# Difference between revisions of "LPE: Ellipse from Points"

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(renewed examples with Perspective circle and Steiner ellipses) |
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=== GUI Parameters === | === GUI Parameters === | ||

[[File:LPE_pts2ellipse_GUI.png]]< | [[File:LPE_pts2ellipse_GUI.png]]<br> | ||

# '''Method:''' select from | # '''Method:''' select from | ||

## '''Auto ellipse:''' if the path contains 2...4 nodes, a circle is created; if the path contains more than 5 nodes, an ellipse is created. Note, that a circle is properly defined with either 2 or 3 points and an ellipse requires at least 5 points. | ## '''Auto ellipse:''' if the path contains 2...4 nodes (or points), a circle is created; if the path contains more than 5 nodes, an ellipse is created. Note, that a circle is properly defined with either 2 or 3 points and an ellipse requires at least 5 points. | ||

## ''' | ## '''Force circle:''' similar to Auto Ellipse, but now a circle is always fitted. Requires a path with at least 2 nodes. | ||

## ''' | ## '''Isometric circle:''' uses the first 2 edges to construct an isometric ellipse. | ||

# '''Arc:''' generates an (open | ## '''Perspective circle:''' uses the first 4 nodes to construct an ellipse representing the circle inside the square viewed under perspective. | ||

# '''Other Arc side:''' uses the opposite side for the arc (only has an effect when Arc is selected). | ## '''Steiner ellipse:''' uses the first 3 nodes to construct an ellipse around the triangle. See also [https://en.wikipedia.org/wiki/Steiner_ellipse] | ||

# '''Slice Arc:''' generates a sliced arc (only has an effect when Arc is selected). | ## '''Steiner inellipse:''' identical to Steiner ellipse, however the ellipse is now inside the triangle. | ||

# '''Frame ( | # '''Arc:''' (only applicable to '''Auto ellipse''' and '''Force circle''' methods) if checked, generates an (open) elliptic arc between the first and last node. Note, that for the fitting of the ellipse only the nodes of the input path count and not the order nor the form. So, going "backwards" is allowed. Just play by moving the nodes of the input path! | ||

# '''Axes:''' generates the (main) axes of the ellipse. | # '''Other Arc side:''' (only enabled if '''Arc''' is checked) if checked, uses the opposite side for the arc (only has an effect when Arc is selected). | ||

# '''Slice Arc:''' (only enabled if '''Arc''' is checked) if checked, generates a sliced arc (only has an effect when Arc is selected). | |||

# '''Frame (isometric rectangle):''' if checked, generates an isometric rectangle – a frame – around the ellipse. Rotates according to '''Axes rotation''' parameter. | |||

# '''Axes:''' if checked, generates the (main) axes of the ellipse. Rotates according to '''Axes rotation''' parameter. | |||

# '''Perspective square:''' (only enabled if '''Perspective circle''' is used) if checked, generates the square viewed under perspective. Rotates according to '''Axes rotation''' parameter in the correct perspective. | |||

# '''Perspective axes:''' (only enabled if '''Perspective circle''' is used) if checked, generates the axes of the circle. Rotates according to '''Axes rotation''' parameter in the correct perspective. | |||

# '''Axes rotation:''' rotates the whole ellipse including the resulting nodes, frame and axes (unit: [deg]). | # '''Axes rotation:''' rotates the whole ellipse including the resulting nodes, frame and axes (unit: [deg]). | ||

# '''Source Path:''' | # '''Source Path:''' if checked, generates the source path. This is useful for modifying the source path and hence the resulting ellipse. | ||

=== Examples === | |||

[[File:Pts2ellipseTests.png]] | |||

[https://gitlab.com/inkscape/inkscape/uploads/0d3c0b065251a2ce4c910cdcf2996139/pts2ellipseTests.svg Example svg file for inkscape] | |||

[https://gitlab.com/inkscape/inkscape/uploads/ed8a1f823d401c498249033d492e53de/pts2ellipseTests.pdf Example saved as pdf file] |

## Latest revision as of 13:16, 24 March 2019

This page describes inkscape's Live Path Effects "Ellipse from Points" introduced in inkscape 0.93.

### GUI Parameters

**Method:**select from**Auto ellipse:**if the path contains 2...4 nodes (or points), a circle is created; if the path contains more than 5 nodes, an ellipse is created. Note, that a circle is properly defined with either 2 or 3 points and an ellipse requires at least 5 points.**Force circle:**similar to Auto Ellipse, but now a circle is always fitted. Requires a path with at least 2 nodes.**Isometric circle:**uses the first 2 edges to construct an isometric ellipse.**Perspective circle:**uses the first 4 nodes to construct an ellipse representing the circle inside the square viewed under perspective.**Steiner ellipse:**uses the first 3 nodes to construct an ellipse around the triangle. See also [1]**Steiner inellipse:**identical to Steiner ellipse, however the ellipse is now inside the triangle.

**Arc:**(only applicable to**Auto ellipse**and**Force circle**methods) if checked, generates an (open) elliptic arc between the first and last node. Note, that for the fitting of the ellipse only the nodes of the input path count and not the order nor the form. So, going "backwards" is allowed. Just play by moving the nodes of the input path!**Other Arc side:**(only enabled if**Arc**is checked) if checked, uses the opposite side for the arc (only has an effect when Arc is selected).**Slice Arc:**(only enabled if**Arc**is checked) if checked, generates a sliced arc (only has an effect when Arc is selected).**Frame (isometric rectangle):**if checked, generates an isometric rectangle – a frame – around the ellipse. Rotates according to**Axes rotation**parameter.**Axes:**if checked, generates the (main) axes of the ellipse. Rotates according to**Axes rotation**parameter.**Perspective square:**(only enabled if**Perspective circle**is used) if checked, generates the square viewed under perspective. Rotates according to**Axes rotation**parameter in the correct perspective.**Perspective axes:**(only enabled if**Perspective circle**is used) if checked, generates the axes of the circle. Rotates according to**Axes rotation**parameter in the correct perspective.**Axes rotation:**rotates the whole ellipse including the resulting nodes, frame and axes (unit: [deg]).**Source Path:**if checked, generates the source path. This is useful for modifying the source path and hence the resulting ellipse.