How to delete part of an object (drawing; bitmap)?

How can I delete part of an object (drawing; bitmap)?

I am aware, that drawings and raster graphics are not the same, but can they be handled the same way?

Your question can’t be answered in one step.

  1. bitmap/raster graphics ::::
    You can crop a bitmap but only in shape of rectangle. If you don’t need the “superfluity” so cut and insert (Paste Special) as bitmap again. The cropped part of the former image then remains as it is.
  2. drawing :::
    This is related on the kind of drawing. In some cases it may be possible to “cut” or delete a part by “shapes”/combine. There is no knife like in CorelDraw. In other cases it may be a way to convert to bitmap and then to proceed. It depends. The question is too general; a drawing can consist as single line or as combination or grouping of different shapes or can have different format (polygon; metafile; curves)…
  1. Open the image in LibreOffice Draw.
  2. Draw a shape (ellipse or rectangle) or a filled curve (for freeform shapes) over the area you want to delete.
  3. Color the fill and stroke of the shape with the same color as the background of the intended deleted area.
  4. Select both the shape and the image; go to File>Export… and choose the format intended making sure that the selection checkbox is clicked.

Good answer!
Point 2 would have been my response.

Cheers,
Lucas.