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Diffstat (limited to 'gtk2_ardour/cursor_context.h')
-rw-r--r-- | gtk2_ardour/cursor_context.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/gtk2_ardour/cursor_context.h b/gtk2_ardour/cursor_context.h new file mode 100644 index 0000000000..9ce086218f --- /dev/null +++ b/gtk2_ardour/cursor_context.h @@ -0,0 +1,75 @@ +/* + Copyright (C) 2014 Paul Davis + Author: David Robillard + + 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 __ardour_gtk_cursor_context_h__ +#define __ardour_gtk_cursor_context_h__ + +#include <boost/shared_ptr.hpp> +#include <gdkmm/cursor.h> + +class Editor; + +/** + A scoped handle for changing the editor mouse cursor. + + This is a safe way to change the cursor that ensures it is only modified in + a strict stack-like fashion. Whenever this handle goes out of scope, the + cursor is restored to the previous one. + + This is not quite entirely fool-proof, there is one case to be careful of: + if a cursor context handle exists, to change it, you must first reset that + handle (destroying the context) then set it. Assigning a new context to a + non-NULL handle will create the new context (pushing a cursor), then destroy + the old one, which would attempt to pop a non-top context which is an + error. To account for this, when replacing a possibly existing context, use + set() which will automatically do the right thing. +*/ +class CursorContext +{ +public: + /** A smart handle for a cursor change context. */ + typedef boost::shared_ptr<CursorContext> Handle; + + ~CursorContext(); + + /** Change the editor cursor and return a cursor context handle. + * + * When the returned handle goes out of scope, the cursor will be reset to + * the previous value. + */ + static Handle create(Editor& editor, Gdk::Cursor* cursor); + + /** Change the editor cursor of an existing cursor context. */ + void change(Gdk::Cursor* cursor); + + /** Set a context handle to a new context. + * + * If the handle points to an existing context, it will first be reset + * before the new context is created. + */ + static void set(Handle* handle, Editor& editor, Gdk::Cursor* cursor); + +private: + Editor& _editor; + size_t _index; + + CursorContext(Editor& editor, Gdk::Cursor* cursor); +}; + +#endif /* __ardour_gtk_cursor_context_h__ */ |