[Chartjs]-Html-pdf: How to ensure image doesn't span a page break

Add into your css an @print section for your div:

@media print {
     div#canvasWrap { width: 2.4cm; }
  }

And add a wrapping div around your canvas:

<div id="canvasWrap">
    <canvas id="bar-chart" class="canvas-styles"></canvas>
</div>

Add any styles you need to the wrapper …