;; Author: David Frese

;; open-display opens the connection to the X Server. It has one optional 
;; argument: a string or a symbol specifying the name of the display. If it is
;; not specified, it defaults to the value of the DISPLAY environment variable.
;; See XOpenDisplay.

(define (open-display . args)
  (let ((display-name (if (null? args)
			  #f
			  (let ((dpy-name (car args)))
			    (cond
			     ((symbol? dpy-name) (symbol->string dpy-name))
			     (else dpy-name))))))
    (let ((Xdisplay (%open-display display-name)))
      (if (= Xdisplay 0)
	  (error "cannot open display" display-name)
	  (make-display Xdisplay #t)))))

(import-lambda-definition %open-display (name) "Open_Display")

;; for compatibility with elk: is that correct?? see error.c
(define set-after-function! display-set-after-function!)
(define after-function display-after-function)

;; display-default-root-window returns the root window of the default screen.
;; See DefaultRootWindow.

(define (display-default-root-window display)
  (let* ((Xdisplay (display-Xdisplay display))
	 (Xwindow (%default-root-window Xdisplay)))
    (make-window Xwindow (make-display Xdisplay) #f)))

;; for compatibility with Elk.
(define display-root-window display-default-root-window)

(import-lambda-definition %default-root-window (Xdisplay) 
   "Display_Default_Root_Window")

;; display-default-colormap return the default colormap for allocation on the
;; default screen of the specified display. See DefaultColormap.

(define (display-default-colormap display)
  (let* ((Xdisplay (display-Xdisplay display))
	 (Xcolormap (%default-colormap Xdisplay)))
    (make-colormap Xcolormap display #f)))

;; for compatibility with Elk.
(define display-colormap display-default-colormap)

(import-lambda-definition %default-colormap (Xdisplay) 
   "Display_Default_Colormap")

;; display-default-gcontext return the default graphics context for the root
;; window of the default screen of the specified display. See DefaultGC.

(define (display-default-gcontext display)
  (let* ((Xdisplay (display-Xdisplay display))
	 (Xgcontext (%default-gcontext Xdisplay)))
    (make-gcontext Xgcontext display #f)))

(import-lambda-definition %default-gcontext (Xdisplay) 
  "Display_Default_Gcontext")

;; display-default-depth returns the depth (number of planes) of the default 
;; root window of the default screen of the specified display. See DefaultDepth.

(define (display-default-depth display)
  (let ((Xdisplay (display-Xdisplay display)))
    (%default-depth Xdisplay)))

(import-lambda-definition %default-depth (Xdisplay)
  "Display_Default_Depth")

;; display-default-screen-number returns the default screen number of the given 
;; display. See DefaultScreen.

(define (display-default-screen-number display)
  (let ((Xdisplay (display-Xdisplay display)))
    (%default-screen-number Xdisplay)))

(import-lambda-definition %default-screen-number (Xdisplay)
  "Display_Default_Screen_Number")

;; internal function
(define (check-screen-number display screen-number)
  (if (or (< screen-number 0)
	  (>= screen-number (display-screen-count display)))
      (error "invalid screen number" screen-number)))

;; display-cells returns the number of entries in the default colormap of the 
;; specified screen. See DisplayCells.

(define (display-cells display screen-number)
  (check-screen-number display screen-number)
  (%display-cells (display-Xdisplay display) screen-number))

(import-lambda-definition %display-cells (Xdisplay screen-number)
  "Display_Cells")

;; display-planes returns the depth of the root window of the specified screen.
;; See DisplayPlanes.

(define (display-planes display screen-number)
  (check-screen-number display screen-number)
  (%display-planes (display-Xdisplay display) screen-number))

(import-lambda-definition %display-planes (Xdisplay screen-number)
  "Display_Planes")

;; display-string returns the name of the display as a string - the same that
;; was specified with open-display. See DisplayString.

(define (display-string display)
  (%display-string (display-Xdisplay display)))

(import-lambda-definition %display-string (Xdisplay)
  "Display_String")

;; Display-Vendor returns a pair, whose car is the vendor identification and 
;; whose cdr is the release number. See DisplayVendor.

(define (display-vendor display)
  (%display-vendor (display-Xdisplay display)))

(import-lambda-definition %display-vendor (Xdisplay)
  "Display_Vendor")

;; Display-protocol-version return a pair of major and minor version numbers of
;; the X protocol.

(define (display-protocol-version display)
  (%display-protocol-version (display-Xdisplay display)))

(import-lambda-definition %display-protocol-version (Xdisplay)
  "Display_Protocol_Version")

;; display-screen-count returns the number of available screen on this display.
;; See ScreenCount.

(define (display-screen-count display)
  (%display-screen-count (display-Xdisplay display)))

(import-lambda-definition %display-screen-count (Xdisplay)
  "Display_Screen_Count")

;; display-image-byte-order returns one of the symbols 'lsb-first and 
;; 'msb-first.

(define (display-image-byte-order display)
  (%display-image-byte-order (display-Xdisplay display)))

(import-lambda-definition %display-image-byte-order (Xdisplay)
  "Display_Image_Byte_Order")

;; display-bitmap-unit returns the size of a bitmap's scanline unit in bits. 
;; See BitmapUnit.

(define (display-bitmap-unit display)
  (%display-bitmap-unit (display-Xdisplay display)))

(import-lambda-definition %display-bitmap-unit (Xdisplay)
  "Display_Bitmap_Unit")

;; display-bitmap-bit-order return one the symbols 'lbs-first and 'msb-first.
;; See BitmapBitOrder.

(define (display-bitmap-bit-order display)
  (%display-bitmap-bit-order (display-Xdisplay display)))

(import-lambda-definition %display-bitmap-bit-order (Xdisplay)
  "Display_Bitmap_Bit_Order")

;; display-bitmap-pad returns the number of bits that each scanline must be 
;; padded. See BitmapPad.

(define (display-bitmap-pad display)
  (%display-bitmap-pad (display-Xdisplay display)))

(import-lambda-definition %display-bitmap-pad (Xdisplay)
  "Display_Bitmap_Pad")

;; display-width (-height) returns the width (height) of the screen in pixels. 
;; See DisplayWidth (DisplayHeight).

(define (display-width display)
  (%display-width (display-Xdisplay display)))

(import-lambda-definition %display-width (Xdisplay)
  "Display_Width")

(define (display-height display)
  (%display-height (display-Xdisplay display)))

(import-lambda-definition %display-height (Xdisplay)
  "Display_Height")

;; display-width-mm (-height-mm) returns the width (height) of the screen in 
;; millimeters. See DisplayWidthMM (DisplayHeightMM).

(define (display-width-mm display)
  (%display-width-mm (display-Xdisplay display)))

(import-lambda-definition %display-width-mm (Xdisplay)
  "Display_Width_Mm")

(define (display-height-mm display)
  (%display-height-mm (display-Xdisplay display)))

(import-lambda-definition %display-height-mm (Xdisplay)
  "Display_Height_Mm")

;; See XDisplayMotionBufferSize.

(define (display-motion-buffer-size display)
  (%display-motion-buffer-size (display-Xdisplay display)))

(import-lambda-definition %display-motion-buffer-size (Xdisplay)
  "Display_Motion_Buffer_Size")

;; The display-flush-output flushes the output buffer. See XFlush.

(define (display-flush-output display)
  (%display-flush-output (display-Xdisplay display)))

(import-lambda-definition %display-flush-output (Xdisplay)
  "Display_Flush_Output")

;; display-wait-output flushes the output buffer and then waits until all 
;; requests have been received and processed by the X server. discard-events? 
;; specifies whether the events in the queue are discarded or nor. See XSync.

(define (display-wait-output display discard-events?)
  (%display-wait-output (display-Xdisplay display)
			discard-events?))

(import-lambda-definition %display-wait-ouput (Xdisplay discard)
  "Display_Wait_Output")

;; display-no-op sends a NoOperation protocol request to the X server, thereby
;; exercising the connection. See XNoOp.

(define (display-no-op display)
  (%no-op (display-Xdisplay display)))

(import-lambda-definition %no-op (Xdisplay)
  "No_Op")

;; for compatibility with Elk.
(define no-op display-no-op)

;; display-list-depths returns a vector of depths (integers) that are available 
;; on the specified screen. See XListDepths.

(define (display-list-depths display screen-number)
  (%display-list-depths (display-Xdisplay display)
			(check-screen-number screen-number)))

(import-lambda-definition %display-list-depths (Xdisplay scr)
  "List_Depths")

;; for compatibility with Elk.
(define list-depths display-list-depths)

;; display-list-pixmap-formats returns a vector of lists with 3 integers: depth,
;; bits per pixel and scanline pad (See above). See XListPixmapFormats.

(define (display-list-pixmap-formats display)
  (%display-list-pixmap-formats (display-Xdisplay display)))

(define list-pixmap-formats display-list-pixmap-formats) ;; compat./Elk

(import-lambda-definition %display-list-pixmap-formats (Xdisplay)
  "List_Pixmap_Formats")

;; synchronize just sets the after-function of the display to 
;; display-wait-output (with #f for discard-events?).

(define (synchronize display)
  (display-set-after-function! 
   display 
   (lambda (display) 
     (display-wait-output display #f))))