pdf

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https://anonymous@code.call-cc.org/svn/chicken-eggs/release/6/pdf

If you want to check out the source code repository of this egg and you are not familiar with Subversion, see this page.

A PDF document under construction is a record of type doc, created by build-doc. The content of a page content is a record of type page-context, created by build-page-context. Both are passed as arguments to the PDF operators described below, so independent documents can be built in the same program without interfering with each other.

Building documents

build-doc

[procedure] (build-doc [COMPRESS-STREAMS?])

Creates and returns a new, empty document. COMPRESS-STREAMS? (default #t) sets whether streams are compressed when the document is written.

with-document

[syntax] (with-document (DOC [COMPRESS-STREAMS?]) BODY ...)

Binds DOC to a new document (as build-doc) for BODY, and evaluates to the finished document.

with-document-to-file

[syntax] (with-document-to-file (DOC [COMPRESS-STREAMS?]) FILENAME BODY ...)

Like with-document, but writes the finished document to FILENAME (as write-document) instead of returning it.

write-document

[procedure] (write-document DOC FILE [VERSION] [TRAILER-EXTRA])

Writes DOC to FILE. VERSION (default "1.3") is the PDF version string. TRAILER-EXTRA (default "") is raw text appended to the trailer dictionary, after /Root.

doc-compress-streams?

[procedure] (doc-compress-streams? DOC)
[procedure] (doc-compress-streams?-set! DOC BOOLEAN)

Reads or sets whether DOC's streams are compressed.

Building pages

build-page-context

[procedure] (build-page-context PORT [WIDTH] [HEIGHT])

Creates and returns a new page context wrapping the output port PORT, for a page of WIDTH by HEIGHT points (defaulting to 612 by 792, i.e. US Letter).

with-page

[syntax] (with-page DOC (PAGE [WIDTH HEIGHT]) BODY ...)

Binds PAGE to a new page context for BODY to draw into, then adds the finished page to DOC. WIDTH and HEIGHT default to the standard page size.

page-context-port

[procedure] (page-context-port PAGE)

Returns the output port PAGE draws into.

page-width

[procedure] (page-width PAGE)
[procedure] (page-height PAGE)

Return PAGE's width or height, in points.

in-text-mode

[syntax] (in-text-mode PAGE BODY ...)

Wraps BODY in a PDF text object (BT/ET) on PAGE. Text must be drawn inside in-text-mode.

Object model

Lower-level procedures for constructing PDF objects directly, e.g. from a library building on top of pdf.

build-font

[procedure] (build-font DOC BASE-FONT)

Adds a font named BASE-FONT (e.g. "Helvetica") to DOC and returns it.

font-name

[procedure] (font-name FONT)

Returns the resource name FONT was assigned (for use with set-font), as a string, e.g. "/CLF1".

build-indirect-obj

[procedure] (build-indirect-obj DOC CONTENT [REGISTER?])

Wraps CONTENT (a dictionary or stream) as an indirect object with a freshly assigned object number, and, unless REGISTER? is #f, registers it in DOC to be written out. Returns the indirect object.

build-dictionary

[procedure] (build-dictionary VALUES)

Returns a PDF dictionary object from VALUES, an alist of ("/Key" . value) pairs.

build-pdf-stream

[procedure] (build-pdf-stream CONTENT [EXTRA] [FORCE-UNCOMPRESSED?])

Returns a PDF stream object holding CONTENT (a string of raw bytes). EXTRA is an alist of additional dictionary entries for the stream. If FORCE-UNCOMPRESSED? is true, the stream is never compressed, regardless of DOC's compression setting.

add-dictionary-item

[procedure] (add-dictionary-item DICT NAME VALUE)

Adds NAME/VALUE to dictionary DICT.

get-obj-ref

[procedure] (get-obj-ref OBJ)

Returns the PDF indirect reference (e.g. "3 0 R") for indirect object OBJ.

doc-catalog

[procedure] (doc-catalog DOC)

Returns DOC's /Catalog indirect object.

indirect-obj-content

[procedure] (indirect-obj-content OBJ)

Returns the dictionary or stream wrapped by indirect object OBJ.

unit-size

[procedure] (unit-size)

Returns the number of points per inch (72).

Text operators

Each operator below writes to PAGE's content stream and must be called inside in-text-mode (except set-font, which may be called anywhere on the page).

(set-font PAGE FONT-NAME SIZE): selects a font and size (Tf)
(move-to-next-line PAGE): moves to the start of the next line (T*)
(draw-text PAGE STR): draws STR at the current position (Tj)
(move-text PAGE DX DY): moves the text position by (DX, DY) (Td)
(draw-text-on-next-line PAGE STR): moves to the next line and draws STR (')
(set-text-rendering-mode PAGE MODE): sets the text rendering mode (Tr)
(set-char-spacing PAGE SPACE): sets extra character spacing (Tc)
(set-text-x-scale PAGE SCALE): sets horizontal text scaling (Tz)
(set-text-leading PAGE SPACE): sets line leading (TL)
(set-text-rise PAGE RISE): sets text rise (baseline offset) (Ts)
(set-text-matrix PAGE A B C D E F): sets the text matrix (Tm)
(draw-and-adjust-string PAGE STRINGS): draws STRINGS, a list mixing substrings and numeric kerning adjustments (TJ)
(escape STR): escapes (, ), and \ in STR for use in a PDF literal string

Graphics state operators

(rotate PAGE DEGREES): rotates the coordinate system
(translate PAGE DX DY): translates the coordinate system
(scale PAGE SX SY): scales the coordinate system
(set-line-width PAGE WIDTH): sets the stroke line width
(set-line-cap PAGE MODE): sets the line cap style
(set-line-join PAGE MODE): sets the line join style
(set-dash-pattern PAGE DASH-ARRAY PHASE): sets the dash pattern
(set-mitter-limit PAGE LIMIT): sets the miter limit

Path construction operators

(move-to PAGE X Y): starts a new subpath at (X, Y)
(line-to PAGE X Y): adds a straight line segment to (X, Y)
(bezier-to PAGE X1 Y1 X2 Y2 X3 Y3): adds a cubic Bezier curve with two control points
(bezier2-to PAGE X2 Y2 X3 Y3): adds a cubic Bezier curve using the current point as its first control point
(bezier3-to PAGE X1 Y1 X3 Y3): adds a cubic Bezier curve using the end point as its second control point
(close-path PAGE): closes the current subpath
(basic-rect PAGE X Y DX DY): adds a rectangle subpath

Painting operators

(stroke PAGE): strokes the current path
(close-and-stroke PAGE): closes and strokes the current path
(fill-path PAGE): fills the current path (nonzero winding rule)
(close-and-fill PAGE): closes and fills the current path
(even-odd-fill PAGE): fills the current path (even-odd rule)
(fill-and-stroke PAGE): fills then strokes the current path
(even-odd-fill-and-stroke PAGE): fills (even-odd rule) then strokes the current path
(close-fill-and-stroke PAGE): closes, fills, then strokes the current path
(close-even-odd-fill-and-stroke PAGE): closes, fills (even-odd rule), then strokes the current path
(end-path-no-op PAGE): ends the current path without painting it
(clip-path PAGE): intersects the clip region with the current path (nonzero winding rule)
(even-odd-clip-path PAGE): intersects the clip region with the current path (even-odd rule)

Color operators

(set-gray-stroke PAGE GRAY): sets the stroke color, gray scale
(set-gray-fill PAGE GRAY): sets the fill color, gray scale
(set-rgb-stroke PAGE R G B): sets the stroke color, RGB
(set-rgb-fill PAGE R G B): sets the fill color, RGB
(set-cymk-stroke PAGE C Y M K): sets the stroke color, CMYK
(set-cymk-fill PAGE C Y M K): sets the fill color, CMYK

Geometry helpers

Higher-level shapes built from the path construction operators above.

+2pi+: the constant 2pi
+pi/2+: the constant pi/2
(arc PAGE CX CY RADIUS START EXTENT): adds an arc subpath, closed with a chord back to the center
(pie PAGE CX CY RADIUS START EXTENT): adds a pie-slice subpath
(circle PAGE CX CY RADIUS): adds a circular subpath
(ellipse PAGE CX CY RADIUS-A RADIUS-B): adds an elliptical subpath
(rectangle PAGE X Y DX DY RADIUS): adds a rectangle subpath, with rounded corners if RADIUS is nonzero
(polyline PAGE POINTS RADIUS CLOSED?): adds a subpath through POINTS (a list of (X Y) pairs), with corners rounded by RADIUS
(regular-polygon PAGE CX CY RADIUS SIDES [FILLET-RADIUS]): adds a regular polygon subpath
(star PAGE CX CY EXT-RADIUS INT-RADIUS SIDES [FILLET-RADIUS]): adds a star subpath

Examples


(import scheme (chicken base) (chicken random) (prefix pdf pdf:))
(define random pseudo-random-integer)

(define-constant pi 3.14159)

(define-syntax dotimes
  (syntax-rules ()
    ((_ (index maxval) body ...)
     (do ((index 0 (+ index 1)))
       ((= index maxval))
       body ...))))

(define (ex1)
  (pdf:with-document-to-file (doc) "ex1.pdf"
   (let ((helvetica (pdf:build-font doc "Helvetica"))
         (courier (pdf:build-font doc "Courier")))
     (pdf:with-page doc (pg)
      (pdf:in-text-mode pg
       (pdf:set-font pg (pdf:font-name helvetica) 36)
       (pdf:move-text pg 100 750)
       (pdf:draw-text pg "scm-pdf: Example 1"))
      (pdf:in-text-mode pg
       (dotimes (i 25)
                    (pdf:set-font pg (pdf:font-name helvetica) (* i 1.5))
                    (pdf:move-text pg (+ i 5) (+ i 10))
                    (pdf:draw-text pg "Helvetica")))
      (pdf:in-text-mode pg
       (dotimes (i 25)
                    (pdf:set-font pg (pdf:font-name courier) (* i 1.5))
                    (pdf:move-text pg (+ i 5) (- 50 (+ i 10)))
                    (pdf:draw-text pg "Courier")))))))

(define (ex2)
  (pdf:with-document-to-file (doc) "ex2.pdf"
   (let ((helvetica (pdf:build-font doc "Helvetica")))
     (pdf:with-page doc (pg)
      (pdf:in-text-mode pg
       (pdf:set-font pg (pdf:font-name helvetica) 36)
       (pdf:move-text pg 100 750)
       (pdf:draw-text pg "scm-pdf: Example 2"))
      (pdf:translate pg 230 500)
      (do ((j 0 (+ j 1))
           (i 0.67 (* i 1.045)))
        ((= j 101))
        (pdf:in-text-mode pg
         (pdf:set-font pg (pdf:font-name helvetica) i)
         (pdf:move-text pg (* i 3) 0)
         (pdf:draw-text pg "rotation"))
        (pdf:rotate pg 18)))
     (pdf:with-page doc (pg)
      (pdf:in-text-mode pg
       (pdf:set-font pg (pdf:font-name helvetica) 40)
       (pdf:move-text pg 230 500)
       (pdf:draw-text pg "That's All, Folks!"))))))

(define (ex3)
  (pdf:with-document-to-file (doc) "ex3.pdf"
   (let ((helvetica (pdf:build-font doc "Helvetica")))
     (pdf:with-page doc (pg 800 1000)
      (pdf:in-text-mode pg
       (pdf:set-font pg (pdf:font-name helvetica) 36.0)
       (pdf:move-text pg 100 900)
       (pdf:draw-text pg "scm-pdf: Example 3"))
      (pdf:move-to pg (+ 10 (random 500))(+ 10 (random 400)))
      (pdf:set-gray-fill pg 0.5)
      (dotimes (i 50)
               (pdf:line-to pg (+ 50 (random 500)) (+ 50 (random 400))))
      (pdf:close-even-odd-fill-and-stroke pg)
      (pdf:move-to pg (+ 50 (random 500))(+ 400 (random 400)))
      (pdf:set-rgb-fill pg 0.5 0.5 0.8)
      (pdf:set-rgb-stroke pg 0.9 0.5 0.1)
      (dotimes (i 50)
               (pdf:bezier2-to pg (+ 50 (random 500)) (+ 400 (random 400))
                           (+ 50 (random 500)) (+ 400 (random 400))))
      (pdf:close-even-odd-fill-and-stroke pg)))))

(define (ex4)
  (pdf:with-document-to-file (doc) "ex4.pdf"
   (let ((helvetica (pdf:build-font doc "Helvetica")))
     (pdf:with-page doc (pg)
       (pdf:in-text-mode pg
        (pdf:set-font pg (pdf:font-name helvetica) 36.0)
        (pdf:move-text pg 100 750)
        (pdf:draw-text pg "scm-pdf: Example 4"))
       (pdf:set-rgb-stroke pg 0.1 0.1 0.1)
       (pdf:set-rgb-fill pg 0.8 0.8 0.8)
       (let ((x 50) (y 600))
         (dotimes (i 2)
                  (pdf:rectangle pg x y 500 140 10)
                  (pdf:close-fill-and-stroke pg)
                  (set! y (- y 180))))
       (pdf:translate pg 50 670)
       (let ((x 50) (y 0))
         (do ((i 0 (+ i 1))
              (j 8 (* j 1.05)))
           ((= i 4))
           (pdf:set-rgb-fill pg (* 0.1 j) (* 0.01 j) (* 0.02 j))
           (pdf:circle pg x y (* 4 j))
           (pdf:close-fill-and-stroke pg)
           (pdf:ellipse pg (+ x 250) y (* 5 j) (* 4 j))
           (pdf:close-fill-and-stroke pg)
           (set! x (+ x 50))))

       (pdf:translate pg 0 -180)
       (pdf:regular-polygon pg 150 0 50 7 8)
       (pdf:close-fill-and-stroke pg)
       (pdf:star pg 350 0 50 30 6 5)
       (pdf:close-fill-and-stroke pg)

       (pdf:set-rgb-fill pg 0.8 0.6 0.2)
       (pdf:regular-polygon pg 150 0 30 5 4)
       (pdf:close-fill-and-stroke pg)
       (pdf:star pg 350 0 40 20 4 6)
       (pdf:close-fill-and-stroke pg)

       (pdf:set-rgb-fill pg 0.4 0.8 0.7)
       (pdf:regular-polygon pg 150 0 15 3 3)
       (pdf:close-fill-and-stroke pg)
       (pdf:star pg 350 0 35 10 12 1)
       (pdf:close-fill-and-stroke pg)

       (pdf:set-line-width pg 0.5)
       (do ((r 2 (+ r 2)))
         ((= r 100))
         (pdf:set-rgb-stroke pg (* 0.01 (random 100))
                             (* 0.01 (random 100))
                             (* 0.01 (random 100)))
         (pdf:arc pg 250 -230 r (* pi 0.001 (random 2000))
                             (* pi 0.001 (random 2000)))
         (pdf:stroke pg))))))


(ex1)
(ex2)
(ex3)
(ex4)

pdf

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