Can I detect the display size/resolution in Emacs?

I'd like to change the window/frame size of my XEmacs based on the current display resolution.

This is useful when I run my laptop either by开发者_运维知识库 itself or attached to a docking station with an external monitor. In either situation, I'd like Emacs to detect the primary screen resolution and adjust its main window frame size accordingly when I start it up.

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For a more cross-platform solution, look at

(display-pixel-width)
(display-pixel-height)

If what you actually want to do is set the Emacs window to full screen on start-up, check out maxframe.el.

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The current display resolution is available using the following functions (both non-interactive).

(x-display-pixel-width)
(x-display-pixel-height)