lib/gpx.rb

   1 module GPX
   2   class File
   3     require "libxml"
   4
   5     include LibXML
   6
   7     attr_reader :possible_points
   8     attr_reader :actual_points
   9     attr_reader :tracksegs
  10
  11     def initialize(file)
  12       @file = file
  13     end
  14
  15     def points
  16       return enum_for(:points) unless block_given?
  17
  18       @possible_points = 0
  19       @actual_points = 0
  20       @tracksegs = 0
  21
  22       @file.rewind
  23
  24       reader = XML::Reader.io(@file)
  25
  26       point = nil
  27
  28       while reader.read
  29         if reader.node_type == XML::Reader::TYPE_ELEMENT
  30           if reader.name == "trkpt"
  31             point = TrkPt.new(@tracksegs, reader["lat"].to_f, reader["lon"].to_f)
  32             @possible_points += 1
  33           elsif reader.name == "ele" && point
  34             point.altitude = reader.read_string.to_f
  35           elsif reader.name == "time" && point
  36             point.timestamp = Time.parse(reader.read_string)
  37           end
  38         elsif reader.node_type == XML::Reader::TYPE_END_ELEMENT
  39           if reader.name == "trkpt" && point && point.valid?
  40             point.altitude ||= 0
  41             yield point
  42             @actual_points += 1
  43           elsif reader.name == "trkseg"
  44             @tracksegs += 1
  45           end
  46         end
  47       end
  48     end
  49
  50     def picture(min_lat, min_lon, max_lat, max_lon, _num_points)
  51       nframes = 10
  52       width = 250
  53       height = 250
  54       delay = 50
  55
  56       ptsper = _num_points / nframes;
  57
  58       proj = OSM::Mercator.new(min_lat, min_lon, max_lat, max_lon, width, height)
  59
  60       frames = Array.new(nframes,  GD2::Image::IndexedColor.new(width, height))
  61
  62       (0..nframes - 1).each do |n|
  63         frames[n] = GD2::Image::IndexedColor.new(width, height)
  64         black = frames[n].palette.allocate(GD2::Color[0, 0, 0])
  65         white = frames[n].palette.allocate(GD2::Color[255, 255, 255])
  66         grey = frames[n].palette.allocate(GD2::Color[187, 187, 187])
  67
  68         frames[n].draw do |pen|
  69           pen.color = white
  70           pen.rectangle(0, 0, width, height, true)
  71         end
  72
  73         frames[n].draw do |pen|
  74           pen.color = black
  75           pen.anti_aliasing = true
  76           pen.dont_blend = false
  77
  78           oldpx = 0.0
  79           oldpy = 0.0
  80
  81           first = true
  82
  83           points.each_with_index do |p, pt|
  84             px = proj.x(p.longitude)
  85             py = proj.y(p.latitude)
  86
  87             if ((pt >= (ptsper * n)) && (pt <= (ptsper * (n+1))))
  88               pen.thickness=(3)
  89               pen.color = black
  90             else
  91               pen.thickness=(1)
  92               pen.color = grey
  93             end
  94
  95             pen.line(px, py, oldpx, oldpy) unless first
  96               first = false
  97               oldpy = py
  98               oldpx = px
  99           end
 100         end
 101       end
 102
 103       res = GD2::AnimatedGif::gif_anim_begin(frames[0])
 104       res << GD2::AnimatedGif::gif_anim_add(frames[0], nil, delay)
 105       (1..nframes - 1).each do |n|
 106         res << GD2::AnimatedGif::gif_anim_add(frames[n], frames[n-1], delay)
 107       end
 108       res << GD2::AnimatedGif::gif_anim_end()
 109
 110       res
 111     end
 112
 113     def icon(min_lat, min_lon, max_lat, max_lon)
 114       width = 50
 115       height = 50
 116       proj = OSM::Mercator.new(min_lat, min_lon, max_lat, max_lon, width, height)
 117
 118       image = GD2::Image::IndexedColor.new(width, height)
 119
 120       black = image.palette.allocate(GD2::Color[0, 0, 0])
 121       white = image.palette.allocate(GD2::Color[255, 255, 255])
 122
 123       image.draw do |pen|
 124         pen.color = white
 125         pen.rectangle(0, 0, width, height, true)
 126       end
 127
 128       image.draw do |pen|
 129         pen.color = black
 130         pen.anti_aliasing = true
 131         pen.dont_blend = false
 132
 133         oldpx = 0.0
 134         oldpy = 0.0
 135
 136         first = true
 137
 138         points do |p|
 139           px = proj.x(p.longitude)
 140           py = proj.y(p.latitude)
 141
 142           pen.line(px, py, oldpx, oldpy) unless first
 143
 144           first = false
 145           oldpy = py
 146           oldpx = px
 147         end
 148       end
 149
 150       image.gif
 151     end
 152   end
 153
 154   TrkPt = Struct.new(:segment, :latitude, :longitude, :altitude, :timestamp) do
 155     def valid?
 156       latitude && longitude && timestamp &&
 157         latitude >= -90 && latitude <= 90 &&
 158         longitude >= -180 && longitude <= 180
 159     end
 160   end
 161 end