an Image Magick Tute by Flo
What are Beziers? They are irregular curves, rather than the more balanced curves of Arcs, Ellipses and Circles.

Beziers need a starting, an ending point, plus at least one in between point.

You may need many points in between to make the curve travel through the image where you want it to go. The more points you use, the more precisely you can place the curve.

If a Fill Color is used in addition to the Stroke Color, the results can be interesting.

Below is a very simple Bezier curve, actually a curve that reverses its direction:

100x100 xc, Stroke Color and Fill Color
10,10 30,100
70,0 90,90
10,10 200,0
-100,100 90,90

100x100 xc, Stroke Color and Fill Color
10,10 30,100
70,0 90,90
10,10 200,0
-100,100 90,90

The Bezier primitive curves the line through AVERAGED readings of the few points. By comparing the Beziers with the Polylines, you can see how much you have to exaggerate those two in-between points to get the Beziers shown.

For further comparisons, please visit Polylines vs. Beziers

Using one or two in-between points with Beziers involves a lot of guess work to get them to go where you want them. So if you need to make a Bezier go where you want it to:

  1. On graph paper (10x10 or 5x5 squares per inch), draw the dimensions of the image on it.

  2. Then Draw the Bezier inside the rectangle.

  3. Count the squares to get each set of numbers you'll need. Start at the top and continue down the curve. Write them down.

  4. Draw the Bezier, typing the numbers in the exact order you have them written. Separate each number within the set with a comma.

  5. Set Fill Color (if any), Stroke Color and Stroke Width. Leave everything else as is.

  6. Click on the Draw button.

  7. On the View page, check the Bezier to see if it looks like the curve you drew on the graph paper. If not, you'll have to figure out which additional sets of numbers to add to the ones already in the Draw box.

    The Bezier "shrinks" its bounaries inside the coordinates that we use. This is true if we use too few coordinates.

    Remember to put them in the proper order among the rest of the numbers you started with.

Drawing with Beziers just isn't for everyone. Beziers involve more time than the other Draw primitives. So only you can decide if you like to work with Beziers or not.

Below are links to some more examples of some of the Beziers I've drawn:

Flamenco Dancer
With coords for playing

Scattered Beziers ~ Buzzin' Beziers
Arched Fountain ~ Confused Beziers
Swingle ~ Purple Tulip ~ Flo's Home
Rolling ~ Sinedot with Bezier Border



Sally's Bezier Tute
   Sally uses only 3 sets of coords for simple curves.

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Friday 22nd of June 2018 10:50:59 PM

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