如何在 HTML5(或 Fabric.js)中制作屋顶文字效果和山谷文字效果 [英] How to make rooftext effect and valley text effect in HTML5 (or Fabric.js)
本文介绍了如何在 HTML5(或 Fabric.js)中制作屋顶文字效果和山谷文字效果的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在使用以下代码:
<script type='text/javascript'>//<![CDATA[
window.onload=function(){
/// (c) Ken Fyrstenberg Nilsen, Abidas Software .com
/// License: CC-Attribute
var ctx = demo.getContext('2d'),
font = '64px impact',
w = demo.width,
h = demo.height,
curve,
offsetY,
bottom,
textHeight,
angleSteps = 255/h,
i = h,
y,
os = document.createElement('canvas'),
octx = os.getContext('2d');
os.width = w;
os.height = h;
octx.font = font;
octx.textBaseline = 'top';
octx.textAlign = 'center';
function renderBridgeText() {
curve = parseInt(iCurve.value, 10);
offsetY = parseInt(iOffset.value, 10);
textHeight = parseInt(iHeight.value, 10);
bottom = parseInt(iBottom.value, 10);
vCurve.innerHTML = curve;
vOffset.innerHTML = offsetY;
vHeight.innerHTML = textHeight;
vBottom.innerHTML = bottom;
octx.clearRect(0, 0, w, h);
ctx.clearRect(0, 0, w, h);
octx.fillText(iText.value, w * 0.5, 0);
/// slide and dice
i = w;
while (i--) {
y = bottom + curve * Math.sin(i / angleSteps * Math.PI /160);
ctx.drawImage(os, i, offsetY, 1, textHeight,i,offsetY, 1, y);
}
}
iCurve.onchange = iOffset.onchange = iHeight.onchange = iBottom.onchange = iText.onkeyup = renderBridgeText;
renderBridgeText()
}//]]>
</script>
</head>
<body>
<canvas id=demo width=600 height=300></canvas>
<br>
<span>Curve:</span>
<input id="iCurve" type="range" min=0 max=200 value=110>
<span id="vCurve">110</span>
<br><span>OffsetY:</span>
<input id="iOffset" type="range" min=0 max=100 value=4>
<span id="vOffset">0</span>
<br><span>Text height:</span>
<input id="iHeight" type="range" min=0 max=200 value=64>
<span id="vHeight">64</span>
<br><span>Bottom:</span>
<input id="iBottom" type="range" min=0 max=200 value=200>
<span id="vBottom">200</span>
<br><span>Text:</span>
<input id="iText" type="text" value="BRIDGE TEXT">
</body>
我需要像下图这样的文字效果，我做了很多尝试，但我做不到.
I need the text effect like below images,I have tried a lot to make this but i cannot.
谁能帮帮我?
我们还可以使用带有上下文的 fabric.js 中的活动对象吗?
Also can we use active object from fabric.js with context?
推荐答案
这是原始代码的修改版本(提供的代码与我的原始代码相比已更改值..-))可以产生所有这些形状只需使用参数即可:
Here is a modified version of the original code (the provided code in question has changed values compared to my original code.. .-) ) which can produce all these shapes just by playing around with the parameters:
屋顶不是超级好，但我会把它留给你来添加缩放支持，因为这只是一个例子.
The roof is not super but I'll leave it to you to add scaling support as this is meant as an example.
初始化:
var ctx = demo.getContext('2d'), /// context
font = '64px impact', /// font
w = demo.width, /// cache canvas width and height
h = demo.height,
curve, /// radius
offsetY, /// offset for text
bottom, /// bottom of text
textHeight, /// text height (region of text)
isTri = false, /// is triangle shaped (roof)
dltY, /// delta for triangle
angleSteps = 180 / w, /// angle steps for curved text
i = w, /// "x" backwards
y, /// top of text
/// offscreen canvas that holds original text
os = document.createElement('canvas'),
octx = os.getContext('2d');
os.width = w;
os.height = h;
/// set font on off-screen canvas where we draw it
octx.font = font;
octx.textBaseline = 'top';
octx.textAlign = 'center';
主要功能:
/// render
function renderBridgeText() {
/// demo stuff snipped (see link)
/// clear canvases
octx.clearRect(0, 0, w, h);
ctx.clearRect(0, 0, w, h);
/// draw text (text may change)
octx.fillText(iText.value.toUpperCase(), w * 0.5, 0);
/// slide and dice
dltY = curve / textHeight; /// calculate delta for roof/triangle
y = 0; /// reset y in case we do roof
i = w; /// init "x"
while (i--) {
if (isTri) {
/// bounce delta value mid-way for triangle
y += dltY;
if (i === (w * 0.5)|0) dltY = -dltY;
} else {
/// calc length based on radius+angle for curve
y = bottom - curve * Math.sin(i * angleSteps * Math.PI / 180);
}
/// draw a slice
ctx.drawImage(os, i, 0, 1, textHeight,
i, h * 0.5 - offsetY / textHeight * y, 1, y);
}
}
这篇关于如何在 HTML5(或 Fabric.js)中制作屋顶文字效果和山谷文字效果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
