+;;;; Frame/display capabilities.
+(defun display-mouse-p (&optional display)
+ "Return non-nil if DISPLAY has a mouse available.
+DISPLAY can be a display name, a frame, or nil (meaning the selected
+frame's display)."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((eq frame-type 'pc)
+ (msdos-mouse-p))
+ ((eq system-type 'windows-nt)
+ (> w32-num-mouse-buttons 0))
+ ((memq frame-type '(x mac))
+ t) ;; We assume X and Mac *always* have a pointing device
+ (t
+ (or (and (featurep 'xt-mouse)
+ xterm-mouse-mode)
+ ;; t-mouse is distributed with the GPM package. It doesn't have
+ ;; a toggle.
+ (featurep 't-mouse))))))
+
+(defun display-popup-menus-p (&optional display)
+ "Return non-nil if popup menus are supported on DISPLAY.
+DISPLAY can be a display name, a frame, or nil (meaning the selected
+frame's display).
+Support for popup menus requires that the mouse be available."
+ (and
+ (let ((frame-type (framep-on-display display)))
+ (memq frame-type '(x w32 pc mac)))
+ (display-mouse-p display)))
+
+(defun display-graphic-p (&optional display)
+ "Return non-nil if DISPLAY is a graphic display.
+Graphical displays are those which are capable of displaying several
+frames and several different fonts at once. This is true for displays
+that use a window system such as X, and false for text-only terminals.
+DISPLAY can be a display name, a frame, or nil (meaning the selected
+frame's display)."
+ (not (null (memq (framep-on-display display) '(x w32 mac)))))
+
+(defun display-images-p (&optional display)
+ "Return non-nil if DISPLAY can display images.
+
+DISPLAY can be a display name, a frame, or nil (meaning the selected
+frame's display)."
+ (and (display-graphic-p display)
+ (fboundp 'image-mask-p)
+ (fboundp 'image-size)))
+
+(defalias 'display-multi-frame-p 'display-graphic-p)
+(defalias 'display-multi-font-p 'display-graphic-p)
+
+(defun display-selections-p (&optional display)
+ "Return non-nil if DISPLAY supports selections.
+A selection is a way to transfer text or other data between programs
+via special system buffers called `selection' or `cut buffer' or
+`clipboard'.
+DISPLAY can be a display name, a frame, or nil (meaning the selected
+frame's display)."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((eq frame-type 'pc)
+ ;; MS-DOG frames support selections when Emacs runs inside
+ ;; the Windows' DOS Box.
+ (not (null dos-windows-version)))
+ ((memq frame-type '(x w32 mac))
+ t) ;; FIXME?
+ (t
+ nil))))
+
+(defun display-screens (&optional display)
+ "Return the number of screens associated with DISPLAY."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32))
+ (x-display-screens display))
+ (t ;; FIXME: is this correct for the Mac?
+ 1))))
+
+(defun display-pixel-height (&optional display)
+ "Return the height of DISPLAY's screen in pixels.
+For character terminals, each character counts as a single pixel."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-pixel-height display))
+ (t
+ (frame-height (if (framep display) display (selected-frame)))))))
+
+(defun display-pixel-width (&optional display)
+ "Return the width of DISPLAY's screen in pixels.
+For character terminals, each character counts as a single pixel."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-pixel-width display))
+ (t
+ (frame-width (if (framep display) display (selected-frame)))))))
+
+(defun display-mm-height (&optional display)
+ "Return the height of DISPLAY's screen in millimeters.
+If the information is unavailable, value is nil."
+ (and (memq (framep-on-display display) '(x w32 mac))
+ (x-display-mm-height display)))
+
+(defun display-mm-width (&optional display)
+ "Return the width of DISPLAY's screen in millimeters.
+If the information is unavailable, value is nil."
+ (and (memq (framep-on-display display) '(x w32 mac))
+ (x-display-mm-width display)))
+
+(defun display-backing-store (&optional display)
+ "Return the backing store capability of DISPLAY's screen.
+The value may be `always', `when-mapped', `not-useful', or nil if
+the question is inapplicable to a certain kind of display."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-backing-store display))
+ (t
+ 'not-useful))))
+
+(defun display-save-under (&optional display)
+ "Return non-nil if DISPLAY's screen supports the SaveUnder feature."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-save-under display))
+ (t
+ 'not-useful))))
+
+(defun display-planes (&optional display)
+ "Return the number of planes supported by DISPLAY."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-planes display))
+ ((eq frame-type 'pc)
+ 4)
+ (t
+ (truncate (log (length (tty-color-alist)) 2))))))
+
+(defun display-color-cells (&optional display)
+ "Return the number of color cells supported by DISPLAY."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-color-cells display))
+ ((eq frame-type 'pc)
+ 16)
+ (t
+ (tty-display-color-cells)))))
+
+(defun display-visual-class (&optional display)
+ "Returns the visual class of DISPLAY.
+The value is one of the symbols `static-gray', `gray-scale',
+`static-color', `pseudo-color', `true-color', or `direct-color'."
+ (let ((frame-type (framep-on-display display)))
+ (cond
+ ((memq frame-type '(x w32 mac))
+ (x-display-visual-class display))
+ ((and (memq frame-type '(pc t))
+ (tty-display-color-p display))
+ 'static-color)
+ (t
+ 'static-gray))))
+
+\f