Merge pull request #669 from danfickle/fix_641_fallback_font

Fixes #641 Support fallback fonts

Author: danfickle

openhtmltopdf-core/src/main/java/com/openhtmltopdf/extend/FontResolver.java

@@ -26,7 +26,4 @@
 
 public interface FontResolver {
     public FSFont resolveFont(SharedContext renderingContext, FontSpecification spec);
-    
-    @Deprecated
-    public void flushCache();
 }

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/BaseRendererBuilder.java

@@ -546,6 +546,35 @@ public TFinalClass useFont(FSSupplier<InputStream> supplier, String fontFamily,
         return (TFinalClass) this;
     }
 
+    /**
+     * <p>Add a font programmatically. If the font is NOT subset, it will be downloaded
+     * when the renderer is run, otherwise, assuming a font-metrics cache has been configured,
+     * the font will only be downloaded if required. Therefore, the user could add many fonts,
+     * confident that only those that are needed will be downloaded and processed.</p>
+     *
+     * <p>The InputStream returned by the supplier will be closed by the caller. Fonts
+     * should generally be subset (Java2D renderer ignores this argument),
+     * except when used in form controls. FSSupplier is a lambda compatible interface.</p>
+     *
+     * <p>Fonts can also be added using a font-face at-rule in the CSS (not
+     * recommended for Java2D usage).</p>
+     * 
+     * <p><strong>IMPORTANT:</strong> This method is not recommended for use with Java2D.
+     * To add fonts for use by Java2D, SVG, etc see:
+     * {@link #useFont(File, String, Integer, FontStyle, boolean, Set)}</p>
+     * 
+     * <p>For gotchas related to font handling please see:
+     * <a href="https://github.com/danfickle/openhtmltopdf/wiki/Fonts">Wiki: Fonts</a></p>
+     *
+     * @return this for method chaining
+     */
+    public TFinalClass useFont(
+            FSSupplier<InputStream> supplier, String fontFamily, Integer fontWeight,
+            FontStyle fontStyle, boolean subset, Set<FSFontUseCase> useFontFlags) {
+        state._fonts.add(new AddedFont(supplier, null, fontWeight, fontFamily, subset, fontStyle, useFontFlags));
+        return (TFinalClass) this;
+    }
+
     /**
      * Simpler overload for
      * {@link #useFont(FSSupplier, String, Integer, FontStyle, boolean)}
@@ -616,6 +645,17 @@ public enum FSFontUseCase {
         /** Main document (PDF or Java2D) */
         DOCUMENT,
         SVG,
-        MATHML
+        MATHML,
+        /**
+         * Use as a fallback font after all supplied fonts have been tried but before
+         * the built-in fonts have been attempted.
+         */
+        FALLBACK_PRE,
+        /**
+         * Use as a fallback fonts after all supplied fonts and the built-in fonts have been
+         * tried. The same font should not be registered with both <code>FALLBACK_PRE</code>
+         * and <code>FALLBACK_FINAL</code>.
+         */
+        FALLBACK_FINAL;
     }
 }

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/FontFamily.java

@@ -8,52 +8,55 @@
 import com.openhtmltopdf.css.constants.IdentValue;
 
 public class FontFamily<T extends MinimalFontDescription> {
-    private List<T> _fontDescriptions;
+    private final List<T> _fontDescriptions = new ArrayList<>(4);
+    private final String _family;
 
-    public FontFamily() {
+    public FontFamily(String family) {
+        this._family = family;
+    }
+
+    public String getFamily() {
+        return _family;
     }
 
     public List<T> getFontDescriptions() {
         return _fontDescriptions;
     }
 
     public void addFontDescription(T descr) {
-        if (_fontDescriptions == null) {
-            _fontDescriptions = new ArrayList<>();
-        }
         _fontDescriptions.add(descr);
-        Collections.sort(_fontDescriptions,
-                new Comparator<T>() {
-                    public int compare(T o1, T o2) {
-                        return o1.getWeight() - o2.getWeight();
-                    }
-        });
-    }
-    
-    public void setName(String fontFamilyName) {
+        Collections.sort(_fontDescriptions, Comparator.comparing(T::getWeight));
     }
 
     public T match(int desiredWeight, IdentValue style) {
-        if (_fontDescriptions == null) {
-            throw new RuntimeException("fontDescriptions is null");
+        if (_fontDescriptions.isEmpty()) {
+            return null;
+        } else if (_fontDescriptions.size() == 1) {
+            return _fontDescriptions.get(0);
         }
 
-        List<T> candidates = new ArrayList<>();
+        List<T> candidates = new ArrayList<>(_fontDescriptions.size());
 
-        for (T description : _fontDescriptions) {
-            if (description.getStyle() == style) {
-                candidates.add(description);
-            }
+        // First try only matching style.
+        getStyleMatches(style, candidates);
+
+        // Then try changing italic to oblique.
+        if (candidates.isEmpty() && style == IdentValue.ITALIC) {
+            getStyleMatches(IdentValue.OBLIQUE, candidates);
         }
 
-        if (candidates.size() == 0) {
-            if (style == IdentValue.ITALIC) {
-                return match(desiredWeight, IdentValue.OBLIQUE);
-            } else if (style == IdentValue.OBLIQUE) {
-                return match(desiredWeight, IdentValue.NORMAL);
-            } else {
-                candidates.addAll(_fontDescriptions);
-            }
+        // Then try changing oblique to normal.
+        if (candidates.isEmpty() && style == IdentValue.OBLIQUE) {
+            getStyleMatches(IdentValue.NORMAL, candidates);
+        }
+
+        // Still nothing!
+        if (candidates.isEmpty()) {
+             candidates.addAll(_fontDescriptions);
+        }
+
+        if (candidates.size() == 1) {
+            return candidates.get(0);
         }
 
         T result = findByWeight(candidates, desiredWeight, SM_EXACT);
@@ -69,6 +72,14 @@ public T match(int desiredWeight, IdentValue style) {
         }
     }
 
+    private void getStyleMatches(IdentValue style, List<T> candidates) {
+        for (T description : _fontDescriptions) {
+            if (description.getStyle() == style) {
+                candidates.add(description);
+            }
+        }
+    }
+
     private static final int SM_EXACT = 1;
     private static final int SM_LIGHTER_OR_DARKER = 2;
     private static final int SM_DARKER_OR_LIGHTER = 3;

openhtmltopdf-examples/src/main/resources/visualtest/expected/text/issue-641-font-fallback.pdf

@@ -0,0 +1,22 @@
+<html>
+<head>
+<style>
+@page {
+  size: 200px 200px;
+  margin: 10px;
+}
+</style>
+</head>
+<body style="font-family: 'no-exist'; font-weight: 400;">
+
+<div style="font-family: 'SourceSans'; font-weight: 400;">
+Text should look normal!
+</div>
+
+<!-- Using fallback font -->
+<div style="font-family: 'no-exist'; font-weight: 400;">
+Text should look bold!
+</div>
+
+</body>
+</html>

openhtmltopdf-examples/src/main/resources/visualtest/html/text/issue-641-font-fallback.html

@@ -8,7 +8,9 @@
 import java.awt.Shape;
 import java.awt.geom.Rectangle2D;
 import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
+import java.util.EnumSet;
 import java.util.Map;
 
 import static org.junit.Assert.assertTrue;
@@ -22,6 +24,7 @@
 import com.openhtmltopdf.extend.FSObjectDrawer;
 import com.openhtmltopdf.extend.FSObjectDrawerFactory;
 import com.openhtmltopdf.extend.OutputDevice;
+import com.openhtmltopdf.outputdevice.helper.BaseRendererBuilder.FSFontUseCase;
 import com.openhtmltopdf.outputdevice.helper.BaseRendererBuilder.FontStyle;
 import com.openhtmltopdf.render.RenderingContext;
 import com.openhtmltopdf.visualtest.TestSupport;
@@ -682,4 +685,38 @@ public void testIssue472AddSemiTransparentWatermark() throws IOException {
              builder.useObjectDrawerFactory(new WatermarkDrawerFactory());
          }));
     }
+
+    /**
+     * Tests the ability to use fallback fonts.
+     */
+    @Test
+    public void testIssue641FontFallback() throws IOException {
+        assertTrue(vtester.runTest("issue-641-font-fallback", builder -> {
+            builder.useFont(
+                    new File("target/test/visual-tests/SourceSansPro-Regular.ttf"),
+                    "SourceSans", 400, FontStyle.NORMAL, true,
+                    EnumSet.of(FSFontUseCase.DOCUMENT));
+            builder.useFont(
+                    new File("target/test/visual-tests/Karla-Bold.ttf"),
+                    "Karla", 700, FontStyle.NORMAL, true,
+                    EnumSet.of(FSFontUseCase.FALLBACK_PRE));
+        }));
+    }
+
+    /**
+     * Tests the ability to use fallback fonts via input streams.
+     */
+    @Test
+    public void testIssue641FontFallbackInputStream() throws IOException {
+        assertTrue(vtester.runTest("issue-641-font-fallback", builder -> {
+            builder.useFont(
+                    () -> TextVisualRegressionTest.class.getResourceAsStream("/visualtest/html/fonts/SourceSansPro-Regular.ttf"),
+                    "SourceSans", 400, FontStyle.NORMAL, true,
+                    EnumSet.of(FSFontUseCase.DOCUMENT));
+            builder.useFont(
+                    () -> TextVisualRegressionTest.class.getResourceAsStream("/visualtest/html/fonts/Karla-Bold.ttf"),
+                    "Karla", 700, FontStyle.NORMAL, true,
+                    EnumSet.of(FSFontUseCase.FALLBACK_PRE));
+        }));
+    }
 }

openhtmltopdf-examples/src/test/java/com/openhtmltopdf/visualregressiontests/TextVisualRegressionTest.java

@@ -182,7 +182,6 @@ private void init() {
     }
 
     @Deprecated
-    @Override
     public void flushCache() {
         instanceHash.clear();
         availableFontsHash.clear();
@@ -266,7 +265,7 @@ public void addFontFile(File fontFile, String fontFamilyNameOverride, Integer fo
     private FontFamily<FontDescription> getFontFamily(String fontFamilyName) {
         FontFamily<FontDescription> fontFamily = _fontFamilies.get(fontFamilyName);
         if (fontFamily == null) {
-            fontFamily = new FontFamily<>();
+            fontFamily = new FontFamily<>(fontFamilyName);
             _fontFamilies.put(fontFamilyName, fontFamily);
         }
         return fontFamily;