Why is the mouse cursor slightly tilted and not straight?
1.歷史因素
This is the historical reason:
(Concept drawing taken from document: VLSI-81-1_The_Optical_Mouse.pdf)
The mouse, and therefore the mouse cursor, was invented by Douglas Engelbart, and was initially an arrow pointing up.
When the XEROX PARC machine was built, the cursor changed into a tilted arrow. It was found that, given the low resolution of the screens in those days, drawing a straight line (left edge of arrow) and a line at a 45 degree angle (right edge of arrow) was easier to do and more recognizable than the straight cursor.
In case anyone wonders : some less known interfaces did use a straight arrow as pointed in Reddit
2.交互因素
One such irregularity is orientation, and it is neatly explained by the following illustration:
You should find it next to impossible to find the search target in 1 (a straight line in a group of straight lines). But rather easy in 2 - finding a tilted line in a group of straight lines. In 3 it should be equally next to impossible to find the tilted line in a group of tilted lines (of the same angle).
Since vertical and horizontal orientations are the most common ones on screens (and in life in general) a tilted mouse pointer will be more easily found.
