1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/include/viewport.h Fri Nov 09 22:50:30 2018 +0100
1.3 @@ -0,0 +1,65 @@
1.4 +/*
1.5 + * Common viewport-related functions.
1.6 + *
1.7 + * Copyright (C) 2018 Paul Boddie <paul@boddie.org.uk>
1.8 + *
1.9 + * This program is free software: you can redistribute it and/or modify
1.10 + * it under the terms of the GNU General Public License as published by
1.11 + * the Free Software Foundation, either version 3 of the License, or
1.12 + * (at your option) any later version.
1.13 + *
1.14 + * This program is distributed in the hope that it will be useful,
1.15 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.17 + * GNU General Public License for more details.
1.18 + *
1.19 + * You should have received a copy of the GNU General Public License
1.20 + * along with this program. If not, see <http://www.gnu.org/licenses/>.
1.21 + */
1.22 +
1.23 +#ifndef __VIEWPORT_H__
1.24 +#define __VIEWPORT_H__
1.25 +
1.26 +#include "display.h"
1.27 +
1.28 +
1.29 +
1.30 +/* An abstraction providing a scrolling viewport. */
1.31 +
1.32 +typedef struct
1.33 +{
1.34 + /* Display configuration. */
1.35 +
1.36 + display_config_t *cfg;
1.37 +
1.38 + /* Scrolling positions for each frame. */
1.39 +
1.40 + int *xorigins, *yorigins;
1.41 +
1.42 + /* Scrolling position. */
1.43 +
1.44 + int xorigin, yorigin;
1.45 +
1.46 + /* Scaling factors, translating the origin coordinates to display columns
1.47 + and rows. */
1.48 +
1.49 + int xscale, yscale;
1.50 +
1.51 + /* Update function after scrolling. */
1.52 +
1.53 + void (*update)();
1.54 +
1.55 +} viewport_t;
1.56 +
1.57 +
1.58 +
1.59 +/* Viewport operations. */
1.60 +
1.61 +void init_viewport(viewport_t *v, display_config_t *cfg,
1.62 + int xorigins[], int yorigins[],
1.63 + int xscale, int yscale,
1.64 + void (*update)());
1.65 +
1.66 +void viewport_update_origin(viewport_t *v, int dx, int dy);
1.67 +
1.68 +#endif /* __VIEWPORT_H__ */