On OSX, the logical(DIP) and physical coordinates are used mixingly.
For example, the captured image has its size in physical pixels(2x) and
location in logical(DIP) pixels. Same to the cursor position. This
causes trouble when we check the relative position of image and cursor
when there are multiple monitors with different DIP setting connected.
This cl proposed a solution to use DIP pixel for any location info,
i.e. top-left of a frame and cursor position. Also propose a method to
get the current scale factor of a window across multiple monitors. And
save the current scale factor in DPI of the capture frame.
Then we can check relative position of cursor and frame correctly
in DIP pixel and compose them in physical pixel.
Bug: webrtc:9178
Change-Id: I3c076aeac2d6f2c1f63d000d7fff03500aa375ac
Reviewed-on: https://webrtc-review.googlesource.com/71621
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: Zijie He <zijiehe@chromium.org>
Commit-Queue: Brave Yao <braveyao@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23263}
89653d5db4