Do not scale TJ array adjustments by the Type 3 FontMatrix

A number in a TJ array is expressed in thousandths of a unit of text
space (ISO 32000-1, 9.4.3). It is a text space quantity, not a glyph
space one, so it must not be transformed by the font's FontMatrix.

Since the FontMatrix scaling introduced in #733 is applied to the whole
text-showing argument, the TJ adjustments are scaled by FontMatrix[0] as
well. For every non-Type 3 font that factor is exactly 1/1000, so the
result is unchanged. For a Type 3 font whose FontMatrix is not the
conventional [0.001 0 0 0.001 0 0] the adjustments are off by the ratio
between the two: with an identity FontMatrix they are 1000 times too
large, which makes each glyph advance backwards and reverses the
extracted reading order.

Glyph widths keep using the FontMatrix, which is correct - those are
glyph space values.

Author: sangwoojin

wcag-validation/src/main/java/org/verapdf/gf/model/factory/chunks/ChunkParser.java

@@ -66,6 +66,13 @@ public class ChunkParser {
 	public static final String REPLACEMENT_CHARACTER_STRING = "\uFFFD";
     public static final Map<String, String> fontNameToFontFamilyMap = new HashMap<>();
 
+	/**
+	 * A number in a TJ array is expressed in thousandths of a unit of text space
+	 * (ISO 32000-1, 9.4.3). Unlike a glyph width, it is not a glyph space value,
+	 * so it is never scaled by the FontMatrix of a Type 3 font.
+	 */
+	private static final double TEXT_SPACE_UNIT = 1.0 / 1000.0;
+
 	private final Deque<GraphicsState> graphicsStateStack = new ArrayDeque<>();
 	private final Stack<Long> markedContentStack = new Stack<>();
     private final Stack<Boolean> visibleContentStack = new Stack<Boolean>();
@@ -842,7 +849,7 @@ private TextPieces parseTextShowArgument(boolean isVertical, COSBase argument, d
 						parseString(isVertical, (COSString) obj.getDirectBase(), textPieces, scalingFactor);
 					} else if (obj.getType().isNumber()) {
 						TextState textState = graphicsState.getTextState();
-						textPieces.shiftCurrent(-obj.getReal() * scalingFactor * textState.getTextFontSize() * 
+						textPieces.shiftCurrent(-obj.getReal() * TEXT_SPACE_UNIT * textState.getTextFontSize() *
 								(isVertical ? 1 : textState.getHorizontalScaling()));
 					}
 				}