On Tue, Sep 27, 2011 at 8:25 PM, Marco Hugentobler < [email protected]> wrote:
> Hi Mohammed > > > How came this time gap? > > A possible reason could be the following: > In QGIS, most point renderers do some caching of the point symbols as > QImage. > So in case you invoke a QPainter->drawCircle/drawRectangle etc. command for > every point, it helps a lot do do the rasterisation only once. > the point is not clear for me maybe because of my misunderstanding will you please eloborate?? > > > Regards, > Marco > > > Am Dienstag, 27. September 2011, 16.18:25 schrieb Mohammed Rashad: > > 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? > > > > i see Rtree and pal libs in src/core source code > > Does they have any role in rendering? > > > > Does QGIS Rendering uses threading? > > > > 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? > > > > How to improve performance in rendering without qgis? > > --- > > Regards, > > Mohammed Rashad K M > > M.S. (By Research) student > > Lab for Spatial Informatics > > Department of CSE > > International Institute of Information Technology > > Hyderabad, India > > -- Regards, Mohammed Rashad K M M.S. (By Research) student Lab for Spatial Informatics Department of CSE International Institute of Information Technology Hyderabad, India
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