[Qgis-developer] Diagrams and labels

[paul.blottiere at oslandia.com]

Hi,

I'm going to work soon on adding some tools for diagrams. The aim is to 
provide features in a specific toolbar such as those in "Label Toolbar", 
but for diagrams.

Before doing that, in order to ensure that I implement the same type of 
thinking, I studied the behavior of the existing features for labels 
(like "Highlight Pinned labels", "Pin/Unpin Labels", "Move Label" and 
"Rotate Label"). By now, I have a couple of questions.

Firstly, I have noticed that a label can be moved even if it's 
"unpinned". If I do that, then the label is automatically "pinned" at 
the end of its move. However, the behavior is different for the 
rotation. Indeed, a label has to be "pinned" to be rotated. Why is there 
a difference between the "move" action and the "rotate" action?

Secondly, I have noticed that when we "unpin" a label previously moved, 
it backs to its initial position. But, the rotation is kept. I thought 
that when a label is "unpinned", then it backs to its starting position 
AND its original rotation (ie no rotation). Could you clarify this for 
me?

Thank you.

Paul