Compacted PS and PDF output files by removing redundant reiterations

of the same font and position designations. Reduced the size of the
Halibut manual PDF to less than half what it started out as, and the
PS one to more like a third of its original size.

[originally from svn r4083]

1 files changed, 55 insertions, 10 deletions

diff --git a/bk_ps.c b/bk_ps.c
index c9f4223..7a59ac0 100644
--- 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");