On Tuesday 13 March 2012 08:28:04 ashish raste wrote: > *Dear all, > > Recently I worked on a paint application, where I implemented a > function to draw whatever a user is scribbling on an image. In the > mouseMove event, I called a function to draw with the previous > point and the current point as its arguments, using the drawLine > function of QPainter. > > Now, I noticed that the pixels sent to this function are not > continuous but some in-between pixels were being left. I assume > that this is due to the delay for a user->kernel and kernel->user > mode switch when calling the underlying paint-engine's functions > to draw the line.
If this only appears since Qt 4.8 with raster engine, this could be https://bugreports.qt-project.org/browse/QTBUG-23430 As a workaround, use drawPixel() for single-pixel "lines". > I have looked-up in the documentation of Qt-painting to find how it > internally calls drawLines(), which instead creates a qpainterPath > to draw a curve, line or whatever we scribble. But I couldn't find > how the missing pixels were added in between just knowing the > start and end point of a line (though we know that a curve will > contain a large set of small lines, each having a start and end > point) > > Is there anyway to track these "missed" pixels i.e to track all the > pixels which are being drawn? > > Thanks you!* -- Christoph Feck http://kdepepo.wordpress.com/ KDE Quality Team _______________________________________________ Interest mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/interest
