F2 cuts off some text features

F2 (Zoom Full) cuts off some of the rotated text in this
bond figure layout. It deals with R0 text OK. This is what
is displayed by F2:

This shows there was more to see, that wasn't displayed:


  • I see ...

    Maybe there is a basic thing I need to explain: unlike Cadence for example, KLayout does not assign a box to a text but just the text's origin. So eventually, a text is just a dot and the text's bounding box is also just a dot. When you press F2, it will fit this dot, not the whole text.

    The reason is threefold: first, when using texts as labels - and this is the main purpose that texts serve in KLayout - texts are actually just points marking a specific location. Second, with the non-scaling text font (which I consider very useful), you cannot assign a box size to a label. So the text box would be zoom level dependent and such a dependency would break every the view/database separation concept and a number of more database algorithms such a pre-built search trees. And third, while GDS has some way of storing text dimensions, there is no convention for storing the font information. For other formats like OASIS there even isn't a official way to store the text orientation. So this text attributes can't be kept reliably for all kind of formats, making the text decoration details volatile information.

    Treating texts as points also explains the strange selection and display behaviour. A text vanishes when the point moves out of the viewport because it's no longer captured by the view region lookup.


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