app/controllers/swf_controller.rb

   1 class SwfController < ApplicationController
   2
   3 # to log:
   4 # RAILS_DEFAULT_LOGGER.error("Args: #{args[0]}, #{args[1]}, #{args[2]}, #{args[3]}")
   5 # $log.puts Time.new.to_s+','+Time.new.usec.to_s+": started GPS script"
   6 # http://localhost:3000/api/0.4/swf/trackpoints?xmin=-2.32402605810577&xmax=-2.18386309423859&ymin=52.1546608755772&ymax=52.2272777906895&baselong=-2.25325793066437&basey=61.3948537948532&masterscale=5825.4222222222
   7
   8         # ====================================================================
   9         # Public methods
  10
  11         # ---- trackpoints      compile SWF of trackpoints
  12
  13         def trackpoints
  14
  15                 # -     Initialise
  16
  17                 baselong        =params['baselong'].to_f
  18                 basey           =params['basey'].to_f
  19                 masterscale     =params['masterscale'].to_f
  20
  21                 xmin=params['xmin'].to_f/0.000001
  22                 xmax=params['xmax'].to_f/0.000001
  23                 ymin=params['ymin'].to_f/0.000001
  24                 ymax=params['ymax'].to_f/0.000001
  25
  26                 # -     Begin movie
  27
  28                 bounds_left  =0
  29                 bounds_right =320*20
  30                 bounds_bottom=0
  31                 bounds_top   =240*20
  32
  33                 m =''
  34                 m+=swfRecord(9,255.chr + 155.chr + 155.chr)                     #ÊBackground
  35                 absx=0
  36                 absy=0
  37                 xl=yb= 9999999
  38                 xr=yt=-9999999
  39
  40                 # -     Send SQL and draw line
  41
  42                 b=''
  43                 lasttime=0
  44                 lastfile='-1'
  45
  46                 if params['token']
  47                         token=sqlescape(params['token'])
  48                         sql="SELECT gps_points.latitude*0.000001 AS lat,gps_points.longitude*0.000001 AS lon,gpx_files.id AS fileid,UNIX_TIMESTAMP(gps_points.timestamp) AS ts "+
  49                                  " FROM gpx_files,gps_points,users "+
  50                                  "WHERE gpx_files.id=gpx_id "+
  51                                  "  AND gpx_files.user_id=users.id "+
  52                                  "  AND token='#{token}' "+
  53                                  "  AND (gps_points.longitude BETWEEN #{xmin} AND #{xmax}) "+
  54                                  "  AND (gps_points.latitude BETWEEN #{ymin} AND #{ymax}) "+
  55                                  "  AND (gps_points.timestamp IS NOT NULL) "+
  56                                  "ORDER BY fileid DESC,ts "+
  57                                  "LIMIT 10000"
  58                 else
  59                         sql="SELECT latitude*0.000001 AS lat,longitude*0.000001 AS lon,gpx_id AS fileid,UNIX_TIMESTAMP(timestamp) AS ts "+
  60                                  " FROM gps_points "+
  61                                  "WHERE (longitude BETWEEN #{xmin} AND #{xmax}) "+
  62                                  "  AND (latitude  BETWEEN #{ymin} AND #{ymax}) "+
  63                                  "  AND (gps_points.timestamp IS NOT NULL) "+
  64                                  "ORDER BY fileid DESC,ts "+
  65                                  "LIMIT 10000"
  66                 end
  67                 gpslist=ActiveRecord::Base.connection.select_all sql
  68
  69                 # - Draw lines
  70
  71                 r=startShape()
  72                 gpslist.each do |row|
  73                         xs=(long2coord(row['lon'].to_f,baselong,masterscale)*20).floor
  74                         ys=(lat2coord(row['lat'].to_f ,basey   ,masterscale)*20).floor
  75                         xl=[xs,xl].min; xr=[xs,xr].max
  76                         yb=[ys,yb].min; yt=[ys,yt].max
  77                         if (row['ts'].to_i-lasttime<180 and row['fileid']==lastfile)
  78                                 b+=drawTo(absx,absy,xs,ys)
  79                         else
  80                                 b+=startAndMove(xs,ys)
  81                         end
  82                         absx=xs.floor; absy=ys.floor
  83                         lasttime=row['ts'].to_i
  84                         lastfile=row['fileid']
  85                         while b.length>80 do
  86                                 r+=[b.slice!(0...80)].pack("B*")
  87                         end
  88                 end
  89
  90                 # - Write shape
  91
  92                 b+=endShape()
  93                 r+=[b].pack("B*")
  94                 m+=swfRecord(2,packUI16(1) + packRect(xl,xr,yb,yt) + r)
  95                 m+=swfRecord(4,packUI16(1) + packUI16(1))
  96
  97                 # -     Create Flash header and write to browser
  98
  99                 m+=swfRecord(1,'')                                                                      # Show frame
 100                 m+=swfRecord(0,'')                                                                      # End
 101
 102                 m=packRect(bounds_left,bounds_right,bounds_bottom,bounds_top) + 0.chr + 12.chr + packUI16(1) + m
 103                 m='FWS' + 6.chr + packUI32(m.length+8) + m
 104
 105                 response.headers["Content-Type"]="application/x-shockwave-flash"
 106                 render :text=>m
 107         end
 108
 109         private
 110
 111         # =======================================================================
 112         # SWF functions
 113
 114         # -----------------------------------------------------------------------
 115         # Line-drawing
 116
 117         def startShape
 118                 s =0.chr                                                                                # No fill styles
 119                 s+=1.chr                                                                                # One line style
 120                 s+=packUI16(5) + 0.chr + 255.chr + 255.chr              # Width 5, RGB #00FFFF
 121                 s+=17.chr                                                                               # 1 fill, 1 line index bit
 122                 s
 123         end
 124
 125         def endShape
 126                 '000000'
 127         end
 128
 129         def startAndMove(x,y)
 130                 d='001001'                                                                              # Line style change, moveTo
 131                 l =[lengthSB(x),lengthSB(y)].max
 132                 d+=sprintf("%05b%0#{l}b%0#{l}b",l,x,y)
 133                 d+='1'                                                                                  # Select line style 1
 134         end
 135
 136         def drawTo(absx,absy,x,y)
 137                 d='11'                                                                                  # TypeFlag, EdgeFlag
 138                 dx=x-absx
 139                 dy=y-absy
 140
 141                 l =[lengthSB(dx),lengthSB(dy)].max
 142                 d+=sprintf("%04b",l-2)
 143                 d+='1'                                                                                  # GeneralLine
 144                 d+=sprintf("%0#{l}b%0#{l}b",dx,dy)
 145         end
 146
 147         # -----------------------------------------------------------------------
 148         # Specific data types
 149
 150         def swfRecord(id,r)
 151                 if r.length>62
 152                         return packUI16((id<<6)+0x3F) + packUI32(r.length) + r
 153                 else
 154                         return packUI16((id<<6)+r.length) + r
 155                 end
 156         end
 157
 158         def packRect(a,b,c,d)
 159                 l=[lengthSB(a),
 160                    lengthSB(b),
 161                    lengthSB(c),
 162                    lengthSB(d)].max
 163                 n=sprintf("%05b%0#{l}b%0#{l}b%0#{l}b%0#{l}b",l,a,b,c,d)
 164                 [n].pack("B*")
 165         end
 166
 167         # -----------------------------------------------------------------------
 168         # Generic pack functions
 169
 170         def packUI16(n)
 171                 [n.floor].pack("v")
 172         end
 173
 174         def packUI32(n)
 175                 [n.floor].pack("V")
 176         end
 177
 178         # Find number of bits required to store arbitrary-length binary
 179
 180         def lengthSB(n)
 181                 Math.frexp(n+ (n==0?1:0) )[1]+1
 182         end
 183
 184         # ====================================================================
 185         # Co-ordinate conversion
 186         # (this is duplicated from amf_controller, should probably share)
 187
 188         def lat2coord(a,basey,masterscale)
 189                 -(lat2y(a)-basey)*masterscale+250
 190         end
 191
 192         def long2coord(a,baselong,masterscale)
 193                 (a-baselong)*masterscale+350
 194         end
 195
 196         def lat2y(a)
 197                 180/Math::PI * Math.log(Math.tan(Math::PI/4+a*(Math::PI/180)/2))
 198         end
 199
 200         def sqlescape(a)
 201                 a.gsub("'","''").gsub(92.chr,92.chr+92.chr)
 202         end
 203
 204 end