The Display UL Coordinates alternative can be chosen instead, to have the origin at the upper-left corner and with the 2nd coordinate increasing downwards. If this is done, images in the TEX document using such coordinates should be preceded by the \MacintoshOrigin command.
To mark a point within the image, simply click with the mouse at the desired point. A small window will pop-up, as in the screen-shot below, allowing a text-label to be typed and confirmation of the selection.
After the first point has been chosen a Log-window appears, containing the bounding-box and other information, as well as data for the 1st marked point. A line of data is added for each subsequent point. Within the image the point is marked by a numbered cross. Guide-rules help position the cursor accurately; gradations may be inches, centimeters, or pixels. The Log-window can be seen in the above picture. Since it contains just plain text, the Log can be edited at any time.
When finished with an image, click its close-box (in the upper-left corner); this also adds the closing comment to the Log. Finally the Log-window should be closed and Save As choosing whatever name is desired--usually ending .bb, though this is not compulsory.
| \MacintoshOrigin | allow for coordinates with origin at upper-left |
| \EndLineAdjust | adjust for awkward line-end characters |