Rotating center positioning

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Andy0101
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Rotating center positioning

Postby Andy0101 » Sun Jun 21, 2009 8:53 pm

Hi! I'm new with Inkscape, and I'm just trying to make my first work (a wallpaper). This is just an example (I'l change the gradient).

Image
I'm having a problem with the rotating of the strokes group located down-right. I want to rotate a copy of it 180° with the rotation center in the middle of the document, so it looks like this (I've made strokes white here so you can see it better):
Image
But I need to get that + precisely in the center so I can make it symmetrical to the other one. Is there a way I can move it to the center or write the coordinates manually?

Thanks!

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TKR101010
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Re: Rotating center positioning

Postby TKR101010 » Mon Jun 22, 2009 3:16 am

I was reading in this post that if you hold shift and click the rotation center "+" it will re-center itself. Something I've been wanting to know for some time too :)

Andy0101
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Re: Rotating center positioning

Postby Andy0101 » Mon Jun 22, 2009 4:05 am

Thanks for trying to help, but that's not what I'm asking. I want to get that rotation center in the center of the document (AKA page), not the center of the object itself. SHIFT works when I want reset it's position to default, but not here.
However I've found the solution using grids. If someone else is wondering this, here is a step-by-step how-to:
    1. Click "File" > "Document Properties"
    2. Click the tab "Grids" and press "New"
    3. Set "Spacing X" and "Spacing Y" to the halfs of your document's size. For example; if your document's dimensions are 150×200 pixels, than set the Spacing X to 75, and Spacing Y to 100.
    4. Click on the desired object two times and move the + to the center of the page.
    5. Now you can delete the grid.
It was not that hard (if I've just used my brain :oops: ), and I haven't explained well in the first post.
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CarlCravens
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Re: Rotating center positioning

Postby CarlCravens » Mon Jun 22, 2009 1:34 pm

You could also:

Use a pair of Guides to find the center (double-click on a guide to manually enter its exact measurement).

or

Position the pivot point by hand and "get it close", then group the two elements and use Align & Distribute to center the group to the Page.

or

In Inkscape preferences, select "Clones -> Move according to transform".

Create your corner element and use Align & Distribute to center it on the page. Create a clone of the object and rotate it 180 degrees. Then move the parent object to the corner.

When you move the parent object, the clone will mirror its movements... move the object to the lower-right, the clone will move to the upper-left equally.

======

That latter option allows you the most freedom in tweaking the position of the two elements without having to constantly realign the second element every time, and it works equally well for "centered on this other object" where creating guides or grids would be tedious. It's biggest drawback is that you don't always want clones to behave that way... I never keep that option set by default. If you work with a lot of clones, requiring different behaviors in the same drawing gets frustrating.

Ideally, how clones move would be an attribute of the individual clone... I would expect that to be possible within the SVG standard as an inkscape-specific attribute, since it wouldn't be used in rendering the drawing, only in telling the editor how the clone acts.

And having those options on the toolbar alongside the "Scale Stroke" and "Scale Pattern" etc buttons would be really nice.

Andy0101
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Re: Rotating center positioning

Postby Andy0101 » Mon Jun 22, 2009 8:16 pm

Thank you! They are all much better methods than setting and deleting grids. I kinda haven't read all of the tutorials, so I'm gonna do that now.

And if you are asking yourself; no, there is no hidden text in my post. YES, THERE IS!
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TKR101010
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Re: Rotating center positioning

Postby TKR101010 » Tue Jun 23, 2009 3:44 am

CarlCravens wrote:Use a pair of Guides to find the center (double-click on a guide to manually enter its exact measurement).

I wasn't aware one could manually enter a guide's location. Thanks :) I'll have to give that a try.

Edit: Ah. That is cool. It also allows you to set the guides at an angle. :)

CarlCravens
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Re: Rotating center positioning

Postby CarlCravens » Wed Jun 24, 2009 1:39 am

TKR101010 wrote:I wasn't aware one could manually enter a guide's location. Thanks :) I'll have to give that a try.

Edit: Ah. That is cool. It also allows you to set the guides at an angle. :)


Yeah, when I discovered that, I was surprised. I can't count the number of times I zoomed way in to position a guide before I learned I could enter exact measurements just a few weeks ago. And angled guides? Had no idea that was an option.

I don't think I've ever seen it in a tutorial... just mentioned in passing by someone on a forum. I haven't been here long, but I've found this forum to be pretty valuable.

Inkscape has a few "hidden" features that aren't on any menus or buttons... you have to know the right key to press or that double-clicking brings up a dialog. Reading tutorials and manuals can be helpful, but they usually cover the basics and avoid overwhelming the new user with fiddly details. And I'm sure some of them are written by people who haven't discovered some of the little tricks.

(And traps. There are some features that interfere with normal usage that can really cause some confusion, and they can't be fixed without starting over or knowing how to manipulate the XML directly.)

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TKR101010
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Re: Rotating center positioning

Postby TKR101010 » Wed Jun 24, 2009 2:29 am

CarlCravens wrote:I can't count the number of times I zoomed way in to position a guide before I learned I could enter exact measurements just a few weeks ago.

That was my usual method as well.

Now for that angled guide thing ... I wish there was an Apply button to apply the angle to the guide without closing the dialog box. I was testing out the angeled guides on a small project yesterday and found that I had to keep opening and closing the dialog to adjust the angle when I was trying to line up the guide with my reference image.

Andy0101
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Re: Rotating center positioning

Postby Andy0101 » Wed Jun 24, 2009 4:25 am

Off topic:
TKR101010 wrote:Inkscape has a few "hidden" features that aren't on any menus or buttons... you have to know the right key to press or that double-clicking brings up a dialog.

I think that Optimus Maximus keyboard would be a very handy tool to use with Inkscape, since almost everything is done by pressing certain key combinations. (Photoshop layout)
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TKR101010
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Re: Rotating center positioning

Postby TKR101010 » Wed Jun 24, 2009 7:25 am

Off topic:
Andy0101 wrote:
CarlCravens wrote:Inkscape has a few "hidden" features that aren't on any menus or buttons... you have to know the right key to press or that double-clicking brings up a dialog.

I think that Optimus Maximus keyboard would be a very handy tool to use with Inkscape, since almost everything is done by pressing certain key combinations.
That keyboard does look sweet. That'd be really handy for using with Blender too :) Unfortunately that $1600+ pricetag is a bit out of my spending league.

CarlCravens
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Re: Rotating center positioning

Postby CarlCravens » Wed Jun 24, 2009 8:33 am

I'd love a keyboard like that, though it'd have to be a "natural"-style ergonomic. I'd especially like one because I'm working on a keyboard layout similar to the Right-Handed Illustration layout, except tailored to the types of work I do. Ideally, I'd never have to take my right hand off the mouse or stylus. (I don't know why the Right-Handed Illustration layout thinks its mostly useful for tablet users... having to use the right hand on the keyboard is equally annoying whether I'm using mouse or tablet.) Having a keyboard like that would make it easier to remember where I assigned all the tools.

The Optimus Aux, which is a secondary keypad with only 15 keys might be more affordable, and could be useful, but it's not nearly as many keys as I'd like to have. (Might be some kind of mode-selector options that let you quickly change what the keys do... hitting the Node Tool key also changes the keymap to node functions, for instance.)

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ErikTiePie
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Re: Rotating center positioning

Postby ErikTiePie » Wed Jun 24, 2009 4:05 pm

TKR101010 wrote:Now for that angled guide thing ... I wish there was an Apply button to apply the angle to the guide without closing the dialog box. I was testing out the angeled guides on a small project yesterday and found that I had to keep opening and closing the dialog to adjust the angle when I was trying to line up the guide with my reference image.

I totally agree!

Andy0101
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Re: Rotating center positioning

Postby Andy0101 » Wed Jun 24, 2009 6:02 pm

Off topic:
CarlCravens wrote:I'd love a keyboard like that, though it'd have to be a "natural"-style ergonomic. I'd especially like one because I'm working on a keyboard layout similar to the Right-Handed Illustration layout, except tailored to the types of work I do. Ideally, I'd never have to take my right hand off the mouse or stylus. (I don't know why the Right-Handed Illustration layout thinks its mostly useful for tablet users... having to use the right hand on the keyboard is equally annoying whether I'm using mouse or tablet.) Having a keyboard like that would make it easier to remember where I assigned all the tools.

The Optimus Aux, which is a secondary keypad with only 15 keys might be more affordable, and could be useful, but it's not nearly as many keys as I'd like to have. (Might be some kind of mode-selector options that let you quickly change what the keys do... hitting the Node Tool key also changes the keymap to node functions, for instance.)

I agree with everything you said. Here is another one: http://www.artlebedev.com/everything/optimus-tactus/. But it's still just a concept, and I don't know how would you type on it. If it doesn't have some kind of sensor that would sense different amount of pressure, I would say no. It's impossible to type while holding your hands in air and touching only those keys that you want to activate. And the pressure activation threshold needs to be configurable for different persons. And; it will be much more expensive than Optimus Maximus.
BTW that link I gave now is the official page
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kelan
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Re: Rotating center positioning

Postby kelan » Wed Jun 24, 2009 11:14 pm

Andy0101 wrote:But I need to get that + precisely in the center so I can make it symmetrical to the other one. Is there a way I can move it to the center or write the coordinates manually?


When aligning things symmetrically, the easiest way I've found is to make another object that is the exact size you need for the symmetry and use that to align the object you're working with.

In your example, you've got some sweeping lines that you want to mirror around the center of the document. Make a rectangle that is the size of the document, so that the sweeping lines align to the correct position on that rectangle. Then group the rectangle and the lines, duplicate the group, mirror it horizontally and then vertically so that the duped lines are in the right position, then ungroup and remove the rectangles. I can put together a series of images demonstrating the technique if description isn't doing the job.


TKR101010 wrote:Now for that angled guide thing ... I wish there was an Apply button to apply the angle to the guide without closing the dialog box. I was testing out the angeled guides on a small project yesterday and found that I had to keep opening and closing the dialog to adjust the angle when I was trying to line up the guide with my reference image.


You can actually rotate guides with the mouse, so you don't need to deal with the dialog at all if you don't need an exact angle measure. When you pull out a guide, you'll see a small circle on it where the mouse was contacting it. That's the guide's rotation point. If you hold Shift and click on the guide, you can drag the mouse and it will rotate around that point. You can move the rotation point by clicking anywhere on the guide and just dragging the mouse.

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ErikTiePie
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Re: Rotating center positioning

Postby ErikTiePie » Wed Jun 24, 2009 11:25 pm

kelan wrote:You can actually rotate guides with the mouse, so you don't need to deal with the dialog at all if you don't need an exact angle measure. When you pull out a guide, you'll see a small circle on it where the mouse was contacting it. That's the guide's rotation point. If you hold Shift and click on the guide, you can drag the mouse and it will rotate around that point. You can move the rotation point by clicking
anywhere on the guide and just dragging the mouse.


Aha, so that's what the little circles are for :)

But they're only available in 0.47 Dev version, not in 0.46.

(And, when you hide guides, using |, the little circles remain visible, but the guides disappear.)

~suv
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Re: Rotating center positioning

Postby ~suv » Wed Jun 24, 2009 11:34 pm

In the 'Align and Distribute...' dialog, you can position the selected elements (as a group or individually) relative to the page - e.g. centered.

Or you could use the extension 'Extensions > Render > Guides creator…' to easily construct a grid of guides relative to the page geometry. Then use 'Snap to path intersections' to position the rotation center on the intersection of the middle guides.

(that's with current 0.46+devel and 0.47pre0 - don't know about 0.46)


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