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c#winformsdrawingcartesian-coordinates
dodoria1992
dodoria1992

Reputation: 127

create cartesian coordinate system c# windows forms drawing

I created simple form and now I want to draw single objects (rectangle, circle, lines..) in relative coordinates. Main problem for me here is to create 2D cartesian coordinate system in middle of the form.Is it possible and how to do it??

Main question is how to efficiently transform absolute coordinates to relative? How to create my own system so I get results in numbers (negative, positive depending on quadrant) and not in pixel?

Idea.

Currently I made MouseMove event to display current location of mouse with Cursor.Position.X, Cursor.Position.Y and display it in label. Displayed coordinates are pixels, how to change that? I've read something about converting with PointToClient method but I don't really understand it.

I am tied to windows forms becouse I already made a program in win forms and now I just want to add this feature to it.

Thanks

Upvotes: 3

Views: 7406

Answers (1)

George Legeza
George Legeza

Reputation: 36

What you're most likely looking for are Graphics.TranslateTransform and Graphics.ScaleTransform.

private void Transform(PaintEventArgs e)
{
    e.Graphics.ScaleTransform(width, height);
    e.Graphics.TranslateTransform(xOffset, yOffset);
}

You'll also need to make sure that whatever drawing method you're using has an overload for either PointF structures or Singles.

Of course, you could also just handle all of this on your end. Scaling your input/output coordinates by the width and height of the form and then translating by half of that will give you the same results.

Edit- To add some clarity, Windows always expects your coordinates to be in pixel form. You can use the above transformations to do your work at a different scale and then transform into the form that Windows expects.

Setting the translation should be straightforward. If you want the middle of the form, you simply want to translate by half the width and half the height. How you choose to scale your coordinates is going to depend on the range that you need to work in (ie, -1.0 to 1.0, -0.5 to 0.5, etc.).

Upvotes: 1

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