title: Semi-transparent colors in Google Charts?
body: <p>A call like</p>
  
  <pre><code>chart.draw(data, { colors: ['#e0440e', '#e6693e', '#ec8f6e', ...], ... });
  </code></pre>
  
  <p><a href="https://developers.google.com/chart/interactive/docs/customizing_charts" rel="nofollow">creates a chart with colors looking like semi-transparent</a>. However, we passed RGB colors, with no alpha parameter!</p>
  
  <p>In other chart apps (like jqPlot, CanvasJS etc) you may pass <strong><em>rgba</em></strong> calls instead, like in</p>
  
  <pre><code>[ 'rgba(255,0,0,0.5)', 'rgba(0,255,0,0.5)', ...]
  </code></pre>
  
  <p>Google Charts does not seem to support this. But is there any other way to pass RGBA custom colors instead, with a simple syntax?</p>
  
  <p>PS: there is a somehow similar question for pie charts, but mine is different, for custom color palettes.</p>