tuxpaint-pencil-sharpener/magic/src/realrainbow.c

/*
  realrainbow.c

  Draws an arc with semi-transparent rainbow colors.

  by Bill Kendrick <bill@newbreedsoftware.com>
  Math assistance by Jeff Newmiller <jdnewmil@dcn.davis.ca.us>

  2009.04.02 - 2014.08.14

FIXME:
* Color/alpha art needs improvement.
* Pixel gaps appear in lines sometimes (esp. larger rainbows).
*/

#include <stdio.h>
#include <string.h>
#include <math.h>
#include "SDL_image.h"

#include "tp_magic_api.h"

Mix_Chunk *realrainbow_snd;
int realrainbow_x1, realrainbow_y1, realrainbow_x2, realrainbow_y2;
SDL_Rect realrainbow_rect;
SDL_Surface *realrainbow_colors[2];
Uint8 realrainbow_blendr, realrainbow_blendg, realrainbow_blendb, realrainbow_blenda;


void realrainbow_arc(magic_api * api, int which, SDL_Surface * canvas, SDL_Surface * last,
                     int x1, int y1, int x2, int y2, int fulldraw, SDL_Rect * update_rect);
static void realrainbow_linecb(void *ptr, int which, SDL_Surface * canvas, SDL_Surface * last, int x, int y);
Uint32 realrainbow_api_version(void);
int realrainbow_init(magic_api * api);
int realrainbow_get_tool_count(magic_api * api);
SDL_Surface *realrainbow_get_icon(magic_api * api, int which);
char *realrainbow_get_name(magic_api * api, int which);
char *realrainbow_get_description(magic_api * api, int which, int mode);
int realrainbow_modes(magic_api * api, int which);
int realrainbow_requires_colors(magic_api * api, int which);
void realrainbow_shutdown(magic_api * api);
void realrainbow_set_color(magic_api * api, Uint8 r, Uint8 g, Uint8 b);
void realrainbow_click(magic_api * api, int which, int mode,
                       SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect);
void realrainbow_drag(magic_api * api, int which,
                      SDL_Surface * canvas, SDL_Surface * last, int ox, int oy, int x, int y, SDL_Rect * update_rect);
void realrainbow_release(magic_api * api, int which,
                         SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect);
void realrainbow_switchin(magic_api * api, int which, int mode, SDL_Surface * canvas);
void realrainbow_switchout(magic_api * api, int which, int mode, SDL_Surface * canvas);


Uint32 realrainbow_api_version(void)
{
  return (TP_MAGIC_API_VERSION);
}

int realrainbow_init(magic_api * api)
{
  char fname[1024];

  snprintf(fname, sizeof(fname), "%simages/magic/realrainbow-colors.png", api->data_directory);
  realrainbow_colors[0] = IMG_Load(fname);
  if (realrainbow_colors[0] == NULL)
    return (0);

  snprintf(fname, sizeof(fname), "%simages/magic/realrainbow-roygbiv-colors.png", api->data_directory);
  realrainbow_colors[1] = IMG_Load(fname);
  if (realrainbow_colors[1] == NULL)
    return (0);

  snprintf(fname, sizeof(fname), "%ssounds/magic/realrainbow.ogg", api->data_directory);
  realrainbow_snd = Mix_LoadWAV(fname);

  return (1);
}

int realrainbow_get_tool_count(magic_api * api ATTRIBUTE_UNUSED)
{
  return (2);
}

SDL_Surface *realrainbow_get_icon(magic_api * api, int which)
{
  char fname[1024];

  if (which == 0)
    snprintf(fname, sizeof(fname), "%simages/magic/realrainbow.png", api->data_directory);
  else
    snprintf(fname, sizeof(fname), "%simages/magic/realrainbow-roygbiv.png", api->data_directory);

  return (IMG_Load(fname));
}

char *realrainbow_get_name(magic_api * api ATTRIBUTE_UNUSED, int which)
{
  if (which == 0)
    return (strdup(gettext_noop("Real Rainbow")));
  else
    return (strdup(gettext_noop("ROYGBIV Rainbow")));
}

char *realrainbow_get_description(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED,
                                  int mode ATTRIBUTE_UNUSED)
{
  return (strdup
          (gettext_noop
           ("Click where you want your rainbow to start, drag to where you want it to end, and then let go to draw a rainbow.")));
}

int realrainbow_modes(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
  return (MODE_PAINT_WITH_PREVIEW);
}

int realrainbow_requires_colors(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
  return (0);
}

void realrainbow_shutdown(magic_api * api ATTRIBUTE_UNUSED)
{
  if (realrainbow_colors[0] != NULL)
    SDL_FreeSurface(realrainbow_colors[0]);
  if (realrainbow_colors[1] != NULL)
    SDL_FreeSurface(realrainbow_colors[1]);
  if (realrainbow_snd != NULL)
    Mix_FreeChunk(realrainbow_snd);
}

void realrainbow_set_color(magic_api * api ATTRIBUTE_UNUSED, Uint8 r ATTRIBUTE_UNUSED, Uint8 g ATTRIBUTE_UNUSED,
                           Uint8 b ATTRIBUTE_UNUSED)
{
}

void realrainbow_click(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED,
                       SDL_Surface * canvas ATTRIBUTE_UNUSED, SDL_Surface * last ATTRIBUTE_UNUSED,
                       int x, int y, SDL_Rect * update_rect ATTRIBUTE_UNUSED)
{
  realrainbow_x1 = x;
  realrainbow_y1 = y;

  realrainbow_rect.x = x;
  realrainbow_rect.y = y;
  realrainbow_rect.w = 1;
  realrainbow_rect.h = 1;
}

void realrainbow_drag(magic_api * api, int which,
                      SDL_Surface * canvas, SDL_Surface * last,
                      int ox ATTRIBUTE_UNUSED, int oy ATTRIBUTE_UNUSED, int x, int y, SDL_Rect * update_rect)
{
  int rx1, ry1, rx2, ry2;
  SDL_Rect rect;

  realrainbow_x2 = x;
  realrainbow_y2 = y;

  SDL_BlitSurface(last, &realrainbow_rect, canvas, &realrainbow_rect);

  realrainbow_arc(api, which, canvas, last, realrainbow_x1, realrainbow_y1, realrainbow_x2, realrainbow_y2, 0,
                  update_rect);

  memcpy(&rect, &realrainbow_rect, sizeof(SDL_Rect));
  memcpy(&realrainbow_rect, update_rect, sizeof(SDL_Rect));

  rx1 = update_rect->x;
  ry1 = update_rect->y;
  rx2 = update_rect->x + update_rect->w;
  ry2 = update_rect->y + update_rect->h;

  if (rect.x < rx1)
    rx1 = rect.x;
  if (rect.x + rect.w > rx2)
    rx2 = rect.x + rect.w;
  if (rect.y < ry1)
    ry1 = rect.y;
  if (rect.y + rect.h > ry2)
    ry2 = rect.y + rect.h;

  update_rect->x = rx1;
  update_rect->y = ry1;
  update_rect->w = rx2 - rx1 + 1;
  update_rect->h = ry2 - ry1 + 1;
}

void realrainbow_release(magic_api * api, int which,
                         SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect)
{
  int rx1, ry1, rx2, ry2;
  SDL_Rect rect;

  realrainbow_x2 = x;
  realrainbow_y2 = y;

  SDL_BlitSurface(last, &realrainbow_rect, canvas, &realrainbow_rect);

  realrainbow_arc(api, which, canvas, last, realrainbow_x1, realrainbow_y1, realrainbow_x2, realrainbow_y2, 1,
                  update_rect);

  memcpy(&rect, &realrainbow_rect, sizeof(SDL_Rect));
  memcpy(&realrainbow_rect, update_rect, sizeof(SDL_Rect));

  rx1 = update_rect->x;
  ry1 = update_rect->y;
  rx2 = update_rect->x + update_rect->w;
  ry2 = update_rect->y + update_rect->h;

  if (rect.x < rx1)
    rx1 = rect.x;
  if (rect.x + rect.w > rx2)
    rx2 = rect.x + rect.w;
  if (rect.y < ry1)
    ry1 = rect.y;
  if (rect.y + rect.h > ry2)
    ry2 = rect.y + rect.h;

  update_rect->x = rx1;
  update_rect->y = ry1;
  update_rect->w = rx2 - rx1 + 1;
  update_rect->h = ry2 - ry1 + 1;

  api->playsound(realrainbow_snd, 128, 255);
}

void realrainbow_switchin(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED,
                          SDL_Surface * canvas ATTRIBUTE_UNUSED)
{
}

void realrainbow_switchout(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED,
                           SDL_Surface * canvas ATTRIBUTE_UNUSED)
{
}


void realrainbow_arc(magic_api * api, int which, SDL_Surface * canvas, SDL_Surface * last, int x1, int y1, int x2,
                     int y2, int fulldraw, SDL_Rect * update_rect)
{
  int lowx, lowy, hix, hiy, xm, ym, xc, yc, r, a1, atan2_a, atan2_b;
  int a, oa, ox, oy, nx, ny, step, thick, rr, done;
  float slope, theta;
  int colorindex;

  if (abs(x2 - x1) < 50)
    {
      if (x2 > x1)
        x2 = x1 + 50;
      else
        x2 = x1 - 50;
    }

  if (y1 == y2)
    {
      xc = x1 + (x2 - x1) / 2;
      yc = y1;
      r = abs(xc - x1);

      a1 = 0;
      theta = -180;
    }
  else
    {
      if (y1 > y2)
        {
          lowx = x1;
          lowy = y1;
          hix = x2;
          hiy = y2;
        }
      else
        {
          lowx = x2;
          lowy = y2;
          hix = x1;
          hiy = y1;
        }

      xm = (lowx + hix) / 2;
      ym = (lowy + hiy) / 2;

      if (hix == lowx)
        return;

      slope = (float)(hiy - lowy) / (float)(hix - lowx);

      yc = lowy;
      xc = slope * (ym - yc) + xm;

      r = abs(xc - lowx);
      atan2_b = hix - xc;
      atan2_a = hiy - yc;
      theta = atan2(atan2_a, atan2_b) * (180.0 / M_PI);

      if (slope > 0)
        a1 = 0;
      else
        a1 = -180;
    }

  if (fulldraw)
    {
      step = 1;
      /* thick = (r / 5); */
    }
  else
    {
      step = 30;
      /* thick = 1; */
    }
  thick = (r / 5);

  if (theta < a1)
    step = -step;
  done = 0;

  oa = a1;

  for (a = (a1 + step); done < 2; a = a + step)
    {
      for (rr = r - (thick / 2); rr <= r + (thick / 2); rr++)
        {
          ox = (rr * cos(oa * M_PI / 180.0)) + xc;
          oy = (rr * sin(oa * M_PI / 180.0)) + yc;

          nx = (rr * cos(a * M_PI / 180.0)) + xc;
          ny = (rr * sin(a * M_PI / 180.0)) + yc;

          colorindex =
            realrainbow_colors[which]->h - 1 - (((rr - r + (thick / 2)) * realrainbow_colors[which]->h) / thick);

          SDL_GetRGBA(api->getpixel(realrainbow_colors[which], 0, colorindex),
                      realrainbow_colors[which]->format, &realrainbow_blendr, &realrainbow_blendg, &realrainbow_blendb,
                      &realrainbow_blenda);

          if (!fulldraw)
            realrainbow_blenda = 255;

          api->line((void *)api, 0, canvas, last, ox, oy, nx, ny, 1, realrainbow_linecb);
        }

      oa = a;

      if ((step > 0 && a + step > theta) || (step < 0 && a + step < theta))
        {
          done++;
          a = theta - step;
        }
    }

  update_rect->y = yc - r - thick - 2;
  update_rect->h = r + thick * 2 + 4;
  update_rect->x = xc - r - thick;
  update_rect->w = r * 2 + thick * 2;
}

static void realrainbow_linecb(void *ptr, int which ATTRIBUTE_UNUSED,
                               SDL_Surface * canvas, SDL_Surface * last, int x, int y)
{
  magic_api *api = (magic_api *) ptr;
  Uint8 origr, origg, origb;
  Uint8 newr, newg, newb;

  SDL_GetRGB(api->getpixel(last, x, y), last->format, &origr, &origg, &origb);

  newr = ((realrainbow_blendr * realrainbow_blenda) / 255) + ((origr * (255 - realrainbow_blenda)) / 255);
  newg = ((realrainbow_blendg * realrainbow_blenda) / 255) + ((origg * (255 - realrainbow_blenda)) / 255);
  newb = ((realrainbow_blendb * realrainbow_blenda) / 255) + ((origb * (255 - realrainbow_blenda)) / 255);

  api->putpixel(canvas, x, y, SDL_MapRGB(canvas->format, newr, newg, newb));
}