如何为徒手画布形状着色？

Question

我正在努力提高我的编码技能，所以任何帮助都会受到赞赏。

当我绘制一个形状（徒手画）时，我希望它在形状完成后填充选定的绘图颜色。

我该怎么做呢？我发现填充形状的唯一填充函数是编码绘制点。

目前我的代码 -

    <script type="text/javascript">

var canvas, ctx, flag = false,
    prevX = 0,
    currX = 0,
    prevY = 0,
    currY = 0,
    dot_flag = false;

var x = "black",
    y = 2;

function init() {
    canvas = document.getElementById('can');
    ctx = canvas.getContext("2d");
    w = canvas.width;
    h = canvas.height;

    canvas.addEventListener("mousemove", function (e) {
        findxy('move', e)
    }, false);
    canvas.addEventListener("mousedown", function (e) {
        findxy('down', e)
    }, false);
    canvas.addEventListener("mouseup", function (e) {
        findxy('up', e)
    }, false);
    canvas.addEventListener("mouseout", function (e) {
        findxy('out', e)
    }, false);
}

function color(obj) {
    switch (obj.id) {

        case "green":
            x = "green";
            break;

        case "blue":
            x = "blue";
            break;

        case "red":
            x = "red";
            break;

        case "yellow":
            x = "yellow";
            break;

        case "orange":
            x = "orange";
            break;

        case "black":
            x = "black";
            break;

        case "white":
            x = "white";
            break;
    }
    if (x == "white") y = 14;
    else y = 2;

}

function draw() {

    ctx.beginPath();
    ctx.moveTo(prevX, prevY);
    ctx.lineTo(currX, currY);
    ctx.strokeStyle = x;
    ctx.lineWidth = y;
    ctx.stroke();
    ctx.closePath();


}

function erase() {
    var m = confirm("Want to clear");
    if (m) {
        ctx.clearRect(0, 0, w, h);
        document.getElementById("canvasimg").style.display = "none";
    }
}

function save() {
    document.getElementById("canvasimg").style.border = "2px solid";
    var dataURL = canvas.toDataURL();
    document.getElementById("canvasimg").src = dataURL;
    document.getElementById("canvasimg").style.display = "inline";
}

function findxy(res, e) {
    if (res == 'down') {
        prevX = currX;
        prevY = currY;
        currX = e.clientX - canvas.offsetLeft;
        currY = e.clientY - canvas.offsetTop;

        flag = true;
        dot_flag = true;
        if (dot_flag) {
            ctx.beginPath();
            ctx.fillStyle = x;
            ctx.fillRect(currX, currY, 2, 2);
            ctx.closePath();
            dot_flag = false;
        }
    }
    if (res == 'up' || res == "out") {
        flag = false;
    }
    if (res == 'move') {
        if (flag) {
            prevX = currX;
            prevY = currY;
            currX = e.clientX - canvas.offsetLeft;
            currY = e.clientY - canvas.offsetTop;
            draw();
        }
    }
}
</script>

HTML代码

    <div style="position:static; display:inline-block; margin-top:10px; margin-bottom:0px; margin-left:5px; margin-right:0px; padding:0px;">Choose Color</div>

    <div style="position:static; display:inline-block; margin-top:10px; margin-bottom:0px; margin-left:142px; margin-right:0px; padding:0px;">Eraser</div>

    <p></p>

    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:0px; padding:0px;width:30px;height:30px;background:green;" id="green" onclick="color(this)"></div>

    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:0px; padding:0px;width:30px;height:30px;background:red;" id="red" onclick="color(this)"></div>

    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:0px; padding:0px;width:30px;height:30px;background:yellow;" id="yellow" onclick="color(this)"></div>

    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:0px; padding:0px;width:30px;height:30px;background:orange;" id="orange" onclick="color(this)"></div>

    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:0px; padding:0px;width:30px;height:30px;background:black;" id="black" onclick="color(this)"></div>


    <div style="position:static; display:inline-block; margin-top:5px; margin-left:5px; margin-right:auto; padding:0px;width:28px;height:28px;background:white; border:2px solid;" id="white" onclick="color(this)"></div>


        </body>