From 511ab26917ed9e856ebbc8f764a5b68613ebc1cd Mon Sep 17 00:00:00 2001

From: Marek Kasik <mkasik@redhat.com>

Date: Mon, 9 May 2016 12:57:20 +0200

Subject: [PATCH] libview: Scroll small pages in non-continuous mode

Check whether currently shown page fits actual view and allow user to scroll

to previous/next page in that case (also in Dual page mode).

Allow also scrolling if only one axis fits the view and the event

happenned in the same axis.

https://bugzilla.gnome.org/show_bug.cgi?id=562257

---

 libview/ev-view.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++--------

 1 file changed, 83 insertions(+), 14 deletions(-)

diff --git a/libview/ev-view.c b/libview/ev-view.c

index f76eca8..f96ad4b 100644

--- a/libview/ev-view.c

+++ b/libview/ev-view.c

@@ -247,6 +247,8 @@ static void 	ev_view_zoom_for_size_dual_page 	       (EvView *view,

 static void	ev_view_zoom_for_size_single_page 	       (EvView *view,

 				    			        int     width,

 					    			int     height);

+static gboolean	ev_view_page_fits			       (EvView         *view,

+								GtkOrientation  orientation);

 /*** Cursors ***/

 static void       ev_view_set_cursor                         (EvView             *view,

 							      EvViewCursor        new_cursor);

@@ -973,7 +998,8 @@ ev_view_scroll (EvView        *view,

 	view->jump_to_find_result = FALSE;

-	if (view->sizing_mode == EV_SIZING_FIT_PAGE) {

+	if ((!horizontal && ev_view_page_fits (view, GTK_ORIENTATION_VERTICAL)) ||

+	    (horizontal && ev_view_page_fits (view, GTK_ORIENTATION_HORIZONTAL))) {

 		switch (scroll) {

 			case GTK_SCROLL_PAGE_BACKWARD:

 			case GTK_SCROLL_STEP_BACKWARD:

@@ -3972,6 +4116,7 @@ ev_view_scroll_event (GtkWidget *widget, GdkEventScroll *event)

 {

 	EvView *view = EV_VIEW (widget);

 	guint state;

+	gboolean fit_width, fit_height;

 	state = event->state & gtk_accelerator_get_default_mod_mask ();

@@ -4026,34 +4174,57 @@ ev_view_scroll_event (GtkWidget *widget, GdkEventScroll *event)

 		state &= ~GDK_SHIFT_MASK;

 	}

-	if (state == 0 && view->sizing_mode == EV_SIZING_FIT_PAGE && !view->continuous) {

+	fit_width = ev_view_page_fits (view, GTK_ORIENTATION_HORIZONTAL);

+	fit_height = ev_view_page_fits (view, GTK_ORIENTATION_VERTICAL);

+	if (state == 0 && !view->continuous && (fit_width || fit_height)) {

 		switch (event->direction) {

 		case GDK_SCROLL_DOWN:

+			if (fit_height) {

+				ev_view_next_page (view);

+				return TRUE;

+			}

+			break;

 		case GDK_SCROLL_RIGHT:

-			ev_view_next_page (view);

+			if (fit_width) {

+				ev_view_next_page (view);

+				return TRUE;

+			}

 			break;

 		case GDK_SCROLL_UP:

+			if (fit_height) {

+				ev_view_previous_page (view);

+				return TRUE;

+			}

+			break;

 		case GDK_SCROLL_LEFT:

-			ev_view_previous_page (view);

+			if (fit_width) {

+				ev_view_previous_page (view);

+				return TRUE;

+			}

 			break;

 		case GDK_SCROLL_SMOOTH: {

 			gdouble decrement;

+			if ((fit_width && fit_height) ||

+			    ((fit_height && event->delta_x == 0.0) ||

+			     (fit_width && event->delta_y == 0.0))) {

+				/* Emulate normal scrolling by summing the deltas */

+				view->total_delta += event->delta_x + event->delta_y;

+

+				decrement = view->total_delta < 0 ? -1.0 : 1.0;

+				for (; fabs (view->total_delta) >= 1.0; view->total_delta -= decrement) {

+					if (decrement < 0)

+						ev_view_previous_page (view);

+					else

+						ev_view_next_page (view);

+				}

-			/* Emulate normal scrolling by summing the deltas */

-			view->total_delta += event->delta_x + event->delta_y;

-

-			decrement = view->total_delta < 0 ? -1.0 : 1.0;

-			for (; fabs (view->total_delta) >= 1.0; view->total_delta -= decrement) {

-				if (decrement < 0)

-					ev_view_previous_page (view);

-				else

-					ev_view_next_page (view);

+				return TRUE;

 			}

 		}

 			break;

 		}

-		return TRUE;

+		return FALSE;

 	}

 	return FALSE;

@@ -8111,6 +8571,48 @@ ev_view_zoom_for_size (EvView *view,

 		ev_view_zoom_for_size_single_page (view, width, height);

 }

+static gboolean

+ev_view_page_fits (EvView         *view,

+		   GtkOrientation  orientation)

+{

+	GtkRequisition requisition;

+	GtkAllocation  allocation;

+	double         size;

+

+	if (view->sizing_mode == EV_SIZING_FIT_PAGE)

+		return TRUE;

+

+	if (orientation == GTK_ORIENTATION_HORIZONTAL &&

+	    (view->sizing_mode == EV_SIZING_FIT_WIDTH ||

+	     view->sizing_mode == EV_SIZING_AUTOMATIC))

+		return TRUE;

+

+	gtk_widget_get_allocation (GTK_WIDGET (view), &allocation);

+	ev_view_size_request (GTK_WIDGET (view), &requisition);

+

+	if (orientation == GTK_ORIENTATION_HORIZONTAL) {

+		if (requisition.width == 1) {

+			size = 1.0;

+		} else {

+			if (allocation.width > 0.0)

+				size = (double) requisition.width / allocation.width;

+			else

+				size = 1.0;

+		}

+	} else {

+		if (requisition.height == 1) {

+			size = 1.0;

+		} else {

+			if (allocation.height > 0.0)

+				size = (double) requisition.height / allocation.height;

+			else

+				size = 1.0;

+		}

+	}

+

+	return size <= 1.0;

+}

+

 /*** Find ***/

 static gint

 ev_view_find_get_n_results (EvView *view, gint page)

-- 

2.7.4