Add support for compressed PDF streams, using Simon's new deflate library.

[sgt/halibut] / bk_pdf.c

diff --git a/bk_pdf.c b/bk_pdf.c
index 2697b16..71307d2 100644 (file)
--- a/bk_pdf.c
+++ b/bk_pdf.c
@@ -5,6 +5,7 @@
 #include <assert.h>
 #include "halibut.h"
 #include "paper.h"
+#include "deflate.h"
 
 #define TREE_BRANCH 2                 /* max branching factor in page tree */
 
@@ -112,7 +113,7 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
 
     /*
      * The catalogue just contains references to the outlines and
-     * pages objects.
+     * pages objects, and the pagelabels dictionary.
      */
     objtext(cat, "<<\n/Type /Catalog");
     if (outlines) {
@@ -121,6 +122,8 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
     }
     objtext(cat, "\n/Pages ");
     objref(cat, pages);
+    /* Halibut just numbers pages 1, 2, 3, ... */
+    objtext(cat, "\n/PageLabels<</Nums[0<</S/D>>]>>");
     if (outlines)
        objtext(cat, "\n/PageMode /UseOutlines");
     objtext(cat, "\n>>\n");
@@ -130,7 +133,7 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
      * providing all the font objects and names to call them by.
      */
     font_index = 0;
-    objtext(resources, "<<\n/Font <<\n");
+    objtext(resources, "<<\n/ProcSet [/PDF/Text]\n/Font <<\n");
     for (fe = doc->fonts->head; fe; fe = fe->next) {
        char fname[40];
        int i, prev;
@@ -422,31 +425,26 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
            objtext(opage, "/Annots [\n");
 
            for (xr = page->first_xref; xr; xr = xr->next) {
-               object *annot;
                char buf[256];
 
-               annot = new_object(&olist);
-               objref(opage, annot);
-               objtext(opage, "\n");
-
-               objtext(annot, "<<\n/Type /Annot\n/Subtype /Link\n/Rect [");
+               objtext(opage, "<</Subtype/Link\n/Rect[");
                sprintf(buf, "%g %g %g %g",
                        xr->lx / FUNITS_PER_PT, xr->by / FUNITS_PER_PT,
                        xr->rx / FUNITS_PER_PT, xr->ty / FUNITS_PER_PT);
-               objtext(annot, buf);
-               objtext(annot, "]\n/Border [0 0 0]\n");
+               objtext(opage, buf);
+               objtext(opage, "]/Border[0 0 0]\n");
 
                if (xr->dest.type == PAGE) {
-                   objtext(annot, "/Dest [");
-                   objref(annot, (object *)xr->dest.page->spare);
-                   objtext(annot, " /XYZ null null null]\n");
+                   objtext(opage, "/Dest[");
+                   objref(opage, (object *)xr->dest.page->spare);
+                   objtext(opage, "/XYZ null null null]");
                } else {
-                   objtext(annot, "/A <<\n/Type /Action\n/S /URI\n/URI ");
-                   pdf_string(objtext, annot, xr->dest.url);
-                   objtext(annot, "\n>>\n");
+                   objtext(opage, "/A<</S/URI/URI");
+                   pdf_string(objtext, opage, xr->dest.url);
+                   objtext(opage, ">>");
                }
 
-               objtext(annot, ">>\n");
+               objtext(opage, ">>\n");
            }
 
            objtext(opage, "]\n");
@@ -475,12 +473,19 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
     for (o = olist.head; o; o = o->next) {
        rdstringc rs = {0, 0, NULL};
        char text[80];
+       deflate_compress_ctx *zcontext;
+       void *zbuf;
+       int zlen;
 
        sprintf(text, "%d 0 obj\n", o->number);
        rdaddsc(&rs, text);
 
        if (!o->main.text && o->stream.text) {
-           sprintf(text, "<<\n/Length %d\n>>\n", o->stream.pos);
+           zcontext = deflate_compress_new(DEFLATE_TYPE_ZLIB);
+           deflate_compress_data(zcontext, o->stream.text, o->stream.pos,
+                                 DEFLATE_END_OF_DATA, &zbuf, &zlen);
+           deflate_compress_free(zcontext);
+           sprintf(text, "<<\n/Filter/FlateDecode\n/Length %d\n>>\n", zlen);
            rdaddsc(&o->main, text);
        }
 
@@ -492,15 +497,11 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
            rdaddc(&rs, '\n');
 
        if (o->stream.text) {
-           /*
-            * FIXME: If we ever start compressing stream data then
-            * it will have zero bytes in it, so we'll have to be
-            * more careful than this.
-            */
            rdaddsc(&rs, "stream\n");
-           rdaddsc(&rs, o->stream.text);
+           rdaddsn(&rs, zbuf, zlen);
            rdaddsc(&rs, "\nendstream\n");
            sfree(o->stream.text);
+           sfree(zbuf);
        }
 
        rdaddsc(&rs, "endobj\n");
@@ -521,9 +522,11 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
 
     /*
      * Header. I'm going to put the version IDs in the header as
-     * well, simply in PDF comments.
+     * well, simply in PDF comments.  The PDF Reference also suggests
+     * that binary PDF files contain four top-bit-set characters in
+     * the second line.
      */
-    fileoff = fprintf(fp, "%%PDF-1.3\n");
+    fileoff = fprintf(fp, "%%PDF-1.3\n%% L\xc3\xba\xc3\xb0""a\n");
     for (p = sourceform; p; p = p->next)
        if (p->type == para_VersionID)
            fileoff += pdf_versionid(fp, p->words);