color inversion

[sam]

Hi
Is there a method, or has anybody already ready written one to determine a
contrasting color to a background color for text. In my case during a paint
of a cell in a data grid.
Thanks

[Peter Proost]

this gives the opposite of a color
TextBox1.ForeCo lor = Color.FromArgb( 255 - TextBox1.BackCo lor.R, 255 -
TextBox1.BackCo lor.G, 255 - TextBox1.BackCo lor.B)

hth Peter

"sam" <sa*@discussion s.microsoft.com > wrote in message
news:08******** *************** ***********@mic rosoft.com...

Hi
Is there a method, or has anybody already ready written one to determine a contrasting color to a background color for text. In my case during a paint of a cell in a data grid.
Thanks

[C-Services Holland b.v.]

Peter Proost wrote:

this gives the opposite of a color
TextBox1.ForeCo lor = Color.FromArgb( 255 - TextBox1.BackCo lor.R, 255 -
TextBox1.BackCo lor.G, 255 - TextBox1.BackCo lor.B)

hth Peter

"sam" <sa*@discussion s.microsoft.com > wrote in message
news:08******** *************** ***********@mic rosoft.com...

Hi
Is there a method, or has anybody already ready written one to determine

a

contrasting color to a background color for text. In my case during a

paint

of a cell in a data grid.
Thanks

But that doesn't always give a contrasting colour as the OP wants. If
the color is close to 50% grey, the resulting colour with your method
will also be close to 50% grey.

Just off the top of my head, you could look at the greyvalue of the
color (20% red, 60% green, 20% blue) and then see if it's below 50%
grey, use white (or a very bright color) and if it's above 50% grey, use
black (or a dark color).

i.e.

dim nGrey,

nGrey = 0.2 * TextBox1.BackCo lor.R + 0.6 * TextBox1.BackCo lor.G + 0.2 *
TextBox1.BackCo lor.B

if nGrey>128 then
Texbox1.ForeCol or(color.black)
Else
Texbox1.ForeCol or(color.white)
Endif

btw those percentages come from the graphics world to convert color intp
greyscale, I didn't make them up.

--
Rinze van Huizen
C-Services Holland b.v.

[Peter Proost]

you're right, it inverts the color it doesn't give the biggest contrast, I
think that in bobpowell's faq there's an example of what the op wants but
I'm not 100% sure

Peter

"C-Services Holland b.v." <cs*@REMOVEcsh4 u.nl> wrote in message
news:7-*************** *****@zeelandne t.nl...

Peter Proost wrote:

this gives the opposite of a color
TextBox1.ForeCo lor = Color.FromArgb( 255 - TextBox1.BackCo lor.R, 255 -
TextBox1.BackCo lor.G, 255 - TextBox1.BackCo lor.B)

hth Peter

"sam" <sa*@discussion s.microsoft.com > wrote in message
news:08******** *************** ***********@mic rosoft.com...

Hi
Is there a method, or has anybody already ready written one to

determine
a

contrasting color to a background color for text. In my case during a

paint

of a cell in a data grid.
Thanks

But that doesn't always give a contrasting colour as the OP wants. If
the color is close to 50% grey, the resulting colour with your method
will also be close to 50% grey.

Just off the top of my head, you could look at the greyvalue of the
color (20% red, 60% green, 20% blue) and then see if it's below 50%
grey, use white (or a very bright color) and if it's above 50% grey, use
black (or a dark color).

i.e.

dim nGrey,

nGrey = 0.2 * TextBox1.BackCo lor.R + 0.6 * TextBox1.BackCo lor.G + 0.2 *
TextBox1.BackCo lor.B

if nGrey>128 then
Texbox1.ForeCol or(color.black)
Else
Texbox1.ForeCol or(color.white)
Endif

btw those percentages come from the graphics world to convert color intp
greyscale, I didn't make them up.

--
Rinze van Huizen
C-Services Holland b.v.

[Mick Doherty]

I don't believe there is any reliable method for what you want.
Heres a selection of methods (in VB) each of which has their own problems.

Private Function InvertColor(ByV al ColorIn As Color) As Color
Return Color.FromArgb( ColorIn.ToArgb Xor &HFFFFFF)
End Function

Private Function ContrastingColo r(ByVal ColorIn As Color) As Color
If MidRange(ColorI n) Then Return Color.White
Return InvertColor(Col orIn)
End Function

Private Function MidRange(ByVal ColorIn As Color) As Boolean
Return ColorIn.R > 100 AndAlso ColorIn.R < 160 AndAlso _
ColorIn.G > 100 AndAlso ColorIn.G < 160 AndAlso _
ColorIn.B > 100 AndAlso ColorIn.B < 160
End Function

Private Function BlackOrWhite(By Val colorin As Color) As Color
If colorin.GetBrig htness < 0.5 Then
Return Color.White
End If
Return Color.Black
End Function

--
Mick Doherty
http://dotnetrix.co.uk/nothing.html
"sam" <sa*@discussion s.microsoft.com > wrote in message
news:08******** *************** ***********@mic rosoft.com...

Hi
Is there a method, or has anybody already ready written one to determine
a
contrasting color to a background color for text. In my case during a
paint
of a cell in a data grid.
Thanks