title: altair grouped bar chart format axis and padding
body: <p>I am working with Altair and loving it for quick visualization. I am struggling a bit regarding fine-tuning the formatting though, especially regarding padding of the grouped bar charts and trying to get a non-repeating title. </p>
  
  <p>Please see the plot so far: <a href="https://i.stack.imgur.com/Assza.png" rel="nofollow noreferrer">Plot so far</a>
  and the code generating the plot:</p>
  
  <pre><code>dfc = pd.DataFrame({'Alternative': {0: 0, 1: 1, 2: 0, 3: 1, 4: 0, 5: 1, 6: 0, 7: 1},
   'Time': {0: 1979,
    1: 1979,
    2: 1980,
    3: 1980,
    4: 1980,
    5: 1980,
    6: 1980,
    7: 1980},
   'Sim #': {0: 2688, 1: 3564, 2: 86, 3: 424, 4: 743, 5: 884, 6: 1530, 7: 1612},
   'Cost_MNOK': {0: .5,
    1: .4,
    2: 2,
    3: 3,
    4: 30,
    5: 40,
    6: 200,
    7: 300},
   'freq': {0: 5.555555555555556e-06,
    1: 5.555555555555556e-05,
    2: 5.555555555555556e-06,
    3: 5.555555555555556e-05,
    4: 5.555555555555556e-06,
    5: 5.555555555555556e-05,
    6: 5.555555555555556e-06,
    7: 5.555555555555556e-05},
   'Bin_text': {0: '0-1 MNOK',
    1: '0-1 MNOK',
    2: '1-10 MNOK',
    3: '1-10 MNOK',
    4: '10-100 MNOK',
    5: '10-100 MNOK',
    6: '100+ MNOK',
    7: '100+ MNOK'},
   'Bin': {0: 1, 1: 1, 2: 2, 3: 2, 4: 3, 5: 3, 6: 4, 7: 4}})
  
  
  heatmap_colors = ['#edf8fb', '#b2e2e2', '#66c2a4', 'red']
  alt.Chart(dfc).mark_bar().encode(
      alt.Column('Bin_text', header=alt.Header(title='Occurrence of failures grouped by cost')),
      alt.X('Alternative:N', axis=alt.Axis(orient='bottom', ), title='Alt'),
      alt.Y('sum(freq)', axis=alt.Axis(grid=False, format='%', title='Frequency')),
      alt.Color('Bin_text', scale=alt.Scale(range=heatmap_colors), legend=alt.Legend(title='Bins')),
      alt.Tooltip('sum(freq)', format='.2%')
  ).configure_view(strokeOpacity=0)
  </code></pre>
  
  <p>What I am trying to achieve is the following:</p>
  
  <ul>
  <li>At the top row, the titles of my bar chart groups are truncated. I would like to prevent that, but also prevent overlap. I expect that this should be done by increasing the distance between the groups, but I cannot figure out how to do this. I tried among others adding a Scale object to the Column object, but this is not an allowed argument anymore (seemed to be ok in altair v1). EDIT: I have found a way to do this: adding <code>.properties(width=200)</code> at the very end of the plot provides more spacing, and the plot titles become readable. The other part of the question still stands though.</li>
  <li>At the bottom of the plot, the title 'Alt' repeats for all groups. I would rather have one title here instead of the same text repeating.</li>
  </ul>
  
  <p>Any ideas and tips are welcome!</p>