COSMCtrl v1.15 An MFC class to support display of OpenStreetMap tiles

Welcome to COSMCtrl, A freeware MFC GUI control class which implements display of OpenStreetMap tiles.

Here's a screen capture of the sample app provided in the download which exercises the class:

Features

• Provides a standard MFC CStatic derived class which can be used just like the CStatic class.
• Supports Mapnik, Osmarender, Cyclemap, Mapquest OSM and Mapquest Open Aerial tile providers.
• Supports downloading via Wininet/WinHTTP to a configurable local file system cache to improve performance.
• Supports zooming via keyboard keys and the wheel mouse. It uses the keys '+' and '-' and a mouse left double click.
• Supports scrolling via the keyboard as well as mouse dragging. It uses the keys "Left", "Back", "Right", "End", "Up", "Prior", "Down" and "Next".
• Implements asynchronous download of visible tiles.
• Supports a scroll rose and zoom bar based on the same controls on the OpenStreeMap web site.
• Supports displaying a simple legend which indicates scale.
• Supports automatically displaying correct OpenStreetMap copyright attribution on the control. This is achieved through the use of a child control SysLink control with hyperlinks to the OpenStreetMap web site and the license it uses.
• All of the control parts which the COSMCtrl class supports namely scroll rose, zoom bar, legend and the copyright items can be attached to specific client locations on the map.
• Tiles from the previous and next zoom level can be used in a stretched and squeezed fashion if not available at the current zoom level.
• Supports used defined markers, polylines, polygons and circles being overlaid on the map. In addition to just allowing static markers, polylines, polygons and circles to be added, the code has comprehensive support for interactively editing, dragging, moving and deleted these items. Please note that these items cannot be correctly displayed if they cross the international date line or if they traverse extreme polar latitudes which the slippy map tiles of OpenStreetMap do not cover.
• Tiles outside the visible edge can be pre-cached for improved performance.
• Provides helper methods to allow download of specific tiles.
• Supports a full set of methods to calculate the distance between two points as well as calculate the end location from a start position given a certain distance and bearing. These methods implement C++ versions of Vincenty's Direct and Inverse algorithms. These methods are required for calculation of the scale bar as well as supporting dragging polygons and polylines. The sample app now uses these features to show the distance and bearing for the first polyline or polygon which is selected in the status bar.
• The class supports a Rectangular selection mode. When this mode is activated, you can select specific markers, polylines and polygons on the map and in conjunction with support for the "Delete" button you can interactively edit the items on the map
• A complete sample app which exercises all the classes functionality including print preview and printing support.
• Supports a comprehensive "Map Operations" dialog. This in conjunction with the rectangular selection mechanism allows you to delete specific tiles, download specific tiles (optionally skipping files which have already been downloaded) as well as support Mapnik re-render requests. This dialog uses a worker thread to remain responsive while these potentially lengthy operations are taking place. In addition this dialog provides feedback via a progress control and a static text notification area as the operation is taking place as well as cancelation support. This dialog on its own provides a good example on how to implement a responsive user interface while a lengthy operation is happening.
• Supports "decimation" of polylines and polygons. This feature adds new nodes between all the existing nodes of a polyline or polygon. This can prove useful where you have a feature where the curvature of the earth can cause distortion of the displayed object. By default this feature is provided for by double clicking on an editable polyline or polygon.
• Support for drawing crosshairs at the center of the map.
• Supports a ZoomToBounds method. This method takes two positions which the method will ensure will be shown on the map at the highest possible zoom level. In conjunction with various "GetBoundingRect*" methods you can now add your various items to the map and then zoom to those items. This avoids client code needing to explicitly handle zoom levels of center positions.
• Provides a comprehensive API via the public methods of the class. In addition numerous virtual functions are provided to further customize the behaviour of the class.
• Provides support for GPS devices via the authors GPSCom2 library.
• As of v1.09, the control now uses the Windows 7 Animation API's if available for zoom level and position changes.
• As of v1.10, the sample app now supports collecting track logs to GPX files and importing GPX files for display on the map.
• As of v1.12, the sample app now supports Nominatim Search and reverse geocoding via the authors CNominatim library.
• As of v1.14, the sample app now includes support for using GPS devices which support the Windows 7 Sensors API in addition to the author's own GPSCom2 library. This functionality is provided using the author's MfcSensor library.
• As of v1.15, the control now supports drawing with Direct2D as well as the older GDI+ graphics API. This new code provides a very good sample to developers who are looking to migrate their large GDI/GDI+ code bases to D2D as the before and after code in COSMCtrl can be compared to each other.

The enclosed zip file contains the COSMCtrl source code and a simple VC 2010 MFC SDI Document View test program to exercise all of the class's functionality.

Copyright

• You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise) when your product is released in binary form.
• You are allowed to modify the source code in any way you want except you cannot modify the copyright details at the top of each module.
• If you want to distribute source code with your application, then you are only allowed to distribute versions released by the author. This is to maintain a single distribution point for the source code.

Updates

V1.0 (28 November 2009)

• Initial public release.

V1.01 (17 December 2009)

• Addition of a SetCenterPosition override method which allows the zoom level to be changed in one go along with the centre position of the map.
• The control now handles a left mouse double click as a request to zoom in the map at the cursor position. This is consistent with how the main OpenStreetMap web site map operates
• Addition of a GetPosition method which converts a client coordinates point into a latitude and longitude position
• Code now allows previous zoom level images to be used in a stretched fashion if the tile does not exist at the current zoom level.
• Code now allows next zoom level images to be used in a squeezed fashion if the tile does not exist at the current zoom level.
• The DrawScaleBar method now takes user preferences as to whether they are using the Metric (Kilometres) or Imperial (Miles) system of measurement into account when drawing the scale
• The DrawScaleBar method now displays a rounded scale value rather than the exact width of one tile
• You can now customize the UserAgent string used by the class via the SetUserAgent method
• You can now customize the ordering of which tiles are downloaded. By default the tiles which are closest to the centre of the map are downloaded first and the algorithm works outwards from there. If you prefer you can download using a simple download Y outer loop and a left to right inner loop. This behaviour can be changed via the SetDownloadOrder method.
• The sample app now explicitly does not draw the scroll rose and zoom bar when the map is being printed.
• By default the control now caches two additional rows/columns of tiles around the edge of the map in anticipation that the end user will scroll around the map. The number of additional row/columns which are cached in this mechanism can be configured via the new SetDownloadTilesEdgeCount method. If you were to use a value of 0, then only the tiles necessary to fully cover the visible client area will be downloaded.
• The sample app now includes static MFC build configurations and the exe included in the download now pulls in MFC this way.

V1.02 (10 January 2010)

• Fixed a bug in the display of the polar regions at low zoom settings.
• You can now scroll horizontally continuously around all longitudes.
• Fixed an issue where the scale would report a distance of 0 meters at zoom level 0.
• Improved the overall responsiveness of the control by ensuring that the download thread returns quickly from any blocking calls when the code needs to terminate the download thread. The trick which the code uses is to share the Wininet session handle between the download thread and the main thread and when it comes time to kill the download thread the session handle is closed via InternetCloseHandle in the main thread. This causes any derived Wininet handles which the download thread has created from this session handle to become invalid and causes any blocking call on these handles to return with an error. This change also means that I do not need to completely re-architect the code to use asynchronous Wininet calls. Having taken a look at how asynchronous Wininet works I'm real glad about this.
• Fixed an issue in DownloadThread() where the code would attempt to download a tile with an invalid Y value. This resulted in spurious TRACE messages in debug builds.
• Fixed a bug where the OnPaint method was not using the values returned from GetDrawScrollRose(), GetDrawZoomBar() & GetDrawScaleBar().
• As a really nice to have, the Zoom Bar is now drawn using transparency, just like on the main OpenStreetMap web site. As you may know GDI does not really handle transparency well, so I found it hard to find a good example on how to achieve this. Most of the examples I found were based on using a pre-existing image with an alpha channel already provided. My COSMCtrl code does not require any pre-rendered bitmaps and I wanted to keep the code this way. I did not also want to throw away all the GDI code and replace it with GDI+ code just for this one effect. For those interested in how the code works, it uses ATL::CImage to generate a 32 bit ARGB DIB section bitmap and select that into a memory device context. Then I use standard GDI calls as before to render most of the parts of the zoom bar, then I directly access the bits of the DIB section via CImage::GetBits and CImage::GetPitch and modify the transparency of specific pixels to achieve the effect I want. At this point you also need to do the calculations to ensure the RGB components of the pixel are premultiplied by the alpha value as this is what is required. Then I use CDC::AlphaBlend to blend the just created zoom bar pixels onto the map data which has already been rendered to the device context. I was worried about the performance of this code as I need to iterate across all the pixels of the DIB section to achieve this effect, but some profiling on my main dev machine showed that it added very little overhead to the total rendering time. All of this code is in COSMCtrl::DrawZoomBar and hopefully you may find this code of interest for your own projects which want to do runtime alpha blending. Finally if you do not want a transparent zoom bar, you can disable this effect using SetUseTransparencyForZoomBar(FALSE).
• You can now optionally draw rectangles around each rendered tile via SetDrawTileOutlines(TRUE).
• The sample app now ships with a VC 2008 solution and project instead of VC 2005.
• The sample app now uses separate cache directories for the different tile providers. In addition the cache directory is now located at " "CSIDL_LOCAL_APPDATA"\OSMCtrlApp\"Provider" "
• The client area is now invalidated when you change tile provider.
• The sample app now can display a tile properties dialog when you right mouse click on the map. This dialog uses SysLink controls and as such will only show up if you build a Unicode version of the app. As such the binary included in the download is now the Static Unicode Release build. This tile properties dialog shows the following tile attributes: Provider, URL to download from, local cache path, the physical dimensions of the tile in vertically and horizontally, The center position of the tile, the tile Coordinates and the Rerender and status URLs if any. Please note that the vertical distance is the actual great arc distance from the top left of the tile to the bottom left, while the horizontal distance is the great arc distance from the bottom left of the tile to the bottom right of the tile. It is important to emphasize this as at lower zoom levels the scale of the map becomes different depending on where you are located in the tile.
• Updated the sample app icon to use the standard OpenStreetMap logo.

V1.03 (16 March 2010)

• Updated the sample app to include copyright details in line with information at http://wiki.openstreetmap.org/wiki/Legal_FAQ#I_would_like_to_use_OpenStreetMap_maps._How_should_I_credit_you.3F. The copyright details are displayed in the about dialog and on the main map itself. For client applications which use COSMCtrl, you should review these details to make sure you are compliant with the OpenStreetMap licensing requirements.
• The zoom bar can now be shown using a standard Win32 slider control instead of custom draw code and this setting is now the default. To change this behaviour you can use SetDrawZoomBarAsSlider(FALSE)
• The setting to allow a zoom via double click has now been separated from the setting to allow a zoom via the wheel mouse.
• Sample app now shows the modified date of the tile in the Tile Properties dialog
• The sample app now allows a specific tile to be refreshed via the view context menu and the main application menu
• The scroll rose, zoom bar, and scale bar can all now be placed on the control in an arbitrary position. This is achieved via two additional parameters to SetDrawScrollRose, SetDrawZoomBar and SetDrawScaleBar. These parameters allow an anchor position on the map to be chosen for the control as well as an offset position.
• Fixed an issue where the download thread would get created if the cache directory was not specified.
• The class now supports markers, polylines, polygons and circles being overlaid on the map. In addition to just allowing static markers, polylines, polygons and circles to be added, the code now has comprehensive support for interactively editing, dragging, moving and deleted these items. The sample app has been extensively modified to demo these features.
• Re-implemented all GDI drawing code with GDI+. This provides much better support for features such as transparency etc and will make it easier to add more features to the code base going forward.
• The class now supports a full set of methods to calculate the distance between two points as well as calculate the end location from a start position given a certain distance and bearing. These methods implement C++ versions of Vincenty's Direct and Inverse algorithms. These methods are required for calculation of the scale bar as well as supporting dragging polygons and polylines. The sample app now uses these features to show the distance and bearing for the first polyline or polygon which is selected in the status bar.
• The code to draw the scale bar has been re-factored to allow further detailed client customization.
• The various strings which are used by the class are now all stored in a string table. You need to ensure that all the string resources of ID "IDS_OSMCTRL*" and dialog resources of "IDD_OSMCTRL*" are included in your client application.
• Fixed a bug where the download thread would not be created if you changed the location of the map using the cursor keys
• The control now supports a Rectangular selection mode. When this mode is activated, you can select specific markers, polylines and polygons on the map and in conjunction with support for the "Delete" button you can interactively edit the items on the map
• Addition of a new comprehensive "Map Operations" dialog. This in conjunction with the rectangular selection mechanism allows you to delete specific tiles, download specific tiles (optionally skipping files which have already been downloaded) as well as support Mapnik re-render requests. This dialog uses a worker thread to remain responsive while these potentially lengthy operations are taking place. In addition this dialog provides feedback via a progress control and a static text notification area as the operation is taking place as well as cancelation support. This dialog on its own provides a good example on how to implement a responsive user interface while a lengthy operation is happening.
• The control now supports "decimation" of polylines and polygons. This feature adds new nodes between all the existing nodes of a polyline or polygon. This can prove useful where you have a feature where the curvature of the earth can cause distortion of the displayed object. By default this feature is provided for by double clicking on an editable polyline or polygon. Thanks to Dermot McNally for prompting this update
• The control now has support for drawing crosshairs at the center of the map.
• The control now supports a ZoomToBounds method. This method takes two positions which the method will ensure will be shown on the map at the highest possible zoom level. In conjunction with various new "GetBoundingRect*" methods you can now add your various items to the map and then zoom to those items. This avoids client code needing to explicitly handle zoom levels of center positions.
• The arrow keys now scroll by a small amount while the likes of PageUp / PageDown keys will scroll by a tile at a time

V1.04 (9 April 2010)

• Reworked the OnPaint code to use classic double buffering via a GDI memory device context rather than using the GDI+ equivalent code. This restructuring of the code gives up a typical improvement of 125 ms down to 52 ms for a redraw over terminal services on my main dev machine (a 240% increase in performance) and a speed up of 140 ms down to 100 ms for a redraw on my primary graphics card on my main dev machine (a 40% increase in performance). My theory on why this new code is faster is probably due to the fact that we the code is now probably avoiding a code path in GDI+ which needs to convert from the internal GDI+ ARGB bitmap format to a format compatible with the display device context. Thanks to Frits van Veen for suggesting this update.
• Following on from the previous performance optimization, the control now maintains an internal cache of Gdiplus::CachedBitmap* tiles in memory. The conversion process which GDI+ itself must perform to convert from its' internal format to the format compatible with the display device context proved to be a significant percentage of the time involved in drawing the control, hence the need for this caching optimization. The default size of this in memory cache array is 100 elements which based on average type tiles in Ireland corresponds to a total application memory usage for the unicode release build of demo app of about 30 MB. You can change this limit by using the new SetMaxInMemoryCachedTiles method. If you want you can turn of this caching by calling SetMaxInMemoryCachedTiles(0) (not advised as it will adversely impact performance of the control). To give you further background on how you would pick a good value for this: at a resolution of 2560 * 1600, a maximized window will display approximately 60 OSM standard sized 256 * 256 tiles. This metric is where I arrived at 100 for the default value. With this optimization now in place and taking the previous optimization example, the drawing time for a full screen window on my primary graphics card on my main dev machine has speeded up of 140 ms to 100 ms to 15 ms. This corresponds to a 930% increase in performance! when compared to v1.03 of the control. You can really now see the difference in performance in the control when you drag the control and notice how really responsive it its. Again many thanks to Frits van Veen for doing all the low level performance testing and suggestions for this update.
• If you hold down the control key while using the arrow keys to navigate around the map, the map now scrolls by a tile rather than a small pixel amount. This is consistent with how most other Map controls behave. Thanks to Frits van Veen for providing this update.
• The amount which the ScrollToNorth/East/South/West() methods scroll by can now be controlled via a new SetScrollPixels() method. The default value for this has been increased from 4 to 20 pixels. Thanks to Frits van Veen for providing this update.

V1.05 (10 April 2010)

• The control now only attempts to keep the position under the cursor when you do a mouse zoom if the position is in the client area, otherwise the control simple zooms in or out at the current center position

V1.06 (1 May 2010)

• The control now has the concept of a GPS position and recent track. This is achieved through the new member variables: m_GPSTrack and m_colorGPSTrackPointer and the new methods of SetMaxGPSTracks, GetMaxGPSTracks & AddGPSTrack. In addition the sample app has been updated to use the authors GPSCom2 library to add comprehensive support to the sample app for GPS devices.

V1.07 (2 May 2010)

• Reduced the m_nMaxGPSTracks default value to 600, which if we are receiving GPS data every second corresponds to the last 10 minutes of the track will be shown.
• Introduced the concept of bearing valid and speed valid to COSMCtrlPosition. In addition the COSMCtrl now visually indicates the lack of a bearing valud by drawing the GPS triangle using black rather than the standard red color.
• Introduced the concept of loss of a GPS fix to the control. If there is no fix, the GPS triangle will now only be drawn as an outline rather than drawn filled.
• The GPS track polyline's attributes are now explicitly set in the COSMCtrl constructor.
• Fixed a clipping problem in the code which calculates the bounding rect for the GPS track.
• Fixed a clipping problem when the GPS triangle moves a significant distance from one fix to the next.
• Optimized the code in AddGPSTrack when perform invalidations of the client area.

V1.08 (22 July 2010)

• Updated the code to work with GDI+ v1.0 which is the version supported prior to Windows Vista. Thanks to Richard Dols for reporting this issue.
• Fixed a bug in DrawScaleBar where the actual distance shown would be out by a factor of two when the zoom value was anything other than zero. Thanks to Richard Dols for reporting this embarrassing mistake.
• Fixed a redraw glitch for polylines by modifying COSMCtrl::GetBoundingRect(const COSMCtrlPolyline& polyline... and COSMCtrl::GetBoundingRect(const COSMCtrlPolygon& polygon... to not be as aggressive with its inclusion of the extra margin.
• The SetTileProvider method now calls Invalidate internally. This ensures that the map cleanly updates when you switch tile providers.

V1.09 (16 August 2010)

• The control now includes support for fractional zoom levels.
• The control now uses the Windows 7 Animation API's if available for zoom level and position changes. If you do not require animations then this behavior can be disabled.
• Updated the sample app to compile cleanly on VC 2010. Also because the sample app now takes advantage of the Windows 7 Animation API's, the project files shipped in the sample are now for VC 2010 as this includes the Windows 7 SDK in the box. You can still use the control in older versions of VC though (>= VC 2005). For example if you want to exclude the Windows 7 Animation support, you can define the "COSMCTRL_NOANIMATION" preprocessor value.
• Included some missing status bar prompts for menu items in the sample app

V1.10 (23 August 2010)

• Fixed a bug in COSMCtrl::SetZoom which caused drawing glitches in the zoom bar
• Made the default animation speed a bit faster
• To avoid requirements for client code to create the control using the WS_CLIPCHILDREN style, the control now forces a repaint on the zoom bar control and copyright control if they are in the clipping rect.
• Fixed some maths problems in the COSMCtrl::HandleLButtonDownStandard when calculating the position of mouse clicks on the zoom bar
• The sample app now includes support for logging tracks to a GPX file. This setting can be enabled in the GPS Settings dialog by checking the "Enable GPX Track Log" checkbox. When this is enabled, then every time a new GPRMC NMEA sentence arrives from your GPS device it will be logged. The location of the GPX file is "CSIDL_LOCAL_APPDATA"\OSMCtrlApp\GPX\YYYYMMDD.gpx". For performance reasons the GPX file will only be written to file every 60th new waypoint. For most GPS devices this should correspond to every minute. The code will also ensure that if the app is closed and restarted, that any existing data in today's GPX file will be preserved and a new track will be created. The code also correctly handles when a GPS fix has been lost under which it will create a new track segment in the GPX file. To support GPX files, a very simple set of MFC classes have been developed in the header file "OSMCtrlGPX.H". These classes use MSXML 6 for its XML parsing and saving requirements. Please note that these classes are not comprehensive wrappers for all the features of GPX files, but just enough to support the COSMCtrl GPX requirements. If there is demand out there I may consider extending these classes to support all the features of GPX files.
• The sample app now has support for importing GPX tracks and displaying them on the map. This can be achieved using the "File -> Import GPX File" menu item.

V1.11 (8 September 2010)

• Updated the zip file to only include the VC 2010 project files. Thanks to Frits van Veen for reporting this issue.
• Fixed up comment in sample app about inclusion of "enumser.h". Thanks to Frits van Veen for reporting this issue.
• Updated the zip file to include missing OSMCtrlGPX.h. Thanks to Frits van Veen for reporting this issue.
• Fixed a bug in COSMCtrlAppView::OnFileImportGPXFile in the sample app where the filename filter was not working correctly. Thanks to Frits van Veen for reporting this issue.
• Updated the error message in the sample app when a GPX file fails to import. It now mentions the need for 1.1 schema GPX files.
• The sample app now saves the track log any time the filename for the log changes e.g. midnight crossovers.
• Updated the GPX class to support saving and loading GPX waypoints. In addition the sample app now displays these waypoints when you import a GPX file.
• Sample app now includes a more specific error message if GPSCom2 cannot be used because of a registration issue. Thanks to Frits van Veen for reporting this issue.

V1.12 (1 November 2010)

• Now supports the Mapquest tile provider as documented at http://devblog.mapquest.com/2010/08/24/mapquest-opens-tiles-and-style-enables-rapid-data-updates/
• CreateCopyrightLinkCtrl method now works correctly if Windows is using a High DPI setting
• Fixed an ASSERT in the Draw method which could occur when m_bDrawZoomBarAsSlider is TRUE.
• The ControlAnchorPosition and offset CPoint values now refers to the edge of the child control which is closest to the border instead of the top left edge of the control. This makes it easier for client applications to control layout behaviour.
• Fixed a bug in the tile properties dialog in the sample app which would report the distance in meters instead of in Kilometers or Miles.
• The sample app has been updated to use the author's CNominatim library to add comprehensive support for Nominatim searches and Address lookups
• Fixed a bug where the download thread would not be restarted if the control uses a Windows animation during panning
• DrawScaleBar has been refactored somewhat and now works correctly if Windows is using a High DPI setting

V1.13 (20 November 2010)

• Added support for a simple event handler mechanism to the class
• Reworked the sample app's Refresh Tile, Tile Properties and Address Lookup functions to allow the user to click on the part of the map where they want the operation performed rather than using the current cursor position. This means that using these options from the main menu is now more useful. Thanks to Frits van Veen for suggesting this update.
• Implemented a Goto Coordinates Dialog in the sample app
• Updated the sample app to use a built in resource for the png default marker rather than a stand alone png file. Thanks to Frits van Veen for suggesting this update.

V1.14 (6 February 2011)

• Now includes support for using GPS devices which support the Windows 7 Sensors API in addition to the author's own GPSCom2 library. The only difference you will see is that any GPS sensor installed will appear in the GPS Settings dialog. Select the sensor instead of a COM port and the sample app will now use the specified Windows 7 GPS sensor. This support for the Windows 7 Sensors API is provided using the author's MfcSensor library.

V1.15 (30 April 2011)

• A major addition to the control: Implemented comprehensive support for Direct2D drawing in COSMCtrl. This support is provided by the new MFC D2D wrapper classes provided with Visual Studio 2010 SP1. By default this support is enabled so you will need to have VS 2010 and SP1 installed to take advantage. If you do not want this you can define COSMCTRL_NOD2D before pulling in the OSMCtrl classes and the code will fall back to using GDI+. This new code provides a very good sample to developers who are looking to migrate their large GDI/GDI+ code bases to D2D as the before and after code in COSMCtrl can be compared to each other. If you want to exclude D2D from COSMCtrl define COSMCTRL_NOD2D and the code will fall back to the original GDI+ drawing logic. Performance testing on my laptop indicates that the drawing code time has reduced from c. 3 - 4 ms for a full screen redraw down to c. 0.3 ms i.e. a speed up of 900%!.
• Updated copyright details.
• Implemented a "Delta" mode for the control. When this mode is enabled via SetDeltaMode(TRUE), any newly updated cached local tiles will be blinked with the old tile it has been replaced with, when you do a refresh/redownload of the tile
• In debug mode the code no longer reports any ERROR_INTERNET_OPERATION_CANCELLED download errors via TRACE.
• Fixed a bug in the download code where you would get intermittent download errors because the file is locked because of how GDI+ locks the file when you open a bitmap from it.
• Sample app now handles the ISensorEvents::OnLeave event. This event occurs when your GPS sensor is removed from the system (such as unplugging the device if it is GPS). The app now closes down GPS mode in the control if this occurs.
• The m_Icons member variable in COSMCtrl now maintains COSMCtrlIcon pointers rather than actual instances. This fixes a bug in the code where previously it was not clear where ownership of the resources belong to. Now since they are pointers, client code is responsible for the lifetime of the icons
• Fixed a bug in the sample app where the CMySensorEvents::OnDataUpdated and CMySensorEvents::OnLeave could cause an access violation if called during shutdown of the sample app.
• The GPS Location triangle is now drawn using some transparency.
• Refactored the ancillary "COSMCtrl*" classes which the main control class depends on. All of these classes are now contained in separate modules.
• GDI+ code path which draws fractionally zoomed tiles now uses in-memory tile cache.
• When drawing fractionally zoomed tiles, the next zoom level tiles are now used in preference to the previous zoom level.
• Reworked tile providers to use a new interface class of IOSMCtrlTileProvider. This allows easier addition of new tile providers.
• Added support for Mapquest Open Aerial tiles via the new COSMCtrlMapquestAerialTileProvider class.
• Optimized ClientToPosition and PositionToClient methods by allowing them to pass in the client rect.
• Markers, Polylines, Polygons and circles can now be excluded from hit testing via a new "m_bHitTest" member variable
• Fixed a memory leak in SetCacheDirectory.
• The classes now have support for using WinHTTP instead of Wininet as the download API. Please note that if you use WinHTTP then the sample app will not provide Nominatim search and addresss lookup as currently the CNominatim class only supports Wininet and not WinHTTP.