[Qt-interest] Convert from a QPixmap into a QByteArray, and back

[Gabriele Kahlout]

yah, that worked. I extracted the code back into my converts.

However, I'm in a situation where a I can show in a QLabel a pixmap but not
save it as a png, i.e.

    const bool saved = bm.save(filePath, "PNG");

returns false.

Any suggestions on why might this be the case (before I try to strip down a
SSCCE from my code)?

2010/5/19 Scott Aron Bloom <Scott.Bloom at onshorecs.com>

>  This this…..
>
>
>
> Scott
>
>
>
> int main( int argc, char ** argv )
>
> {
>
>       QApplication appl( argc, argv );
>
>
>
>       QPixmap screen = QPixmap::grabWindow(
> QApplication::desktop()->winId(), 0, 0, 500, 500 );
>
>
>
>       QLabel label;
>
>       label.setPixmap( screen );
>
>       label.show();
>
>
>
>       screen.save( "7777.png" );
>
>
>
>       QPixmap screenLoaded( "7777.png" );
>
>       QLabel label2;
>
>       label2.setPixmap( screenLoaded );
>
>       label2.show();
>
>
>
>       QByteArray bytes;
>
>       QDataStream out( &bytes, QIODevice::WriteOnly );
>
>       out << screen;
>
>
>
>       QDataStream in( &bytes, QIODevice::ReadOnly );
>
>       QPixmap screenStream;
>
>       in >> screenStream;
>
>       QLabel label3;
>
>       label3.setPixmap( screenStream );
>
>       label3.show();
>
>
>
>       return appl.exec();
>
> }
>
>
>
> Works for me…
>
>
> Scott
>
>
>
>
>
> *From:* qt-interest-bounces at trolltech.com [mailto:
> qt-interest-bounces at trolltech.com] *On Behalf Of *Gabriele Kahlout
> *Sent:* Tuesday, May 18, 2010 2:54 PM
> *To:* qt-interest at trolltech.com
> *Subject:* [Qt-interest] Convert from a QPixmap into a QByteArray, and
> back
>
>
>
> Hello,
>
> In the process of debugging I've found myself unable to assert the
> following code:
>
> int main(int argc, char *argv[])
>
> {
>
>     QApplication a(argc, argv);
>
>     const QPixmap screen = QPixmap::grabWindow(QApplication::desktop()->winId());
>
>     QByteArray *bytes = new QByteArray();
>
>     QDataStream out(bytes, QIODevice::WriteOnly);
>
>     out << screen;
>
>     QPixmap* screen1 = new QPixmap();
>
>     screen1->loadFromData(bytes->data());
>
>     std::cout << screen1->save("7777.png", "PNG") << endl;
>
>     std::cout << screen.save("6666.png", "PNG") << endl;
>
>     return a.exec();
>
> }
>
>
> All I'm doing is trying to convert from a QPixmap into a QByteArray, and
> back. Although the code is mostly verbatim from QPixmap and QDataStream, it
> doens't work. Indeed screen1 fails to save into 7777.png.
>
> Your help, fixing this code, is greatly appreciated.
>
> --
> Regards,
> K. Gabriele
>
> --- unchanged since 25/1/10 ---
> P.S. Unless a notification (LON), please reply either with an answer OR
> with " ACK" appended to this subject within 48 hours. Otherwise, I might
> resend.
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> ⇒ ¬IResend(this).
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> Also note that correspondence may be received only from specified a priori
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>
>


-- 
Regards,
K. Gabriele

--- unchanged since 25/1/10 ---
P.S. Unless a notification (LON), please reply either with an answer OR with
" ACK" appended to this subject within 48 hours. Otherwise, I might resend.
In(LON, this) ∨ In(48h, TimeNow) ∨ ∃x. In(x, MyInbox) ∧ IsAnswerTo(x, this)
∨ (In(subject(this), subject(x)) ∧ In(ACK, subject(x)) ∧
¬IsAnswerTo(x,this)) ⇒ ¬IResend(this).

Also note that correspondence may be received only from specified a priori
senders, or if the subject of this email ends with a code, eg. -LICHT01X,
then also from senders whose reply contains it.
∀x. In(x, MyInbox) ⇒ In(senderAddress(x), MySafeSenderList) ∨ (∃y. In(y,
subject(this) ) ∧ In(y,x) ∧ isCodeLike(y, -LICHT01X) ).
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