Hello Matt, Tuesday, October 15, 2002, 2:36:50 PM, you wrote:
MT> I am trying to change the background colour of a Mapper Window, so that when MT> it re-draws, it begins with a black background. At the moment, I draw the MT> black background using a layer, but this creates a 'flashing' effect when MT> users pan across the map, which is causing one of my users problems. MT> I can, of course, change the windows environment to achieve this, but then I MT> end up with a black background in all in Word too! I think you cannot do what you wnat using Mapbasic. Perhaps you can do it when you change Window class member using SetClassLong function (API). >From MSDN: ============================================================================== WM_ERASEBKGND The WM_ERASEBKGND message is sent when the window background must be erased (for example, when a window is resized). The message is sent to prepare an invalidated portion of a window for painting. A window receives this message through its WindowProc function. Remarks The DefWindowProc function erases the background by using the class background brush specified by the hbrBackground member of the WNDCLASS structure. If hbrBackground is NULL, the application should process the WM_ERASEBKGND message and erase the background. //Lashin: You dont need to process this message - just modify Window Class Long ============================================================================== SetClassLong The SetClassLong function replaces the specified 32-bit (long) value at the specified offset into the extra class memory or the WNDCLASSEX structure for the class to which the specified window belongs. Note This function has been superseded by the SetClassLongPtr function. To write code that is compatible with both 32-bit and 64-bit versions of Windows, use SetClassLongPtr. DWORD SetClassLong( HWND hWnd, // handle to window int nIndex, // index of value to change LONG dwNewLong // new value ); Parameters hWnd [in] Handle to the window and, indirectly, the class to which the window belongs. nIndex [in] Specifies the 32-bit value to replace. To set a 32-bit value in the extra class memory, specify the positive, zero-based byte offset of the value to be set. Valid values are in the range zero through the number of bytes of extra class memory, minus four; for example, if you specified 12 or more bytes of extra class memory, a value of 8 would be an index to the third 32-bit integer. To set any other value from the WNDCLASSEX structure, specify one of the following values. //Lashin: You need modify value of class member at nIndex == GCL_HBRBACKGROUND GCL_HBRBACKGROUND Replaces a handle to the background brush associated with the class. ====================================================================================== CreateSolidBrush The CreateSolidBrush function creates a logical brush that has the specified solid color. HBRUSH CreateSolidBrush( COLORREF crColor // brush color value ); Parameters crColor [in] Specifies the color of the brush. To create a COLORREF color value, use the RGB macro. Return Values If the function succeeds, the return value identifies a logical brush. If the function fails, the return value is NULL. MT> I guess I need to make an API call. I have been playing with SendMessage (in MT> user32.dll) but I cannot find the message ID required to change a window's MT> background. MT> Any ideas? MT> Matt -- Best regards, Vladimir Lashin microOLAP Technologies LLC ------------------------------------------------------------------------------------------------------- MBBuilder - Visual Development Tool for MapBasic - http://www.microolap.com/products/gis/mbbuilder.htm Raster Handler for ERDAS Imagine to MapInfo - http://www.microolap.com/products/gis/imgrhl.htm MapInfo Callbacks Manager ActiveX - http://www.microolap.com/products/gis/micmx.htm EasyMap VCL - http://www.microolap.com/products/gis/easymap.htm ------------------------------------------------------------------------------------------------------- mailto:[EMAIL PROTECTED] http://www.microolap.com/gis/ - GIS related products --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 3573
