title: Different size items in a VariableSizedWrapGrid
body: <p>The app I'm working on uses a grouped GridView. Different templates are being used for different items on display and this is causing me an issue with the layout because the VariableSizedWrapGrid sets the row &amp; column sizes based on the first item in each group.</p>
  
  <p>I've tried to use the commonly-suggested solution of PrepareContainerForItemOverride and I'm encountering two problems:</p>
  
  <ol>
  <li><p>It seems that I can only adjust the height &amp; width around multiples of the column &amp; row spans. That can leave me with quite a bit of wasted space if, say, item #2 needs to have 1.5 x the row height of item #1. I also seem to have to "guess" at what the most appropriate multiple is, which doesn't seem to be appropriate when apps are supposed to scale dynamically.</p></li>
  <li><p>If I get the multiples too big, the content is horizontally &amp; vertically centred. I've tried changing the alignment from stretch to left in various places but I cannot find which control property to set to get this to work.</p></li>
  </ol>
  
  <p>Is there a better way of adjusting the item sizes than grid spans? If there isn't, is there a better way for me to lay out my content with variably sized items?</p>
  
  <p>Thanks.</p>