From f3338c7249f31df6dbaf6983127968eba1be55f5 Mon Sep 17 00:00:00 2001
From: alpine-a110 <alpine-a110@8e941d3f-bd1b-0410-a28a-d453659cc2b4>
Date: Mon, 4 Mar 2024 13:38:29 +0000
Subject: [PATCH] LazMapViewer: Added TGpxWriter (rudimentary) into mvGPX.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@9266 8e941d3f-bd1b-0410-a28a-d453659cc2b4
---
 components/lazmapviewer/source/mvgpx.pas | 80 +++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/components/lazmapviewer/source/mvgpx.pas b/components/lazmapviewer/source/mvgpx.pas
index fc1b3fc0b..f6f078219 100644
--- a/components/lazmapviewer/source/mvgpx.pas
+++ b/components/lazmapviewer/source/mvgpx.pas
@@ -16,10 +16,13 @@ unit mvGPX;
 interface
 
 uses
-  Classes, SysUtils, laz2_DOM, laz2_XMLRead, DateUtils,
+  Classes, SysUtils, laz2_DOM, laz2_XMLRead, laz2_XMLWrite, DateUtils,
   mvTypes, mvGpsObj;
 
 type
+
+  { TGpxReader }
+
   TGpxReader = class
   private
     ID: Integer;
@@ -39,6 +42,14 @@ type
     function LoadFromStream(AStream: TStream; AList: TGpsObjectList; out ABounds: TRealArea): Integer;
   end;
 
+  { TGpxWriter }
+
+  TGpxWriter = class
+  public
+    class procedure SaveToStream(AStream: TStream; AList: TGpsObjectList);
+    class procedure SaveToFile(AFileName: String; AList: TGPSObjectList);
+  end;
+
 
 implementation
 
@@ -257,6 +268,73 @@ begin
   end;
 end;
 
+class procedure TGpxWriter.SaveToStream(AStream: TStream; AList: TGpsObjectList
+  );
+var
+  Doc: TXMLDocument;
+  RootNode: TDOMNode;
+  I: Integer;
+  O: TGPSObj;
+
+  function CreateTextElement(ANode: TDOMNode; ATag, AValue: DOMString): TDOMNode;
+  begin
+    Result := ANode;
+    Result.AppendChild(Doc.CreateElement(ATag)).AppendChild(
+      Doc.CreateTextNode(AValue));
+  end;
+
+  function CreatePoint(AName: String; APOI: TGPSPoint): TDOMElement;
+  begin
+    Result := Doc.CreateElement(AName);
+    Result.SetAttribute('lat', APOI.Lat.ToString);
+    Result.SetAttribute('lon', APOI.Lon.ToString);
+    if APOI.Name <> '' then
+      CreateTextElement(Result, 'name', APOI.Name);
+    if APOI.Elevation <> NO_ELE then
+      CreateTextElement(Result, 'ele', APOI.Elevation.ToString);
+    if APOI.DateTime <> NO_DATE then
+      CreateTextElement(Result, 'time', DateToISO8601(APOI.DateTime));
+  end;
+
+begin
+  Doc := TXMLDocument.Create;
+  try
+    RootNode := Doc.CreateElement('gpx');
+    Doc.AppendChild(RootNode);
+    RootNode := Doc.DocumentElement;
+    TDOMElement(RootNode).SetAttribute('version', '1.1');
+    TDOMElement(RootNode).SetAttribute('creator',
+      'LazMapViewer https://wiki.lazarus.freepascal.org/LazMapViewer');
+
+    for I := 0 to Pred(AList.Count) do
+    begin
+      O := AList[I];
+      if O is TGPSPointOfInterest then
+        RootNode.AppendChild(CreatePoint('wpt', TGPSPoint(O)))
+      else if O is TGPSPoint then
+        RootNode.AppendChild(CreatePoint('wpt', TGPSPoint(O)))
+      else if O is TGPSTrack then
+        {TODO};
+    end;
+    WriteXMLFile(doc, AStream);
+
+  finally
+    Doc.Free;
+  end;
+end;
+
+class procedure TGpxWriter.SaveToFile(AFileName: String; AList: TGPSObjectList);
+var
+  Stream: TStream;
+begin
+  Stream := TFileStream.Create(AFileName, fmCreate);
+  try
+    SaveToStream(Stream, AList);
+  finally
+    Stream.Free;
+  end;
+end;
+
 function TGpxReader.LoadFromStream(AStream: TStream; AList: TGpsObjectList): Integer;
 var
   area: TRealArea;