Time to Complete Progress Control

Introduction

Progress bars are great for giving feedback to the user during lengthy operations. However, sometimes a percentage completion is not enough, so I came up with this little class to display an estimation of the length of time remaining to complete the operation.

The class uses a simple linear time calculation to predict the estimated time remaining. For example, if the progress is at 10% complete and it has taken 5 seconds so far, then it predicts that it will take another 45 seconds to get to 100%

The prediction is repeated every time the control is drawn, therefore assuming that the progress percentage is accurate, then the prediction should be reasonably so too.

TProgressTimeToComplete is provided ready to go and can be used as a direct replacement for the MFC CProgressCtrl class. The start time is taken from when the class is instantiated, but can be reset if the control is instantiated long before the processing by calling the ResetStartTime() member function.

There is one virtual function that can be overloaded in order to customise the display. GetRemainingText is called to format the text string which is written over the top of the progress bar. There are two parameters given the percentage complete and the estimated time to complete - in seconds. The default implementation of the function looks like this:

CString TProgressTimeToComplete::GetRemainingText(double lfPercent, 
    double lfSecsRemaining)
{
    CString str;
    int     nSeconds = (int)fmod(lfSecsRemaining, 60.0);

    if (lfSecsRemaining < 60)
    {
        if (nSeconds < 1)
            str = "Less than a second";
        else
            str.Format("%d second%s remaining", nSeconds, 
                 nSeconds==1? "":"s");
    }
    else
    {
        int nMinutes = (int)(lfSecsRemaining/60.0);
        str.Format("%d minute%s, %d second%s remaining", 
             nMinutes, nMinutes==1? "":"s",
             nSeconds, nSeconds==1? "":"s");
    }

    return str;
}

Features

• Horizontal and Vertical progress bars are supported
• Smooth and Blocked progress bars are supported
• Expandable for custom text formatting
• Interchangable with MFC's CProgressCtrl
• It's free !

Notes

The progress control uses Keith Rule's memory DC class for smooth painting.

Enjoy !