fix: compile

[developer0hye]

@kir19890817

Hi, Kirill.

Thanks for your contribution!

Can you explain your PR?

[pktiuk]

@developer0hye
This commit fixes compilation. (in my case Linux)

g++ -c -pipe -O2 -std=gnu++11 -Wall -W -D_REENTRANT -fPIC -DQT_DEPRECATED_WARNINGS -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I. -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtWidgets -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -I. -I. -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++ -o mainwindow.o mainwindow.cpp
mainwindow.cpp: In member function 'void MainWindow::on_tableWidget_label_cellClicked(int, int)':
mainwindow.cpp:434:64: warning: unused parameter 'column' [-Wunused-parameter]
  434 | void MainWindow::on_tableWidget_label_cellClicked(int row, int column)
      |                                                            ~~~~^~~~~~
mainwindow.cpp: In member function 'void MainWindow::on_horizontalSlider_contrast_sliderMoved(int)':
mainwindow.cpp:476:31: error: 'pow' was not declared in this scope; did you mean 'pos'?
  476 |     float percentageToGamma = pow(1/(valueToPercentage + 0.5), 7.);
      |                               ^~~
      |                               pos
make: *** [Makefile:450: mainwindow.o] Error 1

[developer0hye]

@kir19890817 @pktiuk LGTM Thanks!

[kirill-kondrashov]

@developer0hye thanks for explanation, didn't notice the thread!