Warning: file_get_contents(/data/phpspider/zhask/data//catemap/9/javascript/431.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Javascript 用HTML5在画布上绘制图像_Javascript_Html_Canvas - Fatal编程技术网

Javascript 用HTML5在画布上绘制图像

Javascript 用HTML5在画布上绘制图像,javascript,html,canvas,Javascript,Html,Canvas,我一直试图在画布上绘制一幅图像,但没有成功。HTML代码只创建canvas元素“canvas1”,无需额外处理 以下是JS: function loadlogo(){ var logo = new Image(); var canvas = document.getElementById('canvas1'); var context = canvas.getContext('2d'); //resize the canvas to the current win

我一直试图在画布上绘制一幅图像,但没有成功。HTML代码只创建canvas元素“canvas1”,无需额外处理

以下是JS:

function loadlogo(){
    var logo = new Image();
    var canvas = document.getElementById('canvas1');
    var context = canvas.getContext('2d');
    //resize the canvas to the current window
    context.canvas.width = window.innerWidth;
    context.canvas.height = window.innerHeight / 3;
    logo.src = "images/1.png";
    logo.onload = function() {context.drawImage(logo,0,0;};
    context.shadowOffsetX = 50;
    context.shadowOffsetY = 30;
    context.shadowColor = "pink";
    }

    window.addEventListener("load",loadlogo,false);
    window.addEventListener("resize",loadlogo,false);
你能给我的任何帮助都会很棒!!! 我已经尝试了很多方法,但都被卡住了

谢谢,
Bryan

在分配img src之前,先为img设置加载功能

更改此部分

{context.drawImage(logo,0,0;};
                           ^ Notice the missing end-parenthesis here

正如QBM5一样,我还建议在设置
onload
后放置
src
,以确保它已正确初始化

{context.drawImage(logo,0,0)};