Function GetPlayerCameraAspectRatio retrieves the aspect ratio of a player's camera.
Function GetPlayerCameraAspectRatio was added in 0.3z and will not work in earlier versions!
The return value of this function represents the value of the "widescreen" option in the game's display settings, not the actual aspect ratio of the player's display.

int playerid The ID of the player to get the camera aspect ratio of.

Return Values:
The aspect ratio of the player's camera, as a float. The aspect ratio can be one of three values: 4:3 (1.3333334, Float:0x3FAAAAAB) when widescreen is turned off, 5:4 (1.2470589, Float:0x3F9F9FA0) when letterbox mode is turned on, and 16:9 (1.7764707, Float:0x3FE36364) when widescreen is turned on regardless of the letterbox mode.

new szString[144];
format(szString, sizeof(szString), "Your aspect ratio: %f", GetPlayerCameraAspectRatio(playerid));
SendClientMessage(playerid, -1, szString);

Related Functions
The following functions may be useful, as they are related to this function in one way or another.