You can draw polygons with B4XCanvas.DrawPath. The following code calls B4XCanvas.DrawPath on B4A and B4i and calls a different method in B4J. DrawPath in B4J is slower than the other drawing methods as it requires clipping the canvas (it is only required in B4J).
To summarize, only use this code if you encountered a performance issue with B4XCanvas.DrawPath in B4J:
To summarize, only use this code if you encountered a performance issue with B4XCanvas.DrawPath in B4J:
B4X:
'Example
Sub Page1_Click
DrawPolygon(cvs, Array (Array As Int(100dip, 100dip), Array As Int(200dip, 0), _
Array As Int (300dip, 100dip), Array As Int(200dip, 200dip), Array As Int(100dip, 100dip)), _
xui.Color_Red, True, 2dip)
cvs.Invalidate
End Sub
Sub DrawPolygon (cvs1 As B4XCanvas, Points As List, Color As Int, Filled As Boolean, StrokeWidth As Double)
If Points.Size < 1 Then Return
#if B4A or B4i
Dim FirstPoint() As Int = Points.Get(0)
Dim p As B4XPath
p.Initialize(FirstPoint(0), FirstPoint(1))
For i = 1 To Points.Size - 1
Dim point() As Int = Points.Get(i)
p.LineTo(point(0), point(1))
Next
cvs1.DrawPath(p, Color, Filled, StrokeWidth)
#Else
Dim jcvs As JavaObject = cvs1
jcvs = jcvs.GetFieldJO("cvs").RunMethodJO("getObject", Null).RunMethod("getGraphicsContext2D", Null)
jcvs.RunMethod("save", Null)
Dim xpoints(Points.Size), ypoints(Points.Size) As Double
For i = 0 To Points.Size - 1
Dim point() As Int = Points.Get(i)
xpoints(i) = point(0)
ypoints(i) = point(1)
Next
Dim paint As Object = fx.Colors.From32Bit(Color)
If Filled Then
jcvs.RunMethod("setFill", Array(paint))
jcvs.RunMethod("fillPolygon", Array(xpoints, ypoints, Points.Size))
Else
jcvs.RunMethod("setStroke", Array(paint))
jcvs.RunMethod("setLineWidth", Array(StrokeWidth))
jcvs.RunMethod("strokePolygon", Array(xpoints, ypoints, Points.Size))
End If
jcvs.RunMethod("restore", Null)
#End If
End Sub
