Drawing tangents

Hi all,

is there any way to draw a tangent to a curve in Intaglio? I have read other threads on this matter but they seemed not conclusive.

Best. Daniele

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Hi Daniele,

I made a feature request for this on the forum earlier this year, and Nick said he’d put it on the list. So, no, there’s no way to draw a tangent to/from a curve at present.

Ross

——original message——

Hi all,

is there any way to draw a tangent to a curve in Intaglio? I have read other threads on this matter but they seemed not conclusive.

Best. Daniele

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Using Grapher (Apple Utility) is the best way, maybe. Grapher can copy any lines expressed by mathematical equations as a pdf format into clipboard. Then you can past it and convert / pdf for editing in Intaglio. If necessary, you may use ungroup in order to eliminate backgrounds.

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Using Grapher (Apple Utility) is the best way, maybe. Grapher can copy any lines expressed by mathematical equations as a pdf format into clipboard. Then you can past it and convert / pdf for editing in Intaglio. If necessary, you may use ungroup in order to eliminate backgrounds.

Thanks. I meant to draw tangent of a curve for which I don’t know the analytic expression.

Best. Daniele

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On May 19, 2010, at 6:20 AM, Daniele Avitabile wrote:

Hi all,

is there any way to draw a tangent to a curve in Intaglio? I have read other threads on this matter but they seemed not conclusive.

The way I do it depends on what I need.

—-If the slope of the tangent is given, I draw a line with that slope, then I slide the line until it touches the curve. If need to make sure, I draw a small circle or square next to the contact point and while it is selected, I magnify to, say, 3200%. The selected little circle serves to center the magnified picture,

—-If one point of the tangent is given, I draw a line starting from that point and then I pick the line from its other end and I move it until the line touches the curve.

Not exactly assembly line but it sure works very well. In fact, other than the line “sticking” when it comes near the curve, I can’t see how Intaglio could possibly improve matters.

Regards

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OK, this is what I do, with a bit of practice it is very quick, and you get perfect results every time. Download privatewww.essex.ac.uk/~mjr/tangent.intaglio for the file.

MAKE SURE THAT ALL LINES AND ARCS ARE SET TO BUTT CAP IN THE STROKE PANEL

1) Here is your circle and line.

2) Duplicate the circle and use white arrow to convert it into a 1/4 arc. Make sure the stroke is set to open.

3) Look at the angle of the line in the geometry window, use ROTATE to set the arc so that its end is the same angle as the end of the line. For example, if the line is reading at 340 degrees, you need to rotate the arc by 20 degrees.

4) With smart guides switched on, butt the arc against the line. If you are not used to smart guides, practice with them. They make a lot of tasks much easier, but you need to learn their strengths and weaknesses.

privatewww.essex.ac.uk/~mjr/Picture1.png

shows how the guides look when the objects are butted together correctly.

5) Intaglio can get a bit upset at turning arcs back into circles so do this: Using the white arrow, turn the arc back into an almost-circle. Its top/bottom/left/right extremities fully drawn.

6) Cut the original circle, click the arc, and paste the circle. It should appear exactly centred on the arc (I love Intaglio for this feature).

7) Extend the line if you wish, delete the arc if you wish. You are left with the perfect tangent.

This is a lot less convoluted than it sounds!

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