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---
title: CanvasRenderingContext2D.quadraticCurveTo()
slug: Web/API/CanvasRenderingContext2D/quadraticCurveTo
translation_of: Web/API/CanvasRenderingContext2D/quadraticCurveTo
---
<div>{{APIRef}}</div>
<p>o método <code><strong>CanvasRenderingContext2D</strong></code><strong><code>.quadraticCurveTo()</code></strong> da API Canvas 2D adiciona uma Curva de Bézier quadrática ao caminho. São exigidos dois pontos. O primeiro ponto é um ponto de controle e o segundo é o ponto final. The starting point is the last point in the current path, which can be changed using <code>moveTo()</code> before creating the quadratic Bézier curve.</p>
<h2 id="Sintaxe">Sintaxe</h2>
<pre class="syntaxbox">void <var><em>ctx</em>.quadraticCurveTo(cpx, cpy, x, y);</var>
</pre>
<h3 id="Parâmetros">Parâmetros</h3>
<dl>
<dt><code>cpx</code></dt>
<dd>O eixo X da coordenada para o ponto de controle.</dd>
<dt><code>cpy</code></dt>
<dd>O eixo Y da coordenada para o ponto de controle.</dd>
<dt><code>x</code></dt>
<dd>O eixo X da coordenada para o ponto final.</dd>
<dt><code>y</code></dt>
<dd>O eixo Y da coordenada para o ponto final.</dd>
</dl>
<h2 id="Exemplos">Exemplos</h2>
<h3 id="Usando_o_método_quadraticCurveTo">Usando o método <code>quadraticCurveTo</code></h3>
<p>This is just a simple code snippet drawing a quadratic bezier curve. The <span style="color: red;">control point is red</span> and the <span style="color: blue;">start and end points are blue</span>.</p>
<h4 id="HTML">HTML</h4>
<pre class="brush: html"><canvas id="canvas"></canvas>
</pre>
<h4 id="JavaScript">JavaScript</h4>
<pre class="brush: js; highlight:[6]">var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.beginPath();
ctx.moveTo(50,20);
ctx.quadraticCurveTo(230, 30, 50, 100);
ctx.stroke();
ctx.fillStyle = 'blue';
// start point
ctx.fillRect(50, 20, 10, 10);
// end point
ctx.fillRect(50, 100, 10, 10);
ctx.fillStyle = 'red';
// control point
ctx.fillRect(230, 30, 10, 10);</pre>
<p>{{ EmbedLiveSample('Using_the_quadraticCurveTo_method', 315, 165) }}</p>
<h3 id="Trying_the_quadraticCurveTo_parameters">Trying the <code>quadraticCurveTo</code> parameters</h3>
<p>Edit the code below and see your changes update live in the canvas:</p>
<div class="hidden">
<pre class="brush: html"><canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
<input id="edit" type="button" value="Edit" />
<input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code">
ctx.beginPath();
ctx.moveTo(50,20);
ctx.quadraticCurveTo(230, 30, 50, 100);
ctx.stroke();</textarea>
</pre>
<pre class="brush: js">var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;
function drawCanvas() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
eval(textarea.value);
}
reset.addEventListener("click", function() {
textarea.value = code;
drawCanvas();
});
edit.addEventListener("click", function() {
textarea.focus();
})
textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);
</pre>
</div>
<p>{{ EmbedLiveSample('Trying_the_quadraticCurveTo_parameters', 700, 360) }}</p>
<h2 id="Especificações">Especificações</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('HTML WHATWG', "scripting.html#dom-context-2d-quadraticcurveto", "CanvasRenderingContext2D.quadraticCurveTo")}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Compatibilidade com navegadores</h2>
<p>{{CompatibilityTable}}</p>
<div id="compat-desktop">{{CompatVersionUnknown}}
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Edge</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">{{CompatVersionUnknown}}
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Edge</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="Veja_também">Veja também</h2>
<ul>
<li>The interface defining it, {{domxref("CanvasRenderingContext2D")}}</li>
<li><a href="http://en.wikipedia.org/wiki/B%C3%A9zier_curve">WikiPedia article on Bézier curves</a>.</li>
</ul>
|
