Say, for example, you are somewhere near the middle
of a large file and the cursor is about half way down
the window. You wish to scroll up (or down) to locate
a some code. As you press the cursor key the
cursor moves as you would expect and your gaze
follows the cursor as it moves towards the top (or
bottom) of the window, effectively using the cursor
as a visual reference point to help you find the
text you are looking for.
However, when the cursor reaches the top (or bottom) line
of the window the next key press causes the contents
of the window to scroll, not by a single line to reveal
the next line of the file, but by half the number lines
in the window, moving the cursor back to the
middle line of the window again. Almost instantly your
eyes have to move their focus a significant distance...
You're correct. That is a problem.
What I've seen some apps do that I like better is scroll by
one line when they get to within n lines of the top or
bottom, so that you always have a little context. And n
can be set by the user. And then there needs to be a
little minor exception handling for when the cursor nears
the very top or bottom of the file.
Having 1-10 lines of context makes reading through the
file, and spotting those bugs caused by something a line or
two above the line about which you've been alerted, quite a
bit easier.
