feat: support new rules related to FXL SVG sizing

This change implements the new rules related to expressing the initial
containing block dimensions for SVG documents in Fixed Layout EPUBs.

New messages:

- `HTM-054` (`WARNING`): when the size is given by `width`/`height`
  attributes, but the recommended `viewBox` attribute is missing
- `HTM-055` (`WARNING`): when the values of the `height` and `width`
  attributes are not specified in pixels, and `viewBox` is not present

Changed message:

- `HTM-048` (`ERROR`): now says that either `viewBox` or `height` and
  `width` must be present

Bug fix:

- Only the outer SVG element is checked (previously, all the `svg`
  elements where checked).

Fix #902.

Note: the checking logic may need to be tweaked depending on the outcome
of issue w3c/epub-specs#1236

src/main/java/com/adobe/epubcheck/ctc/EpubSVGCheck.java

@@ -1,6 +1,7 @@
 package com.adobe.epubcheck.ctc;
 
 import java.util.Hashtable;
+import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
 
 import org.w3c.dom.Document;
@@ -116,19 +117,48 @@ void checkSvgDoc(String svgDocEntry)
     }
   }
 
+  // FIXME this RegEX is a bit too naïve for CSS syntax rules
+  // e.g. escape values and comments are theoretically allowed too
+  private static Pattern PIXEL_LENGTH_REGEX = Pattern.compile("\\d+(px)?");
+
   void checkViewBox(String svgDocEntry, Document doc)
   {
     NodeList n = doc.getElementsByTagNameNS(svgNS, "svg");
-    for (int i = 0; i < n.getLength(); i++)
+    if (n.getLength() > 0)
     {
-      Element svgElement = (Element) n.item(i);
+      Element svgElement = (Element) n.item(0);
       String viewport = svgElement.getAttributeNS(svgNS, "viewBox");
-      if (viewport == null || viewport.length() == 0)
+      boolean viewportFound = (viewport != null && viewport.trim().length() > 0);
+      String height = svgElement.getAttributeNS(svgNS, "height");
+      boolean heightFound = (height != null && height.trim().length() > 0);
+      boolean isHeightInPixel = heightFound && PIXEL_LENGTH_REGEX.matcher(height.trim()).matches();
+      String width = svgElement.getAttributeNS(svgNS, "width");
+      boolean widthFound = (width != null && width.trim().length() > 0);
+      boolean isWidthInPixel = widthFound && PIXEL_LENGTH_REGEX.matcher(width.trim()).matches();
+      if (!viewportFound)
       {
-        report.message(MessageId.HTM_048, EPUBLocation.create(svgDocEntry, XmlDocParser.getElementLineNumber(svgElement), XmlDocParser.getElementColumnNumber(svgElement)));
+        if (!heightFound || !widthFound)
+        {
+          report.message(MessageId.HTM_048,
+              EPUBLocation.create(svgDocEntry, XmlDocParser.getElementLineNumber(svgElement),
+                  XmlDocParser.getElementColumnNumber(svgElement)));
+        }
+        else
+        {
+          report.message(MessageId.HTM_054,
+              EPUBLocation.create(svgDocEntry, XmlDocParser.getElementLineNumber(svgElement),
+                  XmlDocParser.getElementColumnNumber(svgElement)));
+          if (!isHeightInPixel || !isWidthInPixel)
+          {
+            report.message(MessageId.HTM_055,
+                EPUBLocation.create(svgDocEntry, XmlDocParser.getElementLineNumber(svgElement),
+                    XmlDocParser.getElementColumnNumber(svgElement)));
+          }
+        }
       }
     }
   }
+
   void checkImageXlinkHrefInline(String svgDocEntry, Document doc)
   {
     NodeList n = doc.getElementsByTagNameNS(svgNS, "image");

src/main/java/com/adobe/epubcheck/messages/DefaultSeverities.java

@@ -134,6 +134,8 @@ private void initialize()
     severities.put(MessageId.HTM_051, Severity.WARNING);
     severities.put(MessageId.HTM_052, Severity.ERROR);
     severities.put(MessageId.HTM_053, Severity.INFO);
+    severities.put(MessageId.HTM_054, Severity.WARNING);
+    severities.put(MessageId.HTM_055, Severity.WARNING);
 
     // Media
     severities.put(MessageId.MED_001, Severity.ERROR);

src/main/java/com/adobe/epubcheck/messages/MessageId.java

@@ -127,6 +127,8 @@ public enum MessageId implements Comparable<MessageId>
   HTM_051("HTM-051"),
   HTM_052("HTM-052"),
   HTM_053("HTM_053"),
+  HTM_054("HTM-054"),
+  HTM_055("HTM-055"),
 
   // Messages associated with media (images, audio and video)
   MED_001("MED-001"),

src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties

@@ -113,14 +113,16 @@ HTM_046=Fixed format item has no viewport defined.
 HTM_046_SUG=A viewport declaration is required for fixed format items.
 HTM_047=Html viewport is missing height and/or width.
 HTM_047_SUG=The viewport declaration must declare both width and height.
-HTM_048=SVG ViewBox is missing on fixed format document.
-HTM_048_SUG=A viewBox declaration is required for fixed format documents.
+HTM_048=SVG ViewBox and width and height are missing on fixed format document.
+HTM_048_SUG=A viewBox declaration or width and height are required for fixed format documents.
 HTM_049=Html element does not have an xmlns set to 'http://www.w3.org/1999/xhtml'.
 HTM_049_SUG=Add xmlns="http://www.w3.org/1999/xhtml" to the html element.
 HTM_050=Found epub:type="pagebreak" attribute in content document.
 HTM_051=Found Microdata semantic enrichments but no RDFa. EDUPUB recommends using RDFa Lite.
 HTM_052=The property 'region-based' is only allowed on nav elements in Data Navigation Documents.
 HTM_053=Found an external file link (file://) in file: '%1$s'.
+HTM_054=The use of a 'viewBox' attribute is recommended on SVG elements.
+HTM_055=When no `viewBox` attribute is present, the values of the 'height' and 'width' attributes should be specified in pixels.
 
 #media
 MED_001=Video poster must have core media image type.

src/test/java/com/adobe/epubcheck/api/Epub30CheckExpandedTest.java

@@ -674,11 +674,31 @@ public void testFont_NonCoreMediaType() {
   public void testFXL_WithSVG() {
     testValidateDocument("valid/fxl-svg/");
   }
+
+  @Test
+  public void testFXL_WithSVG_InnerSVG() {
+    // tests that the ICB-defining rules are only checked on the outer svg element
+    testValidateDocument("valid/fxl-svg-no-viewbox-on-inner-svg");
+  }
 
   @Test
   public void testFXL_WithSVG_NoViewbox() {
     expectedErrors.add(MessageId.HTM_048);
-    testValidateDocument("invalid/fxl-svg-noviewbox/");
+    testValidateDocument("invalid/fxl-svg-no-viewbox-no-heightwidth");
+  }
+
+  @Test
+  public void testFXL_WithSVG_NoViewbox_WidthHeight(){
+    //Testing for Width/Height but no viewbox - re: Issue 902
+    Collections.addAll(expectedWarnings, MessageId.HTM_054);
+    testValidateDocument("invalid/fxl-svg-no-viewbox");
+  }
+
+  @Test
+  public void testFXL_WithSVG_NoViewbox_WidthHeightInPercent(){
+    //Testing for Width/Height but no viewbox - re: Issue 902
+    Collections.addAll(expectedWarnings, MessageId.HTM_054, MessageId.HTM_055);
+    testValidateDocument("invalid/fxl-svg-no-viewbox-widthheight-in-percent");
   }
 
   @Test
@@ -1116,5 +1136,4 @@ public void testBaseURI()
   {
     testValidateDocument("valid/base-uri");
   }
-
 }

src/test/resources/30/expanded/invalid/fxl-svg-noviewbox/EPUB/nav.xhtml → src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-no-heightwidth/EPUB/nav.xhtml

@@ -3,7 +3,6 @@
 	xmlns:epub="http://www.idpf.org/2007/ops">
 	<head>
 		<title>Nav Doc</title>
-		<link type="text/css" rel="stylesheet" href="style.css" />
 		<meta name="viewport" content="width=1200, height=600" />
 	</head>
 	<body>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-no-heightwidth/EPUB/package.opf

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" xml:lang="en" unique-identifier="q">
+    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+        <dc:title id="title">Minimal EPUB 3.0</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="q">NOID</dc:identifier>
+        <meta property="dcterms:modified">2017-06-14T00:00:01Z</meta>
+        <meta property="rendition:layout">pre-paginated</meta>
+    </metadata>
+    <manifest>
+        <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+        <item id="cover" href="cover.svg" media-type="image/svg+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="nav" linear="no"/>
+        <itemref idref="cover"/>
+    </spine>
+</package>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-widthheight-in-percent/EPUB/nav.xhtml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="la" lang="la"
+	xmlns:epub="http://www.idpf.org/2007/ops">
+	<head>
+		<title>Nav Doc</title>
+		<meta name="viewport" content="width=1200, height=600" />
+	</head>
+	<body>
+		<h2>Table of Contents</h2>
+		<nav epub:type="toc">
+			<ol>
+				<li><a href="cover.svg">Cover</a></li>
+			</ol>
+		</nav>
+	</body>
+</html>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-widthheight-in-percent/EPUB/package.opf

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" xml:lang="en" unique-identifier="q">
+    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+        <dc:title id="title">Minimal EPUB 3.0</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="q">NOID</dc:identifier>
+        <meta property="dcterms:modified">2017-06-14T00:00:01Z</meta>
+        <meta property="rendition:layout">pre-paginated</meta>
+    </metadata>
+    <manifest>
+        <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+        <item id="cover" href="cover.svg" media-type="image/svg+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="nav" linear="no"/>
+        <itemref idref="cover"/>
+    </spine>
+</package>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-widthheight-in-percent/META-INF/container.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<container xmlns="urn:oasis:names:tc:opendocument:xmlns:container" version="1.0">
+	<rootfiles>
+		<rootfile full-path="EPUB/package.opf" 	
+			media-type="application/oebps-package+xml"/>
+	</rootfiles>
+</container>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox-widthheight-in-percent/mimetype

@@ -0,0 +1 @@
+application/epub+zip    

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox/EPUB/nav.xhtml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="la" lang="la"
+	xmlns:epub="http://www.idpf.org/2007/ops">
+	<head>
+		<title>Nav Doc</title>
+		<meta name="viewport" content="width=1200, height=600" />
+	</head>
+	<body>
+		<h2>Table of Contents</h2>
+		<nav epub:type="toc">
+			<ol>
+				<li><a href="cover.svg">Cover</a></li>
+			</ol>
+		</nav>
+	</body>
+</html>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox/EPUB/package.opf

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" xml:lang="en" unique-identifier="q">
+    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+        <dc:title id="title">Minimal EPUB 3.0</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="q">NOID</dc:identifier>
+        <meta property="dcterms:modified">2017-06-14T00:00:01Z</meta>
+        <meta property="rendition:layout">pre-paginated</meta>
+    </metadata>
+    <manifest>
+        <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+        <item id="cover" href="cover.svg" media-type="image/svg+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="nav" linear="no"/>
+        <itemref idref="cover"/>
+    </spine>
+</package>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox/META-INF/container.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<container xmlns="urn:oasis:names:tc:opendocument:xmlns:container" version="1.0">
+	<rootfiles>
+		<rootfile full-path="EPUB/package.opf" 	
+			media-type="application/oebps-package+xml"/>
+	</rootfiles>
+</container>

src/test/resources/30/expanded/invalid/fxl-svg-no-viewbox/mimetype

@@ -0,0 +1 @@
+application/epub+zip