Rendering pi more nicely in PDF

[Tom Lane]

In the department of nitpickery ...

"π" renders poorly in our PDF docs: as shown in the attached
screenshot, it doesn't line up on the baseline.  I realized that
this is the same problem I'd run into recently with right-arrow,
and it can be solved in the same way, namely we have to specify
use of the symbol font explicitly.  So attached is a proposed
patch to fix it.

Use of a new processing-instruction might not be the most elegant
way to do this ... anyone have a better suggestion?

(BTW, I tried to use "π" in the stylesheet files and it
didn't work; apparently that entity isn't loaded yet.)

                        regards, tom lane


diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b0afaeb..fdbd4a0 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1365,7 +1365,7 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
         <function>pi</function> (  )
         <returnvalue>double precision</returnvalue>
        <?br?>
-        Approximate value of &pi;
+        Approximate value of <?pi?>
        <?br?>
         <literal>pi()</literal>
         <returnvalue>3.141592653589793</returnvalue>
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 58a2aa3..01bec32 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1528,7 +1528,7 @@ SELECT 4 AS four \; SELECT 5 AS five \aset
       <row>
        <entry><literal><function>pi()</function></literal></entry>
        <entry>double</entry>
-       <entry>value of the constant PI</entry>
+       <entry>value of the constant <?pi?></entry>
        <entry><literal>pi()</literal></entry>
        <entry><literal>3.14159265358979323846</literal></entry>
       </row>
diff --git a/doc/src/sgml/stylesheet-common.xsl b/doc/src/sgml/stylesheet-common.xsl
index b772f87..c9a9181 100644
--- a/doc/src/sgml/stylesheet-common.xsl
+++ b/doc/src/sgml/stylesheet-common.xsl
@@ -108,4 +108,8 @@
   <br/>
 </xsl:template>
 
+<!-- Support for generating pi symbol -->
+
+<xsl:template match="processing-instruction('pi')">&#x3C0;</xsl:template>
+
 </xsl:stylesheet>
diff --git a/doc/src/sgml/stylesheet-fo.xsl b/doc/src/sgml/stylesheet-fo.xsl
index 6797e06..7bfc819 100644
--- a/doc/src/sgml/stylesheet-fo.xsl
+++ b/doc/src/sgml/stylesheet-fo.xsl
@@ -101,6 +101,11 @@
   <fo:block/>
 </xsl:template>
 
+<!-- overrides stylesheet-common.xsl -->
+<xsl:template match="processing-instruction('pi')">
+  <fo:inline font-family="{$symbol.font.family}">&#x3C0;</fo:inline>
+</xsl:template>
+
 <!-- bug fix from <https://sourceforge.net/p/docbook/bugs/1360/#831b> -->
 
 <xsl:template match="varlistentry/term" mode="xref-to">