source: trunk/third/libart_lgpl/art_rgb_svp.c @ 18256

/* Libart_LGPL - library of basic graphic primitives
 * Copyright (C) 1998 Raph Levien
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* Render a sorted vector path into an RGB buffer. */

#include "config.h"
#include "art_rgb_svp.h"

#include "art_svp.h"
#include "art_svp_render_aa.h"
#include "art_rgb.h"

typedef struct _ArtRgbSVPData ArtRgbSVPData;
typedef struct _ArtRgbSVPAlphaData ArtRgbSVPAlphaData;

struct _ArtRgbSVPData {
  art_u32 rgbtab[256];
  art_u8 *buf;
  int rowstride;
  int x0, x1;
};

struct _ArtRgbSVPAlphaData {
  int alphatab[256];
  art_u8 r, g, b, alpha;
  art_u8 *buf;
  int rowstride;
  int x0, x1;
};

static void
art_rgb_svp_callback (void *callback_data, int y,
                      int start, ArtSVPRenderAAStep *steps, int n_steps)
{
  ArtRgbSVPData *data = (ArtRgbSVPData *)callback_data;
  art_u8 *linebuf;
  int run_x0, run_x1;
  art_u32 running_sum = start;
  art_u32 rgb;
  int x0, x1;
  int k;

  linebuf = data->buf;
  x0 = data->x0;
  x1 = data->x1;

  if (n_steps > 0)
    {
      run_x1 = steps[0].x;
      if (run_x1 > x0)
        {
          rgb = data->rgbtab[(running_sum >> 16) & 0xff];
          art_rgb_fill_run (linebuf,
                            rgb >> 16, (rgb >> 8) & 0xff, rgb & 0xff,
                            run_x1 - x0);
        }

      for (k = 0; k < n_steps - 1; k++)
        {
          running_sum += steps[k].delta;
          run_x0 = run_x1;
          run_x1 = steps[k + 1].x;
          if (run_x1 > run_x0)
            {
              rgb = data->rgbtab[(running_sum >> 16) & 0xff];
              art_rgb_fill_run (linebuf + (run_x0 - x0) * 3,
                                rgb >> 16, (rgb >> 8) & 0xff, rgb & 0xff,
                                run_x1 - run_x0);
            }
        }
      running_sum += steps[k].delta;
      if (x1 > run_x1)
        {
          rgb = data->rgbtab[(running_sum >> 16) & 0xff];
          art_rgb_fill_run (linebuf + (run_x1 - x0) * 3,
                            rgb >> 16, (rgb >> 8) & 0xff, rgb & 0xff,
                            x1 - run_x1);
        }
    }
  else
    {
      rgb = data->rgbtab[(running_sum >> 16) & 0xff];
      art_rgb_fill_run (linebuf,
                        rgb >> 16, (rgb >> 8) & 0xff, rgb & 0xff,
                        x1 - x0);
    }

  data->buf += data->rowstride;
}

/* Render the vector path into the RGB buffer. */

/**
 * art_rgb_svp_aa: Render sorted vector path into RGB buffer.
 * @svp: The source sorted vector path.
 * @x0: Left coordinate of destination rectangle.
 * @y0: Top coordinate of destination rectangle.
 * @x1: Right coordinate of destination rectangle.
 * @y1: Bottom coordinate of destination rectangle.
 * @fg_color: Foreground color in 0xRRGGBB format.
 * @bg_color: Background color in 0xRRGGBB format.
 * @buf: Destination RGB buffer.
 * @rowstride: Rowstride of @buf buffer.
 * @alphagamma: #ArtAlphaGamma for gamma-correcting the rendering.
 *
 * Renders the shape specified with @svp into the @buf RGB buffer.
 * @x1 - @x0 specifies the width, and @y1 - @y0 specifies the height,
 * of the rectangle rendered. The new pixels are stored starting at
 * the first byte of @buf. Thus, the @x0 and @y0 parameters specify
 * an offset within @svp, and may be tweaked as a way of doing
 * integer-pixel translations without fiddling with @svp itself.
 *
 * The @fg_color and @bg_color arguments specify the opaque colors to
 * be used for rendering. For pixels of entirely 0 winding-number,
 * @bg_color is used. For pixels of entirely 1 winding number,
 * @fg_color is used. In between, the color is interpolated based on
 * the fraction of the pixel with a winding number of 1. If
 * @alphagamma is NULL, then linear interpolation (in pixel counts) is
 * the default. Otherwise, the interpolation is as specified by
 * @alphagamma.
 **/
void
art_rgb_svp_aa (const ArtSVP *svp,
                int x0, int y0, int x1, int y1,
                art_u32 fg_color, art_u32 bg_color,
                art_u8 *buf, int rowstride,
                ArtAlphaGamma *alphagamma)
{
  ArtRgbSVPData data;

  int r_fg, g_fg, b_fg;
  int r_bg, g_bg, b_bg;
  int r, g, b;
  int dr, dg, db;
  int i;

  if (alphagamma == NULL)
    {
      r_fg = fg_color >> 16;
      g_fg = (fg_color >> 8) & 0xff;
      b_fg = fg_color & 0xff;

      r_bg = bg_color >> 16;
      g_bg = (bg_color >> 8) & 0xff;
      b_bg = bg_color & 0xff;

      r = (r_bg << 16) + 0x8000;
      g = (g_bg << 16) + 0x8000;
      b = (b_bg << 16) + 0x8000;
      dr = ((r_fg - r_bg) << 16) / 255;
      dg = ((g_fg - g_bg) << 16) / 255;
      db = ((b_fg - b_bg) << 16) / 255;

      for (i = 0; i < 256; i++)
        {
          data.rgbtab[i] = (r & 0xff0000) | ((g & 0xff0000) >> 8) | (b >> 16);
          r += dr;
          g += dg;
          b += db;
        }
    }
  else
    {
      int *table;
      art_u8 *invtab;

      table = alphagamma->table;

      r_fg = table[fg_color >> 16];
      g_fg = table[(fg_color >> 8) & 0xff];
      b_fg = table[fg_color & 0xff];

      r_bg = table[bg_color >> 16];
      g_bg = table[(bg_color >> 8) & 0xff];
      b_bg = table[bg_color & 0xff];

      r = (r_bg << 16) + 0x8000;
      g = (g_bg << 16) + 0x8000;
      b = (b_bg << 16) + 0x8000;
      dr = ((r_fg - r_bg) << 16) / 255;
      dg = ((g_fg - g_bg) << 16) / 255;
      db = ((b_fg - b_bg) << 16) / 255;

      invtab = alphagamma->invtable;
      for (i = 0; i < 256; i++)
        {
          data.rgbtab[i] = (invtab[r >> 16] << 16) |
            (invtab[g >> 16] << 8) |
            invtab[b >> 16];
          r += dr;
          g += dg;
          b += db;
        }
    }
  data.buf = buf;
  data.rowstride = rowstride;
  data.x0 = x0;
  data.x1 = x1;
  art_svp_render_aa (svp, x0, y0, x1, y1, art_rgb_svp_callback, &data);
}

static void
art_rgb_svp_alpha_callback (void *callback_data, int y,
                            int start, ArtSVPRenderAAStep *steps, int n_steps)
{
  ArtRgbSVPAlphaData *data = (ArtRgbSVPAlphaData *)callback_data;
  art_u8 *linebuf;
  int run_x0, run_x1;
  art_u32 running_sum = start;
  int x0, x1;
  int k;
  art_u8 r, g, b;
  int *alphatab;
  int alpha;

  linebuf = data->buf;
  x0 = data->x0;
  x1 = data->x1;

  r = data->r;
  g = data->g;
  b = data->b;
  alphatab = data->alphatab;

  if (n_steps > 0)
    {
      run_x1 = steps[0].x;
      if (run_x1 > x0)
        {
          alpha = (running_sum >> 16) & 0xff;
          if (alpha)
            art_rgb_run_alpha (linebuf,
                               r, g, b, alphatab[alpha],
                               run_x1 - x0);
        }

      for (k = 0; k < n_steps - 1; k++)
        {
          running_sum += steps[k].delta;
          run_x0 = run_x1;
          run_x1 = steps[k + 1].x;
          if (run_x1 > run_x0)
            {
              alpha = (running_sum >> 16) & 0xff;
              if (alpha)
                art_rgb_run_alpha (linebuf + (run_x0 - x0) * 3,
                                   r, g, b, alphatab[alpha],
                                   run_x1 - run_x0);
            }
        }
      running_sum += steps[k].delta;
      if (x1 > run_x1)
        {
          alpha = (running_sum >> 16) & 0xff;
          if (alpha)
            art_rgb_run_alpha (linebuf + (run_x1 - x0) * 3,
                               r, g, b, alphatab[alpha],
                               x1 - run_x1);
        }
    }
  else
    {
      alpha = (running_sum >> 16) & 0xff;
      if (alpha)
        art_rgb_run_alpha (linebuf,
                           r, g, b, alphatab[alpha],
                           x1 - x0);
    }

  data->buf += data->rowstride;
}

static void
art_rgb_svp_alpha_opaque_callback (void *callback_data, int y,
                                   int start,
                                   ArtSVPRenderAAStep *steps, int n_steps)
{
  ArtRgbSVPAlphaData *data = (ArtRgbSVPAlphaData *)callback_data;
  art_u8 *linebuf;
  int run_x0, run_x1;
  art_u32 running_sum = start;
  int x0, x1;
  int k;
  art_u8 r, g, b;
  int *alphatab;
  int alpha;

  linebuf = data->buf;
  x0 = data->x0;
  x1 = data->x1;

  r = data->r;
  g = data->g;
  b = data->b;
  alphatab = data->alphatab;

  if (n_steps > 0)
    {
      run_x1 = steps[0].x;
      if (run_x1 > x0)
        {
          alpha = running_sum >> 16;
          if (alpha)
            {
              if (alpha >= 255)
                art_rgb_fill_run (linebuf,
                                  r, g, b,
                                  run_x1 - x0);
              else
                art_rgb_run_alpha (linebuf,
                                   r, g, b, alphatab[alpha],
                                   run_x1 - x0);
            }
        }

      for (k = 0; k < n_steps - 1; k++)
        {
          running_sum += steps[k].delta;
          run_x0 = run_x1;
          run_x1 = steps[k + 1].x;
          if (run_x1 > run_x0)
            {
              alpha = running_sum >> 16;
              if (alpha)
                {
                  if (alpha >= 255)
                    art_rgb_fill_run (linebuf + (run_x0 - x0) * 3,
                                      r, g, b,
                                      run_x1 - run_x0);
                  else
                    art_rgb_run_alpha (linebuf + (run_x0 - x0) * 3,
                                       r, g, b, alphatab[alpha],
                                       run_x1 - run_x0);
                }
            }
        }
      running_sum += steps[k].delta;
      if (x1 > run_x1)
        {
          alpha = running_sum >> 16;
          if (alpha)
            {
              if (alpha >= 255)
                art_rgb_fill_run (linebuf + (run_x1 - x0) * 3,
                                  r, g, b,
                                  x1 - run_x1);
              else
                art_rgb_run_alpha (linebuf + (run_x1 - x0) * 3,
                                   r, g, b, alphatab[alpha],
                                   x1 - run_x1);
            }
        }
    }
  else
    {
      alpha = running_sum >> 16;
      if (alpha)
        {
          if (alpha >= 255)
            art_rgb_fill_run (linebuf,
                              r, g, b,
                              x1 - x0);
          else
            art_rgb_run_alpha (linebuf,
                               r, g, b, alphatab[alpha],
                               x1 - x0);
        }
    }

  data->buf += data->rowstride;
}

/**
 * art_rgb_svp_alpha: Alpha-composite sorted vector path over RGB buffer.
 * @svp: The source sorted vector path.
 * @x0: Left coordinate of destination rectangle.
 * @y0: Top coordinate of destination rectangle.
 * @x1: Right coordinate of destination rectangle.
 * @y1: Bottom coordinate of destination rectangle.
 * @rgba: Color in 0xRRGGBBAA format.
 * @buf: Destination RGB buffer.
 * @rowstride: Rowstride of @buf buffer.
 * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
 *
 * Renders the shape specified with @svp over the @buf RGB buffer.
 * @x1 - @x0 specifies the width, and @y1 - @y0 specifies the height,
 * of the rectangle rendered. The new pixels are stored starting at
 * the first byte of @buf. Thus, the @x0 and @y0 parameters specify
 * an offset within @svp, and may be tweaked as a way of doing
 * integer-pixel translations without fiddling with @svp itself.
 *
 * The @rgba argument specifies the color for the rendering. Pixels of
 * entirely 0 winding number are left untouched. Pixels of entirely
 * 1 winding number have the color @rgba composited over them (ie,
 * are replaced by the red, green, blue components of @rgba if the alpha
 * component is 0xff). Pixels of intermediate coverage are interpolated
 * according to the rule in @alphagamma, or default to linear if
 * @alphagamma is NULL.
 **/
void
art_rgb_svp_alpha (const ArtSVP *svp,
                   int x0, int y0, int x1, int y1,
                   art_u32 rgba,
                   art_u8 *buf, int rowstride,
                   ArtAlphaGamma *alphagamma)
{
  ArtRgbSVPAlphaData data;
  int r, g, b, alpha;
  int i;
  int a, da;

  r = rgba >> 24;
  g = (rgba >> 16) & 0xff;
  b = (rgba >> 8) & 0xff;
  alpha = rgba & 0xff;

  data.r = r;
  data.g = g;
  data.b = b;
  data.alpha = alpha;

  a = 0x8000;
  da = (alpha * 66051 + 0x80) >> 8; /* 66051 equals 2 ^ 32 / (255 * 255) */

  for (i = 0; i < 256; i++)
    {
      data.alphatab[i] = a >> 16;
      a += da;
    }

  data.buf = buf;
  data.rowstride = rowstride;
  data.x0 = x0;
  data.x1 = x1;
  if (alpha == 255)
    art_svp_render_aa (svp, x0, y0, x1, y1, art_rgb_svp_alpha_opaque_callback,
                       &data);
  else
    art_svp_render_aa (svp, x0, y0, x1, y1, art_rgb_svp_alpha_callback, &data);
}