gui/graph_displayer_canvas-zoom.cc
author ladanyi
Fri, 04 Nov 2005 19:07:15 +0000
changeset 1777 a70cee06ae9c
parent 1632 93ac8c521fe5
child 1819 fd82adfbe905
permissions -rwxr-xr-x
improved zooming
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#include "graph_displayer_canvas.h"
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#include "broken_edge.h"
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#include <cmath>
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void GraphDisplayerCanvas::zoomIn()
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{
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  set_pixels_per_unit(
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      (1.0 + (double) zoom_step / 100.0) * get_pixels_per_unit());
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}
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void GraphDisplayerCanvas::zoomOut()
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{
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  set_pixels_per_unit(
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      (1.0 - (double) zoom_step / 100.0) * get_pixels_per_unit());
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}
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void GraphDisplayerCanvas::zoomFit()
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{
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  updateScrollRegion();
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  // get the height and width of the canvas
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  Gtk::Allocation a = get_allocation();
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  int aw = a.get_width();
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  int ah = a.get_height();
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  // get the bounding box of the graph
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  update_now();
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  double x1, y1, x2, y2;
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  root()->get_bounds(x1, y1, x2, y2);
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  // fit the graph to the window
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  double ppu1 = (double) aw / fabs(x2 - x1);
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  double ppu2 = (double) ah / fabs(y2 - y1);
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  set_pixels_per_unit((ppu1 < ppu2) ? ppu1 : ppu2);
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}
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void GraphDisplayerCanvas::zoom100()
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{
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  updateScrollRegion();
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  set_pixels_per_unit(1.0);
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}
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void GraphDisplayerCanvas::updateScrollRegion()
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{
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  // get_bounds() yields something sane only when no updates are pending
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  // and it returns a sufficient, not an exact bounding box
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  update_now();
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  double x1, y1, x2, y2;
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  root()->get_bounds(x1, y1, x2, y2);
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  set_scroll_region(x1, y1, x2, y2);
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}