Monogame windows - make a textview scrollable

Question

I am trying to do an appication in monogame windows. I have a long text to be displayed on screen. I tried to render it on screen using spriteBatch.Drawstring, was succesful to an extent. But, the text did not fit into a required area. I had followed this tutorial. I need a vertical scroll to be implemented to have the entire text inside my desired area. Can anyone suggest some help. This is my current code :

protected override void LoadContent()
    {
        spriteBatch = new SpriteBatch(GraphicsDevice);
        _boxTexture = new SolidColorTexture(GraphicsDevice, Color.Red);
        _borderRectangle = new Rectangle(100, 100, 500, 500);
        _textboxRectangle = new Rectangle(105, 105, 490, 490);
        _font = Content.Load<SpriteFont>("Rockwell");
        _text = "He determined to drop his litigation with the monastry, and relinguish his claims to the wood-cuting and fishery rihgts at once. He was the more ready to do this becuase the rights had becom much less valuable, and he had indeed the vaguest idea where the wood and river in quedtion were.";

    }
private String parseText(String text)
{
String line = String.Empty;
String returnString = String.Empty;
String[] wordArray = text.Split(' ');

foreach (String word in wordArray)
{
    if (font.MeasureString(line + word).Length() > textBox.Width)
    {
        returnString = returnString + line + '\n';
        line = String.Empty;
    }

    line = line + word + ' ';
}

return returnString + line;
}

and inside draw function :

spriteBatch.DrawString(font, parseText(text), new Vector2(textBox.X, textBox.Y), Color.White);

Answer 1

You can do it in the draw method instead. Then just do what you're doing now, but instead of creating a string that you return, you just call

spriteBatch.DrawString(font, line, textPostion, Color.White);

instead. Where textPosition is just equal to the textbox position, to begin with and then you increase the Y position with font.MeasureString(line).Y for each iteration:

textPosition.Y += font.MeasureString(line).Y; 

Then you check for

if(font.MeasureString(line).Y + textPosition.Y < textBox.Y + textBox.Height 
   || textPosition.Y > textBox.Y)    
{
     continue;
}

Then just look for input of the keyboard arrows for instance (or create some buttons for scrolling up and down), and increase or decrease the textPosition.Y accordingly. Then you will have vertically scrolling textbox.

You can then make some lock by defining a minimum Y value for the position, such that the text stop when scrolling to the bottom or to the top.