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Daniel Walton
Daniel Walton

Reputation: 113

JavaFX affine transform from 2D transformation matrix

I'm getting started with JavaFX and am struggling with the way that transforms are handled. I understand that you can add various transforms to a node but I want to be able to accumulate the transforms due to user interaction with nodes.

I'm able to create a 2D affine transformation matrix for the transform i want to perform. eg:

| a b c |
| d e f |
| g h i |

The JavaFX affine transform is defined as:

| mxx  mxy  mxz  tx  |
| myx  myy  myz  ty  |
| mzx  mzy  mzz  tz  |

My question is: How do I convert the transformation matrix to the JavaFX affine transform?

Upvotes: 0

Views: 1207

Answers (1)

Ștefan
Ștefan

Reputation: 758

What you have is a projective transformation matrix for a 2D space and JavaFX expects one for a 3D space.

Assuming you don't have any projections (since you want a 2D affine transformation), your matrix should look like:

| mxx mxy tx |
| myx myy ty |
|  0   0   1 |

For the other parameters you have mzz = 1 and mxz = myz = mzx = mzy = tz = 0.

Therefore, the JavaFX matrix (using your original notation) should look like:

| a b 0 c |
| d e 0 f |
| 0 0 1 0 |
| 0 0 0 1 |

Edit: I think when you have non-affine transformations, the JavaFx matrix should look like:

| a b 0 c |
| d e 0 f |
| 0 0 1 0 |
| g h 0 i |

Upvotes: 1

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