pcb-rnd knowledge pool

 

Negative/positive selection directions

negselect by Tibor 'Igor2' Palinkas on 2015-12-31

Tags: howto, ui, gui, selection, select

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Abstract: A positive direction selection box will select any object that is fully enclosed by the box; a negative direction box will select any object that touches the box.

  When a selection is made using drag&drop (box selection), depending on the direction the rule for object selection differ:

As an example, we look at the features in the following layout, which will be subsequently combined to form a footprint for a B7G thermionic valve. Using a click and drag selection box going from the top left and then down and rightwards to the middle of the set of features, as follows:

we obtain the following selection, namely, only objects that lie entirely within the selection box, which in this case is only a single pin:

If we now use a click and drag selection box going from the bottom right to the middle of the set of features, as follows:

we obtain the following selection, namely, any objects which lie partly or entirely within the selection box, which includes the silk circle, the text, the hole and two of the pins:

This feature is of most use on crowded layouts or when selecting from amongst closely spaced features.

The feature can be disabled using the editor/selection/disable_negative conf setting.

It's possible to limit the feature so that only horizontal-negative is considered negative size (i.e. only right-to-left dragging), using the editor/selection/symmetric_negative conf setting.