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;;; Chickadee Game Toolkit
;;; Copyright © 2021 David Thompson <dthompson2@worcester.edu>
;;;
;;; Licensed under the Apache License, Version 2.0 (the "License");
;;; you may not use this file except in compliance with the License.
;;; You may obtain a copy of the License at
;;;
;;; http://www.apache.org/licenses/LICENSE-2.0
;;;
;;; Unless required by applicable law or agreed to in writing, software
;;; distributed under the License is distributed on an "AS IS" BASIS,
;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;;; See the License for the specific language governing permissions and
;;; limitations under the License.
;;; Commentary:
;;
;; JPEG image loading.
;;
;;; Code:
(define-module (chickadee image jpeg)
#:use-module (chickadee config)
#:use-module (chickadee data bytestruct)
#:use-module (ice-9 binary-ports)
#:use-module (ice-9 exceptions)
#:use-module (ice-9 format)
#:use-module (ice-9 match)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-11)
#:use-module (system foreign)
#:export (load-jpeg))
;;;
;;; Enums
;;;
(define TJERR_WARNING 0)
(define TJERR_FATAL 1)
(define TJPF_RGBA 7)
(define TJFLAG_BOTTOMUP 2)
;;;
;;; Low-level bindings
;;;
(define libturbojpeg-func
(let ((lib (dynamic-link* %libturbojpeg)))
(lambda (return-type function-name arg-types)
(pointer->procedure return-type
(dynamic-func function-name lib)
arg-types))))
(define-syntax-rule (define-foreign name return-type func-name arg-types)
(define name
(libturbojpeg-func return-type func-name arg-types)))
(define-foreign tj-get-error-code
int "tjGetErrorCode" '(*))
(define-foreign tj-get-error-str2
'* "tjGetErrorStr2" '(*))
(define-foreign tj-init-decompress
'* "tjInitDecompress" '())
(define-foreign tj-destroy
int "tjDestroy" '(*))
(define-foreign tj-decompress-header3
int "tjDecompressHeader3" (list '* '* unsigned-long '* '* '* '*))
(define-foreign tj-decompress2
int "tjDecompress2" (list '* '* unsigned-long '* int int int int int))
;;;
;;; High-level bindings
;;;
(define-byterecord-type <header>
(make-header)
header?
(width int header-width)
(height int header-height)
(jpeg-subsamp int header-jpeg-subsamp)
(jpeg-colorspace int header-jpeg-colorspace))
(define (display-tjhandle handle port)
(display "#<tjhandle>" port))
(define-wrapped-pointer-type <tjhandle> tjhandle?
wrap-tjhandle unwrap-tjhandle display-tjhandle)
(define (check-error handle)
(let* ((ptr (if handle (unwrap-tjhandle handle) %null-pointer))
(error-code (tj-get-error-code ptr))
(error-string (pointer->string (tj-get-error-str2 ptr))))
(if (= error-code TJERR_FATAL)
(raise-exception (make-exception-with-message error-string))
(format (current-error-port) "warning: ~a~%" error-string))))
(define (init-decompress)
(wrap-tjhandle (tj-init-decompress)))
(define (destroy-handle handle)
(tj-destroy (unwrap-tjhandle handle)))
(define (decompress-headers handle buffer)
(let ((header (bytestruct-alloc <header>)))
(unless (zero?
(tj-decompress-header3
(unwrap-tjhandle handle)
(bytevector->pointer buffer)
(bytevector-length buffer)
(bytestruct-&ref <header> (width) header)
(bytestruct-&ref <header> (height) header)
(bytestruct-&ref <header> (jpeg-subsamp) header)
(bytestruct-&ref <header> (jpeg-colorspace) header)))
(check-error handle))
header))
(define (decompress handle buffer width pitch height pixel-format flags)
(let ((bv (make-bytevector (* pitch height))))
(unless (zero? (tj-decompress2 (unwrap-tjhandle handle)
(bytevector->pointer buffer)
(bytevector-length buffer)
(bytevector->pointer bv)
width pitch height pixel-format flags))
(check-error handle))
bv))
(define (load-jpeg file-name)
(if (file-exists? file-name)
(let ((buffer (call-with-input-file file-name get-bytevector-all))
(handle (init-decompress)))
(dynamic-wind
(lambda () #t)
(lambda ()
(let* ((header (decompress-headers handle buffer))
(width (header-width header))
(height (header-height header))
(pitch (* width 4)))
(values (decompress handle buffer width pitch height
TJPF_RGBA 0) ; TJFLAG_BOTTOMUP
width height)))
(lambda ()
(destroy-handle handle))))
(raise-exception
(make-exception (make-external-error)
(make-exception-with-message
(string-append "file not found: " file-name))))))
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