Show canvas as span has extra padding
HTML
<div>
<canvas id="c1"></canvas>
</div>
<div>
<canvas id="c2"></canvas>
</div>
CSS
div { border: 1px solid black; margin: 1em; }
canvas { background: pink; }
#c2 { display: block; }
<div>
<canvas id="c1"></canvas>
</div>
<div>
<canvas id="c2"></canvas>
</div>
div { border: 1px solid black; margin: 1em; }
canvas { background: pink; }
#c2 { display: block; }