CODEWITHSUNDEEP
qtqt5
jmatthieu
jmatthieu

Reputation: 83

Is there a default color table / colormap available in Qt?

I can't seem to find a default or any provided colormap in Qt (5.7 in my case).

All I find is people generating their own color table such as:

QVector<QRgb> ctable;
for(int i = 0; i < 256; ++i)
{
    ctable.append(qRgb(i,i,i));
}

So is there any colormap available in Qt (as there is in matplotlib or matlab like here ?

enter image description here

Edit: a colormap to go with QImage::Format_Indexed8 image format and QImage::setColorTable()

A solution, as Qt does not provide any colormap:

I downloaded a colormap from AMA's link http://www.kennethmoreland.com/color-advice/black-body/black-body-table-byte-0256.csv

Then I read the file to generate my own colormap:

QVector<QRgb> ctable;

QFile file("black-body-table-byte-0128.csv");
if(!file.open(QIODevice::ReadOnly))
{
    QMessageBox::information(0, "error", file.errorString());
}

QTextStream in(&file);

while(!in.atEnd())
{
    QString line = in.readLine();    
    QStringList values = line.split(",");
    ctable.append(qRgb(values[1].toInt(), values[2].toInt(), values[3].toInt()));
}

file.close();

now ctable can be used as a colormap using:

QImage myImage;
myImage.setColorTable(ctable);

Upvotes: 4

Views: 5439

Answers (1)

AMA
AMA

Reputation: 4214

No, unfortunately Qt does not provide any. You will have to build it yourself. But there are plenty of sources with color table values for all sorts of needs.

Edit: I successfully used some perceptually uniform colormaps from http://www.kennethmoreland.com for my data visualization needs.

Upvotes: 4

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