diff options
author | Paul Davis <paul@linuxaudiosystems.com> | 2014-05-20 23:08:15 -0400 |
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committer | Paul Davis <paul@linuxaudiosystems.com> | 2014-06-03 16:10:27 -0400 |
commit | 6019f06bdf919e1d95dd0912116cdec0834af8db (patch) | |
tree | be8d2e41e692c2e8a572f531b546efde67b1503f /libs/canvas/canvas/scroll_group.h | |
parent | fc9e6651dd804672822e06cbd4092c043dc8406d (diff) |
different approach to independent scrolling, involving ArdourCanvas::ScrollGroup
The idea now is that a scroll group item can be added to the canvas which will causes its children to scroll in either or both
directions (horizontal or vertical). There are few complications: the position() of the ScrollGroup is ambiguous depending
on whether you want it with scroll taken into account or not, so Item::canvas_position() was added, which defaults to
the same value as Item::position() but is overridden by ScrollGroup to return the position independent of scrolling. This
method is used when translating between item/canvas/window coordinate systems.
Note that the basic idea is that we MOVE the scroll group when a scroll happens. This mirrors what happens in the GnomeCanvas,
where Nick Mainsbridge came up with a great idea that allowed unification of the time bar and track canvases.
Diffstat (limited to 'libs/canvas/canvas/scroll_group.h')
-rw-r--r-- | libs/canvas/canvas/scroll_group.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/libs/canvas/canvas/scroll_group.h b/libs/canvas/canvas/scroll_group.h new file mode 100644 index 0000000000..c2b26bf9d9 --- /dev/null +++ b/libs/canvas/canvas/scroll_group.h @@ -0,0 +1,47 @@ +/* + Copyright (C) 2014 Paul Davis + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#ifndef __CANVAS_SCROLL_GROUP_H__ +#define __CANVAS_SCROLL_GROUP_H__ + +#include "canvas/group.h" + +namespace ArdourCanvas { + +class LIBCANVAS_API ScrollGroup : public Group +{ + public: + enum ScrollSensitivity { + ScrollsVertically = 0x1, + ScrollsHorizontally = 0x2 + }; + + explicit ScrollGroup (Group *, ScrollSensitivity); + explicit ScrollGroup (Group *, Duple, ScrollSensitivity); + + void scroll_to (Duple const& d); + Duple canvas_position() const; + + private: + ScrollSensitivity _scroll_sensitivity; + Duple _scroll_offset; +}; + +} + +#endif |