On Tue, Sep 27, 2011 at 4:18 PM, Mohammed Rashad <[email protected]> wrote: > Hi All, > I am developing tiled vector rendering in OSSIM. I like the Qgis vector > rendering system > point.shp contains 9,99,999 points which are generated by grass for using > v.random and ~27MB in size > roads.shp contains 2,28,068 linestrings and is ~50MB in size > these point.shp and roads.shp data gets rendered in ~10 sec > When I read vector using ogr and parse feature and draw point/linestring my > application taking about 40 sec to render point.shp > and > I am using Qt4 with QPainter not QGraphicsView > How came this time gap?
Most likely you have some inefficiencies in your implementation. > i see Rtree and pal libs in src/core source code > Does they have any role in rendering? No - unless you also draw labels. > Does QGIS Rendering uses threading? No - only in threading branch which has not yet been integrated. > How to get a minimal of QGIS code to hack it and build a new vector > rendering because I need it to make it tiled rendering vectors? You can use qgis_core library to do tiled drawing. > How to improve performance in rendering without qgis? Learn how to profile programs - i.e. get time spent in individual functions, analyze the results and fix the places where most of the time is spent. Martin _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
