Bug? Canvas draw line and textTransparent

[rossati]

Hi

The draw line (and text) do not accept

Colors.Transparent

nor

ARGB (0,0,0,0)

. See image attached.

    Dim Can As Canvas
    Can.Initialize(PanelMain)
    Can.DrawColor(Colors.White)
    Can.DrawLine(10dip,10dip,100dip,10dip,Colors.Transparent,2dip)
    Can.DrawLine(10dip,25dip,100dip,25dip,Colors.ARGB(0,0,0,0),2dip)
    Can.DrawLine(10dip,40dip,100dip,40dip,Colors.ARGB(0,0,0,1),2dip)
    Can.DrawLine(10dip,55dip,100dip,55dip,Colors.Black,2dip)
    Can.DrawText("Transparent",110dip, 10dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Black Transparent",110dip, 25dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Transparent",110dip, 40dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Not Transparent",110dip, 55dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")

The work around is

Can.DrawLine(10dip,40dip,100dip,40dip,Colors.ARGB(0,0,0,1),2dip)

 

[Erel]

Not sure that I understand the issue. What do you see and what did you expect?

 

[rossati]

I apologize my concision:

The Colors.transparent has no effect when applied to DrawLine (and DrawText).
You can see this in the image included: the first two lines they should have been invisible.
For obtain "transparence" I have used a user transparent color, like this:

Colors.ARGB(0,0,0,1)

.

 

[Erel]

Seems to work as expected:

Sub Activity_Create(FirstTime As Boolean)
   Activity.LoadLayout("1")
   Dim cvs As Canvas
   cvs.Initialize(Panel1)
   cvs.DrawColor(Colors.Red)
   cvs.DrawLine(0, 0, 100dip, 100dip, Colors.Transparent, 5dip)
   cvs.DrawText("XXX", 50dip, 50dip, Typeface.DEFAULT_BOLD, 40, Colors.Transparent, "CENTER")
   Panel1.Invalidate
End Sub

 

[rossati]

thanks Erel
my be is a bug on version 7.01 or I am misunderstanding how Transparent works.

    Dim Can As Canvas
    Can.Initialize(PanelMain)
    Can.DrawColor(Colors.White)
    Can.DrawLine(10dip,10dip,100dip,10dip,Colors.Transparent,2dip)
    Can.DrawLine(10dip,25dip,100dip,25dip,Colors.ARGB(0,0,0,0),2dip)
    Can.DrawLine(10dip,40dip,100dip,40dip,Colors.ARGB(0,0,0,255),2dip)
    Can.DrawLine(10dip,55dip,100dip,55dip,Colors.Black,2dip)
    Can.DrawText("Transparent",110dip, 10dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Black Transparent",110dip, 25dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Transparent",110dip, 40dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawText("Not Transparent",110dip, 55dip,Typeface.DEFAULT,12,Colors.Magenta,"LEFT")
    Can.DrawLine(0, 0, 100dip, 100dip, Colors.Transparent, 5dip)
    Can.DrawText("XXX", 50dip, 50dip, Typeface.DEFAULT_BOLD, 40, Colors.Transparent, "CENTER")

 

[Erel]

When you draw with a fully transparent color you see the color behind the current view.

 

[rossati]

Thanks
I suppose full transparent is black Transparent, because

Can.DrawLine(10dip,40dip,100dip,40dip,Colors.ARGB(0,0,0,255),2dip)

works as I would.

 

[LucaMs]

Black, Blue, Red... full transparent is... FULLY transparent (if you set the alpha parameter to 0).

 

[Erel]

There is no bug here. For further questions please start a new thread in the questions forum.