screen resolution

Unity has many screen resolutions.
For example,
WVGA Landscape corresponds 800 pixels by 400 pixels.
But.
“3:2 portrait” does not corresponds any A pixels by any B pixels.
Which number is A and B?

When selecting a screen size (such as WVGA Landscape), the Game view will be rescaled to match exactly the given screen size. You will also see a little slider at the top of the game view indicating whether the Game view is zoom scale.

When selecting an aspect ratio (such as 3:2 portrait). The Game view will have the given aspect ratio and fit the tab. The screen size (in pixels) will depend on the size of the tab of the Game view.