How to draw a HSV Triangle in ue4 Materials - triangle

This material will be applied to the image object in the widget.
It is also important that there is an opportunity to change the color!
Hue Ring & Triangle

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Is there a way to create a hollowed circle in A-Frame?

I'm trying to build a Flower of Life VR example using A-Frame.
The closest thing that I found is using the opacity property in <a-circle>.
Is there a way to create just the border of the circle?
Not sure if it fits your use case but you could use a cylinder with a small height:
https://aframe.io/docs/1.0.0/primitives/a-cylinder.html
Or a tube:
https://github.com/donmccurdy/aframe-extras/tree/master/src/primitives
Or just a flat plane with png texture with a circle with transparency

Can position accuracy indicator be animated in here maps?

I am implementing a scenario where I am trying to animate map accuracy indicator surrounding the position indicator using here maps
It should animate like ripples along the route with position indicator
But could not find any interface in HereMaps Android SDK document
Can you help with the same ? !
Ripple animated circle
What about using different MapCircles on the coordinates of the current position in different colors?
A MapCircle represents a type of MapObject in the shape of a circle with an assigned radius distance and a GeoCoordinate center. It can be created by calling the constructor MapCircle(double radius, GeoCoordinate center).

QPainter drawing lines - configuring line softness (horizontal opacity gradient)

I am looking for a way to apply a horizontal opacity gradient when painting QLine elements using QPainter. Put simply, I want to be able to have the line opacity decrease the further away from the line center it is being painted. The effect I want to achieve corresponds to what a lot of image editing tools comonly describe as hardness of a brush.
Here is a sample image that compares a line using a hard brush to a soft one:
This would be a minimum example for painting a regular QLine:
QPainter p;
p.setPen(QPen(Qt::black, 12, Qt::SolidLine, Qt::RoundCap));
p.drawLine(QPointF(0,0), QPointF(1024,1024));
How and where would I configure the line hardness I am describing? Is there something like a fall-off property when painting QLine elements?
In the docs I could only find examples for how to apply linear gradients between set points, which is not what I am looking for.
That's not QPen painting, that's brush painting, like in say photoshop, and Qt doesn't really support such functionality out of the box.
But it is quite easy to implement, you need a brush stencil pixmap, and you simply draw that pixmap on your target paint device along a line at a given step.
The line interpolation part is already answered here.
It is recommended that the brush stencil is an 8 bit grayscale QImage, then you can easily get a colorized version of that by using the greyscale value as an alpha value for the solid color of choice. QImage is preferable, as it offers individual pixel access. This allows to have any type of brush aside from hard and soft, including certain artistic brushes.
Naturally, if all you need is a soft brush, you can generate that directly in the desired color by utilizing Qt's existing gradients and skip the stencil colorizing part. You can use QPainter to procedurally draw colorizable or full color stencils to use as a brush.

How to get a both side colored plane in A-Frame

When I create an a-plane and assign an attribute color="red", the color is applied to one side only. I added rotation animation to the plane and the back of the plane is white: fiddle.
What would be the method to get a plane colored from both sides? Should I create 2 planes of same color and then rotate one so that they are back to back and to the user looks like a single plane?
There is a material property called side. If you set it to double, the material will be applied both to front and back
<a-entity material="side: double"></a-entity>
updated codepen.

Qt data visualization background image and transparency support

Does the data visualization module support background image especially Surface3D element , also is there any why to apply transparency to plot color. Basically I need to place an image on x-z plane and draw surface plot above it with some transparency, so the user can see the background image through the surface plot.

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