#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);

 }