Text Formatter

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Introduction

I wrote this code back in times where most of the user interfaces were text based. But some years ago, I again had to use this code for formatting emails which were automatically generated and sent to our customers. So I grabbed the change, and rewrote the whole thing in C++. The outcome of this refactoring process is an easy to use class called TextFormatter which provides row justification with a modifiable block size. It also has a special table formatting feature which avoids using tabs between its columns, thus providing a character based column size control and alignment.

How does it work?

The idea behind the row justification is, to automatically wrap the words if the length of one row is greater than the given block size. The diagram below shows the technique of wrapping the line into parts where each part's length is less than the block size. This job is done in makeRowsUnderBlockMax().

Once each row isn't greater than block size anymore, spaces are inserted between words by calculating the amount of characters needed to let the row fit exactly into the block size.

Using the class

The constructor of TextFormatter expects an output stream and a block size for row justifying. You can use either output streams. After an instance of this class is created you can call print(const char *text) as often as you want. This operation will print the given text to the output stream while row justifying it. By calling createTable(), you initiate table formatting. Before you can print the rows of the table, you have to define the column size and alignment. Please refer to the example below. You are also able to print text while you are printing tables. Just modify the code below and try it out. Hope you find this class useful.

void CTextformatterDialogDlg::OnButTesttable() 
{
    std::stringstream out;
    TF::TextFormatter tf(out, m_ColumnWidthControl.GetPos());
    tf.print(standard_text);

    tf.newLines(3);

    tf.createTable();
    tf.addColumn("Name", 10); tf.addColumn("First Name", 14); 
    tf.addColumn("Age", 6);
    tf.setColumnAlignment(2, TF::TextFormatter::right);
    tf.printHeader(true);

    tf.printRow(3, "Kandinsky", "Wassily", "139");
    tf.printRow(3, "Marc", "Franz", "125");
    tf.printRow(3, "Mueller", "Otto", "1131");
    tf.printRow(3, "Dali", "Salvador", "101");
    tf.printRowLine();
    tf.print("Mr.Mueller's age was slightly modified.");

    tf.newLines(5);

    tf.setBlockMax(m_ColumnWidthControl.GetPos()*2);
    tf.print(standard_text);

    m_Output = out.str().c_str();

    this->UpdateData(FALSE);
}