I need to display a portrait-mode app from my Samsung Galaxy S9 on a horizontal pc-screen. The pc-screen is able to rotate to portrait mode, but the problem is that the image rotates with it. The image is always displayed horizontally in regards to the pc-screen. This means that when the pc-screen is horizontal, the image is displayed in portrait-mode in the middle of the screen, covering only a small "pillar". When I rotate the PC screen to portrait-mode, the image rotates with it, leaving the same "pillar" covered (though now rotated 90°).
What I need is for the image to be displayed in portrait-mode while the screen is in portrait-mode (meaning the image is rotated -90° when the screen is in horizontal, making it utilize the entirety of the screen).
It's a difficult issue to describe, but I hope these images help.