iOS Question how to convert panel color to rgb ?

[bagazhou]

HI

i want to use ColorTemplate.SelectedColor to set color to panel, and how to use panel color to drawline ? thanks

   Dialog.Title = "select color"
   
   Wait For (Dialog.ShowTemplate(ColorTemplate, "OK", "", "Exit")) Complete (Result As Int)
   If Result = XUI.DialogResponse_Positive Then
       Log("ColorTemplate.SelectedColor:" & ColorTemplate.SelectedColor)
       
      PanelColorCurrent.Color = ColorTemplate.SelectedColor
   
      'in this line , how to change panel color to rgb?
      'Canv.DrawLine(oldX, oldY, newX, newY, Colors.ARGB(color_A,color_R,color_G,color_B), 5)
      'Canv.Refresh

       
   End If

 

[Brandsum]

https://www.b4x.com/android/forum/threads/get-the-rgb-color-from-getpixel.56760/#post-357302

Sub GetARGB(Color As Int) As Int()
    Private res(4) As Int
    res(0) = Bit.UnsignedShiftRight(Bit.And(Color, 0xff000000), 24)
    res(1) = Bit.UnsignedShiftRight(Bit.And(Color, 0xff0000), 16)
    res(2) = Bit.UnsignedShiftRight(Bit.And(Color, 0xff00), 8)
    res(3) = Bit.And(Color, 0xff)
    Return res
End Sub

 

[bagazhou]

Thank you for your help ，I'll give it a try.

 

[Erel]

Why do you need the ARGB values?

Dim pnl As B4XView = YourPanel
Canv.DrawLine(oldX, oldY, newX, newY, pnl.Color, 5dip)

 

[emexes]

https://www.b4x.com/android/forum/threads/get-the-rgb-color-from-getpixel.56760/#post-357302

The bit-shifting approach works fine, but does have an edgy feel about it due to Int being signed.

The ByteConverter library has methods specifically for packing and unpacking different-sized variables, and is often better suited to the task (admittedly, for this particular example, it's a 51:49 toss-up... but I'd argue that generally: consistent approach = simpler programming life):

Sub GetARGB(Color As Int) As Byte()
    Dim bc As ByteConverter
    Dim ColorComponents() As Byte = bc.IntsToBytes(Array As Int(Color))    'split 32-bit Color Int into four 8-bit bytes
    Return ColorComponents
End Sub

 

[emexes]

or even, no need for temporary array, so could just be:

Sub GetARGB(Color As Int) As Byte()
    Dim bc As ByteConverter
    return bc.IntsToBytes(Array As Int(Color))    'split 32-bit Color Int into four 8-bit bytes
End Sub