Add bookmarks so we can find a location after reflowing a document.

10 files changed, 227 insertions, 3 deletions

diff --git a/include/mupdf/fitz/document.h b/include/mupdf/fitz/document.h
index d7dbd447..c66dc2ca 100644
--- a/include/mupdf/fitz/document.h
+++ b/include/mupdf/fitz/document.h
@@ -16,6 +16,7 @@ typedef struct fz_document_s fz_document;
 typedef struct fz_document_handler_s fz_document_handler;
 typedef struct fz_page_s fz_page;
 typedef struct fz_annot_s fz_annot;
+typedef intptr_t fz_bookmark;
 
 typedef enum
 {
@@ -36,6 +37,8 @@ typedef int (fz_document_resolve_link_fn)(fz_context *ctx, fz_document *doc, con
 typedef int (fz_document_count_pages_fn)(fz_context *ctx, fz_document *doc);
 typedef fz_page *(fz_document_load_page_fn)(fz_context *ctx, fz_document *doc, int number);
 typedef int (fz_document_lookup_metadata_fn)(fz_context *ctx, fz_document *doc, const char *key, char *buf, int size);
+typedef fz_bookmark (fz_document_make_bookmark_fn)(fz_context *ctx, fz_document *doc, int page);
+typedef int (fz_document_lookup_bookmark_fn)(fz_context *ctx, fz_document *doc, fz_bookmark mark);
 
 typedef fz_link *(fz_page_load_links_fn)(fz_context *ctx, fz_page *page);
 typedef fz_rect *(fz_page_bound_page_fn)(fz_context *ctx, fz_page *page, fz_rect *);
@@ -100,6 +103,8 @@ struct fz_document_s
 	fz_document_has_permission_fn *has_permission;
 	fz_document_load_outline_fn *load_outline;
 	fz_document_layout_fn *layout;
+	fz_document_make_bookmark_fn *make_bookmark;
+	fz_document_lookup_bookmark_fn *lookup_bookmark;
 	fz_document_resolve_link_fn *resolve_link;
 	fz_document_count_pages_fn *count_pages;
 	fz_document_load_page_fn *load_page;
@@ -217,6 +222,18 @@ int fz_is_document_reflowable(fz_context *ctx, fz_document *doc);
 void fz_layout_document(fz_context *ctx, fz_document *doc, float w, float h, float em);
 
 /*
+	Create a bookmark for the given page, which can be used to find the
+	same location after the document has been laid out with different
+	parameters.
+*/
+fz_bookmark fz_make_bookmark(fz_context *ctx, fz_document *doc, int page);
+
+/*
+	Find a bookmark and return its page number.
+*/
+int fz_lookup_bookmark(fz_context *ctx, fz_document *doc, fz_bookmark mark);
+
+/*
 	fz_count_pages: Return the number of pages in document
 
 	May return 0 for documents with no pages.
diff --git a/include/mupdf/html.h b/include/mupdf/html.h
index be0808d1..e23a606d 100644
--- a/include/mupdf/html.h
+++ b/include/mupdf/html.h
@@ -283,5 +283,7 @@ void fz_draw_html(fz_context *ctx, fz_device *dev, const fz_matrix *ctm, fz_html
 float fz_find_html_target(fz_context *ctx, fz_html *html, const char *id);
 fz_link *fz_load_html_links(fz_context *ctx, fz_html *html, int page, const char *base_uri);
 void fz_drop_html(fz_context *ctx, fz_html *html);
+fz_bookmark fz_make_html_bookmark(fz_context *ctx, fz_html *html, int page);
+int fz_lookup_html_bookmark(fz_context *ctx, fz_html *html, fz_bookmark mark);
 
 #endif
diff --git a/platform/java/example/Viewer.java b/platform/java/example/Viewer.java
index 1361a538..a924cf4b 100644
--- a/platform/java/example/Viewer.java
+++ b/platform/java/example/Viewer.java
@@ -383,12 +383,12 @@ public class Viewer extends Frame implements WindowListener, ActionListener, Ite
 		}
 
 		if (layoutEm != oldLayoutEm) {
-			float oldPos = (pageNumber + 0.5f) / (float)pageCount;
+			long mark = doc.makeBookmark(pageNumber);
 			doc.layout(layoutWidth, layoutHeight, layoutEm);
 			updateOutline();
 			pageCount = doc.countPages();
 			pageLabel.setText("/ " + pageCount);
-			pageNumber = (int)(oldPos * pageCount);
+			pageNumber = doc.findBookmark(mark);
 		}
 
 		if (zoomLevel != oldZoomLevel || pageNumber != oldPageNumber || layoutEm != oldLayoutEm || searchHits != oldSearchHits)
diff --git a/platform/java/mupdf_native.c b/platform/java/mupdf_native.c
index cbb3dd7a..aec932c4 100644
--- a/platform/java/mupdf_native.c
+++ b/platform/java/mupdf_native.c
@@ -4222,6 +4222,42 @@ FUN(Document_loadOutline)(JNIEnv *env, jobject self)
 	return joutline;
 }
 
+JNIEXPORT jlong JNICALL
+FUN(Document_makeBookmark)(JNIEnv *env, jobject self, jint page)
+{
+	fz_context *ctx = get_context(env);
+	fz_document *doc = from_Document(env, self);
+	fz_bookmark mark = 0;
+
+	fz_try(ctx)
+		mark = fz_make_bookmark(ctx, doc, page);
+	fz_catch(ctx)
+	{
+		jni_rethrow(env, ctx);
+		return 0;
+	}
+
+	return mark;
+}
+
+JNIEXPORT jint JNICALL
+FUN(Document_findBookmark)(JNIEnv *env, jobject self, jlong mark)
+{
+	fz_context *ctx = get_context(env);
+	fz_document *doc = from_Document(env, self);
+	int page = -1;
+
+	fz_try(ctx)
+		page = fz_lookup_bookmark(ctx, doc, mark);
+	fz_catch(ctx)
+	{
+		jni_rethrow(env, ctx);
+		return -1;
+	}
+
+	return page;
+}
+
 JNIEXPORT jobject JNICALL
 FUN(Document_toPDFDocument)(JNIEnv *env, jobject self)
 {
diff --git a/platform/java/mupdf_native.h b/platform/java/mupdf_native.h
index 3e6c51b3..8b0b2fe3 100644
--- a/platform/java/mupdf_native.h
+++ b/platform/java/mupdf_native.h
@@ -683,6 +683,22 @@ JNIEXPORT void JNICALL Java_com_artifex_mupdf_fitz_Document_layout
 
 /*
  * Class:     com_artifex_mupdf_fitz_Document
+ * Method:    makeBookmark
+ * Signature: (I)J
+ */
+JNIEXPORT jlong JNICALL Java_com_artifex_mupdf_fitz_Document_makeBookmark
+  (JNIEnv *, jobject, jint);
+
+/*
+ * Class:     com_artifex_mupdf_fitz_Document
+ * Method:    findBookmark
+ * Signature: (J)I
+ */
+JNIEXPORT jint JNICALL Java_com_artifex_mupdf_fitz_Document_findBookmark
+  (JNIEnv *, jobject, jlong);
+
+/*
+ * Class:     com_artifex_mupdf_fitz_Document
  * Method:    isUnencryptedPDF
  * Signature: ()Z
  */
diff --git a/platform/java/src/com/artifex/mupdf/fitz/Document.java b/platform/java/src/com/artifex/mupdf/fitz/Document.java
index 29cad4db..1fc21c13 100644
--- a/platform/java/src/com/artifex/mupdf/fitz/Document.java
+++ b/platform/java/src/com/artifex/mupdf/fitz/Document.java
@@ -49,6 +49,9 @@ public class Document
 	public native boolean isReflowable();
 	public native void layout(float width, float height, float em);
 
+	public native long makeBookmark(int page);
+	public native int findBookmark(long mark);
+
 	public native boolean isUnencryptedPDF();
 
 	public native PDFDocument toPDFDocument();
diff --git a/source/fitz/document.c b/source/fitz/document.c
index 684c8523..41abb736 100644
--- a/source/fitz/document.c
+++ b/source/fitz/document.c
@@ -182,6 +182,20 @@ fz_is_document_reflowable(fz_context *ctx, fz_document *doc)
 	return doc ? doc->is_reflowable : 0;
 }
 
+fz_bookmark fz_make_bookmark(fz_context *ctx, fz_document *doc, int page)
+{
+	if (doc && doc->make_bookmark)
+		return doc->make_bookmark(ctx, doc, page);
+	return (fz_bookmark)page;
+}
+
+int fz_lookup_bookmark(fz_context *ctx, fz_document *doc, fz_bookmark mark)
+{
+	if (doc && doc->lookup_bookmark)
+		return doc->lookup_bookmark(ctx, doc, mark);
+	return (int)mark;
+}
+
 int
 fz_needs_password(fz_context *ctx, fz_document *doc)
 {
diff --git a/source/html/epub-doc.c b/source/html/epub-doc.c
index d220816d..3cfa3f06 100644
--- a/source/html/epub-doc.c
+++ b/source/html/epub-doc.c
@@ -178,6 +178,39 @@ epub_load_links(fz_context *ctx, fz_page *page_)
 	return NULL;
 }
 
+static fz_bookmark
+epub_make_bookmark(fz_context *ctx, fz_document *doc_, int n)
+{
+	epub_document *doc = (epub_document*)doc_;
+	epub_chapter *ch;
+	int count = 0;
+
+	for (ch = doc->spine; ch; ch = ch->next)
+	{
+		int cn = ceilf(ch->html->root->h / ch->html->page_h);
+		if (n < count + cn)
+			return fz_make_html_bookmark(ctx, ch->html, n - count);
+		count += cn;
+	}
+
+	return 0;
+}
+
+static int
+epub_lookup_bookmark(fz_context *ctx, fz_document *doc_, fz_bookmark mark)
+{
+	epub_document *doc = (epub_document*)doc_;
+	epub_chapter *ch;
+
+	for (ch = doc->spine; ch; ch = ch->next)
+	{
+		int p = fz_lookup_html_bookmark(ctx, ch->html, mark);
+		if (p != -1)
+			return ch->start + p;
+	}
+	return -1;
+}
+
 static fz_page *
 epub_load_page(fz_context *ctx, fz_document *doc_, int number)
 {
@@ -440,6 +473,8 @@ epub_init(fz_context *ctx, fz_archive *zip)
 	doc->super.layout = epub_layout;
 	doc->super.load_outline = epub_load_outline;
 	doc->super.resolve_link = epub_resolve_link;
+	doc->super.make_bookmark = epub_make_bookmark;
+	doc->super.lookup_bookmark = epub_lookup_bookmark;
 	doc->super.count_pages = epub_count_pages;
 	doc->super.load_page = epub_load_page;
 	doc->super.lookup_metadata = epub_lookup_metadata;
diff --git a/source/html/html-doc.c b/source/html/html-doc.c
index c19d5049..47225c06 100644
--- a/source/html/html-doc.c
+++ b/source/html/html-doc.c
@@ -97,6 +97,20 @@ htdoc_load_links(fz_context *ctx, fz_page *page_)
 	return fz_load_html_links(ctx, doc->html, page->number, "");
 }
 
+static fz_bookmark
+htdoc_make_bookmark(fz_context *ctx, fz_document *doc_, int page)
+{
+	html_document *doc = (html_document*)doc_;
+	return fz_make_html_bookmark(ctx, doc->html, page);
+}
+
+static int
+htdoc_lookup_bookmark(fz_context *ctx, fz_document *doc_, fz_bookmark mark)
+{
+	html_document *doc = (html_document*)doc_;
+	return fz_lookup_html_bookmark(ctx, doc->html, mark);
+}
+
 static fz_page *
 htdoc_load_page(fz_context *ctx, fz_document *doc_, int number)
 {
@@ -111,7 +125,7 @@ htdoc_load_page(fz_context *ctx, fz_document *doc_, int number)
 	return (fz_page*)page;
 }
 
-int
+static int
 htdoc_lookup_metadata(fz_context *ctx, fz_document *doc_, const char *key, char *buf, int size)
 {
 	if (!strcmp(key, "format"))
@@ -162,6 +176,8 @@ htdoc_open_document(fz_context *ctx, const char *filename)
 	doc->super.drop_document = htdoc_drop_document;
 	doc->super.layout = htdoc_layout;
 	doc->super.resolve_link = htdoc_resolve_link;
+	doc->super.make_bookmark = htdoc_make_bookmark;
+	doc->super.lookup_bookmark = htdoc_lookup_bookmark;
 	doc->super.count_pages = htdoc_count_pages;
 	doc->super.load_page = htdoc_load_page;
 	doc->super.lookup_metadata = htdoc_lookup_metadata;
diff --git a/source/html/html-layout.c b/source/html/html-layout.c
index f06e6cbd..1cac935b 100644
--- a/source/html/html-layout.c
+++ b/source/html/html-layout.c
@@ -2101,6 +2101,91 @@ fz_find_html_target(fz_context *ctx, fz_html *html, const char *id)
 	return find_box_target(html->root, id);
 }
 
+static fz_html_flow *
+make_flow_bookmark(fz_context *ctx, fz_html_flow *flow, float y)
+{
+	while (flow)
+	{
+		if (flow->y >= y)
+			return flow;
+		flow = flow->next;
+	}
+	return NULL;
+}
+
+static fz_html_flow *
+make_box_bookmark(fz_context *ctx, fz_html_box *box, float y)
+{
+	fz_html_flow *mark;
+	while (box)
+	{
+		if (box->type == BOX_FLOW)
+		{
+			if (box->y >= y)
+			{
+				mark = make_flow_bookmark(ctx, box->flow_head, y);
+				if (mark)
+					return mark;
+			}
+		}
+		else
+		{
+			mark = make_box_bookmark(ctx, box->down, y);
+			if (mark)
+				return mark;
+		}
+		box = box->next;
+	}
+	return NULL;
+}
+
+fz_bookmark
+fz_make_html_bookmark(fz_context *ctx, fz_html *html, int page)
+{
+	return (fz_bookmark)make_box_bookmark(ctx, html->root, page * html->page_h);
+}
+
+static int
+lookup_flow_bookmark(fz_context *ctx, fz_html_flow *flow, fz_html_flow *mark)
+{
+	while (flow)
+	{
+		if (flow == mark)
+			return 1;
+		flow = flow->next;
+	}
+	return 0;
+}
+
+static int
+lookup_box_bookmark(fz_context *ctx, fz_html_box *box, fz_html_flow *mark)
+{
+	while (box)
+	{
+		if (box->type == BOX_FLOW)
+		{
+			if (lookup_flow_bookmark(ctx, box->flow_head, mark))
+				return 1;
+		}
+		else
+		{
+			if (lookup_box_bookmark(ctx, box->down, mark))
+				return 1;
+		}
+		box = box->next;
+	}
+	return 0;
+}
+
+int
+fz_lookup_html_bookmark(fz_context *ctx, fz_html *html, fz_bookmark mark)
+{
+	fz_html_flow *flow = (fz_html_flow*)mark;
+	if (flow && lookup_box_bookmark(ctx, html->root, flow))
+		return (int)(flow->y / html->page_h);
+	return -1;
+}
+
 static char *concat_text(fz_context *ctx, fz_xml *root)
 {
 	fz_xml *node;