[PATCH 2/2] Add document.browse.scrolling.vertical_overlap

Add an option to specify the number of overlapping lines when scrolling
page by page (0 by default because this is ELinks' current behaviour).

Signed-off-by: Fabienne Ducroquet <[email protected]>
---
 src/config/options.inc |    5 +++++
 src/viewer/text/view.c |   14 ++++++++++----
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/config/options.inc b/src/config/options.inc
index 0448f90..a267abf 100644
--- a/src/config/options.inc
+++ b/src/config/options.inc
@@ -397,6 +397,11 @@ static struct option_info config_options_info[] = {
 		N_("Number of lines to scroll when a key bound to scroll-up "
 		"or scroll-down is pressed and no prefix was given.")),
 
+	INIT_OPT_INT("document.browse.scrolling", N_("Vertical overlap"),
+		"vertical_overlap", 0, 0, 10, 0,
+		N_("Number of overlapping lines between the new page displayed "
+		"and the previous one when scrolling one page up or down.")),
+
 
 	INIT_OPT_TREE("document.browse", N_("Searching"),
 		"search", 0,
diff --git a/src/viewer/text/view.c b/src/viewer/text/view.c
index e4a9648..9bd9436 100644
--- a/src/viewer/text/view.c
+++ b/src/viewer/text/view.c
@@ -94,7 +94,10 @@ move_down(struct session *ses, struct document_view *doc_view, int type, int ove
 
 	assert(ses->navigate_mode == NAVIGATE_LINKWISE);	/* XXX: drop it at some time. --Zas */
 
-	newpos = doc_view->vs->y + doc_view->box.height - overlap;
+	if (overlap < doc_view->box.height)
+		newpos = doc_view->vs->y + doc_view->box.height - overlap;
+	else
+		newpos = doc_view->vs->y + doc_view->box.height;
 
 	if (newpos < doc_view->document->height)
 		doc_view->vs->y = newpos;
@@ -126,7 +129,7 @@ move_part_page_down(struct session *ses, struct document_view *doc_view, int ove
 enum frame_event_status
 move_page_down(struct session *ses, struct document_view *doc_view)
 {
-	return move_part_page_down(ses, doc_view, 0);
+	return move_part_page_down(ses, doc_view, get_opt_int("document.browse.scrolling.vertical_overlap", ses));
 }
 
 enum frame_event_status
@@ -147,7 +150,10 @@ move_up(struct session *ses, struct document_view *doc_view, int type, int overl
 
 	if (doc_view->vs->y == 0) return;
 
-	doc_view->vs->y -= (doc_view->box.height - overlap);
+	if (overlap < doc_view->box.height)
+		doc_view->vs->y -= (doc_view->box.height - overlap);
+	else
+		doc_view->vs->y -= doc_view->box.height;
 
 	int_lower_bound(&doc_view->vs->y, 0);
 
@@ -178,7 +184,7 @@ move_part_page_up(struct session *ses, struct document_view *doc_view, int overl
 enum frame_event_status
 move_page_up(struct session *ses, struct document_view *doc_view)
 {
-	return move_part_page_up(ses, doc_view, 0);
+	return move_part_page_up(ses, doc_view, get_opt_int("document.browse.scrolling.vertical_overlap", ses));
 }
 
 enum frame_event_status
-- 
1.7.1