[aXSL-commit] SF.net SVN: axsl:[2688] trunk/axsl
An API for XSL-FO.
Status: Alpha
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[aXSL-commit] SF.net SVN: axsl:[2688] trunk/axsl
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From: <vic...@us...> - 2023-01-18 19:02:03
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Revision: 2688
http://sourceforge.net/p/axsl/code/2688
Author: victormote
Date: 2023-01-18 19:02:02 +0000 (Wed, 18 Jan 2023)
Log Message:
-----------
1. Add ipd to creation methods for word content. 2. Add method returning a horizontal stretch value for text items. 3. Add doc regarding meaning and completeness of various items related to text state.
Modified Paths:
--------------
trunk/axsl/axsl-areatree/src/main/java/org/axsl/area/factory/LineContentFactory.java
trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/GlyphAreaSequenceG5.java
trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/trait/CharacterTraitsTa.java
Modified: trunk/axsl/axsl-areatree/src/main/java/org/axsl/area/factory/LineContentFactory.java
===================================================================
--- trunk/axsl/axsl-areatree/src/main/java/org/axsl/area/factory/LineContentFactory.java 2023-01-14 15:46:15 UTC (rev 2687)
+++ trunk/axsl/axsl-areatree/src/main/java/org/axsl/area/factory/LineContentFactory.java 2023-01-18 19:02:02 UTC (rev 2688)
@@ -86,12 +86,14 @@
* @param paragraph The text words for which the glyph areas should be created.
* @param startLocation The starting location in {@code paragraph} for the text in the new area, inclusive.
* @param endLocation The ending location in {@code paragraph} for the text in the new area, exclusive.
+ * @param ipd The inline-progression-dimension, in millipoints, which the new {@link GlyphAreaSequenceG5} consumes
+ * on the line.
* @param hasFauxSmallCaps True if and only if the new {@link GlyphAreaSequenceG5} item content should be handled as
* faux small caps.
* @return The new {@link GlyphAreaSequenceG5} instance, or null if there is no content.
*/
GlyphAreaSequenceG5 createGlyphAreaSequence(FoTextWords paragraph, TextTokenFlowLocation startLocation,
- TextTokenFlowLocation endLocation, boolean hasFauxSmallCaps);
+ TextTokenFlowLocation endLocation, int ipd, boolean hasFauxSmallCaps);
/**
* Creates a new Area for external-graphic content.
Modified: trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/GlyphAreaSequenceG5.java
===================================================================
--- trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/GlyphAreaSequenceG5.java 2023-01-14 15:46:15 UTC (rev 2687)
+++ trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/GlyphAreaSequenceG5.java 2023-01-18 19:02:02 UTC (rev 2688)
@@ -29,7 +29,46 @@
import org.axsl.galley.trait.NominalFontTa;
/**
- * An Area containing text.
+ * <p>An Area containing text.
+ * This class does not map directly to a concept in the XSL-FO Area Tree.
+ * XSL-FO has a notion of a "glyph-area" which is useful for the abstract description of the laid-out document.
+ * As a practical matter, it is much more convenient to treat contiguous glyph-areas that have identical text-related
+ * traits as a sequence of such glyph-areas, which is what this class represents.</p>
+ *
+ * <p>Implementations of this interface are primarily concerned with providing information about the
+ * inline-progression-dimension.
+ * We will use PDF as a baseline format to which we might render documents.
+ * The PDF "Text State Parameters and Operators" lists nine parameters that can be set when writing text.</p>
+ * <ul>
+ * <li>"Character spacing" is handled by {@link CharacterTraitsTa#traitLetterSpacing()}.</li>
+ * <li>"Word spacing" is handled by {@link CharacterTraitsTa#traitWordSpacing()}.</li>
+ * <li>"Horizontal scaling" is handled by {@link CharacterTraitsTa#getIpdScaling()}.</li>
+ * <li>"Leading" is specifically handled by other areas, specifically those that stack the line areas of which this
+ * glyph-area sequence might be a part.</li>
+ * <li>"Text font" is handled by {@link NominalFontTa#traitNominalFont()}.</li>
+ * <li>"Text font size" is handled by {@link FontSizeTa#traitFontSize()}.</li>
+ * <li>"Text rendering mode" handles how glyphs are stroked and filled and clipped.
+ * XSL-FO only considers that text will be filled, so we do not consider this parameter.</li>
+ * <li>"Text rise" has to do with temporary positioning for items like subscripts and superscripts.
+ * This is handled by the method {@link GeneralInlineAreaG5#baselineY()}.</li>
+ * <li>"Text knockout" is a relatively esoteric concept that doesn't map to anything in XSL-FO and is therefore not
+ * supported.</li>
+ * </ul>
+ *
+ * <p>The order in which these parameters is applied is significant.
+ * Again, we will follow the PDF model:</p>
+ * <ol>
+ * <li>Conceptually, font-size is applied to everything for purposes of scaling both block-progression-dimension and
+ * inline-progression-dimension.
+ * Then any "horizontal scaling" is applied, but only to the inline-progression-dimension.</li>
+ * <li>Character spacing and word spacing are provided in text-space units.
+ * In other words, when computing their actual size, the font-size must first be applied, then any ipd stretching.
+ * For example, word spacing of 20 at 12 points and 100% stretch would result in 240 millipoints.
+ * If a stretch of 105% were applied, the result would be 240 * 1.05 = 252 millipoints.
+ * Stated another way, character spacing and word spacing are both affected by the horizontal scaling.</li>
+ * </ol>
+ *
+ * @see "PDF Reference, Sixth Edition (PDF Format Version 1.7), Section 5.2, Text State Parameters and Operators."
*/
public interface GlyphAreaSequenceG5 extends GeneralInlineAreaG5,
NominalFontTa,
Modified: trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/trait/CharacterTraitsTa.java
===================================================================
--- trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/trait/CharacterTraitsTa.java 2023-01-14 15:46:15 UTC (rev 2687)
+++ trunk/axsl/axsl-galley/src/main/java/org/axsl/galley/trait/CharacterTraitsTa.java 2023-01-18 19:02:02 UTC (rev 2688)
@@ -23,22 +23,46 @@
package org.axsl.galley.trait;
+import java.math.BigDecimal;
+
/**
* Accessor for the character traits.
*/
public interface CharacterTraitsTa {
+ /** The default inline-progression-dimension scaling factor. */
+ BigDecimal DEFAULT_IPD_SCALING = new BigDecimal("100");
+
/**
- * The "letter-spacing" trait for this area.
- * @return The letter-spacing, in millipoints.
+ * The "letter-spacing" trait for this area, i.e. the extra space between glyphs in a word.
+ * @return The letter-spacing, in thousandths of a text-space unit.
+ * To convert the returned value to millipoints, multiply by the font-size.
+ * For example, letter-spacing of 20 at 13 points would be 260 millipoints.
*/
- int traitLetterSpacing();
+ default int traitLetterSpacing() {
+ return 0;
+ }
/**
- * The "word-spacing" trait for this area, i.e. the extra size that should be added to the width of the space
- * character.
- * @return Returns the amount of word-spacing, in millipoints.
+ * The "word-spacing" trait for this area, i.e. the extra space to be added between words, or added to the width of
+ * the space character.
+ * @return Returns the amount of word-spacing, in thousandths of a text-space unit.
+ * To convert the returned value to millipoints, multiply by the font-size.
+ * For example, word-spacing of -3 at 12 points would -36 millipoints.
*/
- int traitWordSpacing();
+ default int traitWordSpacing() {
+ return 0;
+ }
+ /**
+ * Returns the scaling percentage to be applied to the inline-progression-dimension for this area.
+ * A factor of 100% indicates that no scaling should be done.
+ * This does not map directly to an XSL-FO trait, but is used for cases where font-stretch is simulated, or where
+ * the ipd of the font characters themselves has been adjusted as part of the line-breaking logic.
+ * @return The scaling percentage to be applied to the inline-progression-dimension for this area.
+ */
+ default BigDecimal getIpdScaling() {
+ return DEFAULT_IPD_SCALING;
+ }
+
}
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