Compacted PS and PDF output files by removing redundant reiterations

[sgt/halibut] / bk_ps.c

diff --git a/bk_ps.c b/bk_ps.c
index c9f4223..7a59ac0 100644 (file)
--- a/bk_ps.c
+++ b/bk_ps.c
@@ -73,6 +73,27 @@ void ps_backend(paragraph *sourceform, keywordlist *keywords,
     fprintf(fp, "%%%%EndComments\n");
 
     fprintf(fp, "%%%%BeginProlog\n");
+    /*
+     * Supply a prologue function which allows a reasonably
+     * compressed representation of the text on the pages.
+     * 
+     * Expects two arguments: a y-coordinate, and then an array.
+     * Elements of the array are processed sequentially as follows:
+     * 
+     *  - a number is treated as an x-coordinate
+     *  - an array is treated as a (font, size) pair
+     *  - a string is shown
+     */
+    fprintf(fp,
+           "/t {\n"
+           "  exch /y exch def {\n"
+           "    /x exch def\n"
+           "    x type [] type eq {x aload pop scalefont setfont} if\n"
+           "    x type dup 1 type eq exch 1.0 type eq or {x y moveto} if\n"
+           "    x type () type eq {x show} if\n"
+           "  } forall\n"
+           "} def\n");
+
     fprintf(fp, "%%%%EndProlog\n");
 
     fprintf(fp, "%%%%BeginSetup\n");
@@ -119,7 +140,7 @@ void ps_backend(paragraph *sourceform, keywordlist *keywords,
      */
     pageno = 0;
     for (page = doc->pages; page; page = page->next) {
-       text_fragment *frag;
+       text_fragment *frag, *frag_end;
        rect *r;
 
        pageno++;
@@ -154,20 +175,44 @@ void ps_backend(paragraph *sourceform, keywordlist *keywords,
                    r->h / 4096.0, r->w / 4096.0);
        }
 
-       for (frag = page->first_text; frag; frag = frag->next) {
+       frag = page->first_text;
+       while (frag) {
+           font_encoding *fe;
+           int fs;
            char *c;
 
-           fprintf(fp, "%s %d scalefont setfont %g %g moveto (",
-                  frag->fe->name, frag->fontsize,
-                  frag->x/4096.0, frag->y/4096.0);
+           /*
+            * Collect all the adjacent text fragments with the
+            * same y-coordinate.
+            */
+           for (frag_end = frag;
+                frag_end && frag_end->y == frag->y;
+                frag_end = frag_end->next);
+
+           fprintf(fp, "%g[", frag->y / 4096.0);
+
+           fe = NULL;
+           fs = -1;
+
+           while (frag && frag != frag_end) {
+
+               if (frag->fe != fe || frag->fontsize != fs)
+                   fprintf(fp, "[%s %d]", frag->fe->name, frag->fontsize);
+               fe = frag->fe;
+               fs = frag->fontsize;
+
+               fprintf(fp, "%g(", frag->x/4096.0);
+               for (c = frag->text; *c; c++) {
+                   if (*c == '(' || *c == ')' || *c == '\\')
+                       fputc('\\', fp);
+                   fputc(*c, fp);
+               }
+               fprintf(fp, ")");
 
-           for (c = frag->text; *c; c++) {
-               if (*c == '(' || *c == ')' || *c == '\\')
-                   fputc('\\', fp);
-               fputc(*c, fp);
+               frag = frag->next;
            }
 
-           fprintf(fp, ") show\n");
+           fprintf(fp, "]t\n");
        }
 
        fprintf(fp, "showpage\n");