ubolonton · February 8, 2015 12:09
diff --git a/firebase.html b/firebase.html
 <!DOCTYPE html>
 <html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=edge" >
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta charset="utf-8">
    <meta name="description" content="">
    <meta name="author" content="">
    <title>Rx for JavaScript Rocks!</title>
  </head>
  <body>
    <div class="container">
      <div class="page-header">
        <h1>Shared Whiteboard</h1>
      </div>
      <div class="pull-left controls-group">
        <label>Color:</label>
        <input id="color" value="#df4b26">
      </div>
      <button class="pull-right btn btn-primary" id="clear">
        Clear Canvas
      </button>
      <div class="row-fluid">
        <canvas id="tutorial" width="640" height="480" style="background:gray;">

        </canvas>
      </div>
    </div>
    <script type="text/javascript" src="../../build/csp.bundled.browser.js"></script>
    <script src="https://cdn.firebase.com/js/client/2.1.1/firebase.js"></script>
    <script type="text/javascript;version=1.8">
    let csp = require("csp");
    let chan = csp.chan,
        go = csp.go,
        buffers = csp.buffers,
        take = csp.take,
        put = csp.put,
        alts = csp.alts,
        putAsync = csp.putAsync;

    function fromEvent(element, eventName) {
      let ch = chan(buffers.sliding(1));
      element.addEventListener(eventName, function(event) {
        putAsync(ch, event);
      });
      return ch;
    }

    function fromFirebase(ref, event) {
      let ch = chan(8);
      ref.on(event, function() {
        putAsync(ch, Array.prototype.slice.apply(arguments));
      });
      return ch;
    }

    function coordinate(event, canvas) {
      let rect = canvas.getBoundingClientRect();
      return {
        x: event.clientX - rect.left,
        y: event.clientY - rect.top
      }
    }

    function takeUntil(input, signal, output) {
      output = output || chan();
      go(function*() {
        let r;
        while (input === (r = yield alts([input, signal])).channel) {
          yield put(output, r.value);
        }
      });
      return output;
    }

    let _ref = new Firebase("https://dazzling-torch-6325.firebaseio.com/scribble");

    let canvas = document.getElementById("tutorial");

    let mouseDowns  = fromEvent(canvas, 'mousedown');
    let mouseUps    = fromEvent(document, 'mouseup');
    let mouseMoves  = fromEvent(canvas, 'mousemove');

    go(function*() {
      let clear = fromEvent(document.getElementById("clear"), "click");
      while (csp.CLOSED !== (yield clear)) {
        _ref.remove();
      }
    });

    let mouseDrags = chan(8);
    /* Generating drags */
    go(function*() {
      for (;;) {
        let event = yield mouseDowns;
        // console.log("start drag");
        let drag = chan(8);
        yield put(drag, event);
        putAsync(mouseDrags, drag);
        let r;
        while (mouseMoves === (r = yield alts([mouseMoves, mouseUps])).channel) {
          event = r.value;
          // console.log(["drag point", event]);
          yield put(drag, event);
        }
        // console.log("stop drag");
        drag.close();
      }
    });

    /* Saving to firebase */
    go(function*() {
      for (;;) {
        let drag = yield mouseDrags;
        go(function*() {
          let color = document.getElementById("color").value || "blue";
          let _dragref = _ref.push({color: color});
          let event;
          while (csp.CLOSED !== (event = yield drag)) {
            _dragref.ref().child("points").push(coordinate(event, canvas));
          }
        });
      }
    });

    /* Drawing stuff coming from firebase */
    go(function*() {
      let lines = fromFirebase(_ref, "child_added");
      let d;
      while (csp.CLOSED !== (d = yield lines)) {
        let [lineSnapshot, _] = d;
        let color = lineSnapshot.child("color").val();
        // console.log("Got new line", color);
        let points = fromFirebase(lineSnapshot.child("points").ref(), "child_added");
        go(function*() {
          let prevPoint;
          let ctx = canvas.getContext('2d');
          ctx.lineWidth = 3;
          let d;
          while (csp.CLOSED !== (d = yield points)) {
            let [pointSnapshot, _] = d;
            let point = pointSnapshot.val();
            // console.log("Got new point", point);
            if (prevPoint) {
              ctx.beginPath();
              ctx.strokeStyle = color;
              ctx.moveTo(prevPoint.x, prevPoint.y);
              ctx.lineTo(point.x, point.y);
              ctx.stroke();
            }
            prevPoint = point;
          }
        });
      }
    });

    go(function*() {
      let removed = fromFirebase(_ref, "child_removed");
      while (csp.CLOSED !== (yield removed)) {
        canvas.width = canvas.width;
      }
    });
    </script>
  </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta http-equiv="X-UA-Compatible" content="IE=edge" >
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta charset="utf-8">
	<meta name="description" content="">
	<meta name="author" content="">
	<title>Rx for JavaScript Rocks!</title>
	</head>
	<body>
	<div class="container">
	<div class="page-header">
	<h1>Shared Whiteboard</h1>
	</div>
	<div class="pull-left controls-group">
	<label>Color:</label>
	<input id="color" value="#df4b26">
	</div>
	<button class="pull-right btn btn-primary" id="clear">
	Clear Canvas
	</button>
	<div class="row-fluid">
	<canvas id="tutorial" width="640" height="480" style="background:gray;">

	</canvas>
	</div>
	</div>
	<script type="text/javascript" src="../../build/csp.bundled.browser.js"></script>
	<script src="https://cdn.firebase.com/js/client/2.1.1/firebase.js"></script>
	<script type="text/javascript;version=1.8">
	let csp = require("csp");
	let chan = csp.chan,
	go = csp.go,
	buffers = csp.buffers,
	take = csp.take,
	put = csp.put,
	alts = csp.alts,
	putAsync = csp.putAsync;

	function fromEvent(element, eventName) {
	let ch = chan(buffers.sliding(1));
	element.addEventListener(eventName, function(event) {
	putAsync(ch, event);
	});
	return ch;
	}

	function fromFirebase(ref, event) {
	let ch = chan(8);
	ref.on(event, function() {
	putAsync(ch, Array.prototype.slice.apply(arguments));
	});
	return ch;
	}

	function coordinate(event, canvas) {
	let rect = canvas.getBoundingClientRect();
	return {
	x: event.clientX - rect.left,
	y: event.clientY - rect.top
	}
	}

	function takeUntil(input, signal, output) {
	output = output \|\| chan();
	go(function*() {
	let r;
	while (input === (r = yield alts([input, signal])).channel) {
	yield put(output, r.value);
	}
	});
	return output;
	}

	let _ref = new Firebase("https://dazzling-torch-6325.firebaseio.com/scribble");

	let canvas = document.getElementById("tutorial");

	let mouseDowns = fromEvent(canvas, 'mousedown');
	let mouseUps = fromEvent(document, 'mouseup');
	let mouseMoves = fromEvent(canvas, 'mousemove');

	go(function*() {
	let clear = fromEvent(document.getElementById("clear"), "click");
	while (csp.CLOSED !== (yield clear)) {
	_ref.remove();
	}
	});

	let mouseDrags = chan(8);
	/* Generating drags */
	go(function*() {
	for (;;) {
	let event = yield mouseDowns;
	// console.log("start drag");
	let drag = chan(8);
	yield put(drag, event);
	putAsync(mouseDrags, drag);
	let r;
	while (mouseMoves === (r = yield alts([mouseMoves, mouseUps])).channel) {
	event = r.value;
	// console.log(["drag point", event]);
	yield put(drag, event);
	}
	// console.log("stop drag");
	drag.close();
	}
	});

	/* Saving to firebase */
	go(function*() {
	for (;;) {
	let drag = yield mouseDrags;
	go(function*() {
	let color = document.getElementById("color").value \|\| "blue";
	let _dragref = _ref.push({color: color});
	let event;
	while (csp.CLOSED !== (event = yield drag)) {
	_dragref.ref().child("points").push(coordinate(event, canvas));
	}
	});
	}
	});

	/* Drawing stuff coming from firebase */
	go(function*() {
	let lines = fromFirebase(_ref, "child_added");
	let d;
	while (csp.CLOSED !== (d = yield lines)) {
	let [lineSnapshot, _] = d;
	let color = lineSnapshot.child("color").val();
	// console.log("Got new line", color);
	let points = fromFirebase(lineSnapshot.child("points").ref(), "child_added");
	go(function*() {
	let prevPoint;
	let ctx = canvas.getContext('2d');
	ctx.lineWidth = 3;
	let d;
	while (csp.CLOSED !== (d = yield points)) {
	let [pointSnapshot, _] = d;
	let point = pointSnapshot.val();
	// console.log("Got new point", point);
	if (prevPoint) {
	ctx.beginPath();
	ctx.strokeStyle = color;
	ctx.moveTo(prevPoint.x, prevPoint.y);
	ctx.lineTo(point.x, point.y);
	ctx.stroke();
	}
	prevPoint = point;
	}
	});
	}
	});

	go(function*() {
	let removed = fromFirebase(_ref, "child_removed");
	while (csp.CLOSED !== (yield removed)) {
	canvas.width = canvas.width;
	}
	});
	</script>
	</body>
	</html>