[aXSL-commit] SF.net SVN: axsl: [585] trunk/axsl/axsl-font-r/src/java/org/axsl/fontR/Font.java

[<vic...@us...>]

Revision: 585
Author:   victormote
Date:     2006-05-25 09:04:40 -0700 (Thu, 25 May 2006)
ViewCVS:  http://svn.sourceforge.net/axsl/?rev=585&view=rev

Log Message:
-----------
Add method for computing normal line-height.

Modified Paths:
--------------
    trunk/axsl/axsl-font-r/src/java/org/axsl/fontR/Font.java
Modified: trunk/axsl/axsl-font-r/src/java/org/axsl/fontR/Font.java
===================================================================
--- trunk/axsl/axsl-font-r/src/java/org/axsl/fontR/Font.java	2006-05-24 20:50:19 UTC (rev 584)
+++ trunk/axsl/axsl-font-r/src/java/org/axsl/fontR/Font.java	2006-05-25 16:04:40 UTC (rev 585)
@@ -156,6 +156,11 @@
      */
     public static final byte FORMAT_OTF_CFF = 4;
 
+    /** Normal line-height computation constant indicating that the
+     * implementation is in complete control of the normal line-height
+     * computation. */
+    public static final byte LH_ALGORITHM_DEFAULT = 0;
+
     /**
      * Returns the Ascender value for this font, scaled to a specific point
      * size.
@@ -366,4 +371,33 @@
      */
     public boolean isPDFStandardFont();
 
+    /**
+     * <p>Returns a factor suitable for computing a "normal" line-height as
+     * defined in the CSS and XSL-FO standards.
+     * The line-height is the distance, including leading, between the baselines
+     * of stacked lines of text.
+     * The CSS and XSL-FO standards recommend that the "normal" value for
+     * line-height fall between 1.0 and 1.2. (see Section 7.15.4 of XSL-FO
+     * 1.0)
+     * This method attempts to find a suitable value based on the
+     * characteristics of the font itself.</p>
+     *
+     * <p>Design Note 1: This method returns a float factor instead of a
+     * computation of the actual line-height to facilitate the handling of
+     * inheritance where that is required.
+     * For example, for CSS and XSL-FO, the factor is what is inherited instead
+     * of the computed line-height.</p>
+     *
+     * @param algorithm The specifier of an algorithm that should be used to
+     * compute the factor.
+     * Valid values include {@link #LH_ALGORITHM_DEFAULT}, which puts the
+     * implementation in complete control of the computation.
+     * Other algorithms may be added in the future.
+     * @return The factor to be applied to the font-size to compute the "normal"
+     * line-height.
+     * For example, if the font-size is 12 points, and this method returns 1.2,
+     * the computed "normal" line-height is 14.4 points.
+     */
+    public float normalLineHeightFactor(int algorithm) ;
+
 }


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