LazMapViewer: Add new example project "elevations" reading elevations from opentopodata.org

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@9184 8e941d3f-bd1b-0410-a28a-d453659cc2b4
2024-01-30 12:46:27 +00:00 · 2024-01-30 12:46:27 +00:00 · 9a323d5529
commit 9a323d5529
parent fddd97d93e
7 changed files with 689 additions and 5 deletions
--- a/components/lazmapviewer/examples/colored_tracks/main.pas
+++ b/components/lazmapviewer/examples/colored_tracks/main.pas
@ -65,12 +65,14 @@ var
  crs: TCursor;
  totalArea: TRealArea;
  trackArea: TRealArea;
+  dir: String;
 begin
  crs := Screen.Cursor;
  Screen.Cursor := crHourglass;
  try
-    // Threaded painting interferes with track painting over several tiles
-    MapView.UseThreads := true; //false;
+    dir := ExpandFileName(Application.Location + '../../../cache/');
+    ForceDirectories(dir);
+    MapView.UseThreads := true;
    MapView.MapProvider := cbProviders.Text;
    MapView.Active := true;

--- a/components/lazmapviewer/examples/elevations/Elevations_Demo.lpi
+++ b/components/lazmapviewer/examples/elevations/Elevations_Demo.lpi
@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<CONFIG>
+  <ProjectOptions>
+    <Version Value="12"/>
+    <PathDelim Value="\"/>
+    <General>
+      <SessionStorage Value="InProjectDir"/>
+      <Title Value="Elevations_Demo"/>
+      <Scaled Value="True"/>
+      <ResourceType Value="res"/>
+      <UseXPManifest Value="True"/>
+      <XPManifest>
+        <DpiAware Value="True"/>
+      </XPManifest>
+    </General>
+    <BuildModes>
+      <Item Name="Default" Default="True"/>
+    </BuildModes>
+    <PublishOptions>
+      <Version Value="2"/>
+      <UseFileFilters Value="True"/>
+    </PublishOptions>
+    <RunParams>
+      <FormatVersion Value="2"/>
+    </RunParams>
+    <RequiredPackages>
+      <Item>
+        <PackageName Value="lazMapViewerPkg"/>
+      </Item>
+      <Item>
+        <PackageName Value="LCL"/>
+      </Item>
+    </RequiredPackages>
+    <Units>
+      <Unit>
+        <Filename Value="Elevations_Demo.lpr"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
+      <Unit>
+        <Filename Value="main.pas"/>
+        <IsPartOfProject Value="True"/>
+        <ComponentName Value="MainForm"/>
+        <HasResources Value="True"/>
+        <ResourceBaseClass Value="Form"/>
+        <UnitName Value="Main"/>
+      </Unit>
+    </Units>
+  </ProjectOptions>
+  <CompilerOptions>
+    <Version Value="11"/>
+    <PathDelim Value="\"/>
+    <Target>
+      <Filename Value="bin\$(TargetCPU)-$(TargetOS)\elevations_demo"/>
+    </Target>
+    <SearchPaths>
+      <IncludeFiles Value="$(ProjOutDir)"/>
+      <UnitOutputDirectory Value="lib\$(TargetCPU)-$(TargetOS)"/>
+    </SearchPaths>
+    <Linking>
+      <Debugging>
+        <DebugInfoType Value="dsDwarf3"/>
+      </Debugging>
+      <Options>
+        <Win32>
+          <GraphicApplication Value="True"/>
+        </Win32>
+      </Options>
+    </Linking>
+  </CompilerOptions>
+  <Debugging>
+    <Exceptions>
+      <Item>
+        <Name Value="EAbort"/>
+      </Item>
+      <Item>
+        <Name Value="ECodetoolError"/>
+      </Item>
+      <Item>
+        <Name Value="EFOpenError"/>
+      </Item>
+    </Exceptions>
+  </Debugging>
+</CONFIG>
--- a/components/lazmapviewer/examples/elevations/Elevations_Demo.lpr
+++ b/components/lazmapviewer/examples/elevations/Elevations_Demo.lpr
@ -0,0 +1,25 @@
+program Elevations_Demo;
+
+{$mode objfpc}{$H+}
+
+uses
+  {$IFDEF UNIX}
+  cthreads,
+  {$ENDIF}
+  {$IFDEF HASAMIGA}
+  athreads,
+  {$ENDIF}
+  Interfaces, // this includes the LCL widgetset
+  Forms, Main
+  { you can add units after this };
+
+{$R *.res}
+
+begin
+  RequireDerivedFormResource:=True;
+  Application.Scaled:=True;
+  Application.Initialize;
+  Application.CreateForm(TMainForm, MainForm);
+  Application.Run;
+end.
+
--- a/components/lazmapviewer/examples/elevations/main.lfm
+++ b/components/lazmapviewer/examples/elevations/main.lfm
@ -0,0 +1,258 @@
+object MainForm: TMainForm
+  Left = 314
+  Height = 515
+  Top = 130
+  Width = 991
+  Caption = 'MainForm'
+  ClientHeight = 515
+  ClientWidth = 991
+  ShowHint = True
+  LCLVersion = '3.99.0.0'
+  OnCreate = FormCreate
+  object MapView: TMapView
+    Left = 0
+    Height = 515
+    Top = 0
+    Width = 614
+    Align = alClient
+    DownloadEngine = MapView.BuiltInDLE
+    DrawingEngine = MapView.BuiltInDE
+    Font.Color = clBlack
+    MapProvider = 'OpenStreetMap Mapnik'
+    UseThreads = True
+    OnDrawGpsPoint = MapViewDrawGpsPoint
+    OnMouseDown = MapViewMouseDown
+  end
+  object Panel1: TPanel
+    Left = 622
+    Height = 503
+    Top = 6
+    Width = 363
+    Align = alRight
+    BorderSpacing.Left = 3
+    BorderSpacing.Top = 6
+    BorderSpacing.Right = 6
+    BorderSpacing.Bottom = 6
+    BevelOuter = bvNone
+    ClientHeight = 503
+    ClientWidth = 363
+    TabOrder = 1
+    object Log: TMemo
+      AnchorSideLeft.Control = Panel1
+      AnchorSideTop.Control = Splitter1
+      AnchorSideTop.Side = asrBottom
+      AnchorSideRight.Control = Panel1
+      AnchorSideRight.Side = asrBottom
+      AnchorSideBottom.Control = Panel1
+      AnchorSideBottom.Side = asrBottom
+      Left = 0
+      Height = 205
+      Top = 298
+      Width = 363
+      Anchors = [akTop, akLeft, akRight, akBottom]
+      Font.Height = -11
+      Font.Name = 'Courier New'
+      Lines.Strings = (
+        ''
+      )
+      ParentFont = False
+      TabOrder = 0
+    end
+    object DataGrid: TDrawGrid
+      AnchorSideLeft.Control = Panel1
+      AnchorSideTop.Control = cbElevDatasets
+      AnchorSideTop.Side = asrBottom
+      AnchorSideRight.Control = Panel1
+      AnchorSideRight.Side = asrBottom
+      AnchorSideBottom.Control = Splitter1
+      Left = 0
+      Height = 247
+      Top = 46
+      Width = 363
+      Anchors = [akTop, akLeft, akRight, akBottom]
+      BorderSpacing.Top = 6
+      ColCount = 4
+      ExtendedSelect = False
+      Options = [goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine, goRangeSelect, goRowSelect, goSmoothScroll]
+      RowCount = 1
+      TabOrder = 1
+      OnDrawCell = DataGridDrawCell
+      OnPrepareCanvas = DataGridPrepareCanvas
+    end
+    object cbElevDatasets: TComboBox
+      AnchorSideLeft.Control = Panel1
+      AnchorSideTop.Control = lblDatasets
+      AnchorSideTop.Side = asrBottom
+      AnchorSideRight.Control = btnDelete
+      Left = 0
+      Height = 23
+      Top = 17
+      Width = 338
+      Anchors = [akTop, akLeft, akRight]
+      BorderSpacing.Top = 2
+      BorderSpacing.Right = 2
+      ItemHeight = 15
+      ItemIndex = 3
+      Items.Strings = (
+        'nzdem8m (New Zealand, resolution 8 m)'
+        'ned10m (Continental U.S.A., Hawaii, parts of Alaska, resolution 10 m)'
+        'eudem25m (Europe, resolution 25 m)'
+        'mapzen (global,  resolution 30 m)'
+        'aster30m (global, resolution 30 m)'
+        'bkg200m (Germany, resolution 200 m)'
+      )
+      Style = csDropDownList
+      TabOrder = 2
+      Text = 'mapzen (global,  resolution 30 m)'
+    end
+    object lblDatasets: TLabel
+      AnchorSideLeft.Control = Panel1
+      AnchorSideTop.Control = Panel1
+      Left = 0
+      Height = 15
+      Top = 0
+      Width = 166
+      Caption = 'Elevation datasets, provided by '
+    end
+    object lblURL: TLabel
+      AnchorSideLeft.Control = lblDatasets
+      AnchorSideLeft.Side = asrBottom
+      AnchorSideTop.Control = Panel1
+      Cursor = crHandPoint
+      Left = 166
+      Height = 15
+      Top = 0
+      Width = 166
+      Caption = 'https://www.opentopodata.org'
+      Font.Color = clBlue
+      ParentColor = False
+      ParentFont = False
+      OnClick = lblURLClick
+      OnMouseEnter = lblURLMouseEnter
+      OnMouseLeave = lblURLMouseLeave
+    end
+    object Splitter1: TSplitter
+      AnchorSideLeft.Control = Panel1
+      AnchorSideRight.Control = Panel1
+      AnchorSideRight.Side = asrBottom
+      Cursor = crVSplit
+      Left = 0
+      Height = 5
+      Top = 293
+      Width = 363
+      Align = alNone
+      Anchors = [akTop, akLeft, akRight]
+      ResizeAnchor = akTop
+    end
+    object btnDelete: TSpeedButton
+      AnchorSideTop.Control = cbElevDatasets
+      AnchorSideTop.Side = asrCenter
+      AnchorSideRight.Control = Panel1
+      AnchorSideRight.Side = asrBottom
+      Left = 340
+      Height = 22
+      Hint = 'Delete selected data point'
+      Top = 17
+      Width = 23
+      Anchors = [akTop, akRight]
+      Images = ImageList1
+      ImageIndex = 0
+      OnClick = btnDeleteClick
+    end
+  end
+  object Splitter2: TSplitter
+    Left = 614
+    Height = 515
+    Top = 0
+    Width = 5
+    Align = alRight
+    ResizeAnchor = akRight
+    ResizeStyle = rsPattern
+  end
+  object ImageList1: TImageList
+    Scaled = True
+    Left = 421
+    Top = 89
+    Bitmap = {
+      4C7A010000001000000010000000D20100000000000078DA8D934B2F035114C7
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+      52F6140B0147CA920F387925B3F3EBFC299908793F276779FE407B00FE93BF0C
+      743AF30115F110EB
+    }
+    BitmapAdv = {
+      4C69020000004C7A010000001800000018000000210300000000000078DAA595
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+      DD7FADE818A989FD437E0C3CA5587F00DD799616
+    }
+  end
+  object ApplicationProperties: TApplicationProperties
+    OnIdle = ApplicationPropertiesIdle
+    Left = 421
+    Top = 150
+  end
+end
--- a/components/lazmapviewer/examples/elevations/main.pas
+++ b/components/lazmapviewer/examples/elevations/main.pas
@ -0,0 +1,311 @@
+unit Main;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, LazFileUtils,
+  LCLIntf, Forms, Controls, Graphics, Dialogs, StdCtrls,
+  ExtCtrls, Grids, Buttons, mvMapViewer, mvTypes, mvEngine, Types, mvGpsObj,
+  mvDrawingEngine;
+
+type
+  { TMainForm }
+
+  TMainForm = class(TForm)
+    ApplicationProperties: TApplicationProperties;
+    cbElevDatasets: TComboBox;
+    DataGrid: TDrawGrid;
+    ImageList1: TImageList;
+    lblDatasets: TLabel;
+    lblURL: TLabel;
+    MapView: TMapView;
+    Log: TMemo;
+    Panel1: TPanel;
+    btnDelete: TSpeedButton;
+    Splitter1: TSplitter;
+    Splitter2: TSplitter;
+    procedure ApplicationPropertiesIdle(Sender: TObject; var Done: Boolean);
+    procedure DataGridDrawCell(Sender: TObject; aCol, aRow: Integer;
+      aRect: TRect; aState: TGridDrawState);
+    procedure DataGridPrepareCanvas(Sender: TObject; aCol, aRow: Integer;
+      aState: TGridDrawState);
+    procedure FormCreate(Sender: TObject);
+    procedure lblURLClick(Sender: TObject);
+    procedure lblURLMouseEnter(Sender: TObject);
+    procedure lblURLMouseLeave(Sender: TObject);
+    procedure MapViewDrawGpsPoint(Sender: TObject;
+      ADrawer: TMvCustomDrawingEngine; APoint: TGpsPoint);
+    procedure MapViewMouseDown(Sender: TObject; Button: TMouseButton;
+      Shift: TShiftState; X, Y: Integer);
+    procedure btnDeleteClick(Sender: TObject);
+  private
+    FCounter: Integer;
+    function GetElevation(APoint: TRealPoint): Double;
+    function SelectedDataset: String;
+
+  public
+
+  end;
+
+var
+  MainForm: TMainForm;
+
+implementation
+
+{$R *.lfm}
+
+uses
+  Math, fpjson, jsonparser;
+
+const
+  _CLICKED_POINTS_ = 10;
+
+{ TMainForm }
+
+procedure TMainForm.FormCreate(Sender: TObject);
+var
+  dir: String;
+begin
+  dir := ExpandFileName(Application.Location + '../../../cache/');
+  ForceDirectories(dir);
+  MapView.CachePath := dir;
+  MapView.Center := RealPoint(47, 11);
+  MapView.Zoom := 8;
+  MapView.MapProvider := 'Google Satellite';
+  MapView.Active := true;
+
+  DataGrid.ColWidths[0] := 40;
+  DataGrid.ColWidths[1] := 100;
+  DataGrid.ColWidths[2] := 100;
+  DataGrid.ColWidths[3] := 90;
+end;
+
+// Sends a request to opentopodata.org and extracts the elevation from the
+// returned json stream which is structures as follows:
+(*
+{
+    "results": [{
+        "elevation": 815.0,
+        "location": {
+            "lat": 56.0,
+            "lng": 123.0
+        },
+        "dataset": "test-dataset"
+    }],
+    "status": "OK"
+}
+*)
+function TMainForm.GetElevation(APoint: TRealPoint): Double;
+var
+  url: String;
+  fs: TFormatSettings;
+  stream: TStream;
+  json: TJsonData;
+  jsonData: TJsonData;
+begin
+  fs := DefaultFormatSettings;
+  fs.DecimalSeparator := '.';
+
+  url := Format('https://api.opentopodata.org/v1/%s?locations=%.9f,%.9f', [
+    SelectedDataset, APoint.Lat, APoint.Lon
+  ], fs);
+  stream := TMemoryStream.Create;
+  try
+    MapView.Engine.DownloadEngine.DownloadFile(url, stream);
+    json := GetJSON(stream);
+    try
+      Log.Text := json.FormatJSON;
+      jsonData := json.FindPath('results[0]').FindPath('elevation');
+      if jsonData.IsNull then
+        Result := NaN
+      else
+        Result := jsonData.AsFloat;
+    finally
+      json.Free;
+    end;
+  finally
+    stream.free;
+  end;
+end;
+
+// Calculates the selected dataset parameter for the opentopodata URL.
+function TMainForm.SelectedDataset: String;
+var
+  s: String;
+  p: Integer;
+begin
+  Result := '';
+  if cbElevDatasets.ItemIndex <> -1 then
+  begin
+    s := cbElevDatasets.Items[cbElevDatasets.ItemIndex];
+    p := pos(' ', s);
+    if p > 0 then
+      Result := Copy(s, 1, p-1);
+  end;
+end;
+
+// Draws the stored GPS points
+procedure TMainForm.MapViewDrawGpsPoint(Sender: TObject;
+  ADrawer: TMvCustomDrawingEngine; APoint: TGpsPoint);
+const
+  MARGIN = 8;
+var
+  P: TPoint;
+  d: Integer;
+  extent: TSize;
+  R: TRect;
+begin
+  // Screen coordinates of the GPS point
+  P := TMapView(Sender).LonLatToScreen(APoint.RealPoint);
+
+  // Draw the point symbol
+  ADrawer.PenColor := clRed;
+  ADrawer.PenWidth := 3;
+  d := 5;
+  ADrawer.Line(P.x - d, P.Y - d, P.X + d, P.Y + d);
+  ADrawer.Line(P.x - d, P.Y + d, P.X + d, P.Y - d);
+
+  // Prepare text output: background color...
+  inc(P.Y, d + 4);
+  extent := ADrawer.TextExtent(APoint.Name);
+  R := Rect(0, 0, extent.CX, extent.CY);
+  OffsetRect(R, P.X - extent.CX div 2, P.Y);
+  InflateRect(R, MARGIN, 0);
+  ADrawer.BrushStyle := bsSolid;
+  ADrawer.BrushColor := clRed;
+  ADrawer.FillRect(R.Left, R.Top, R.Right, R.Bottom);
+
+  // ... and font
+  ADrawer.FontColor := clWhite; //MapView.Font.Color;
+  ADrawer.FontName := MapView.Font.Name;
+  ADrawer.FontSize := MapView.Font.Size;
+  ADrawer.FontStyle := MapView.Font.Style;
+
+  // Write the POI text
+  ADrawer.TextOut(P.X - extent.CX div 2, P.Y, APoint.Name);
+end;
+
+{ Gets the GPS coordinates of the clicked point in the map view and query the
+  elevation. Store as a data point in the GPSItems of the MapView. }
+procedure TMainForm.MapViewMouseDown(Sender: TObject; Button: TMouseButton;
+  Shift: TShiftState; X, Y: Integer);
+var
+  p: TRealPoint;
+  gpsPt: TGpsPoint;
+  elev: Double;
+begin
+  if (ssCtrl in Shift) then
+  begin
+    p := MapView.ScreenToLonLat(Point(X, Y));
+    elev := GetElevation(p);
+
+    gpsPt := TGpsPoint.CreateFrom(p, elev);
+    inc(FCounter);
+    gpsPt.Name := IntToStr(FCounter);
+    MapView.GpsItems.Add(gpsPt, _CLICKED_POINTS_);
+
+    DataGrid.RowCount := MapView.GPSItems.Count + DataGrid.FixedRows;
+  end;
+end;
+
+{ Draws a cell in the DataGrid which gets is data from the GPS points stored in
+  the MapView component. }
+procedure TMainForm.DataGridDrawCell(Sender: TObject; aCol, aRow: Integer;
+  aRect: TRect; aState: TGridDrawState);
+var
+  cellText: String;
+  idx: Integer;
+  pt: TGPSPoint;
+begin
+  cellText := '';
+  if ARow = 0 then
+    case ACol of
+      0: cellText := 'No.';
+      1: cellText := 'Longitude';
+      2: cellText := 'Latitude';
+      3: cellText := 'Elevation (m)';
+    end
+  else
+  begin
+    idx := ARow - DataGrid.FixedRows;
+    pt := MapView.GPSItems[idx] as TGPSPoint;
+    case ACol of
+      0: cellText := pt.Name;
+      1: cellText := LonToStr(pt.Lon, true);
+      2: cellText := LatToStr(pt.Lat, true);
+      3: if IsNaN(pt.Elevation) then
+           cellText := '(unknown)'
+         else
+           cellText := FormatFloat('0', pt.Elevation);
+    end;
+  end;
+  InflateRect(ARect, -varCellPadding, -varCellPadding);
+  DataGrid.Canvas.TextRect(ARect, ARect.Left, ARect.Top, cellText);
+end;
+
+procedure TMainForm.ApplicationPropertiesIdle(Sender: TObject; var Done: Boolean);
+begin
+  btnDelete.Enabled := (DataGrid.RowCount > 1) and (DataGrid.Row > 0);
+end;
+
+// Some formatting for the DataGrid: Headers will be bold and centered,
+// data cells will be right-aligned.
+procedure TMainForm.DataGridPrepareCanvas(Sender: TObject; aCol, aRow: Integer;
+  aState: TGridDrawState);
+var
+  ts: TTextStyle;
+begin
+  ts := DataGrid.Canvas.TextStyle;
+  if aRow = 0 then
+  begin
+    DataGrid.Canvas.Font.Style := [fsBold];
+    ts.Alignment := taCenter;
+  end else
+  begin
+    ts.Alignment := taRightJustify;
+  end;
+  DataGrid.Canvas.TextStyle := ts;
+end;
+
+//  Deletes the selected datapoint in the DataGrid.
+procedure TMainForm.btnDeleteClick(Sender: TObject);
+var
+  idx: Integer;
+  item: TGPSObj;
+  i: Integer;
+begin
+  idx := DataGrid.Row - DataGrid.FixedRows;
+  if idx < 0 then
+    exit;
+
+  // Delete from map's GPS items
+  item := MapView.GPSItems[idx];
+  MapView.GPSItems.Delete(item);
+  MapView.Invalidate;
+
+  // Update grid
+  DataGrid.RowCount := DataGrid.RowCount-1;
+  DataGrid.Invalidate;
+end;
+
+// Open the browser with the opentopodata.org web-site.
+procedure TMainForm.lblURLClick(Sender: TObject);
+begin
+  OpenURL('https://www.opentopodata.org/');
+end;
+
+// Underline the opentopodata.org URL when the mouse enters the label
+procedure TMainForm.lblURLMouseEnter(Sender: TObject);
+begin
+  lblURL.Font.Style := [fsUnderline];
+end;
+
+procedure TMainForm.lblURLMouseLeave(Sender: TObject);
+begin
+  lblURL.Font.Style := [];
+end;
+
+end.
+
--- a/components/lazmapviewer/examples/fulldemo/main.lfm
+++ b/components/lazmapviewer/examples/fulldemo/main.lfm
@ -633,7 +633,7 @@ object MainForm: TMainForm
            MinSize = 8
            MaxSize = 166
            Title.Caption = 'Provider'
-            Width = 166
+            Width = 154
          end>
        Options = [goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine, goRangeSelect, goEditing, goSmoothScroll, goRowHighlight]
        RowCount = 11
@ -644,7 +644,7 @@ object MainForm: TMainForm
        ColWidths = (
          30
          54
-          166
+          154
        )
        Cells = (
          11
--- a/components/lazmapviewer/examples/trackdemo/main.pas
+++ b/components/lazmapviewer/examples/trackdemo/main.pas
@ -70,15 +70,20 @@ end;
 procedure TMainForm.FormActivate(Sender: TObject);
 var
  crs: TCursor;
+  dir: String;
 begin
  crs := Screen.Cursor;
  Screen.Cursor := crHourglass;
  try
+    dir := ExpandFileName(Application.Location + '../../../cache/');
+    ForceDirectories(dir);
+    MapView.CachePath := dir;
    MapView.MapProvider := 'Google Maps'; //'Open Topo Map';
    MapView.Active := true;
+
    // Center on Grand Canyon Village
-    MapView.Zoom := 13;
    MapView.Center := RealPoint(DMSToDeg(36, 4, 32.2), -DMSToDeg(112, 7, 17.4));
+    MapView.Zoom := 13;

    clbTrackColor.Selected := MapView.DefaultTrackColor;