# How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

Page 1 of 1

## 3 Replies - 543 Views - Last Post: 21 September 2019 - 10:08 AM

### #1 Dalmango

Reputation: 0
• Posts: 7
• Joined: 15-August 19

# How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

Posted 21 September 2019 - 08:34 AM

I'm a Construction Estimator & have been fascinated by how programmes like Foxit Pdf Reader, Acrobat Pro deduce the length & areas of structural drawings in pdf format.

A user sets the scale of the drawing; which is easy to understand. Then the user digitizes (clicks) where each point is, for a length, perimeter or area. So what happens is an array must be created for them specific vectors, until the process for that particular item (element in the array) is complete. Then some math must be used to determine the differences in x,y & z axis'.

My understanding this is a geometry kernel of some sort. There are many programmes out there already and have been for decades for measuring pdfs. Even some mainstream basic apps have a very basic feature of this such as Foxit Reader Pdf & Adobe. Surely there is some code out there that already has these features out there?

Is This A Good Question/Topic? 0

## Replies To: How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

### #2 modi123_1

• Suitor #2

Reputation: 15806
• Posts: 63,313
• Joined: 12-June 08

## Re: How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

Posted 21 September 2019 - 09:07 AM

I: am not sure what you mean by 'geometry kernel', but most likely the information is stored as vector graphics... similar to 'SVG' web graphics. From that it would be a relative easy jump to apply basic geometry on points to get distance and area.

### #3 Dalmango

Reputation: 0
• Posts: 7
• Joined: 15-August 19

## Re: How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

Posted 21 September 2019 - 09:54 AM

Thanks Beardy, yeah that's what I was thinking. Looking at the code of a pdf (very briefly) I was surprised at the amount of funny characters in the hard-code of a pdf. I was hoping there was some serious articles out there on this stuff, with open-source/ paid for code that already calculates the position of vectors.

Geometry Kernel's in case you wanted to read up a little.

### #4 modi123_1

• Suitor #2

Reputation: 15806
• Posts: 63,313
• Joined: 12-June 08

## Re: How Does Scaling From A Pdf Work - Foxit, Acrobat Pro Etc... ?

Posted 21 September 2019 - 10:08 AM

It's basic math. You have a set of points you can do the easy calculations or build a class that does that.