scx/scheme/xlib/font.scm

127 lines
4.2 KiB
Scheme

;; Copyright (c) 2001-2003 by Norbert Freudemann, David Frese
(define-enumerated-type font-direction :font-direction
font-direction? font-directions font-direction-name font-direction-index
(left-to-right right-to-left))
(define-exported-binding "scx-font-direction" :font-direction)
(define-exported-binding "scx-font-directions" font-directions)
(define-record-type char-struct :char-struct
(make-char-struct lbearing rbearing width ascent descent attributes)
char-struct?
(lbearing char-struct:lbearing)
(rbearing char-struct:rbearing)
(width char-struct:width)
(ascent char-struct:ascent)
(descent char-struct:descent)
(attributes char-struct:attributes))
(define-exported-binding "scx-char-struct" :char-struct)
(define-record-type font-struct :font-struct
(make-font-struct cpointer
fid direction min-char-or-byte2 max-char-or-byte2
min-byte1 max-byte1 all-char-exist? default-char
properties min-bounds max-bounds per-char ascent descent)
font-struct?
;; properties is an alist atom -> number
;; per-char is a vector of char-structs
;; min-bounds, max-bounds are a char-struct
(cpointer font-struct:cpointer)
(fid font-struct:fid)
(direction font-struct:direction)
(min-char-or-byte2 font-struct:min-char-or-byte2)
(max-char-or-byte2 font-struct:max-char-or-byte2)
(min-byte1 font-struct:min-byte1)
(max-byte1 font-struct:max-byte1)
(all-char-exist? font-struct:all-char-exist?)
(default-char font-struct:default-char)
(properties font-struct:properties)
(min-bounds font-struct:min-bounds)
(max-bounds font-struct:max-bounds)
(per-char font-struct:per-char)
(ascent font-struct:ascent)
(descent font-struct:descent))
(define-exported-binding "scx-fontstruct" :font-struct)
;; *** load or unload fonts ******************************************
(import-xlib-function load-font (display name)
"scx_Load_Font")
(import-xlib-function unload-font (display font)
"scx_Unload_Font")
;; returns a font-struct record or #f
(import-xlib-function query-font (display font-id)
"scx_Query_Font")
;; returns a font-struct record or #f
(import-xlib-function load-query-font (display name)
"scx_Load_Query_Font")
(import-xlib-function free-font (display font-struct)
"scx_Free_Font")
(define (get-font-property font-struct atom)
(let ((a (assq atom (font-struct:properties font-struct)))) ;; assq ??
(and a (cdr a))))
;; *** obtain or free font names and information *********************
(import-xlib-function list-fonts (display pattern maxnames)
"scx_List_Fonts")
;; returns an alist mapping name -> font-struct
(import-xlib-function list-fonts-with-info (display pattern maxnames)
"scx_List_Fonts_With_Info")
;; *** set or get the font search path *******************************
(import-xlib-function set-font-path (display directories)
"scx_Set_Font_Path")
(import-xlib-function get-font-path (display)
"scx_Get_Font_Path")
;; TODO: ??
;; calc-index calculates the array-position in XFontStruct.per_char by giving
;; the character index which ranges between [font-min-byte2...font-max-byte2]
;; for one-byte fonts or for two-byte fonts the lower 8 bits must be between
;; [font-min-byte1...font-max-byte1] and the higher 8 bits must be between
;; [font-min-byte2...font-max-byte2]. An error is raised if the index does not
;; fit into these boundaries.
;(define (calc-index font index)
; (let ((min1 (font-min-byte1 font))
; (max1 (font-max-byte1 font))
; (min2 (font-min-byte2 font))
; (max2 (font-max-byte2 font))
; (check-bounds
; (lambda (min max i s)
; (if (or (< i min)
; (> i max))
; (error (string-append s
; (number->string min)
; " and "
; (number->string max)
; "; given")
; index)))))
; (if (and (= 0 min1) (= 0 max1))
; ;; two-byte font
; (let ((b1 (bitwise-and index 255))
; (b2 (bitwise-and (arithmetic-shift index -8) 255)))
; (check-bounds min1 max1 b1
; "expected an integer with lower 8 bits between ")
; (check-bounds min2 max2 b2
; "expected an integer with higher 8 bits between ")
; (+ (* b1 (+ (- max2 min2) 1))
; b2))
; ;; one-byte font
; (begin
; (check-bounds min2 max2 index
; "expected an integer between ")
; index))))