#include <petsc/private/drawimpl.h> /*I "petscdraw.h" I*/

/*@C
  PetscDrawIndicatorFunction - Draws an indicator function (where a relationship is true) on a `PetscDraw`

  Not Collective

  Input Parameters:
+ draw      - a `PetscDraw`
. xmin      - region to draw indicator function
. xmax      - region to draw indicator function
. ymin      - region to draw indicator function
. ymax      - region to draw indicator function
. c         - the color of the region
. indicator - the indicator function
- ctx       - the context to pass to the indicator function

  Level: developer

.seealso: `PetscDraw`
@*/
PetscErrorCode PetscDrawIndicatorFunction(PetscDraw draw, PetscReal xmin, PetscReal xmax, PetscReal ymin, PetscReal ymax, int c, PetscErrorCode (*indicator)(PetscCtx, PetscReal, PetscReal, PetscBool *), PetscCtx ctx)
{
  int       i, j, xstart, ystart, xend, yend;
  PetscReal x, y;
  PetscBool isnull, flg;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw, PETSC_DRAW_CLASSID, 1);
  PetscCall(PetscDrawIsNull(draw, &isnull));
  if (isnull) PetscFunctionReturn(PETSC_SUCCESS);

  PetscCall(PetscDrawCoordinateToPixel(draw, xmin, ymin, &xstart, &ystart));
  PetscCall(PetscDrawCoordinateToPixel(draw, xmax, ymax, &xend, &yend));
  if (yend < ystart) {
    int tmp = ystart;
    ystart  = yend;
    yend    = tmp;
  }

  for (i = xstart; i <= xend; i++) {
    for (j = ystart; j <= yend; j++) {
      PetscCall(PetscDrawPixelToCoordinate(draw, i, j, &x, &y));
      PetscCall(indicator(ctx, x, y, &flg));
      if (flg) PetscCall(PetscDrawPointPixel(draw, i, j, c));
    }
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscDrawCoordinateToPixel - given a coordinate in a `PetscDraw` returns the pixel location

  Not Collective

  Input Parameters:
+ draw - the draw where the coordinates are defined
. x    - the horizontal coordinate
- y    - the vertical coordinate

  Output Parameters:
+ i - the horizontal pixel location
- j - the vertical pixel location

  Level: developer

.seealso: `PetscDraw`
@*/
PetscErrorCode PetscDrawCoordinateToPixel(PetscDraw draw, PetscReal x, PetscReal y, int *i, int *j)
{
  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw, PETSC_DRAW_CLASSID, 1);
  PetscUseTypeMethod(draw, coordinatetopixel, x, y, i, j);
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscDrawPixelToCoordinate - given a pixel in a `PetscDraw` returns the coordinate

  Not Collective

  Input Parameters:
+ draw - the draw where the coordinates are defined
. i    - the horizontal pixel location
- j    - the vertical pixel location

  Output Parameters:
+ x - the horizontal coordinate
- y - the vertical coordinate

  Level: developer

.seealso: `PetscDraw`
@*/
PetscErrorCode PetscDrawPixelToCoordinate(PetscDraw draw, int i, int j, PetscReal *x, PetscReal *y)
{
  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw, PETSC_DRAW_CLASSID, 1);
  PetscUseTypeMethod(draw, pixeltocoordinate, i, j, x, y);
  PetscFunctionReturn(PETSC_SUCCESS);
}

/*@
  PetscDrawRectangle - draws a rectangle onto a `PetscDraw` object

  Not Collective

  Input Parameters:
+ draw - the drawing context
. xl   - coordinates of the lower left corner
. yl   - coordinates of the lower left corner
. xr   - coordinate of the upper right corner
. yr   - coordinate of the upper right corner
. c1   - the color of the first corner
. c2   - the color of the second corner
. c3   - the color of the third corner
- c4   - the color of the fourth corner

  Level: beginner

.seealso: `PetscDraw`, `PetscDrawLine()`, `PetscDrawTriangle()`, `PetscDrawEllipse()`,
          `PetscDrawMarker()`, `PetscDrawPoint()`, `PetscDrawString()`, `PetscDrawArrow()`
@*/
PetscErrorCode PetscDrawRectangle(PetscDraw draw, PetscReal xl, PetscReal yl, PetscReal xr, PetscReal yr, int c1, int c2, int c3, int c4)
{
  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw, PETSC_DRAW_CLASSID, 1);
  PetscUseTypeMethod(draw, rectangle, xl, yl, xr, yr, c1, c2, c3, c4);
  PetscFunctionReturn(PETSC_SUCCESS);
}
