glib_polygon.c

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 /*************************************************************************/
/* C-header files */
#include <stdint.h>

/* EM types */
#include "em_types.h"

/* GLIB header files */
#include "glib.h"

/**************************************************************************/
EMSTATUS GLIB_drawPolygon(GLIB_Context_t *pContext,
                          uint32_t numPoints, const int32_t *polyPoints)
{
  EMSTATUS status;
  uint32_t drawnElements = 0;
  uint32_t point;
  int32_t firstX;
  int32_t firstY;
  int32_t startX;
  int32_t startY;
  int32_t endX;
  int32_t endY;

  /* Check arguments */
  if (pContext == NULL || polyPoints == NULL || numPoints < 2) return GLIB_ERROR_INVALID_ARGUMENT;

  startX = *polyPoints++;
  startY = *polyPoints++;
  firstX = startX;
  firstY = startY;

  /* Loop through the points by moving the pointer */
  for (point = 1; point < numPoints; point++)
  {
    endX = *polyPoints++;
    endY = *polyPoints++;

    /* Draw a line between each pair of points */
    status = GLIB_drawLine(pContext, startX, startY, endX, endY);
    if (status > GLIB_ERROR_NOTHING_TO_DRAW) return status;
    if (status == GLIB_OK) drawnElements++;

    startX = endX;
    startY = endY;
  }

  /* Draw a line from last point to first point */
  if ((endX != firstX) || (endY != firstY))
  {
    status = GLIB_drawLine(pContext, firstX, firstY, endX, endY);
    if (status > GLIB_ERROR_NOTHING_TO_DRAW) return status;
    if (status == GLIB_OK) drawnElements++;
  }
  return ((drawnElements == 0) ? GLIB_ERROR_NOTHING_TO_DRAW : GLIB_OK);
}