Some small URI tweaks.

Based on suggestions from Greg K., made so the "Enter URL" entry is more forgiving of text preceding the actual URI path; e.g., instead now "https://interspec.example.com/?_=/G0/3000/eNrVj..." will read in okay.  The URL used will now start with {"/G0/", "/drf/", "/specsum/", "/flux/", ...}.
Added checking the "internal" URL on page load to see if it contains the beginning of a recognized URI, and if so handle it.
Switched email QR code to use lowest error correction.

src/AppUtils.cpp

@@ -111,7 +111,7 @@ namespace AppUtils
     const string host_path = url.substr( 0, path_end );
     const string::size_type host_end = host_path.find( '/' );
 
-    // If "host/path" is only one compnent (i.e., no slash), then populate host,
+    // If "host/path" is only one component (i.e., no slash), then populate host,
     //  and have path be empty
     host = (host_end == string::npos) ? host_path : host_path.substr(0,host_end);
     path = (host_end == string::npos) ? string("") : host_path.substr(host_end+1);

src/ExportSpecFile.cpp

@@ -153,11 +153,19 @@ std::string clean_uuid( string uuid )
     if( urls.size() > 1 )
       seqnum += ", " + to_string(index + 1) + " of " + to_string( urls.size() );
 
+    string desc = seqnum;
     string title = "Spectrum File " + seqnum;
     if( urls.size() == 1 )
+    {
       title = "";
+
+      // If a single URL, and on a phone, save screen space by skipping the description
+      InterSpec *viewer = InterSpec::instance();
+      if( viewer && viewer->isPhone() )
+        desc = "";
+    }//if( urls.size() == 1 )
+
 
-    string desc = seqnum;
     SimpleDialog *dialog = QrCode::displayTxtAsQrCode( urls[index].m_url, title, desc );
 
     if( (index + 1) < urls.size() )

src/InterSpec.cpp

@@ -336,6 +336,17 @@ namespace
 
     return false;
   }//try_update_hint_peak(...)
+
+  template<typename charT>
+  struct char_iequal
+  {
+    char_iequal( const std::locale &loc ) : m_loc(loc) {}
+    bool operator()(charT ch1, charT ch2) {
+      return std::toupper(ch1, m_loc) == std::toupper(ch2, m_loc);
+    }
+  private:
+    const std::locale &m_loc;
+  };
 }//namespace
 
 
@@ -11058,6 +11069,7 @@ void InterSpec::handleAppUrl( const std::string &url_encoded_url )
 
 void InterSpec::makeEnterAppUrlWindow()
 {
+  // TODO: could probably put this functions implementation into its own source file.
   if( m_enterUri )
     return;
 
@@ -11078,23 +11090,34 @@ void InterSpec::makeEnterAppUrlWindow()
   WPushButton *cancel = m_enterUri->addButton( "Cancel" );
   WPushButton *okay = m_enterUri->addButton( "Okay" );
 
+  const string acceptable_paths[] = {
+    "G0", "drf", "specsum", "flux", "specexport", "decay", "dose", "gammaxs", "1overr2", "unit"
+  };//acceptable_paths[]
+
+
   // We will validate the URL starts with 'interspec://' or 'raddata://', end enable/disable the
   //  "Okay" button in javascript
   const string jsokay = okay->jsRef();
-  const string validate_js = "function(textarea,event){ "
-    "const matches = /^((interspec:\\/\\/)|(raddata:)).+/i.test(textarea.value);"
+  string validate_js = "function(textarea,event){ "
+  "const matches = /^((interspec:\\/\\/)|(raddata:\\/\\/))";
+
+  for( const string &path : acceptable_paths )
+    validate_js += "|(.*\\/" + path + "\\/)";
+
+  validate_js += ".+/i.test(textarea.value);"
     "$(" + jsokay + ").prop('disabled', !matches);"
   " }";
   text->keyWentUp().connect( validate_js );
 
+
   // Dont disable okay button during undo/redo - would be better to validate after we might put text
   //  into the textarea - but not bothering to do it correctly, at the moment.
   if( !m_undo || !m_undo->isInUndoOrRedo() )
     okay->doJavaScript( "$(" + jsokay + ").prop('disabled', true);" );
 
   // TODO: All this undo/redo stuff is still probably not quite right - could use a little more work
 
-  okay->clicked().connect( std::bind([this, text](){
+  okay->clicked().connect( std::bind([this, text, acceptable_paths](){
     string uri = text->text().toUTF8();
     SpecUtils::trim( uri );
     m_enterUri = nullptr;
@@ -11137,9 +11160,24 @@ void InterSpec::makeEnterAppUrlWindow()
         handleAppUrl( uri );
       }else
       {
-        throw runtime_error( "URL must start with 'interspec://' or 'raddata:'." );
-      }
-
+        bool found_sub = false;
+        for( const string &path : acceptable_paths )
+        {
+          const string key = "/" + path + "/";
+          const auto it = std::search( begin(uri), end(uri), begin(key), end(key),
+                                       char_iequal<char>(std::locale()) );
+          if( it != end(uri) )
+          {
+            const string sub_uri = "interspec:/" + string(it, end(uri));
+            handleAppUrl( sub_uri );
+            found_sub = true;
+            break;
+          }//if( it != end(uri) )
+        }//for( const string &path : acceptable_paths )
+
+        if( !found_sub )
+          throw runtime_error( "URL must start with 'interspec://', 'raddata://', or have a /G0/ component." );
+      }//
     }catch( std::exception &e )
     {
       SimpleDialog *errdialog = new SimpleDialog( "Error with entered URL", e.what() );

src/InterSpecApp.cpp

@@ -636,6 +636,29 @@ void InterSpecApp::setupWidgets( const bool attemptStateLoad  )
   }//if( !m_externalToken.empty() )
 #endif
 
+#if( USE_QR_CODES  && (BUILD_FOR_WEB_DEPLOYMENT || BUILD_AS_LOCAL_SERVER) )
+  // Allow having an "internal" path where URI data is represented as part of the URL, for
+  //   example https://interspec.example.com/?_=/G0/3000/eNrV...
+  //  It probably doesnt make sense to support "drf", "specsum", "flux", and "specexport" here.
+  const string &internal_path = environment().internalPath();
+  if( !loadedSpecFile
+     && (SpecUtils::istarts_with(internal_path, "/G0/")
+         || SpecUtils::istarts_with(internal_path, "/decay/")
+         || SpecUtils::istarts_with(internal_path, "/dose/")
+         || SpecUtils::istarts_with(internal_path, "/gammaxs/")
+         || SpecUtils::istarts_with(internal_path, "/1overr2/")
+         || SpecUtils::istarts_with(internal_path, "/unit/") ) )
+  {
+    try
+    {
+      m_viewer->handleAppUrl( "interspec:/" + internal_path );
+      loadedSpecFile = true;
+    }catch( std::exception & )
+    {
+    }
+  }//
+#endif // #if( USE_QR_CODES  && (BUILD_FOR_WEB_DEPLOYMENT || BUILD_AS_LOCAL_SERVER) )
+
 
 #if( USE_DB_TO_STORE_SPECTRA )
   //Check to see if we should load the apps last saved state

src/QrCode.cpp

@@ -23,6 +23,7 @@
 
 #include "InterSpec_config.h"
 
+#include <cctype>
 #include <string>
 #include <sstream>
 #include <iostream>
@@ -106,6 +107,23 @@ WT_DECLARE_WT_MEMBER
 }
   );
 
+
+bool starts_with( const std::string &line, const char *label )
+{
+  const size_t len1 = line.size();
+  const size_t len2 = strlen(label);
+
+  if( len1 < len2 )
+    return false;
+
+  for( size_t i = 0; i < len2; ++i )
+  {
+    if( std::toupper( (int)line[i] ) != std::toupper( (int)label[i] ) )
+      return false;
+  }
+
+  return true;
+}//bool starts_with( const std::string &line, const char *label )
 }//namespace
 
 
@@ -236,8 +254,14 @@ SimpleDialog *displayTxtAsQrCode( const std::string &url,
 {
   try
   {
-    const tuple<string,int,ErrorCorrLevel> qr_svg
-                                = utf8_string_to_svg_qr( url, ErrorCorrLevel::About30Percent, 3 );
+    // If its a "mailto:" URI, then put error correction to lowest level, to make the QR code
+    //  as small as possible, since user will most likely be directly reading the QR code onto
+    //  their phone.
+    QrCode::ErrorCorrLevel wanted_ecl = ErrorCorrLevel::About30Percent;
+    if( starts_with( url, "mailto:") )
+      wanted_ecl = ErrorCorrLevel::About7Percent;
+
+    const tuple<string,int,ErrorCorrLevel> qr_svg = utf8_string_to_svg_qr( url, wanted_ecl, 3 );
     const string &qr_svg_str = get<0>(qr_svg);
     const int qr_size = get<1>(qr_svg);  //A simple DRF is like 70, or so
     const ErrorCorrLevel ecl = get<2>(qr_svg);