Capped StrokeWidth on canvas.Line

[ajstarks]

Describe the bug:

After 10, the StrokeWidth of canvas.Line is capped, and will not increase.

To Reproduce:

Steps to reproduce the behaviour:

Specify a StrokeWidth > 10, compare to widths

Screenshots:

expected behavior

Example code:

deck
	slide
		line 10 10 10 90 0.1 "blue"
		line 20 10 20 90 0.2 "blue"
		line 30 10 30 90 0.3 "blue"
		line 40 10 40 90 0.4 "blue"
		line 50 10 50 90 1   "blue"
		line 60 10 60 90 2   "blue"
		line 70 10 70 90 3   "blue"
		line 80 10 80 90 4   "blue"
		line 90 10 90 90 7   "blue"
	eslide
edeck

Trace of calls to canvas.Line

line=&canvas.Line{Position1:fyne.Position{X:79, Y:550}, Position2:fyne.Position{X:79, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:0.792}
line=&canvas.Line{Position1:fyne.Position{X:158, Y:550}, Position2:fyne.Position{X:158, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:1.584}
line=&canvas.Line{Position1:fyne.Position{X:237, Y:550}, Position2:fyne.Position{X:237, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:2.376}
line=&canvas.Line{Position1:fyne.Position{X:316, Y:550}, Position2:fyne.Position{X:316, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:3.168}
line=&canvas.Line{Position1:fyne.Position{X:396, Y:550}, Position2:fyne.Position{X:396, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:7.92}
line=&canvas.Line{Position1:fyne.Position{X:475, Y:550}, Position2:fyne.Position{X:475, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:15.84}
line=&canvas.Line{Position1:fyne.Position{X:554, Y:550}, Position2:fyne.Position{X:554, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:23.76}
line=&canvas.Line{Position1:fyne.Position{X:633, Y:550}, Position2:fyne.Position{X:633, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:31.68}
line=&canvas.Line{Position1:fyne.Position{X:712, Y:550}, Position2:fyne.Position{X:712, Y:61}, Hidden:false, StrokeColor:color.RGBA{R:0x0, G:0x0, B:0xff, A:0xff}, StrokeWidth:55.44}

Device (please complete the following information):

• OS: [Linux, MacOS ]
• Go version: [1.14.1]
• Fyne version: [1.2.3]

[andydotxyz]

As discussed on the call yesterday I wonder if this "cap" (which exists for memory bandwidth / performance reasons) could be a little more dynamic?
Instead of "10" it could possibly be as simple as setting it to StrokeWidth+2 (adding a little for possible antialiasing etc)? Is this something you can experiment with at your end @ajstarks?

[ajstarks]

Sure.. Happy to help

[andydotxyz]

On develop ready for release