Flip text vertically using Drawstring

Question

I have some code that writes some text to a defined region.

 graphics.DrawString(text, goodFont, Brushes.Black, textarea, stringFormat);

There are some cases where I would like to flip the text on the horizontal so that it goes from:

To

I have tried to measure the string width and take the inverse of that:

float w = graphics.MeasureString(text, goodFont).Width;
graphics.DrawString(text, goodFont, Brushes.Black, -w, 0, stringFormat);

but then my issue is that the text extends outside the boundary of the box I wish to draw it in (textarea).

I would like to flip the text on the horizontal while maintaining my box boundary. Can anybody point me in the right direction for how to accomplish my task?

Thanks in advance!

EDIT: I am trying to avoid having to create a bitmap and then do the transformation.

Ivan Stoev · Accepted Answer · 2016-08-18T19:01:34.647

You can use graphics transformation. The easier I see is to use the this Matrix Constructor (Rectangle, Point[]) like this:

Point[] transformPoints =
{
    // upper-left:
    new Point(textarea.Right - 1, textarea.Top),
    // upper-right:
    new Point(textarea.Left + 1, textarea.Top),
    // lower-left:
    new Point(textarea.Right - 1, textarea.Bottom),
};
var oldMatrix = graphics.Transform; 
var matrix = new Matrix(textarea, transformPoints);
try
{
    graphics.Transform = matrix;
    graphics.DrawString(text, goodFont, Brushes.Black, textarea, stringFormat);
}
finally
{
    graphics.Transform = oldMatrix;
    matrix.Dispose();
}

P.S. Although @serhiyb posted similar answer a few seconds before mine, I think this is easier to understand - you define the transformation by simply specifying a source rectangle and how to transform its upper-left, upper-right and lower-left points.

This solution gave me what I need. Thanks so much. – markdozer Aug 19 '16 at 16:29 — markdozer, Aug 19 '16 at 16:29

Raktim Biswas · Answer 2 · 2016-08-18T21:15:56.670

You can use the Matrix Constructor to transform the graphics and later draw the graphics using the DrawString method.

Try this:

private void Form1_Paint(object sender, PaintEventArgs e)
{
    Graphics g = e.Graphics;
    string text = "This is a Test";
    g.DrawString(text, Font, Brushes.Black, 0, 0);

    g.MultiplyTransform(new Matrix(-1, 0, 0, 1, 68, 50));

    g.DrawString(text, Font, Brushes.Black, 0, 0);
    g.ResetTransform();
}

Output:

score 2 · Answer 3 · edited Jul 08 '17 at 13:41

You can use Transformation Matrix for that

Something like:

float w = graphics.MeasureString(text, goodFont).Width;
graphics.MultiplyTransform(new Matrix(-1, 0, 0, 1, w, 0));
/*
 Matrix:
 -1 0
  0 1
 newX -> -x
 newY -> y
 and dx offset = w (since we need to move image to right because of new negative x)
*/
graphics.DrawString(text, goodFont, Brushes.Black, textarea, stringFormat);
graphics.ResetTransform();

You may need to play with Matrix/area parameters as I'm coding it blindly but I hope you got the idea.

Flip text vertically using Drawstring

3 Answers3