renlinear: make zero-width sbs elements independent of barratio/spaceratio

Author: terryburton

src/renlinear.ps.src

@@ -150,7 +150,10 @@ begin
     0 1 sbs length 1 add 2 idiv 2 mul 2 sub {
         /i exch def
         i 2 mod 0 eq {           % i is even
-            /d sbs i get barratio mul barratio sub 1 add def  % d = digit*r-r+1
+            /d sbs i get dup 0 eq
+                { pop 0 }                                 % 0 is zero-width regardless of ratio
+                { barratio mul barratio sub 1 add }       % d = digit*r-r+1
+            ifelse def
             sbs i get 0 ne {
                 /h bhs i 2 idiv get 72 mul def  % Height from bhs
                 /c d 2 div pixx add def         % Centre of the bar = pixx + d/2
@@ -162,7 +165,10 @@ begin
                 bars i 2 idiv -1 put            % Dummy entry
             } ifelse
         } {
-            /d sbs i get spaceratio mul spaceratio sub 1 add def  % d = digit*r-r+1
+            /d sbs i get dup 0 eq
+                { pop 0 }                                 % 0 is zero-width regardless of ratio
+                { spaceratio mul spaceratio sub 1 add }   % d = digit*r-r+1
+            ifelse def
         } ifelse
         /pixx pixx d add def  % pixx += d
     } for

tests/ps_tests/renlinear.ps.test

@@ -175,6 +175,44 @@
     72 4.5 0 1
 ] debugIsEqual
 
+%
+% Zero-width bar is zero-width regardless of barratio (does not shift pixx)
+%
+{
+    0 0 moveto
+    <<
+        /ren /renlinear
+        /sbs [1 1 0 1 1]
+        /bhs [1 1 1]
+        /bbs [0 0 0]
+        /inkspread 0
+        /barratio 2
+        /opt << /debugbars true >>
+    >> renlinear
+} [
+    72 0.5 0 1
+    72 3.5 0 1
+] debugIsEqual
+
+%
+% Zero-width space is zero-width regardless of spaceratio (does not shift pixx)
+%
+{
+    0 0 moveto
+    <<
+        /ren /renlinear
+        /sbs [1 0 1]
+        /bhs [1 1]
+        /bbs [0 0]
+        /inkspread 0
+        /spaceratio 2
+        /opt << /debugbars true >>
+    >> renlinear
+} [
+    72 0.5 0 1
+    72 1.5 0 1
+] debugIsEqual
+
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