【发布时间】：2014-05-24 18:43:38
【问题描述】：
我在网上做了一个小测验，这是我第一次使用画布功能。当我输入自己的问题时，它们显示为一行，我不知道如何将这些行分开，以便问题正确显示。有人可以帮忙吗？
这是我目前所拥有的：
<!DOCTYPE HTML>
<html>
<head>
<style>
body{
background-color: black;
}
#ccontainer{
width: 550px;
margin: 0 auto;
margin-top: 110px;
}
#myCanvas{
/*/ background: #FFF; /*/
}
</style>
<script>
window.onload = function(){
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext("2d");
var quizbg = new Image();
var Question = new String;
var Option1 = new String;
var Option2 = new String;
var Option3 = new String;
var mx=0;
var my=0;
var CorrectAnswer = 0;
var qnumber = 0;
var rightanswers=0;
var wronganswers=0;
var QuizFinished = false;
var lock = false;
var textpos1=25;
var textpos2=145;
var textpos3=230;
var textpos4=325;
var Questions = ["Which Manchester United Player won \n the 2008 Golden Boot with 31 Goals?","At which club did Bobby Charlton start his football career?","Which year did Wayne Rooney win the BBC Young Sports Personality of the year award?"];
var Options = [["Cristiano Ronaldo","Wayne Rooney","Ryan Giggs"],["Manchester United","Manchester City","Chelsea"],["2002","2003","2004"]];
quizbg.onload = function(){
context.drawImage(quizbg, 0, 0);
SetQuestions();
}
quizbg.src = "quizbg.png";
SetQuestions = function(){
Question=Questions[qnumber];
CorrectAnswer=1+Math.floor(Math.random()*3);
if(CorrectAnswer==1){Option1=Options[qnumber][0];Option2=Options[qnumber][1];Option3=Options[qnumber][2];}
if(CorrectAnswer==2){Option1=Options[qnumber][2];Option2=Options[qnumber][0];Option3=Options[qnumber][1];}
if(CorrectAnswer==3){Option1=Options[qnumber][1];Option2=Options[qnumber][2];Option3=Options[qnumber][0];}
context.textBaseline = "middle";
context.font = "16pt sans-serif,Arial";
context.fillText(Question,20,textpos1);
context.font = "14pt sans-serif,Arial";
context.fillText(Option1,20,textpos2);
context.fillText(Option2,20,textpos3);
context.fillText(Option3,20,textpos4);
}//SetQuestions
canvas.addEventListener('click',ProcessClick,false);
function ProcessClick(ev) {
my=ev.y-canvas.offsetTop;
if(ev.y == undefined){
my = ev.pageY - canvas.offsetTop;
}
if(lock){
ResetQ();
}//if lock
else{
if(my>110 && my<180){GetFeedback(1);}
if(my>200 && my<270){GetFeedback(2);}
if(my>290 && my<360){GetFeedback(3);}
}//!lock
}//process click
GetFeedback = function(a){
if(a==CorrectAnswer){
context.drawImage(quizbg, 0,400,75,70,480,110+(90*(a-1)),75,70);
rightanswers++;
//drawImage(image, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight)
}
else{
context.drawImage(quizbg, 75,400,75,70,480,110+(90*(a-1)),75,70);
wronganswers++;
}
lock=true;
context.font = "14pt sans-serif,Arial";
context.fillText("Click again to continue",20,380);
}//get feedback
ResetQ= function(){
lock=false;
context.clearRect(0,0,550,400);
qnumber++;
if(qnumber==Questions.length){EndQuiz();}
else{
context.drawImage(quizbg, 0, 0);
SetQuestions();}
}
EndQuiz=function(){
canvas.removeEventListener('click',ProcessClick,false);
context.drawImage(quizbg, 0,0,550,90,0,0,550,400);
context.font = "20pt sans-serif,Arial";
context.fillText("You have finished the quiz!",20,100);
context.font = "16pt sans-serif,Arial";
context.fillText("Correct answers: "+String(rightanswers),20,200);
context.fillText("Wrong answers: "+String(wronganswers),20,240);
}
};
</script>
</head>
<body>
<div id="ccontainer">
<canvas id="myCanvas" width="550" height="400"></canvas>
</div>
</body>
</html>
谢谢！
【问题讨论】：
-
当我尝试拉小提琴时，我看到的只是黑屏。也许某种图像会很好，还有一个工作小提琴
-
抱歉，这是因为我将背景设置为黑色并使用了背景图像。让我试着让小提琴工作，以前从未使用过那个网站！
-
请不要转储您的整个代码库。找出相关的代码并发布它。如果您确实需要整个脚本，请制作一个 JSFiddle，然后STILL 在此处仅发布相关代码。
-
我摆脱了黑色背景并取消了画布
#FFF，但我没有看到我应该看到的内容 -
我的背景图片只包含 4 行白色，一行用于问题，3 行用于个人答案。每个 textPos 标记文本开始的位置，当 filltext 执行时，问题打印在一行上，因此无法查看整个问题。试图让 JSfiddle 工作，但我不认为我可以在那里上传我的背景图片？
标签： javascript css html canvas