static char help[] = "Demonstrates drawing primitives in a window\n";

#include <petscdraw.h>

int main(int argc, char **argv)
{
  PetscDraw draw;

  int i, j, w, h;
  int k  = PETSC_DRAW_BLACK;
  int r  = PETSC_DRAW_RED;
  int g  = PETSC_DRAW_GREEN;
  int b  = PETSC_DRAW_BLUE;
  int y  = PETSC_DRAW_YELLOW;
  int c0 = PETSC_DRAW_BASIC_COLORS;
  int c2 = 255;
  int c1 = (c0 + c2) / 2;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));

  PetscCall(PetscDrawCreate(PETSC_COMM_WORLD, 0, "Draw Example", PETSC_DECIDE, PETSC_DECIDE, 101, 101, &draw));
  /* PetscCall(PetscDrawSetPause(draw,2.0)); */
  PetscCall(PetscDrawSetFromOptions(draw));

  PetscCall(PetscDrawCheckResizedWindow(draw));
  PetscCall(PetscDrawGetWindowSize(draw, &w, &h));
  PetscCall(PetscDrawSetCoordinates(draw, 0, 0, --w, --h));
  PetscCall(PetscDrawClear(draw));
  /* one-pixel lines in the window corners */
  PetscCall(PetscDrawLine(draw, 0, 0, 0, 0, r));
  PetscCall(PetscDrawLine(draw, w, 0, w, 0, r));
  PetscCall(PetscDrawLine(draw, 0, h, 0, h, r));
  PetscCall(PetscDrawLine(draw, w, h, w, h, r));
  /* border lines with two pixels from  borders */
  PetscCall(PetscDrawLine(draw, 0 + 2, 0, w - 2, 0, k));
  PetscCall(PetscDrawLine(draw, 0 + 2, h, w - 2, h, k));
  PetscCall(PetscDrawLine(draw, 0, 0 + 2, 0, h - 2, k));
  PetscCall(PetscDrawLine(draw, w, 0 + 2, w, h - 2, k));
  /* oblique lines */
  PetscCall(PetscDrawLine(draw, 0 + 2, h / 2, w - 2, h - 2, b));
  PetscCall(PetscDrawLine(draw, 0 + 1, h - 1, w - 1, 0 + 1, b));
  /* vertical up and down arrow, two pixels from borders  */
  PetscCall(PetscDrawArrow(draw, 1 * w / 4, 0 + 2, 1 * w / 4, h - 2, g));
  PetscCall(PetscDrawArrow(draw, 3 * w / 4, h - 2, 3 * w / 4, 0 + 2, g));
  /* horizontal right and left arrow, two pixels from borders  */
  PetscCall(PetscDrawArrow(draw, 0 + 2, 3 * h / 4, w - 2, 3 * h / 4, g));
  PetscCall(PetscDrawArrow(draw, w - 2, 1 * h / 4, 0 + 2, 1 * h / 4, g));
  /* flush, save, and pause */
  PetscCall(PetscDrawFlush(draw));
  PetscCall(PetscDrawSave(draw));
  PetscCall(PetscDrawPause(draw));

  PetscCall(PetscDrawCheckResizedWindow(draw));
  PetscCall(PetscDrawGetWindowSize(draw, &w, &h));
  PetscCall(PetscDrawSetCoordinates(draw, 0, 0, --w, --h));
  PetscCall(PetscDrawClear(draw));
  /* one-pixel rectangles in the window corners */
  PetscCall(PetscDrawRectangle(draw, 0, 0, 0, 0, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, w, 0, w, 0, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, 0, h, 0, h, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, w, h, w, h, k, k, k, k));
  /* border rectangles with two pixels from  borders */
  PetscCall(PetscDrawRectangle(draw, 0 + 2, 0, w - 2, 0, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, 0 + 2, h, w - 2, h, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, 0, 0 + 2, 0, h - 2, k, k, k, k));
  PetscCall(PetscDrawRectangle(draw, w, 0 + 2, w, h - 2, k, k, k, k));
  /* more rectangles */
  PetscCall(PetscDrawRectangle(draw, 0 + 2, 0 + 2, w / 2 - 1, h / 2 - 1, b, b, b, b));
  PetscCall(PetscDrawRectangle(draw, 0 + 2, h / 2 + 1, w / 2 - 1, h - 2, r, r, r, r));
  PetscCall(PetscDrawRectangle(draw, w / 2 + 1, h / 2 + 1, w - 2, h - 2, g, g, g, g));
  PetscCall(PetscDrawRectangle(draw, w / 2 + 1, 0 + 2, w - 2, h / 2 - 1, y, y, y, y));
  /* flush, save, and pause */
  PetscCall(PetscDrawFlush(draw));
  PetscCall(PetscDrawSave(draw));
  PetscCall(PetscDrawPause(draw));

  PetscCall(PetscDrawCheckResizedWindow(draw));
  PetscCall(PetscDrawGetWindowSize(draw, &w, &h));
  PetscCall(PetscDrawSetCoordinates(draw, 0, 0, --w, --h));
  PetscCall(PetscDrawClear(draw));
  /* interpolated triangles, one pixel from borders */
  PetscCall(PetscDrawTriangle(draw, 0 + 1, 0 + 1, w - 1, 0 + 1, w - 1, h - 1, c0, c1, c2));
  PetscCall(PetscDrawTriangle(draw, 0 + 1, 0 + 1, 0 + 1, h - 1, w - 1, h - 1, c0, c1, c2));
  /* interpolated triangle, oblique, inside canvas */
  PetscCall(PetscDrawTriangle(draw, w / 4, h / 4, w / 2, 3 * h / 4, 3 * w / 4, h / 2, c2, c1, c0));
  /* flush, save, and pause */
  PetscCall(PetscDrawFlush(draw));
  PetscCall(PetscDrawSave(draw));
  PetscCall(PetscDrawPause(draw));

  PetscCall(PetscDrawCheckResizedWindow(draw));
  PetscCall(PetscDrawGetWindowSize(draw, &w, &h));
  PetscCall(PetscDrawSetCoordinates(draw, 0, 0, --w, --h));
  PetscCall(PetscDrawClear(draw));
  /* circles and ellipses */
  PetscCall(PetscDrawEllipse(draw, w / 2, h / 2, w - 1, h - 1, r));
  PetscCall(PetscDrawEllipse(draw, w, h / 2, w / 2, h, g));
  PetscCall(PetscDrawEllipse(draw, 0, 0, w, h / 2, b));
  PetscCall(PetscDrawEllipse(draw, w / 4, 3 * h / 4, w / 2, h / 4, y));
  PetscCall(PetscDrawCoordinateToPixel(draw, w / 2, h / 2, &i, &j));
  PetscCall(PetscDrawPointPixel(draw, i, j, k));
  /* flush, save, and pause */
  PetscCall(PetscDrawFlush(draw));
  PetscCall(PetscDrawSave(draw));
  PetscCall(PetscDrawPause(draw));

  PetscCall(PetscDrawDestroy(&draw));
  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   build:
     requires: x

   test:
     output_file: output/empty.out

TEST*/