The two ways of window selection

Ever tried on LibreCAD or AutoCAD? And then played with the selection using mouse drag in the drawing area. This feature is agile and it requires a little attention to catch the difference when selecting in increasing and decreasing values of x-axis.

The logic of this feature’s implementation in eCAD was clearly associated with the intersection of bounding rectangles of items being selected and the rubber band drag window/widget. The two different cases that had to be deployed included:

  • With increase in values of x, an entity is selected if the entity lies completely inside the selection area. See figure 1 below.
  • Mouse is dragged from top left to bottom right to select but it is not selected
    Entity not selected when a portion of it is in selection rectangle
    Mouse is dragged from top left to bottom right to select and it is selected since it lies entirely in the selection box.
    Mouse is dragged from top left to bottom right to select and it is selected since it lies entirely in the selection box.
  • With decrease in values of x, an entity is selected if a portion of the entity lies inside the selection area,
  • Mouse is dragged from bottomright to topleft corner and item is selected even when a portion of entity lies inside the selection box.
    Mouse is dragged from bottomright to topleft corner and item is selected even when a portion of entity lies inside the selection box.

Now I will be moving onto Deselect Window and selection of intersected entities.

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