Compacted PS and PDF output files by removing redundant reiterations

[sgt/halibut] / bk_pdf.c

diff --git a/bk_pdf.c b/bk_pdf.c
index fe10894..f6babe5 100644 (file)
--- a/bk_pdf.c
+++ b/bk_pdf.c
@@ -56,6 +56,8 @@ struct objlist_Tag {
 static object *new_object(objlist *list);
 static void objtext(object *o, char const *text);
 static void objstream(object *o, char const *text);
+static void pdf_string(void (*add)(object *, char const *),
+                      object *, char const *);
 static void objref(object *o, object *dest);
 
 static void make_pages_node(object *node, object *parent, page_data *first,
@@ -195,8 +197,9 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
     for (page = doc->pages; page; page = page->next) {
        object *opage, *cstr;
        rect *r;
-       text_fragment *frag;
+       text_fragment *frag, *frag_end;
        char buf[256];
+       int x, y, lx, ly;
 
        opage = (object *)page->spare;
        /*
@@ -236,24 +239,89 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
        }
 
        objstream(cstr, "BT\n");
-       for (frag = page->first_text; frag; frag = frag->next) {
-           char *c;
 
+       /*
+        * PDF tracks two separate current positions: the position
+        * given in the `line matrix' and the position given in the
+        * `text matrix'. We must therefore track both as well.
+        * They start off at -1 (unset).
+        */
+       lx = ly = -1;
+       x = y = -1;
+
+       frag = page->first_text;
+       while (frag) {
+           /*
+            * For compactness, I'm going to group text fragments
+            * into subsequences that use the same font+size. So
+            * first find the end of this subsequence.
+            */
+           for (frag_end = frag;
+                (frag_end &&
+                 frag_end->fe == frag->fe &&
+                 frag_end->fontsize == frag->fontsize);
+                frag_end = frag_end->next);
+
+           /*
+            * Now select the text fragment, and prepare to display
+            * the text.
+            */
            objstream(cstr, "/");
            objstream(cstr, frag->fe->name);
-           sprintf(buf, " %d Tf 1 0 0 1 %g %g Tm (", frag->fontsize,
-                   frag->x/4096.0, frag->y/4096.0);
+           sprintf(buf, " %d Tf ", frag->fontsize);
            objstream(cstr, buf);
 
-           for (c = frag->text; *c; c++) {
-               if (*c == '(' || *c == ')' || *c == '\\')
-                   objstream(cstr, "\\");
-               buf[0] = *c;
-               buf[1] = '\0';
+           while (frag && frag != frag_end) {
+               /*
+                * Place the text position for the first piece of
+                * text.
+                */
+               if (lx < 0) {
+                   sprintf(buf, "1 0 0 1 %g %g Tm ",
+                           frag->x/4096.0, frag->y/4096.0);
+               } else {
+                   sprintf(buf, "%g %g Td ",
+                           (frag->x - lx)/4096.0, (frag->y - ly)/4096.0);
+               }
                objstream(cstr, buf);
+               lx = x = frag->x;
+               ly = y = frag->y;
+
+               /*
+                * See if we're going to use Tj (show a single
+                * string) or TJ (show an array of strings with
+                * x-spacings between them). We determine this by
+                * seeing if there's more than one text fragment in
+                * sequence with the same y-coordinate.
+                */
+               if (frag->next && frag->next != frag_end &&
+                   frag->next->y == y) {
+                   /*
+                    * The TJ strategy.
+                    */
+                   objstream(cstr, "[");
+                   while (frag && frag != frag_end && frag->y == y) {
+                       if (frag->x != x) {
+                           sprintf(buf, "%g",
+                                   (x - frag->x) * 1000.0 /
+                                   (4096.0 * frag->fontsize));
+                           objstream(cstr, buf);
+                       }
+                       pdf_string(objstream, cstr, frag->text);
+                       x = frag->x + frag->width;
+                       frag = frag->next;
+                   }
+                   objstream(cstr, "]TJ\n");
+               } else
+               {
+                   /*
+                    * The Tj strategy.
+                    */
+                   pdf_string(objstream, cstr, frag->text);
+                   objstream(cstr, "Tj\n");
+                   frag = frag->next;
+               }
            }
-
-           objstream(cstr, ") Tj\n");
        }
        objstream(cstr, "ET");
 
@@ -285,18 +353,9 @@ void pdf_backend(paragraph *sourceform, keywordlist *keywords,
                    objref(annot, (object *)xr->dest.page->spare);
                    objtext(annot, " /XYZ null null null]\n");
                } else {
-                   char *p;
-
-                   objtext(annot, "/A <<\n/Type /Action\n/S /URI\n/URI (");
-                   for (p = xr->dest.url; *p; p++) {
-                       char c[2];
-                       c[0] = *p;
-                       c[1] = '\0';
-                       if (*p == '(' || *p == ')' || *p == '\\')
-                           objtext(annot, "\\");
-                       objtext(annot, c);
-                   }
-                   objtext(annot, ")\n>>\n");
+                   objtext(annot, "/A <<\n/Type /Action\n/S /URI\n/URI ");
+                   pdf_string(objtext, annot, xr->dest.url);
+                   objtext(annot, "\n>>\n");
                }
 
                objtext(annot, ">>\n");
@@ -596,7 +655,7 @@ static int make_outline(object *parent, outline_element *items, int n,
     level = items->level;
 
     while (n > 0) {
-       char *title, *p;
+       char *title;
 
        /*
         * Here we expect to be sitting on an item at the given
@@ -611,16 +670,9 @@ static int make_outline(object *parent, outline_element *items, int n,
        curr = new_object(parent->list);
        if (!first) first = curr;
        last = curr;
-       objtext(curr, "<<\n/Title (");
-       for (p = title; *p; p++) {
-           char c[2];
-           if (*p == '\\' || *p == '(' || *p == ')')
-               objtext(curr, "\\");
-           c[0] = *p;
-           c[1] = '\0';
-           objtext(curr, c);
-       }
-       objtext(curr, ")\n/Parent ");
+       objtext(curr, "<<\n/Title ");
+       pdf_string(objtext, curr, title);
+       objtext(curr, "\n/Parent ");
        objref(curr, parent);
        objtext(curr, "\n/Dest [");
        objref(curr, (object *)items->pdata->first->page->spare);
@@ -709,3 +761,20 @@ static int pdf_versionid(FILE *fp, word *words)
 
     return ret;
 }
+
+static void pdf_string(void (*add)(object *, char const *),
+                      object *o, char const *str)
+{
+    char const *p;
+
+    add(o, "(");
+    for (p = str; *p; p++) {
+       char c[2];
+       if (*p == '\\' || *p == '(' || *p == ')')
+           add(o, "\\");
+       c[0] = *p;
+       c[1] = '\0';
+       add(o, c);
+    }
+    add(o, ")");
+}