#include "graph_displayer_canvas.h"
#include "broken_edge.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);
}