-----Original Message-----
From: Interest <interest-bounces+mike.jackson=bluequartz....@qt-project.org> on
behalf of Jason H <jh...@gmx.com>
Date: Tuesday, May 22, 2018 at 10:16 AM
To: Thiago Macieira <thiago.macie...@intel.com>
Cc: <interest@qt-project.org>
Subject: Re: [Interest] QDatastream, QMap, QImage serialization
> > There is a difference. As you already stated, a QPixmap requires more
than
> > a QImage, so what should be provided is a QImage,
>
> Now think about how it's constructed internally.
>
> QBrush only exists to paint, which means GUI (QPaintDevice is the basis
of all
> GUI). It is meant to paint efficiently. If QPixmap can do that more
> efficiently, why should it store a QImage instead?
Admittedly I don't understand the nuances of QPixmap. But I know working
with a QImage should not require a windowing server.
THIS. I had to refactor a bunch of our code because our application needs to
create an "image" of some data. I was using QPainter/QImage to do this, but
then the use case came up of having to run the code on a headless server or
through command line Python. I would get failures because there was no
windowing system to use for QImage. I ended finding "libHaru" which allows one
to "Draw" a PDF without the need for a windowing system. The API is similar to
QPainter, one can draw basic polygons, fills, brushes, pens, lines. All
_without_ the need for a windowing system. I didn't really want to bring in
another dependency but I didn't really have a choice: QImage simply will not
work in this situation.
For Qt6 what I would like to see is QPainter abstracted out to just an
interface and have the normal accelerated implementation that we have now in
QtGui but also have a non-accelerated version living in QtCore or a library
that does NOT depend on a windowing system. All the other classes that have
been discussed as having to be moved like the Polygon/Matrix classes should
also be moved. There are a lot of science type of apps that could instantly
make use of these kinds of things. Instead I have to bring in something huge
like ITK just to read/write some images.
My point is that for me, I am ok with a non-accelerated 2D drawing system if it
does not depend on a windowing system. Qt is a wonderful overall toolkit. It
isn't *just* a GUI toolkit as another poster has suggested. It is a unifying
toolkit that is well written and documented that is cross platform.
Just my nickel's worth.
--
Mike Jackson
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