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當我移動我的滑塊時，我畫了一條弧線。我使它變得動態。如果我改變弧的點，那麼繪製的線也會改變。我想用一條線做同樣的事情。如果我移動滑塊，則應該繪製線條。另外我想讓它變成動態的手段如果我改變線條點，線條也應該改變。html5-canvas javascript畫線與滑塊
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>CH5EX10: Moving In A Simple Geometric Spiral </title>
<style>
.wrapper {
margin: 0 auto;
width: 1000px;
}
.uppleft {
float: left;
width: 1000px;
position: relative;
margin: 0 0 500px 10px;
}
.dnleft {
float: left;
width: 1000px;
}
.clear {
clear: both;
}
</style>
</head>
<body>
<div class="wrapper">
<div class="uppleft">
<canvas id="canvasOne" width="300" height="300"width="500" height="500" style="position:absolute; left:5px; top:10px; border:1px solid red;">
Your browser does not support HTML5 Canvas.
</canvas>
<canvas id="canvasTwo" width="300" height="300" style="position:absolute; left:250px; top:30px; border:1px solid red;">
Your browser does not support HTML5 Canvas.
</canvas>
</div>
<div class="clear"></div>
<div class="dnleft">
<input id="slide1" type="range" min="0" max="100" step="1" value="0" onchange="counterSliderNew('slide1', '100');"/>
</div>
</div>
</body>
<script type="text/javascript">
drawSlopeCurve2('canvasTwo', 16, 170, 200, 80)
function counterSliderNew(sID, maxValue) {
var slideVal = document.getElementById(sID).value;
//alert(slideVal);
if (maxValue == 100) {
slideVal = slideVal/100;
}
if (slideVal == 0) {
} else if (slideVal > 0 && slideVal <= 34) {
erase('canvasOne');
drawBezier2('canvasOne', new Array({
x : 18.8,
y : 75
}, {
x : 28,
y : 160
}, {
x : 228,
y : 165
}), slideVal);
} else if (slideVal > 34 && slideVal <= 67) {
//alert(slideVal);
erase('canvasOne');
drawBezier2('canvasOne', new Array({
x : 18.8,
y : 75
}, {
x : 28,
y : 160
}, {
x : 228,
y : 165
}), slideVal);
staticGraph5('canvasTwo');
} else if (slideVal > 67 && slideVal <= 100) {
erase('canvasOne');
drawBezier2('canvasOne', new Array({
x : 18.8,
y : 75
}, {
x : 28,
y : 160
}, {
x : 228,
y : 165
}), slideVal);
}
}
function drawBezier2(canId, points, slideVal) {
var canvas = document.getElementById(canId);
var context = canvas.getContext("2d");
// Draw guides
context.lineWidth = 2;
context.strokeStyle = "rgb(113, 113, 213)";
context.beginPath();
// Label end points
context.fillStyle = "rgb(0, 0, 0)";
// Draw spline segemnts
context.moveTo(points[0].x, points[0].y);
for (var t = 0; t <= slideVal; t += 0.1) {
context.lineTo(Math.pow(1 - t, 2) * points[0].x + 2 * (1 - t) * t * points[1].x + Math.pow(t, 2) * points[2].x, Math.pow(1 - t, 2) * points[0].y + 2 * (1 - t) * t * points[1].y + Math.pow(t, 2) * points[2].y);
}
// Stroke path
context.stroke();
}
function erase(canvasId) {
var canvas = document.getElementById(canvasId);
var context = canvas.getContext("2d");
context.beginPath();
context.clearRect(0, 0, canvas.width, canvas.height);
canvas.width = canvas.width;
}
function drawSlopeCurve2(canId, mvx, mvy, lnx, lny) {
var canvas = document.getElementById(canId);
var context = canvas.getContext('2d');
context.beginPath();
context.moveTo(mvx, mvy);
context.lineTo(lnx, lny);
context.lineWidth = 0.6;
context.stroke();
}
</script>
</html>
這隻適用於chrome。我想用drawSlopeCurve2('canvasTwo', 16, 170, 200, 80);這個函數來繪製滑塊移動的一條線。我正在尋找一些公式，因爲我曾用它來移動滑塊移動的弧線。