Let's supposed we've got a ring with inner radius R2 and outer radius R1. According documentation: Inner radius of the ring expressed as a ratio of the ring's width.For instance, if innerRadiusRatio=9, then the inner radius equals the ring's width divided by 9 As I understand this means that innerRadiusRatio = 2*R1 / R2.
About thicknessRatio there is that: Thickness of the ring expressed as a ratio of the ring's width. For instance, if thicknessRatio=3, then the thickness equals the ring's width divided by 3. So thicknessRatio = 2*R1 / (R1 - R2).
thicknessRatio*(1-2/innerRadiusRatio)=2 which means that there is a connection between thicknessRatio and innerRadiusRatio. But there is nothing about this connection in GradientDrawable class documentation. And it doesn't seem that there is any connections between them as I can set thicknessRatio and innerRadiusRatio which doesn't satisfying last equation.
So tell me please where I'm wrong in my consideration or what are this parameters really responsible for?
Ratios are a comparison of two numbers, so the above two equations can be rewritten as
Ratio1 = InnerRadius : Ring Width (where Ratio1 = InnerRadiusRatio)
Ratio2 = Thickness : Ring Width (where Ratio2 = ThicknessRatio)
Which means...
Ring Width = Ratio1 x Inner Radius = Ratio2 x Thickness
The "2" appeared since you added it into your equation. The only common denominator in all equation is "Ring Width". Trying it out with real numbers helps too.
I know this is pretty late, but it may help others looking for this.
In the documentation it says:
Inner radius of the ring expressed as a ratio of the ring's width.
The ring's width is not the Radius of the ring, it is the width of the view containing the ring. I draw this for an easier explanation:
That's the scheme of a view with a ring inside. The letters mean:
- W: Width
- P: Padding
- Th: Thickness
- Ir: Inner Radius.
And I will add:
- R: Radius.
- IRR: InnerRadiusRatio.
- THR: ThicknesRatio.
The documentation actually describes the following relationship:
So you can actually calculate the Radius.
- R = Ir + Th = W (1/IRR + 1/THR).
You can prove this by creating a view with a Ring that has:
InnerRadiusRatio="4" ThicknessRatio="4".
This will create a ring that has exactly the same width as the view.
Note: All of the previous formulas are calculated with no padding. If there is padding on the View, you should replace every W with (W - P).
