Add custom image converters

5 files changed, 89 insertions, 16 deletions

diff --git a/src/main/java/org/zwobble/mammoth/DocumentConverter.java b/src/main/java/org/zwobble/mammoth/DocumentConverter.java
index feba5ac..2dea8e8 100644
--- a/src/main/java/org/zwobble/mammoth/DocumentConverter.java
+++ b/src/main/java/org/zwobble/mammoth/DocumentConverter.java
@@ -1,5 +1,6 @@
 package org.zwobble.mammoth;
 
+import org.zwobble.mammoth.images.ImageConverter;
 import org.zwobble.mammoth.internal.InternalDocumentConverter;
 import org.zwobble.mammoth.internal.conversion.DocumentToHtmlOptions;
 
@@ -60,6 +61,14 @@ public class DocumentConverter {
     }
 
     /**
+     * By default, images are converted to {@code <img>} elements with the source included inline in the {@code src} attribute.
+     * Call this to change how images are converted.
+     */
+    public DocumentConverter imageConverter(ImageConverter.ImgElement imageConverter) {
+        return new DocumentConverter(options.imageConverter(imageConverter));
+    }
+
+    /**
      * Converts {@code stream} into an HTML string.
      * Note that using this method instead of {@link #convertToHtml(File file)}
      * means that relative paths to other files, such as images, cannot be resolved.
diff --git a/src/main/java/org/zwobble/mammoth/images/Image.java b/src/main/java/org/zwobble/mammoth/images/Image.java
new file mode 100644
index 0000000..977e27d
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/images/Image.java
@@ -0,0 +1,11 @@
+package org.zwobble.mammoth.images;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Optional;
+
+public interface Image {
+    Optional<String> getAltText();
+    String getContentType();
+    InputStream getInputStream() throws IOException;
+}
diff --git a/src/main/java/org/zwobble/mammoth/images/ImageConverter.java b/src/main/java/org/zwobble/mammoth/images/ImageConverter.java
new file mode 100644
index 0000000..83480f2
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/images/ImageConverter.java
@@ -0,0 +1,13 @@
+package org.zwobble.mammoth.images;
+
+import java.io.IOException;
+import java.util.Map;
+
+public class ImageConverter {
+    private ImageConverter() {
+    }
+
+    public interface ImgElement {
+        Map<String, String> convert(Image image) throws IOException;
+    }
+}
diff --git a/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtml.java b/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtml.java
index cfa4f56..bdb3d01 100644
--- a/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtml.java
+++ b/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtml.java
@@ -1,16 +1,17 @@
 package org.zwobble.mammoth.internal.conversion;
 
+import org.zwobble.mammoth.images.ImageConverter;
 import org.zwobble.mammoth.internal.documents.*;
 import org.zwobble.mammoth.internal.html.Html;
 import org.zwobble.mammoth.internal.html.HtmlNode;
 import org.zwobble.mammoth.internal.results.InternalResult;
 import org.zwobble.mammoth.internal.styles.HtmlPath;
 import org.zwobble.mammoth.internal.styles.StyleMap;
-import org.zwobble.mammoth.internal.util.Base64Encoding;
 import org.zwobble.mammoth.internal.util.Lists;
 import org.zwobble.mammoth.internal.util.Maps;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.*;
 import java.util.function.Supplier;
 
@@ -53,6 +54,7 @@ public class DocumentToHtml {
     private final String idPrefix;
     private final boolean preserveEmptyParagraphs;
     private final StyleMap styleMap;
+    private final ImageConverter.ImgElement imageConverter;
     private final Map<String, Comment> comments;
     private final List<NoteReference> noteReferences = new ArrayList<>();
     private final List<ReferencedComment> referencedComments = new ArrayList<>();
@@ -62,6 +64,7 @@ public class DocumentToHtml {
         this.idPrefix = options.idPrefix();
         this.preserveEmptyParagraphs = options.shouldPreserveEmptyParagraphs();
         this.styleMap = options.styleMap();
+        this.imageConverter = options.imageConverter();
         this.comments = Maps.toMapWithKey(comments, Comment::getCommentId);
     }
 
@@ -278,14 +281,23 @@ public class DocumentToHtml {
                 return image.getContentType()
                     .map(contentType -> {
                         try {
-                            Map<String, String> attributes = new HashMap<>();
-
-                            String base64 = Base64Encoding.streamToBase64(image::open);
-                            String src = "data:" + contentType + ";base64," + base64;
-                            attributes.put("src", src);
-
+                            Map<String, String> attributes = new HashMap<>(imageConverter.convert(new org.zwobble.mammoth.images.Image() {
+                                @Override
+                                public Optional<String> getAltText() {
+                                    return image.getAltText();
+                                }
+
+                                @Override
+                                public String getContentType() {
+                                    return contentType;
+                                }
+
+                                @Override
+                                public InputStream getInputStream() throws IOException {
+                                    return image.open();
+                                }
+                            }));
                             image.getAltText().ifPresent(altText -> attributes.put("alt", altText));
-
                             return list(Html.element("img", attributes));
                         } catch (IOException exception) {
                             warnings.add(exception.getMessage());
diff --git a/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtmlOptions.java b/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtmlOptions.java
index 8a709af..52b2558 100644
--- a/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtmlOptions.java
+++ b/src/main/java/org/zwobble/mammoth/internal/conversion/DocumentToHtmlOptions.java
@@ -1,11 +1,28 @@
 package org.zwobble.mammoth.internal.conversion;
 
+import org.zwobble.mammoth.images.ImageConverter;
 import org.zwobble.mammoth.internal.styles.DefaultStyles;
 import org.zwobble.mammoth.internal.styles.StyleMap;
 import org.zwobble.mammoth.internal.styles.parsing.StyleMapParser;
+import org.zwobble.mammoth.internal.util.Base64Encoding;
+
+import static org.zwobble.mammoth.internal.util.Maps.map;
 
 public class DocumentToHtmlOptions {
-    public static final DocumentToHtmlOptions DEFAULT = new DocumentToHtmlOptions("", false, StyleMap.EMPTY, StyleMap.EMPTY, false, false);
+    public static final DocumentToHtmlOptions DEFAULT = new DocumentToHtmlOptions(
+        "",
+        false,
+        StyleMap.EMPTY,
+        StyleMap.EMPTY,
+        false,
+        false,
+        image -> {
+            String base64 = Base64Encoding.streamToBase64(image::getInputStream);
+            String src = "data:" + image.getContentType() + ";base64," + base64;
+            return map("src", src);
+        }
+
+    );
 
     private final String idPrefix;
     private final boolean preserveEmptyParagraphs;
@@ -13,6 +30,7 @@ public class DocumentToHtmlOptions {
     private final StyleMap embeddedStyleMap;
     private final boolean disableDefaultStyleMap;
     private final boolean disableEmbeddedStyleMap;
+    private final ImageConverter.ImgElement imageConverter;
 
     public DocumentToHtmlOptions(
         String idPrefix,
@@ -20,7 +38,8 @@ public class DocumentToHtmlOptions {
         StyleMap styleMap,
         StyleMap embeddedStyleMap,
         boolean disableDefaultStyleMap,
-        boolean disableEmbeddedStyleMap
+        boolean disableEmbeddedStyleMap,
+        ImageConverter.ImgElement imageConverter
     ) {
         this.idPrefix = idPrefix;
         this.preserveEmptyParagraphs = preserveEmptyParagraphs;
@@ -28,14 +47,15 @@ public class DocumentToHtmlOptions {
         this.embeddedStyleMap = embeddedStyleMap;
         this.disableDefaultStyleMap = disableDefaultStyleMap;
         this.disableEmbeddedStyleMap = disableEmbeddedStyleMap;
+        this.imageConverter = imageConverter;
     }
 
     public DocumentToHtmlOptions idPrefix(String prefix) {
-        return new DocumentToHtmlOptions(prefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap);
+        return new DocumentToHtmlOptions(prefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap, imageConverter);
     }
 
     public DocumentToHtmlOptions preserveEmptyParagraphs() {
-        return new DocumentToHtmlOptions(idPrefix, true, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap);
+        return new DocumentToHtmlOptions(idPrefix, true, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap, imageConverter);
     }
 
     public DocumentToHtmlOptions addStyleMap(String styleMap) {
@@ -43,19 +63,23 @@ public class DocumentToHtmlOptions {
     }
 
     public DocumentToHtmlOptions addStyleMap(StyleMap styleMap) {
-        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, this.styleMap.update(styleMap), embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap);
+        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, this.styleMap.update(styleMap), embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap, imageConverter);
     }
 
     public DocumentToHtmlOptions disableDefaultStyleMap() {
-        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, true, disableEmbeddedStyleMap);
+        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, true, disableEmbeddedStyleMap, imageConverter);
     }
 
     public DocumentToHtmlOptions disableEmbeddedStyleMap() {
-        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, true);
+        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, true, imageConverter);
     }
 
     public DocumentToHtmlOptions addEmbeddedStyleMap(StyleMap embeddedStyleMap) {
-        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap);
+        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap, imageConverter);
+    }
+
+    public DocumentToHtmlOptions imageConverter(ImageConverter.ImgElement imageConverter) {
+        return new DocumentToHtmlOptions(idPrefix, preserveEmptyParagraphs, styleMap, embeddedStyleMap, disableDefaultStyleMap, disableEmbeddedStyleMap, imageConverter);
     }
 
     public String idPrefix() {
@@ -77,4 +101,8 @@ public class DocumentToHtmlOptions {
         styleMap = styleMap.update(this.styleMap);
         return styleMap;
     }
+
+    public ImageConverter.ImgElement imageConverter() {
+        return imageConverter;
+    }
 }