# Items tagged with filledfilled Tagged Items Feed

### Plotting a filled semicircle rotated...

December 01 2012 by Maple

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I can't solve probably very easy problem. How to plot a filled semicircle which is rotated across one axis by an angle alpha? I came to the solution which I don't consider as the best one (since e.g. it will not work for alpha=Pi/2*(odd integer)) and I believe someone of you will show me a better approach. Thank you in advance.

My solution:

alpha := (1/6)*Pi:plot3d([x, y, y*tan(alpha)], x = -1 .. 1, y = 0 .. sqrt(1-x^2)*cos(alpha), axes = normal, labels = ["x", "y", "z"...

### plotting region between two functions

December 12 2011 by Maple

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Suppose that I wanted to produce a 2D plot which was coloured in the region between two functions.

I mean not just between two curves, but between two functions. I would like to make the curves appear as smooth as Maple knows how, but without getting any jaggedness due to using a high grid in an implicitpot.

Consider this example. These two curves are displayed as being quite smooth (using adaptive plotting or whatever plot knows to use). How best can the regions between these two curves be filled, without having to recourse perhaps to a rough implicit plot?

plot([x^2-1, -x-1], x=-1.5..1.5, y=-1.5..1.5, color=black);


A simple trick with a product provides a defined implicit region that implicitplot can handle. But there can be small gaps, or irregularities, because the formulas for the curves are being solved in a complicated way and no longer being used as mere functions.

plots:-implicitplot( (y - (x^2-1))*(y - (-x-1)),
x=-1.5..1.5, y=-1.5..1.5,
filledregions=true, gridrefine=4,
coloring=[COLOUR(RGB,.8,.8,.9),"white"],
axes=boxed, labels=["x","y"],
view=[-1.5..1.5,-1.5..1.5] );


Another technique is to overlay two simpler implicit plots, colouring and layering them carefully so as to give the impression that only the inner regions had been coloured. The problem here is that the intersections all have to be computed and the problem split up piecemeal (which I did not do) so that the layered colouring is adjusted to whichever curve lies on top. Without that care, then something like this happens, with odd subregions appearing uncoloured.

plots:-display(
plots:-implicitplot( x^2-1 >= y, x=-1.5..1.5, y=-1.5..1.5,
filledregions=true, gridrefine=4,
coloring=["white","white"] ),
plots:-implicitplot( -x-1 >= y, x=-1.5..1.5, y=-1.5..1.5,
filledregions=true, gridrefine=2,
coloring=[COLOUR(RGB,.8,.8,.9),"white"] ),
axes=boxed, labels=["x","y"], view=[-1.5..1.5,-1.5..1.5]);


Did I miss something obvious? Is there some other calling sequence or command that makes this much easier (and smoother, by default)?

### Draw a triangle filled with specific...

November 07 2010 by Maple

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I am trying to draw a triangle with black lines and fill it in gray. Based on the maple help code i am trying this code:

draw(T, thickness = 3, filled = [color = "Blue"])

It does draw the triangle T with the right thickness, but the triangle isn't filled. Any thoughts?

help appreciated

Pieter

### Maple 14 enhancement to plot option...

June 28 2010 by

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Christopher2222's recent post reminded me of a new plot feature that inadvertently (and through my own fault) got left out of the new-features help pages. The 'filled' option now takes a true/false value or a list of suboptions. The suboptions apply to the polygons that make up the filled region under the curve.

plot(x^2, x=0..1, color="NavyBlue", thickness=3, filled=[color="Blue", transparency=0.7]);

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