matplotlib/matplotlib — pull request #642 by leejjoon (2011-12-28 02:41:04+00:00)
Title: clabel can be called with approximate  postions of labels

This is to address #613.

With this patch, *clabel* can take a list of positions and contour labels will be created near those positions.
For example,

```python
plt.figure()
CS = plt.contour(X, Y, Z)
manual_locations = [(-1, -1.4), (-0.62, -0.7), (-2, 0.5), (1.7, 1.2), (2.0, 1.4), (2.4, 1.7)]
plt.clabel(CS, inline=1, fontsize=10, manual=manual_locations)
```
The positions should be in data coordinate.