Resizing changes angle

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Gedep
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Joined: Sat Apr 21, 2012 8:58 pm

Resizing changes angle

Postby Gedep » Sat Apr 21, 2012 9:19 pm

Hi there,

I just posted a question on markers, but I've got another question.

When making an physics drawing with angled lines I did the following:
  • Because I needed exact angles I first drew a horizontal line
  • I used the Transform option to rotate the line exactly 30 degrees
  • I connected the line to a node where it had to meet a line
  • Now I resized the line to the wanted length

It seems that the angle is now changed a little. I have "snapping to..." turned off.

Have I observed this correctly or is this just my imagination?

Thank you

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brynn
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Re: Resizing changes angle

Postby brynn » Sun Apr 22, 2012 12:14 am

If you moved the whole line, it should not have changed.
I can think of a couple of things that might have happened. If the following doesn't help, would you please say exactly what steps you took (specifically which tools and which commands/buttons)?

For example, if you used the Node tool to move the line, maybe you didn't have all the nodes selected. If that happened, then the line would no longer be straight. Or when you say you "connected the line to a node", maybe you used 'Join Seleceted Nodes'? If they were not exactly on top of each other, occupying the same coordinates, the node where they are now connected is halfway between the original 2. That could have distorted both lines.

Do I understand the problem correctly? One straight line lying at 30 degrees, and another straight line, angle unknown. The 30 degree line needs to meet the other line at a certain point. If that's the situation, there are probably a few ways to accomplish this.

I would use Snapping (Enable Snapping, Snap Nodes or Handles, Snap to Cusp Nodes, and if the other node is smooth, also Snap to Smooth Nodes. So that 3 or 4 buttons on the Snap control bar are engaged, and all the others not. Using the Selection tool, grab the 30 deg line near the end where it will connect to the other line, and drag it towards that node. When it gets close, it will Snap (jump out of your control and land precisely on the node so that both nodes now occupy the same coordinates). (Note this also requires enabling Inkscape Preferences > Snapping > Only snap the node closest to the pointer. It's not required for snapping, but I find I have better control using that option. Without that option enabled, it will still snap to the node, no matter where you grab the line. But if you were in tight spaces, other nodes could try to snap as well.)

If I've misunderstood the situation though, please correct me, and I (or someone) will try again :D

Gedep
Posts: 20
Joined: Sat Apr 21, 2012 8:58 pm

Re: Resizing changes angle

Postby Gedep » Sun Apr 22, 2012 12:39 am

I tried again (seeing the same thing) and did the following:

  • With snapping on, I drew a vertical line with the starting node exactly at a crossing of the grid.
  • I duplicated this line and with the Transform tool I rotated it 30 degrees.
  • With snapping still on, I replaced the rotated line, so that the starting node is at the same crossing of the grid.
  • I duplicated the rotate line again and turned snapping off.
  • I selected the rotated (the top one) and resized it (using the crtl-key).

Now it seems that the first and second rotated lines do not overlay exactly...

Gedep
Posts: 20
Joined: Sat Apr 21, 2012 8:58 pm

Re: Resizing changes angle

Postby Gedep » Mon Apr 23, 2012 12:33 am

Here is a screenshot of what I'm experiencing:
Image

First I drew the two black lines. Then I duplicated the rotated black line and selected it (F1). I switched snapping off and changed the size of the red line. Now they don't overlap anymore...

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brynn
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Re: Resizing changes angle

Postby brynn » Mon Apr 23, 2012 5:53 am

Ooohhh! I missed the part where you resized it. I realize now that's what the title of the message says, but didn't read anything about resizing in the original message text.

You're resizing it using Selection tool, Ctrl + drag a corner arrow? If you have not deselected it, there's an option that scales the stroke on Selection tool control bar. But that should not change the angle of the line. I'll do some testing, and report what I learn.

Edit
Oh, would you look at that! I have the exact same result! This is on Win7, 64-bit and Inkscape 0.48.1.

Image

It could be a problem with the renderer, and we're expecting a new renderer with 0.49. But I'm not sure that's the source of the problem. I suspect this is probably already known. You could search Launchpad (https://launchpad.net/inkscape) to try and find out.

Hopefully ~suv or someone who knows the technical aspects of Inkscape will reply. If it's not already reported, it certainly should be! I'm in edit mode, so I can't see your other messages at the moment. But if you have not already, would you please tell us your Inkscape version and operating system?

Gedep
Posts: 20
Joined: Sat Apr 21, 2012 8:58 pm

Re: Resizing changes angle

Postby Gedep » Mon Apr 23, 2012 6:21 am

Inkscape version: Inkscape 0.48.2 r9819

OS: Windows 7 Home Premium 64 bits


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