How to rotate a text before drawing

[ggolda]

Is it possible to rotate a text that is being drawn atop of an image? Can't find a method that accepts an angle for rotation.

[tocsoft]

image.Mutate(x => x
          .SetDrawingTransform(Matrix3x2Extensions.CreateRotationDegrees(45, new PointF(50, 50))) // set a transform to be applied to all drawing operations
          .DrawText("foo bar", font, Color.Black, new PointF(50, 50))); // draw the text

The one gotcha you might hit is the rotation origin of the matrix thus you will most likely need/want to set the point in the CreateRotationDegrees(angle, point) call to the same as the text drawing point to get the result you expect otherwise we will end up rotating around 0,0 (top left) and you can end up with text in odd places.

This API can be used to apply full matrix transforms to the items being drawn so can also be used for skewing, translating/offsetting, and scaling and as its a transformation matrix you can do them all at once.

or alternatively using DrawingOptions directly you do it thusly:

  image.Mutate(x => x
            .DrawText(
                new DrawingOptions { 
                    Transform = Matrix3x2Extensions.CreateRotationDegrees(45, new PointF(50, 50))
                },  
               "foo bar", 
               font, 
               Color.Black, 
               new PointF(50, 50)));

[tocsoft]

@ggolda I moved this to the correct repo as it was not a Fonts question but a Drawing one.

[ggolda]

@tocsoft thanks for a great answer 👍

[vrmvgf]

I used CreateRotationDegrees(angle, point), but the letters didn't fully displayed, liked this:

Did I do something wrong?

           var g = new SixLabors.ImageSharp.Image<Rgba32>(1000, 1000);
            g.Mutate(x => x.Fill(Color.White));
            var fontpath = new FontCollection().Install(System.IO.Path.Combine(System.Environment.GetEnvironmentVariable("windir"), "Fonts/arialn.TTF"));
            var font = new SixLabors.Fonts.Font(fontpath, 90);
            g.Mutate(x => x.SetDrawingTransform(Matrix3x2Extensions.CreateRotationDegrees(270, new PointF(500.0F, 900.0F)))
            .DrawText("foo bar 123456", font, Color.Crimson, new PointF(500.0F, 900.0F)));
            g.Save("bar1.jpg");

[tocsoft]

nope, looks fine. Its going to be the same issue we have already reported as #175

[vrmvgf]

Thank you.