#include "graph_displayer_canvas.h"

#include <cmath>

void GraphDisplayerCanvas::zoomIn()

{

  set_pixels_per_unit(

      (1.0 + (double) zoom_step / 100.0) * get_pixels_per_unit());

}

void GraphDisplayerCanvas::zoomOut()

{

  set_pixels_per_unit(

      (1.0 - (double) zoom_step / 100.0) * get_pixels_per_unit());

}

void GraphDisplayerCanvas::zoomFit()

{

  updateScrollRegion();

  // get the height and width of the canvas

  Gtk::Allocation a = get_allocation();

  int aw = a.get_width();

  int ah = a.get_height();

  // get the bounding box of the graph

  update_now();

  double x1, y1, x2, y2;

  root()->get_bounds(x1, y1, x2, y2);

  // fit the graph to the window

  double ppu1 = (double) aw / fabs(x2 - x1);

  double ppu2 = (double) ah / fabs(y2 - y1);

  set_pixels_per_unit((ppu1 < ppu2) ? ppu1 : ppu2);

}

void GraphDisplayerCanvas::zoom100()

{

  updateScrollRegion();

  set_pixels_per_unit(1.0);

}

void GraphDisplayerCanvas::updateScrollRegion()

{

  // get_bounds() yields something sane only when no updates are pending

  // and it returns a sufficient, not an exact bounding box

  update_now();

  double x1, y1, x2, y2;

  root()->get_bounds(x1, y1, x2, y2);

  set_scroll_region(x1, y1, x2, y2);

}