src/Projection/MapWindowProjection.cpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #include "MapWindowProjection.hpp"
  25 #include "Screen/Layout.hpp"
  26 #include "Waypoint/Waypoint.hpp"
  27 #include "Util/Macros.hpp"
  28 #include "Util/Clamp.hpp"
  29
  30 #include <stdlib.h>
  31 #include <math.h>
  32 #include <assert.h>
  33
  34 static constexpr unsigned ScaleList[] = {
  35   100,
  36   200,
  37   300,
  38   500,
  39   1000,
  40   2000,
  41   3000,
  42   5000,
  43   10000,
  44   20000,
  45   30000,
  46   50000,
  47   100000,
  48   200000,
  49   300000,
  50   500000,
  51   1000000,
  52 };
  53
  54 static constexpr unsigned ScaleListCount = ARRAY_SIZE(ScaleList);
  55
  56 bool
  57 MapWindowProjection::WaypointInScaleFilter(const Waypoint &way_point) const
  58 {
  59   return (GetMapScale() <= (way_point.IsLandable() ? fixed(20000) : fixed(10000)));
  60 }
  61
  62 fixed
  63 MapWindowProjection::CalculateMapScale(unsigned scale) const
  64 {
  65   assert(scale < ScaleListCount);
  66   return fixed(ScaleList[scale]) *
  67     GetMapResolutionFactor() / Layout::Scale(GetScreenWidth());
  68 }
  69
  70 fixed
  71 MapWindowProjection::LimitMapScale(const fixed value) const
  72 {
  73   return HaveScaleList() ? CalculateMapScale(FindMapScale(value)) : value;
  74 }
  75
  76 fixed
  77 MapWindowProjection::StepMapScale(const fixed scale, int Step) const
  78 {
  79   int i = FindMapScale(scale) + Step;
  80   i = Clamp(i, 0, (int)ScaleListCount - 1);
  81   return CalculateMapScale(i);
  82 }
  83
  84 unsigned
  85 MapWindowProjection::FindMapScale(const fixed Value) const
  86 {
  87   unsigned DesiredScale(Value * Layout::Scale(GetScreenWidth())
  88                         / GetMapResolutionFactor());
  89
  90   unsigned i;
  91   for (i = 0; i < ScaleListCount; i++) {
  92     if (DesiredScale < ScaleList[i]) {
  93       if (i == 0)
  94         return 0;
  95
  96       return i - (DesiredScale < (ScaleList[i] + ScaleList[i - 1]) / 2);
  97     }
  98   }
  99
 100   return ScaleListCount - 1;
 101 }
 102
 103 void
 104 MapWindowProjection::SetFreeMapScale(const fixed x)
 105 {
 106   SetScale(fixed(GetMapResolutionFactor()) / x);
 107 }
 108
 109 void
 110 MapWindowProjection::SetMapScale(const fixed x)
 111 {
 112   SetScale(fixed(GetMapResolutionFactor()) / LimitMapScale(x));
 113 }