Question

首先，我使用弧画一个圆圈并填充它。（按钮1）

然后，我在上绘制一个矩形和另一个弧并将其填充为红色。（按钮2）

然而，在第二个功能之后，第一个弧停留在那里并且突然变成红色。帮助

import QtQuick 2.0 import QtQml 2.0 ListView { anchors.fill: parent model: myModel //this is your main model delegate: Rectangle { height: 100 width: 100 color: "red" Text { id: cc text: id } ListView { anchors.fill: parent model: mm //the internal QVariantList delegate: Rectangle { anchors.right: parent.right width: 50 height: 50 color: "green" border.color: "black" Text { text: type //role to get data from internal model } } } } }

var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); function function1() { context.fillStyle = "black"; context.fillRect(0, 0, 400, 400); context.fillStyle = "white"; context.arc(100, 200, 50, 0, 2*Math.PI); context.fill(); } function function2() { context.fillStyle = "black"; context.fillRect(0, 0, 400, 400); context.fillStyle = "red"; context.arc(300, 200, 50, 0, 2*Math.PI); context.fill(); }

Answer 1

OH。哇。我只是像一年前发布的一个问题那样得到了同样的错误，我忘了放context.beginPath();。愚蠢的我。

＆＃13;

var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");
function function1() {
  context.fillStyle = "black";
  context.fillRect(0, 0, 400, 400);
  context.fillStyle = "white";
  context.beginPath();
  context.arc(100, 200, 50, 0, 2*Math.PI);
  context.fill();
}
function function2() {
  context.fillStyle = "black";
  context.fillRect(0, 0, 400, 400);
  context.fillStyle = "red";
  context.beginPath();
  context.arc(300, 200, 50, 0, 2*Math.PI);
  context.fill();
}

＆＃13;

<canvas id="canvas" width="400" height="400" style="border: 1px solid black"></canvas>
<button onClick="function1()">Button 1</button>
<button onClick="function2()">Button 2</button>

＆＃13;

弧正在绘制直线

1 个答案: