text: /* GStreamer
   * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
   *
   * 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., 51 Franklin St, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   */
  
  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  
  #include <math.h>
  #include <stdlib.h>
  #include "paint.h"
  
  #ifndef M_PI
  #define M_PI  3.14159265358979323846
  #endif
  
  void
  gst_smpte_paint_vbox (guint32 * dest, gint stride,
      gint x0, gint y0, gint c0, gint x1, gint y1, gint c1)
  {
    gint i, j;
    gint width, height;
  
    width = x1 - x0;
    height = y1 - y0;
  
    g_assert (width > 0);
    g_assert (height > 0);
  
    dest = dest + y0 * stride + x0;
  
    for (i = 0; i < height; i++) {
      for (j = 0; j < width; j++) {
        dest[j] = (c1 * j + c0 * (width - j)) / width;
      }
      dest += stride;
    }
  }
  
  void
  gst_smpte_paint_hbox (guint32 * dest, gint stride,
      gint x0, gint y0, gint c0, gint x1, gint y1, gint c1)
  {
    gint i, j;
    gint width, height;
  
    width = x1 - x0;
    height = y1 - y0;
  
    g_assert (width > 0);
    g_assert (height > 0);
  
    dest = dest + y0 * stride + x0;
  
    for (i = 0; i < height; i++) {
      guint32 value = (c1 * i + c0 * (height - i)) / height;
  
      for (j = 0; j < width; j++) {
        dest[j] = value;
      }
      dest += stride;
    }
  }
  
  #define STEP_3D_LINE(dxabs,dyabs,dzabs,sdx,sdy,sdz,xr,yr,zr,px,py,pz)           \
  G_STMT_START {                                          \
    if (dxabs >= dyabs && dxabs >= dzabs) {               \
      yr += dyabs;                                        \
      zr += dzabs;                                        \
      if (yr >= dxabs) {                                  \
        py += sdy;                                        \
        yr -= dxabs;                                      \
      }                                                   \
      if (zr >= dzabs) {                                  \
        pz += sdz;                                        \
        zr -= dxabs;                                      \
      }                                                   \
      px += sdx;                                          \
    } else if (dyabs >= dxabs && dyabs >= dzabs) {        \
      xr += dxabs;                                        \
      zr += dzabs;                                        \
      if (xr >= dyabs) {                                  \
        px += sdx;                                        \
        xr -= dyabs;                                      \
      }                                                   \
      if (zr >= dzabs) {                                  \
        pz += sdz;                                        \
        zr -= dyabs;                                      \
      }                                                   \
      py += sdy;                                          \
    } else {                                              \
      yr += dyabs;                                        \
      xr += dxabs;                                        \
      if (yr >= dyabs) {                                  \
        py += sdy;                                        \
        yr -= dzabs;                                      \
      }                                                   \
      if (xr >= dyabs) {                                  \
        px += sdx;                                        \
        xr -= dzabs;                                      \
      }                                                   \
      pz += sdz;                                          \
    }                                                     \
  } G_STMT_END
  
  #define SWAP_INT(a,b)           \
  G_STMT_START {                  \
    gint tmp;                     \
    tmp = (a);                    \
    (a) = (b);                    \
    (b) = (tmp);                  \
  } G_STMT_END
  
  #define SIGN(a) ((a) < 0 ? -1 : 1)
  
  #define PREPARE_3D_LINE(x0,y0,z0,x1,y1,z1,dxabs,dyabs,dzabs,sdx,sdy,sdz,xr,yr,zr,px,py,pz)\
  G_STMT_START {                  \
    gint dx, dy, dz;              \
    dx = x1 - x0;                 \
    dy = y1 - y0;                 \
    dz = z1 - z0;                 \
    dxabs = abs (dx);             \
    dyabs = abs (dy);             \
    dzabs = abs (dz);             \
    sdx = SIGN (dx);              \
    sdy = SIGN (dy);              \
    sdz = SIGN (dz);              \
    xr = dxabs >> 1;              \
    yr = dyabs >> 1;              \
    zr = dzabs >> 1;              \
    px = x0;                      \
    py = y0;                      \
    pz = z0;                      \
  } G_STMT_END
  
  void
  gst_smpte_paint_triangle_linear (guint32 * dest, gint stride,
      gint x0, gint y0, gint c0,
      gint x1, gint y1, gint c1, gint x2, gint y2, gint c2)
  {
    gint sdxl, sdyl, sdcl, dxlabs, dylabs, dclabs, xrl, yrl, crl, pxl, pyl, pcl;
    gint sdxr, sdyr, sdcr, dxrabs, dyrabs, dcrabs, xrr, yrr, crr, pxr, pyr, pcr;
    gint i, j, k, seg_start, seg_end;
  
    if (y0 > y1) {
      SWAP_INT (x0, x1);
      SWAP_INT (y0, y1);
      SWAP_INT (c0, c1);
    }
    if (y0 > y2) {
      SWAP_INT (x0, x2);
      SWAP_INT (y0, y2);
      SWAP_INT (c0, c2);
    }
    if (y1 > y2) {
      SWAP_INT (x1, x2);
      SWAP_INT (y1, y2);
      SWAP_INT (c1, c2);
    }
  
    PREPARE_3D_LINE (x0, y0, c0, x2, y2, c2,
        dxlabs, dylabs, dclabs, sdxl, sdyl, sdcl, xrl, yrl, crl, pxl, pyl, pcl);
  
    PREPARE_3D_LINE (x0, y0, c0, x1, y1, c1,
        dxrabs, dyrabs, dcrabs, sdxr, sdyr, sdcr, xrr, yrr, crr, pxr, pyr, pcr);
  
    dest = dest + stride * y0;
    seg_start = y0;
    seg_end = y1;
  
    /* do two passes */
    for (k = 0; k < 2; k++) {
      for (i = seg_start; i < seg_end; i++) {
        gint s = pxl, e = pxr, sc = pcl, ec = pcr;
        gint sign = SIGN (e - s);
  
        e += sign;
        for (j = s; j != e; j += sign) {
          dest[j] = (ec * (j - s) + sc * (e - j)) / (e - s);
        }
  
        while (pyr == i) {
          STEP_3D_LINE (dxrabs, dyrabs, dcrabs, sdxr, sdyr, sdcr,
              xrr, yrr, crr, pxr, pyr, pcr);
        }
        while (pyl == i) {
          STEP_3D_LINE (dxlabs, dylabs, dclabs, sdxl, sdyl, sdcl,
              xrl, yrl, crl, pxl, pyl, pcl);
        }
        dest += stride;
      }
  
      PREPARE_3D_LINE (x1, y1, c1, x2, y2, c2,
          dxrabs, dyrabs, dcrabs, sdxr, sdyr, sdcr, xrr, yrr, crr, pxr, pyr, pcr);
  
      seg_start = y1;
      seg_end = y2;
    }
  }
  
  static void
  draw_bresenham_line (guint32 * dest, gint stride,
      gint x0, gint y0, gint x1, gint y1, guint32 col)
  {
    gint dx, dy;
    gint x_incr, y_incr;
    gint i, dpr, dpru, P, indep;
  
    dx = abs (x1 - x0);
    dy = abs (y1 - y0);
  
    dest = dest + y0 * stride + x0;
  
    x_incr = SIGN (x1 - x0);
    y_incr = SIGN (y1 - y0) * stride;
  
    if (dx >= dy) {
      dpr = dy << 1;
      i = dx;
      indep = x_incr;
    } else {
      dpr = dx << 1;
      i = dy;
      indep = y_incr;
    }
  
    dpru = dpr - (i << 1);
    P = dpr - i;
  
    for (; i >= 0; i--) {
      *dest = col;
  
      if (P > 0) {
        dest += x_incr;
        dest += y_incr;
        P += dpru;
      } else {
        dest += indep;
        P += dpr;
      }
    }
  }
  
  void
  gst_smpte_paint_triangle_clock (guint32 * dest, gint stride,
      gint x0, gint y0, gint c0,
      gint x1, gint y1, gint c1, gint x2, gint y2, gint c2)
  {
    gint i;
    gint sign;
    gfloat angle, angle_e;
    gfloat len1;
  
    angle_e = acos (((x1 - x0) * (x2 - x0) + (y1 - y0) * (y2 - y0)) /
        (sqrt ((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0)) *
            sqrt ((x2 - x0) * (x2 - x0) + (y2 - y0) * (y2 - y0))));
  
    len1 = sqrt ((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0));
  
    if (x1 == x2) {
      sign = SIGN (y2 - y1);
  
      for (i = y1; i != (y2 + sign); i += sign) {
        if (y1 == i)
          angle = 0;
        else
          angle = acos (((x1 - x0) * (x2 - x0) + (y1 - y0) * (i - y0)) /
              (len1 * sqrt ((x1 - x0) * (x1 - x0) + (i - y0) * (i -
                          y0)))) / angle_e;
  
        draw_bresenham_line (dest, stride,
            x0, y0, x1, i, (c2 * angle + c1 * (1.0 - angle)));
      }
    } else if (y1 == y2) {
      sign = SIGN (x2 - x1);
  
      for (i = x1; i != (x2 + sign); i += sign) {
        if (x1 == i)
          angle = 0;
        else
          angle = acos (((x1 - x0) * (i - x0) + (y1 - y0) * (y2 - y0)) /
              (len1 * sqrt ((i - x0) * (i - x0) + (y2 - y0) * (y2 -
                          y0)))) / angle_e;
  
        draw_bresenham_line (dest, stride,
            x0, y0, i, y1, (c2 * angle + c1 * (1.0 - angle)));
      }
    } else {
      g_warning ("paint triangle clock: not supported");
      return;
    }
  }
  
  void
  gst_smpte_paint_box_clock (guint32 * dest, gint stride,
      gint x0, gint y0, gint c0,
      gint x1, gint y1, gint c1, gint x2, gint y2, gint c2)
  {
    gfloat angle_m, col_m;
    gint xv, yv;
  
    if (x1 == x0) {
      xv = x2;
      yv = y1;
    } else if (y1 == y0) {
      xv = x1;
      yv = y2;
    } else {
      g_warning ("paint box clock: not supported");
      return;
    }
  
    angle_m = 2 * acos (((x1 - x0) * (xv - x0) + (y1 - y0) * (yv - y0)) /
        (sqrt ((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0)) *
            sqrt ((xv - x0) * (xv - x0) + (yv - y0) * (yv - y0)))) / M_PI;
  
    col_m = c2 * angle_m + c1 * (1.0 - angle_m);
  
    gst_smpte_paint_triangle_clock (dest, stride,
        x0, y0, c0, x1, y1, c1, xv, yv, col_m);
    gst_smpte_paint_triangle_clock (dest, stride,
        x0, y0, c0, xv, yv, col_m, x2, y2, c2);
  }
  