From c9ea2a34dc33224bdcc34286b3424eff44ddbe8f Mon Sep 17 00:00:00 2001 From: Colomban Wendling Date: Tue, 4 Sep 2018 14:22:04 +0200 Subject: EvView: Fix cursor movement when logical and visual line order differs Make sure not to move the caret in the wrong direction when restoring the visual line X offset, in case the visual and logical order is slightly different. The algorithm used to move the cursor on the next line and restore the X position across lines works as follows: 1. Move `cursor_offset` to the next line by incrementing it until reaching a line break; 2. Find the Y coordinate corresponding to the new cursor_offset; 3. Find the text closest to the new Y coordinate and the previous X coordinate. 4. Move cursor_offset to the text at this new (X, Y) location. The issue lies in step 3, which can find a position on a different line than expected in case several lines have a nearly the same Y position. Evince references: * https://gitlab.gnome.org/GNOME/evince/issues/889 * https://gitlab.gnome.org/GNOME/evince/merge_requests/81 * https://gitlab.gnome.org/GNOME/evince/commit/dddd98b4c7922e2906bba6a31afa07837ae6c39c --- libview/ev-view.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/libview/ev-view.c b/libview/ev-view.c index 61505728..2db3eb2b 100644 --- a/libview/ev-view.c +++ b/libview/ev-view.c @@ -5406,6 +5406,7 @@ ev_view_move_cursor (EvView *view, gint prev_page; cairo_region_t *damage_region; gboolean clear_selections = FALSE; + const gboolean forward = count >= 0; if (!view->caret_enabled || view->rotation != 0) return FALSE; @@ -5475,9 +5476,18 @@ ev_view_move_cursor (EvView *view, return TRUE; if (step == GTK_MOVEMENT_DISPLAY_LINES) { + const gint prev_cursor_offset = view->cursor_offset; + position_caret_cursor_at_location (view, MAX (rect.x, view->cursor_line_offset), rect.y + (rect.height / 2)); + /* Make sure we didn't move the cursor in the wrong direction + * in case the visual order isn't the same as the logical one, + * in order to avoid cursor movement loops */ + if ((forward && prev_cursor_offset > view->cursor_offset) || + (!forward && prev_cursor_offset < view->cursor_offset)) { + view->cursor_offset = prev_cursor_offset; + } if (!clear_selections && prev_offset == view->cursor_offset && prev_page == view->cursor_page) { gtk_widget_error_bell (GTK_WIDGET (view)); -- cgit v1.2.1