Allow the vertical rhythm to adjust to half lines when -to-nearest-half-line is set to true in order to avoid awkwardly large gaps between lines. This setting is false by default.

doc-src/content/CHANGELOG.markdown

@@ -14,6 +14,14 @@ The Documentation for the [latest stable release](http://compass-style.org/docs/
 
 The Documentation for the [latest preview release](http://beta.compass-style.org/)
 
+0.12.alpha.3 (UNRELEASED)
+-------------------------
+
+* The `$round-to-nearest-half-line` config variable was added. When
+  true, the vertical rhythm module will round line heights to the
+  nearest half-line to avoid awkwardly large gaps between lines of text.
+  Defaults to false.
+
 0.12.alpha.2 (11/28/2011)
 -------------------------
 

frameworks/compass/stylesheets/compass/typography/_vertical_rhythm.scss

@@ -15,6 +15,11 @@ $ie-font-ratio: 16px / 100%;
 // Set to false if you want to use absolute pixes in sizing your typography.
 $relative-font-sizing: true !default;
 
+// Allows the `adjust-font-size-to` mixin and the `lines-for-font-size` function
+// to round the line height to the nearest half line height instead of the
+// nearest integral line height to avoid large spacing between lines.
+$round-to-nearest-half-line: false !default;
+
 // Ensure there is at least this many pixels
 // of vertical padding above and below the text.
 $min-line-padding: 2px;
@@ -103,9 +108,11 @@ $base-half-leader: $base-leader / 2;
 }
 
 @function lines-for-font-size($font-size) {
-  $lines: ceil($font-size / $base-line-height);
+  $lines: if($round-to-nearest-half-line,
+              ceil(2 * $font-size / $base-line-height) / 2,
+              ceil($font-size / $base-line-height));
   @if $lines * $base-line-height - $font-size < $min-line-padding * 2 {
-    $lines: $lines + 1;
+    $lines: $lines + if($round-to-nearest-half-line, 0.5, 1);
   }
   @return $lines;
 }