view src/video/SDL_drawline.c @ 2900:3a9636c83849

Make it possible to switch algorithms in the future
author Sam Lantinga <slouken@libsdl.org>
date Sun, 21 Dec 2008 08:59:56 +0000
parents e40448bc7727
children 133601e3b255
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include "SDL_draw.h"

#define SETPIXEL(x, y, type, bpp, color) \
    *(type *)(dst->pixels + y * dst->pitch + x * bpp) = (type) color

#define SETPIXEL1(x, y) SETPIXEL(x, y, Uint8, 1, color);
#define SETPIXEL2(x, y) SETPIXEL(x, y, Uint16, 2, color);
#define SETPIXEL4(x, y) SETPIXEL(x, y, Uint32, 4, color);

SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color)
{
    /* This function doesn't work on surfaces < 8 bpp */
    if (dst->format->BitsPerPixel < 8) {
        SDL_SetError("SDL_DrawLine(): Unsupported surface format");
        return (-1);
    }

    /* Perform clipping */
    /* FIXME
       if (!SDL_IntersectRect(dstrect, &dst->clip_rect, dstrect)) {
       return (0);
       }
     */

    switch (dst->format->BytesPerPixel) {
    case 1:
        DRAWLINE(x1, y1, x2, y2, SETPIXEL1);
        break;
    case 2:
        DRAWLINE(x1, y1, x2, y2, SETPIXEL2);
        break;
    case 3:
        SDL_Unsupported();
        return -1;
    case 4:
        DRAWLINE(x1, y1, x2, y2, SETPIXEL4);
        break;
    }
    return 0;
}

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