#lang racket
(require ffi/unsafe
         ffi/unsafe/define
         racket/draw
         racket/draw/unsafe/cairo
         racket/snip)

(define-ffi-definer define-glib (ffi-lib "/opt/local/lib/libgtk-x11-2.0"))
(define-glib gtk_init (_fun _pointer _pointer -> _void))
(define-ffi-definer define-poppler (ffi-lib "libpoppler-glib"))

(define _PopplerDocumentPointer (_cpointer 'PopplerDocument))
(define _PopplerPagePointer (_cpointer 'PopplerPage))

(define-poppler poppler_document_new_from_file (_fun _string _string _pointer -> (_or-null _PopplerDocumentPointer)))
;;; PopplerDocument *poppler_document_new_from_file(const char *uri, const char *password, GError **error);
; Creates a new PopplerDocument. If NULL is returned, then error will be set. 
; Possible errors include those in the POPPLER_ERROR and G_FILE_ERROR domains.
;    uri:      uri of the file to load
;    password: password to unlock the file with, or NULL. [allow-none]
;    error:    Return location for an error, or NULL. [allow-none]
; Returns:     A newly created PopplerDocument, or NULL

(define-poppler poppler_document_get_page (_fun _PopplerDocumentPointer _int -> _PopplerPagePointer))
;;; PopplerPage * poppler_document_get_page(PopplerDocument *document, int index);
; Returns the PopplerPage indexed at index. This object is owned by the caller.
;    document:  A PopplerDocument
;    index:     a page index
; Returns :     (transfer full) : The PopplerPage at index

(define-poppler poppler_page_render (_fun _PopplerPagePointer _cairo_t -> _void))
;;; void poppler_page_render (PopplerPage *page, cairo_t *cairo);
; Render the page to the given cairo context. 
; This function is for rendering a page that will be displayed. 
; If you want to render a page that will be printed use poppler_page_render_for_printing() instead
;    page:  the page to render from
;    cairo: cairo context to render to

;;;
;;; EXAMPLE
;;;

(define WIDTH  800)
(define HEIGHT 800)

(gtk_init #f #f)
(define document (poppler_document_new_from_file "file:/Users/soegaard/Dropbox/GitHub/racket-poppler/bla.pdf" #f #f))
(define page     (poppler_document_get_page document 0))
(define surface  (cairo_image_surface_create CAIRO_FORMAT_ARGB32 WIDTH HEIGHT))
(define context  (cairo_create surface))
(poppler_page_render page context)

; Testing: Write the pdf to x.png
(define-ffi-definer define-cairo (ffi-lib "libcairo.2.dylib"))  ; in racket/draw/unsafe/cairo
(define _cairo_surface_t (_cpointer 'cairo_surface_t))          ; ; in racket/draw/unsafe/cairo
;;; cairo_status_t cairo_surface_write_to_png(cairo_surface_t *surface, const char *filename);
(define-cairo cairo_surface_write_to_png (_fun _cairo_surface_t _string -> _int))
(cairo_surface_write_to_png surface "x.png")
; and display it in an image-snip.
(make-object image-snip% "x.png")