Question

我对此主题有疑问
How to add text on image using Javascript and Canvas

我无法在第一时间获得图像。但是当我点击刷新时就会加载图片。

这是我来自php文件的代码：

<canvas id="canvas"> </canvas>
<form class="myNameForm">
    <?php echo '<img style="display:none" class="myimage" 
        src="./save/'.$filenamewithoutExt.'" crossorigin="anonymous">';?>
    <label class="inpLable" for="input">Enter Name: </label>
    <input class="inp" maxlength="12" type="text" id="inp"/>
</form>

这是我的js文件中的代码：

window.onload = function() {
    var canvas = document.getElementById('canvas'),
        ctx = canvas.getContext('2d');
    canvas.width = $('img').width();
    canvas.crossOrigin = "Anonymous";
    canvas.height = $('img').height();
    ctx.drawImage($('img').get(0), 0, 0);
    $(document).on('input', '#inp', function() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.font = "20pt Verdana";
        ctx.drawImage($('img').get(0), 0, 0);
        ctx.fillStyle = "white";
        ctx.fillText($(this).val(), 170, 590);
    });
};

Answer 1

我对您的代码进行了小改动

<canvas id="canvas"> </canvas>
<img style="display: none" class="myimage" src='https://picsum.photos/200/200'/>
<label class="inpLable" for="input">Enter Name: </label>
<input class="inp" maxlength="12" type="text" id="inp"/>

还有JS

$('#inp').on('input', function(){
  var canvas = document.getElementById('canvas'),
  ctx = canvas.getContext('2d');
  canvas.width = $('img').width();
  canvas.crossOrigin = "Anonymous";
  canvas.height = $('img').height();
  ctx.drawImage($('img').get(0), 0, 0);
  ctx.clearRect(0,0,canvas.width,canvas.height);
  ctx.font = "20px Verdana";
  ctx.drawImage($('img').get(0), 0, 0);
  ctx.fillStyle = "white";
  ctx.fillText($(this).val(), 10, 50);
});

我在这里创建了一个有效的JSFiddle

使用Javascript和Canvas在图像上添加文本

1 个答案: