src/MapWindow/MapCanvas.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 "MapCanvas.hpp"
  25 #include "Screen/Canvas.hpp"
  26 #include "Projection/WindowProjection.hpp"
  27 #include "Asset.hpp"
  28 #include "Screen/Layout.hpp"
  29 #include "Math/Screen.hpp"
  30 #include "Geo/SearchPointVector.hpp"
  31
  32 void
  33 MapCanvas::DrawLine(GeoPoint a, GeoPoint b)
  34 {
  35   if (!clip.ClipLine(a, b))
  36     return;
  37
  38   RasterPoint pts[2];
  39   pts[0] = projection.GeoToScreen(a);
  40   pts[1] = projection.GeoToScreen(b);
  41
  42   canvas.DrawLine(pts[0], pts[1]);
  43 }
  44
  45 void
  46 MapCanvas::DrawLineWithOffset(GeoPoint a, GeoPoint b)
  47 {
  48   if (!clip.ClipLine(a, b))
  49     return;
  50
  51   RasterPoint pts[3];
  52   pts[0] = projection.GeoToScreen(a);
  53   pts[1] = projection.GeoToScreen(b);
  54   ScreenClosestPoint(pts[0], pts[1], pts[0], &pts[2], Layout::Scale(20));
  55   canvas.DrawLine(pts[2], pts[1]);
  56 }
  57
  58
  59 void
  60 MapCanvas::DrawCircle(const GeoPoint &center, fixed radius)
  61 {
  62   RasterPoint screen_center = projection.GeoToScreen(center);
  63   unsigned screen_radius = projection.GeoToScreenDistance(radius);
  64   canvas.DrawCircle(screen_center.x, screen_center.y, screen_radius);
  65 }
  66
  67 void
  68 MapCanvas::Project(const Projection &projection,
  69                    const SearchPointVector &points, RasterPoint *screen)
  70 {
  71   for (auto it = points.begin(); it != points.end(); ++it)
  72     *screen++ = projection.GeoToScreen(it->GetLocation());
  73 }
  74
  75 static void
  76 UpdateBounds(PixelRect &bounds, const RasterPoint &pt)
  77 {
  78   if (pt.x < bounds.left)
  79     bounds.left = pt.x;
  80   if (pt.x >= bounds.right)
  81     bounds.right = pt.x + 1;
  82   if (pt.y < bounds.top)
  83     bounds.top = pt.y;
  84   if (pt.y >= bounds.bottom)
  85     bounds.bottom = pt.y + 1;
  86 }
  87
  88 bool
  89 MapCanvas::IsVisible(const Canvas &canvas,
  90                      const RasterPoint *screen, unsigned num)
  91 {
  92   PixelRect bounds;
  93   bounds.left = 0x7fff;
  94   bounds.top = 0x7fff;
  95   bounds.right = -1;
  96   bounds.bottom = -1;
  97
  98   for (unsigned i = 0; i < num; ++i)
  99     UpdateBounds(bounds, screen[i]);
 100
 101   return bounds.left < (int)canvas.GetWidth() && bounds.right >= 0 &&
 102     bounds.top < (int)canvas.GetHeight() && bounds.bottom >= 0;
 103 }
 104
 105 bool
 106 MapCanvas::PreparePolygon(const SearchPointVector &points)
 107 {
 108   unsigned num_points = points.size();
 109   if (num_points < 3)
 110     return false;
 111
 112   /* copy all SearchPointVector elements to geo_points */
 113   geo_points.GrowDiscard(num_points * 3);
 114   for (unsigned i = 0; i < num_points; ++i)
 115     geo_points[i] = points[i].GetLocation();
 116
 117   /* clip them */
 118   num_raster_points = clip.ClipPolygon(geo_points.begin(),
 119                                        geo_points.begin(), num_points);
 120   if (num_raster_points < 3)
 121     /* it's completely outside the screen */
 122     return false;
 123
 124   /* project all GeoPoints to screen coordinates */
 125   raster_points.GrowDiscard(num_raster_points);
 126   for (unsigned i = 0; i < num_raster_points; ++i)
 127     raster_points[i] = projection.GeoToScreen(geo_points[i]);
 128
 129   return IsVisible(raster_points.begin(), num_raster_points);
 130 }
 131
 132 void
 133 MapCanvas::DrawPrepared()
 134 {
 135   /* draw it all */
 136   canvas.DrawPolygon(raster_points.begin(), num_raster_points);
 137 }