (!isNaN(x1)) {
var y1 = m * x1 + yint;
construction.interPoints.push([x1, y1]);
}
if (!isNaN(x2)) {
var y2 = m * x2 + yint;
construction.interPoints.push([x2, y2]);
}
}
// two circles
else if (tool1.center != null && tool2.center != null) {
var a = tool1.center.coord[0];
var b = tool1.center.coord[1];
var c = tool2.center.coord[0];
var d = tool2.center.coord[1];
var r = tool1.radius;
var s = tool2.radius;
var e = c - a;
var f = d - b;
var p = Math.sqrt(Math.pow(e, 2) + Math.pow(f, 2));
var k = (Math.pow(p, 2) + Math.pow(r, 2) -
Math.pow(s, 2)) / (2 * p);
var x1 = a + e * k / p + (f / p) *
Math.sqrt(Math.pow(r, 2) - Math.pow(k, 2));
var y1 = b + f * k / p - (e / p) *
Math.sqrt(Math.pow(r, 2) - Math.pow(k, 2));
var x2 = a + e * k / p - (f / p) *
Math.sqrt(Math.pow(r, 2) - Math.pow(k, 2));
var y2 = b + f * k / p + (e / p) *
Math.sqrt(Math.pow(r, 2) - Math.pow(k, 2));
if (!isNaN(x1)) {
construction.interPoints.push([x1, y1]);
}
if (!isNaN(x2)) {
construction.interPoints.push([x2, y2]);
}
}
}
});
});
};
},
// add non-interactive straightedge
addDummyStraightedge: function(coord1, coord2, extend) {
var construction = KhanUtil.construction;
extend = extend == null ? true : extend;
construction.tool = {
interType: "line",
dummy: true,
first: {coord: [coord1, coord2]},
second: {coord: [coord1, coord2]},
edge: KhanUtil.currentGraph.addMovableLineSegment({
coordA: coord1,
coordZ: coord2,
normalStyle: {stroke: "black", "stroke-width": 2},
highlightStyle: {stroke: KhanUtil.BLUE, "stroke-width": 3},
extendLine: extend,
fixed: true
})
};
construction.tool.edge.dummy = true;
// not sure about execution order here (vis-a-vis addConstruction),
// so be careful
if (construction.tools == null) {
construction.tools = [construction.tool];
} else {
construction.tools.push(construction.tool);
}
if (construction.snapLines == null) {
construction.snapLines = [construction.tool.edge];
} else {
construction.snapLines.push(construction.tool.edge);
}
KhanUtil.construction.updateIntersections();
},
// add non-interactive circle
addDummyCircle: function(center, radius) {
var construction = KhanUtil.construction;
var dummy = {coord: center, dummy:true};
KhanUtil.currentGraph.circle(center, {
r: radius,
fill: "none",
stroke: "black",
"stroke-width": 2
});
if (construction.snapPoints == null) {
construction.snapPoints = [dummy];
} else {
construction.snapPoints.push(dummy);
}
KhanUtil.construction.updateIntersections();
},
// add non-interactive point (can't just use circle or snapping
// won't work)
addDummyPoint: function(coordinates) {
var dummy = {coord: coordinates, dummy:true};
KhanUtil.currentGraph.circle(coordinates,
{r: 0.08, fill: "black", stroke: "none"});
var construction = KhanUtil.construction;
if (construction.snapPoints == null) {
construction.snapPoints = [dummy];
} else {
construction.snapPoints.push(dummy);
}
KhanUtil.construction.updateIntersections();
},
// add non-interactive ray
addDummyRay: function(end, other) {
var construction = KhanUtil.construction;
construction.tool = {interType: "line", dummy: true,
first: {coord: end},
second: {coord: other},
edge: {coordA: end, coordZ: other, dummy:true}};
KhanUtil.currentGraph.line(end, other,
{stroke: "black", "stroke-width": 2, arrows: "->"});
KhanUtil.addDummyPoint(end);
// not sure about execution order here (vis-a-vis addConstruction),
// so be careful
if (construction.tools == null) {
construction.tools = [construction.tool];
} else {
construction.tools.push(construction.tool);
}
if (construction.snapLines == null) {
construction.snapLines = [construction.tool.edge];
} else {
construction.snapLines.push(construction.tool.edge);
}
KhanUtil.construction.updateIntersections();
},
constructionGuess: null,
// show guess, given pruned tools which
// only store coordinates of important
// points
showConstructionGuess: function(guessTools) {
var graph = KhanUtil.currentGraph;
if (KhanUtil.constructionGuess != null) {
KhanUtil.constructionGuess.remove();
}
KhanUtil.constructionGuess = graph.raphael.set();
_.each(guessTools, function(tool) {
if (tool.first != null) {
KhanUtil.constructionGuess.push(graph.addMovableLineSegment({
coordA: tool.first.coord,
coordZ: tool.second.coord,
normalStyle: {
stroke: KhanUtil.BLUE,
"stroke-width": 2
},
extendLine: true,
fixed: true
}).visibleLine);
KhanUtil.constructionGuess.push(graph.circle(
tool.first.coord, 0.1, {
fill: KhanUtil.BLUE,
stroke: null
}));
KhanUtil.constructionGuess.push(graph.circle(
tool.second.coord, 0.1, {
fill: KhanUtil.BLUE,
stroke: null
}));
} else if (tool.center != null) {
KhanUtil.constructionGuess.push(graph.circle(
tool.center.coord, 0.1, {
fill: KhanUtil.BLUE,
stroke: null
}));
KhanUtil.constructionGuess.push(graph.circle(
tool.center.coord, tool.radius, {
fill: "none",
stroke: KhanUtil.BLUE,
strokeDasharray: "- "
}));
}
});
},
// shorthand for euclidean distance
// maybe I value brevity too much?
eDist: function(coords1, coords2) {
return Math.sqrt(Math.pow(coords1[0] - coords2[0], 2) +
Math.pow(coords1[1] - coords2[1], 2));
},
// distance from a point to a line, measured
// as the distance along a perpendicular
lDist: function(coord, line) {
var slope = (line.coordZ[1] - line.coordA[1]) /
(line.coordZ[0] - line.coordA[0]);
var perpSlope = slope === 0 ? "vert" : -1 / slope;
var coord2;
if (perpSlope === "vert") {
coord2 = [coord[0], coord[1] + 1];
} else {
coord2 = [coord[0] + 1, coord[1] + perpSlope];
}
var intersect = findIntersection([coord, coord2],
[line.coordA, line.coordZ]);
return [KhanUtil.eDist(intersect, coord), intersect];
},
// Find whether two points are a given distance apart
// given a certain precision
distEqual: function(p1, p2, distance, precision) {
precision = precision || 0.5;
return Math.abs(KhanUtil.eDist(p1, p2) - distance) < precision;
},
// Find whether a line has a given angle
// to a certain precision (in degrees)
angleEqual: function(line, angle, precision) {
var ang = Math.atan2(line.second.coord[1] - line.first.coord[1],
line.second.coord[0] - line.first.coord[0]);
ang *= 180 / Math.PI;
if (ang < 0) {
ang += 180;
}
return Math.abs(angle - ang) < precision;
},
// Given an array of construction tools, return an array
// with either coordinates of a line and the center and
// radius of a circle.
// Submitted as the guess for a construction problem
getToolProperties: function (construction) {
return _.map(_.filter(construction.tools, function(tool) {
return tool.dummy !== true;
}), function(tool) {
if (tool.first != null) {
return {
first: {
coord: [
tool.first.coord[0],
tool.first.coord[1]
]
},
second: {
coord: [
tool.second.coord[0],
tool.second.coord[1]
]
}
};
} else if (tool.center != null) {
return {
center: {
coord: [
tool.center.coord[0],
tool.center.coord[1]
]
},
radius: tool.radius
};
}
});
},
findCompass: function (guess, properties) {
var testFunctions = [];
if (properties.radius != null) {
testFunctions.push(function (tool) {
return Math.abs(tool.radius - properties.radius) < 0.5;
});
}
if (properties.cx != null) {
testFunctions.push(function (tool) {
return Math.abs(tool.center.coord[0] - properties.cx) < 0.5;
});
}
if (properties.cy != null) {
testFunctions.push(function (tool) {
return Math.abs(tool.center.coord[1] - properties.cy) < 0.5;
});
}