exp005 - Influenza Map Visualization


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#include "mousewheel.h"
#include "performzoom.h"
#include <GL/glut.h>

void
mousewheel (int button, int dir, int x, int y)
{
  /*
   * Get the current coordinates, substract some fixed amount and
   * then perform the zoom.
   */
  GLint viewport[4];
  glGetIntegerv (GL_VIEWPORT, viewport);

  /*
   * The step size could be either a fixed number of pixels or a percentage.
   */
  //  int step = 5;
  int step = (viewport[3] - viewport[1]) * 0.10;

  /*
   * Not that the focus of the zoom is currently the center of the
   * window but could alternatively be the mouse pointer's position.
   */

  // Zoom in
  if (dir > 0)
    {
      performzoom (step,
		   step,
		   viewport[3] - step,
		   viewport[3] - step);
    }

  // Zoom out
  else
    {
      performzoom (-step,
		   -step,
		   viewport[3] + step,
		   viewport[3] + step);
    }

  return;
}