I have long found that when I need to print something from the computer screen, the easiest way to do it was to hit PrintScreen, then paste it into an Excel spreadsheet, then crop and resize it till I have what I want. For instance, I frequently want to crop & overlay two Google Maps screenshots so they fit together. Or save an entire year of cropped screenshots of payroll tax confirmation screens on the same spreadsheet page. (For me, Excel does these things far more easily than Word or Paint.)
For years I've occasionally tried the same thing using first OpenOffice Calc 3.x and now LibreOffice 4.0.x, and found that it is much more difficult. Calc brings up a window with measurements you can change, and its own small snapshot of the graphic that shows where you are moving the borders to. It works, but it is hard to get it just right. You cannot see it well, and must repeatedly invoke the tool, change the measurements, and quit the tool to see what you've really got. It takes several iterations to get it where you want it.
Excel's cropping tool (at least as far back as Excel 97) allows the mouse to grab the handles on the graphic's edges and drag them where you want them, which is far easier both to see and to do.
PLEASE add a mouse tool that can be used directly on the image in the spreadsheet. The cropping icon could still bring up the window (for those who prefer it), and then a button in that window could replace the window with the mouse tool.
Indeed. There is such a crop tool available in Draw and Impress but not in Calc or Writer. It should be relatively easy to add it to Calc (but Writer is a problem, luckily your request is not about Writer).
I have found a duplicate of this bug.
*** This bug has been marked as a duplicate of bug 61991 ***