topic Re: How to change text color ? in Revit API Forum

How to change text color ?

Anonymous — Mon, 05 Oct 2009 22:09:08 GMT

Hi everyone,

I am using the ColorDialog control from VisualStudio 2008 in order to
select a color and then I retrieve the RGB components in three variables:

ColorComponentRed
ColorComponentGreen
ColorComponentBlue

What I want is to assign this color to some text (it is text because it's
filtered as this) but the following code is not working:

[code]
Dim colorparam As Parameter
colorparam =
elem.ObjectType.Parameter(parameterId:=Parameters.BuiltInParameter.TEXT_COLOR)

Dim app As New Autodesk.Revit.Creation.Application()
Dim color As Autodesk.Revit.Color = app.NewColor()

color.Red = ColorComponentRed
color.Green = ColorComponentGreen
color.Blue = ColorComponentBlue

colorparam.Set(color)
[/code]

Can anybody tell me what I am doing wrong and how to do it, please ?

TIA

--
Humans are born with a wide horizon.
As time goes by, the horizon narrows and
narrows, until it becomes a point of view.

Re: How to change text color ?

Anonymous — Wed, 21 Feb 2018 09:17:55 GMT

I have the same problem. Did you find a solution?

Re: How to change text color ?

Anonymous — Wed, 21 Feb 2018 10:01:53 GMT

Do you want to change the color of an annotation in Revit? If so, have you tried opening a transaction to do that? You can only change anything in the model if it is inside a transaction.

https://knowledge.autodesk.com/search-result/caas/CloudHelp/cloudhelp/2016/ENU/Revit-API/files/GUID-BECA30DB-23B4-4E71-BE24-DC4DD176E52D-htm.html

Re: How to change text color ?

Revitalizer — Wed, 21 Feb 2018 10:29:46 GMT

Hi,

private int GetRevitTextColorFromSystemColor(System.Drawing.Color color)
{
return (int)color.R * (int)Math.Pow(2, 0) + (int)color.G * (int)Math.Pow(2, 8) + (int)color.B * (int)Math.Pow(2, 16);
}

...I know that 2^0 is just 1, so you could better use:

private int GetRevitTextColorFromSystemColor(System.Drawing.Color color)
{
return (int)color.R + (int)color.G * (int)Math.Pow(2, 8) + (int)color.B * (int)Math.Pow(2, 16);
}

Then, for example:

int color= GetRevitTextColorFromSystemColor(yourSystemColor);

textNoteType.get_Parameter(BuiltInParameter.LINE_COLOR).Set(color);

Also note that starting with Revit 2017, there is a ColorSelectionDialog available.

You can use its SelectedColor property to get a Revit color instead of a system color.

Revitalizer

Re: How to change text color ?

jeremytammik — Thu, 22 Feb 2018 13:44:00 GMT

Dear Rudi,

Would this be equivalent (and faster) using the bitwise shift operator?

    /// <summary>
    /// Revit text colour parameter value stored as an integer 
    /// in text note type BuiltInParameter.LINE_COLOR.
    /// </summary>
    private int GetRevitTextColorFromSystemColor( 
      System.Drawing.Color color )
    {
      //return (int) color.R
      //  + (int) color.G * (int) Math.Pow( 2, 8 )
      //  + (int) color.B * (int) Math.Pow( 2, 16 );

      return (int) color.R 
        + (int) color.G << 8
        + (int) color.B << 16;
    }

Thank you!

Cheers,

Jeremy

P.S. Probably not... cf. https://stackoverflow.com/questions/1933597/when-to-use-shift-operators-in-c

Re: How to change text color ?

Revitalizer — Thu, 22 Feb 2018 14:02:41 GMT

Hi Jeremy,

I didn't use the bitwise operators so far,

but if providing the same result, it is the more elegant way.

One could replace the System.Drawing.Color by Autodesk.Revit.DB.Color,

the R, G, B properties by their Red, Green, Blue equivalent.

Rudi

Re: How to change text color ?

jeremytammik — Sat, 24 Feb 2018 21:33:55 GMT

Dear Rudi,

I tried it out, but it seems to have no effect:

https://github.com/jeremytammik/the_building_coder_samples/blob/master/BuildingCoder/BuildingCoder/CmdNewTextNote.cs#L196-L211

      using( Transaction t = new Transaction( doc ) )
      {
        t.Start( "Change Text Colour" );

        int color = Util.ToColorParameterValue( 
          255, 0, 0 );

        Element textNoteType = doc.GetElement( 
          txNote.GetTypeId() );

        textNoteType.get_Parameter( 
          BuiltInParameter.LINE_COLOR )
            .Set( color );

        t.Commit();
      }

Any idea why?

Thank you!

Cheers,

Jeremy

Re: How to change text color ?

FAIR59 — Sat, 24 Feb 2018 23:13:14 GMT

the return value for the GetRevitTextColorFromSystemColor() method needs to be:

return (int)( color.R + (color.G << 8) + (color.B << 16));

Re: How to change text color ?

RPTHOMAS108 — Sun, 25 Feb 2018 01:19:09 GMT

Quite convenient as extension methods:

 <Extension()> _
    Public Function AsRGB(ByVal Parameter As Parameter) As Byte()
        Dim I As Integer = Parameter.AsInteger
        Dim Red As Byte = I Mod 256
        I = I \ 256
        Dim Green As Byte = I Mod 256
        I = I \ 256
        Dim Blue As Byte = I Mod 256
        Return New Byte(2) {Red, Green, Blue}
    End Function
    <Extension()> _
    Public Function AsParameterValue(ByVal Color As Color) As Integer
        Return Color.Red + (256 * Color.Green) + (65536 * Color.Blue)
    End Function
    <Extension()> _
    Public Function AsParameterValue(ByVal Color As Windows.Media.Color) As Integer
        Return Color.R + (256 * Color.G) + (65536 * Color.B)
    End Function
    <Extension()> _
    Public Function AsParameterValue(ByVal Color As System.Drawing.Color) As Integer
        Return Color.R + (256 * Color.G) + (65536 * Color.B)
    End Function

Re: How to change text color ?

jeremytammik — Tue, 27 Feb 2018 15:18:31 GMT

Thank you for the suggestions.

The problem was the .NET shift operator precedence.

Plus '+' tkaes higher precedence than left shift '<<', so I had to add parentheses like this:

    /// <summary>
    /// Revit text colour parameter value stored as an integer 
    /// in text note type BuiltInParameter.LINE_COLOR.
    /// </summary>
    public static int ToColorParameterValue( 
      int red, 
      int green, 
      int blue )
    {
      return red + (green << 8) + (blue << 16);
    }

Final result tested and working in The Building Coder samples:

https://github.com/jeremytammik/the_building_coder_samples/blob/master/BuildingCoder/BuildingCoder/Util.cs#L455-L488

https://github.com/jeremytammik/the_building_coder_samples/blob/master/BuildingCoder/BuildingCoder/CmdNewTextNote.cs#L196-L216

Cheers,

Jeremy