maple resolution stretched vertically and distorted

For window mode unless you can get a monitor with a vertical resolution higher than 768 pixels what I can suggest is reducing the size of the title bar (reducing text size will allow you to further reduce the size of the title bar) and the border padding. I believe it is possible to use a 3rd party program to remove the title bar and padding altogether but I can't remember.

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For full screen, assuming that you have the same graphics card configuration program, if you change the setting shown below to "Maintain aspect ratio" you can prevent it from stretching but it will put black bars on the side of the screen. If "Maintain aspect ratio" is greyed out then reducing your resolution should allow you to modify the settings.

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