Adam, all Thanks for the comments and updates, I am working as fast as I can (after a long weekend without a computer :-) ) to capture all of your comments and interface definitions and to produce the documented interfaces (header definitions) for the RFC. I am taking the last email from Tamas, and the enum definition below and will hopefully have an updated RFC out for comment tomorrow.
Please add your names to the RFC in the author section, this is a collaborative effort, and after I have put up the code interfaces please edit directly. Many thanks, Norman -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Adam Nowacki Sent: Tuesday, September 02, 2008 1:40 PM To: [email protected] Subject: Re: [gdal-dev] RE: progressive rendering Tamas Szekeres wrote: > Hi All, > > Upon thinking about the issues I've been come up with previously, I > consider the following approach could be implemented easily either at > driver or at SWIG interface level. Requires a new class to be > implemented by the async IO supported drivers and a new additional > method should be added to the GDALDataset and GDALRasterBand. > The user could implement the async IO by using the following pseudo sequence: > > <Code> > ... > </Code> I like it :) typedef enum { ..., CE_Again = 5 // timeout, buffer not updated, call RasterIO() again } CPLErr; typedef enum { // Async raster io status GRS_Complete = 0, // raster io is complete, call to GDALRasterIOContext->RasterIO() will return CE_Failure GRS_InProgress = 1, // raster io in progress, call GDALRasterIOContext->RasterIO() to get more data GRS_Error = 2 // error, call to GDALRasterIOContext->RasterIO() will return CE_Failure } GDALRasterIOStatus; typedef enum { // Hints for GDALRasterIOContext->RasterIO(), driver implementations may ignore any or all GRH_SingleBlock = 0x1, // exit after single block update, even if there is more data immediately available GRH_Progressive = 0x2, // update with lower resolution data / fill with interlaced rows GRH_WaitForTimeout = 0x4 // wait for timeout even if already updated some data } GDALRasterIOHint; class GDALRasterIOContext { public: GDALRasterIOContext() { eStatus = GRS_Continue; pszError = NULL; } public: // Continue raster io, update pData buffer with new data, nUpdate??? = bounding box of all updated blocks // return CE_None if updated with new data // return CE_Again on timeout // return CE_Failure on error virtual CPLErr RasterIO(void *pData, int nTimeoutMilliseconds = -1, int nHint = 0); public: GDALRasterIOStatus eStatus; char *pszError; // if eStatus == GRS_Error this should contain human readable error message, NULL otherwise int nUpdateXOff; int nUpdateYOff; int nUpdateXSize; int nUpdateYSize; }; class GDALDataset { ... public: virtual GDALRasterIOContext *StartRasterIO( GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, int nPixelSpace, int nLineSpace, int nBandSpace ); virtual void EndRasterIO(GDALAsyncRasterIOContext *poContext); }; _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
