@as2388

Yes there is, do the drawing in another thread on a QImage and then trigger the update with that image.

I'd add to @SGaist's great point - even convert the image to a QPixmap in the worker (after drawing it), and in the paint event just splat it onto the widget.

Ubuntu 14.? provides older Qt version than the one you use!
You should either provide Qt libraries which are used by your application or use Ubuntu Qt libraries to build your app if you use same Ubuntu version.
See http://doc.qt.io/qt-5/deployment.html

I was able to resolve the issue by changing the QCameraViewFinderSettings on my QCamera to use QVideoFrame::Format_ARGB32 @ 1920x1080. After this change, the QVideoFrame reported the proper number of mappedBytes.

One interesting note, I had to QCameraViewFinderSettings.setMinimumFrameRate(0). For some reason there was a lag on the viewfinder in low light, but changing this setting fixed it.

Fixed!
I posted the problem there
http://stackoverflow.com/questions/33130691/qimage-and-openmp-when-updating-image-display/33133653#33133653

I needed to declare variables private for the pragma directive. So, instead of using cred, cgreen, and cblue as I was, the code becomes:

int cred2, cgreen2, cblue2 #pragma omp parallel for private(cred2, cgreen2, cblue2) for ( int ii = 0; ii < nPixels; ++ii ) { cred2 = (int) 255 * red16[ii] / range; cgreen2 = (int) 255 * green16[ii] / range; cblue2 = (int) 255 * blue16[ii] / range; QRgb argb = qRgba( cred2, cgreen2, cblue2, 255); QRgb* rowData = (QRgb*) newPaintImage->scanLine(ii/naxis1); rowData[ii%naxis1] = argb; }

That's all. Then all methods become strictly equivalent regarding the end result. Haven't compared speed though, which is a concern in my context.

Hi. Well, it's working. Here's what I've done:

QFile f("D:/img.bin"); if(f.open(QIODevice::ReadOnly)){ QByteArray b = f.readAll(); QImage img((const uchar*) b.constData(), 4096, 2160, 4096, QImage::Format_Indexed8); QVector<QRgb> colorTable; for (int i = 0; i < 256; i++){ colorTable.push_back(qRgb(i,i,i)); } img.setColorTable(colorTable); img.save("D:/img.png"); f.close(); }

And here's what I got:

There seems to be a regression in 5.5.0 that's been fixed for 5.5.1. See this bug report

Just don't create it on heap. QPixmap is implicitly shared.

It does not matter how you create pixmap. What does is total number of allocated resources.
Changes to your code might fix something if your previous code did not clean the memory -did not delete pixmap.
So code causing problem was not posted.

Yeah as I said above, I had a quick look and I believe it can be done relatively with ease. I will definitely give it a try as soon as I find some time :)

Hi,

Are you deploying everything the same for both WinXP and Win7 ?

I figured out what is going on, sort of. download_content in QByteArray seems to contains ^M (MSDOS newline) in some parts of the file when written to dump. When written to the desired file, it does not have those. Later on, in compareDownload the QBytearray does ontain the "^M" characters and the written file does not, therefore their bytes are different by x*^M. I currently do not understand why ^M is there and then not when written and I do not know how to remove from the QByteArray in the compareDownload function. Also during my tests to figure this out, QByteArray new_contents saves to file with ^M once I added that in there to compare with QByteArray file_byte_array.
Edit: Actually the regular file that becomes file_byte_array does have the ^M, but the QByteArray that reads the file lacks it.

Thank you so much. It is in fact a URL and you can use this to load it into a Image.

void dataSender::fetchImage(QString filePath)
{
const QUrl url =filePath;
if (url.isValid()) {
qDebug() << "Valid URL: " ;
QString test = url.path();
QImage myImage(test);
qDebug() << "Image Size " << myImage.size();
}
else{
qDebug() << "the url is invalid";
}
}

From the doc, the data array must be 32-bits aligned. I guess that's your problem: some data are lost because of the alignment.

the QImage class has a pixel(x,y) and setPixel(x,y,value) methods
QImage::setPixel()
you can also use QImage::bits()

@SGaist
Hi SGaist,
i solved manupulating my BA manually
int bW = bitmap.value("width").toInt();
int bH = bitmap.value("height").toInt();
QString shortFileName = bitmap.value("id").toString();
QString fileName = btb::ResourceManager().getClipDir().absolutePath().append("/"+shortFileName+".png");
QByteArray ba = bitmap.value("rect").toByteArray();
QByteArray to = QByteArray();
for(int i=0; i<bWbH;i++)
{
// ARGB -> ABGR
to.append( ba[i4+3]);
to.append( ba[i4+2]);
to.append( ba[i4+1]);
to.append( ba[i4]);
}
QImage image((const unsigned char)to.data(),bW,bH,QImage::Format_RGB32);
//image.invertPixels();
image.save(fileName,"PNG");

thanks for help!

Hi,

That's a question better asked on the interest mailing list. You'll find there Qt's developers/maintainers (this forum is more user oriented)

Best Place to start is Qt itself. They have an example for doing exactly this.

If there is a better way though, it would be nice to know.

@SGaist
Ok, I just tried to rescaled my image array within an intensity between 0 to 255 and cast a uchar*, it's working now.

Thanks