How to 'scale' a jpg or png image?

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kscott
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Joined: Wed Feb 04, 2015 10:09 pm

How to 'scale' a jpg or png image?

Post by kscott » Wed Feb 04, 2015 10:19 pm

I have several plan views in the format of jpg and png files (and some pdfs). I'd like to import the image into Qcad, and scale it until a Qcad reported dimension measurement matches a known physical measured dimension ofrom the real world. Then any number of other dimensions and/or areas on the drawing could be calculated using the now "calibrated" Qcad. How to do this or is it even possible?

Thanks in advance

Ken

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Husky
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Re: How to 'scale' a jpg or png image?

Post by Husky » Thu Feb 05, 2015 8:54 am

Hello Ken - welcome to the forum!
kscott wrote:How to do this or is it even possible?
Yes - it's possible. There are different ways to do something like that - I will show you one of them:

Make sure your drawing has the correct unit settings (mm, inch etc) - check it below Edit/Drawing preferences.
Insert your jpg into the drawing.
Ideality you have the knowledge of an "x" and "y" dimension of your jpg.
Lets start with "x":
Use the "Info Tool" / "Distance Point to Point"(Menu Info),
Place the first point exactly to start the measurement, then click the "Restrict horizontally" (Menu Snap) and place the second point of your measurement.
The Info tool shows you now the "x" distance and you can use it with the scale tool.
Husky-2015.02.04-01.png
Husky-2015.02.04-01.png (47.88 KiB) Viewed 4977 times
Select the jpg (upper right corner works best),
Start the Scale tool,
Use the known "real world dimension" and the Info tool dimension as operator.
In my case:
Real Dim = 5.00
Info Tool result = 9.71235329
To scale my jpg only in "x" direction I type in: 5/9.71235329
Husky-2015.02.04-04.png
Husky-2015.02.04-04.png (26.58 KiB) Viewed 4977 times
Maybe you need to do the same thing with "y" - to be sure doublecheck again your x and y measurements.

Needless to say that you could scale the whole jpg in one task for "x" and "y" at the same time ...
... but I think it' s easier to understand the procedure just with one scale direction. :wink:
Last edited by Husky on Fri Jun 05, 2015 8:51 am, edited 1 time in total.
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kscott
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Joined: Wed Feb 04, 2015 10:09 pm

Re: How to 'scale' a jpg or png image?

Post by kscott » Fri Feb 06, 2015 5:36 pm

Thansk , That's very helpful.

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