libs/gfx/GP_VLineAA.gen.c.t

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
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   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz>                       *
  20  *                                                                           *
  21  *****************************************************************************/
  22
  23 /* Anti Aliased Vertical Line */
  24
  25 #include "core/GP_Pixmap.h"
  26 #include "core/GP_MixPixels.h"
  27 #include "core/GP_FixedPoint.h"
  28 #include "core/GP_GammaCorrection.h"
  29
  30 #define FP_TO_PERC(a) (GP_FP_ROUND_TO_INT((a) * 255))
  31
  32 void GP_VLineAA_Raw(GP_Pixmap *pixmap, GP_Coord x, GP_Coord y0,
  33                     GP_Coord y1, GP_Pixel pixel)
  34 {
  35         if (y1 < y0)
  36                 GP_SWAP(y1, y0);
  37
  38         y0 -= GP_FP_1_2;
  39         y1 += GP_FP_1_2;
  40         x  -= GP_FP_1_2;
  41
  42         GP_Coord int_y0 = GP_FP_TO_INT(y0);
  43         GP_Coord int_y1 = GP_FP_TO_INT(y1);
  44         GP_Coord int_x  = GP_FP_TO_INT(x);
  45
  46         /* Line is shorter than two pixels */
  47         if (int_y0 == int_y1) {
  48                 //TODO
  49                 return;
  50         }
  51
  52         /* Draw the starting and ending pixel */
  53         uint8_t perc;
  54
  55         perc = FP_TO_PERC(GP_FP_MUL(GP_FP_RFRAC(x), GP_FP_RFRAC(y0)));
  56         GP_MixPixel_Raw_Clipped(pixmap, int_x, int_y0, pixel, perc);
  57
  58         perc = FP_TO_PERC(GP_FP_MUL(GP_FP_FRAC(x), GP_FP_RFRAC(y0)));
  59         GP_MixPixel_Raw_Clipped(pixmap, int_x+1, int_y0, pixel, perc);
  60
  61         perc = FP_TO_PERC(GP_FP_MUL(GP_FP_RFRAC(x), GP_FP_FRAC(y1)));
  62         GP_MixPixel_Raw_Clipped(pixmap, int_x, int_y1, pixel, perc);
  63
  64         perc = FP_TO_PERC(GP_FP_MUL(GP_FP_FRAC(x), GP_FP_FRAC(y1)));
  65         GP_MixPixel_Raw_Clipped(pixmap, int_x+1, int_y1, pixel, perc);
  66
  67         /* Draw the middle pixels */
  68         uint8_t up = FP_TO_PERC(GP_FP_RFRAC(x));
  69         uint8_t lp = FP_TO_PERC(GP_FP_FRAC(x));
  70
  71         GP_Coord y;
  72
  73         for (y = int_y0 + 1; y < int_y1; y++) {
  74                 GP_MixPixel_Raw_Clipped(pixmap, int_x, y, pixel, up);
  75                 GP_MixPixel_Raw_Clipped(pixmap, int_x+1, y, pixel, lp);
  76         }
  77 }