[Development] Rotating JPEG images by default
André Pönitz
apoenitz at t-online.de
Wed Apr 22 20:54:06 CEST 2015
On Wed, Apr 22, 2015 at 02:32:51PM +0300, Alberto Mardegan wrote:
> On 04/22/2015 09:39 AM, André Somers wrote:
> > I'm with Konstatin on this one:
I am, too.
> > it seems like a regression to me. It
> > would be a useful feature to add, but then add it in such a way that it
> > is actually clear what it does, the user can control it, and it does not
> > break applications. I think it _is_ relevant how the image is encoded.
And I agree with André here.
> It may be that we disagree because we have a different view of what is
> the goal of QImage and friends.
QImage is traditionally closer to "pixel manipulation" than to "display",
which is QPixmap's domain, albeit both with quite some wiggle room.
> To me, what matters is not the pixel
> data, but how the image looks like when I blit it.
That's of course one possible expectation, and without further context
possibly even a reasonable one.
However, we do have context here, namely existing behaviour in Qt 5.x,
as well as certain general promises given for changes between Qt 5.x and
Qt 5.(x+1).
> I'm writing an image viewer using QML, and I just expect that
>
> Image {
> source: "file.jpg"
> }
>
> will show me the file as it's intended to be viewed. I don't think that
> it's acceptable to require the developer to play with flags in order to
> see the image with the correct rotation.
Even though "no behaviour change" isn't one of the guarantees, I don't
think rotating part of an application's GUI by 90 degrees behind the
developer's back is acceptable.
If an application accepts such change it should announce it by explicitly
opting in, i.e. by setting a flag/calling a function/whatever.
Andre' [another one]
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