Positioning Formulas for import layer

[bdelmon78]

Hello,
I'm using PDF-Xchange Editor Plus v10.8.2.407.
For "Import Layer" in the "Layer" context menu, what are the positioning formulas based on the requested rotation, scale, and offset parameters?
I would like to overlay two drawings with a perfect overlap of a vector on each drawing, and I can't seem to calculate these parameters (rotation, scale, and offsets) from the coordinates ((x_begin,y_begin);(x_end,y_end)) of these vectors.

Thank you in advance for your help.

[Daniel - PDF-XChange]

Hello, bdelmon78

I must apologize but I do not know how to answer this question... Are you using one of our SDK products perhaps? I ask because you have posted in the end user forums here.

In any case, I do not believe such properties/values exist for layers, as in PDF, layers are simply a "visibility flag" and have no relation to the position of content in the first place. The only purpose layers serve in PDF is to control visibility either manually or based on a conditional, such as the system language.

Beyond that, if the two files you are comparing are the same size, using the "overlay" tool on the organize tab, would likely be what you are actually looking for. This allows you to place the overlay page with a color modification, even a blend mode if you wish, and you can even put the overlay content on a layer, so you have the option to toggle its visibility as needed:

image.png

Kind regards,

[bdelmon78]

Hello,
Thank you for your feedback.

No, I don't use one of your SDKs, but I'm just a regular user!

Unless I'm mistaken, it's possible to overlay PDFs using the "import as layer" function in the context menu of the "layers" panel (sorry, it's in French!):

Capture d’écran 2026-02-07 152111.png

This function allows me to overlay plans with different orientations and scales!

To achieve acceptable accuracy, manual alignment is laborious, requiring multiple attempts, especially if rotation is necessary.

It's possible to define the required parameters (rotation, scale, offsets) by defining a "superposition vector" for each PDF, based on the coordinates of these vectors. It's "simple" geometry!

I'm having a "problem" with the "rotation" parameter: with left or right, or up or down, offsets, I can't understand the resulting positioning logic!

Can you help me understand?

Sincerely
bdelmon78

[Daniel - PDF-XChange]

Hello, bdelmon78

I see, the import as Layer Dialogue is essentially the same as the "overlay" function I mentioned above, note that all the same options are in place in the same layout.

With regards to the Rotation, it rotates the overlaid document - at its own centerpoint, meaning it is not affected by the below positioning options.

As for Placement options - the "offset" numerical values define how far to move the page away, from the "from" field's item. EG;
- In the Horizontal row, If you specified to move the page 100mm from the "right" the overlaid page will move 100mm towards the left.
- In the Vertical row, If you specified to move the page 20mm from the "top" - the overlaid page would move 20mm down.
- If you leave the "from" options on "center" than you can use negative numbers to move the page in the opposite direction - relative to where a positive number would move it. (giving the same controls as using "from right/left" options, but without needing to check a separate field.

Kind regards,

[bdelmon78]

Hello Daniel,
Thank you for these explanations.

Indeed, the rotation is defined relative to the center of the page in question.

=> For consistent behavior, the offsets should therefore be set to "center".

I can now calculate the "rotation", "scale", and "offsets" parameters from the coordinates of the vectors to be superimposed and the page sizes!

Thanks again for your help.
bdelmon78

[Daniel - PDF-XChange]