ToneOperatorParameters for Viewport

[AVCPlugins]

AutoCAD Viewports have color and brightness settings for texture rendering. The user configures them in the _RenderExposure palette. I found in the .Net API that viewports have a ToneOperatorParameters property. This object already has the properties I need, including Exposure. But here's the problem: AutoCAD ignores changes to these properties. Although all the setters are available, you can assign properties to the ToneOperatorParameters object, and you can change the viewport's ToneOperatorParameters itself. No errors occur. But the new values ​​aren't saved! If anyone has worked with these settings, please let me know. I have a feeling this is a bug in the API. I'm testing on AutoCAD 2025 and 2026.

[ActivistInvestor]

I think you need to assign/re-assign the ToneOperatorParameters instance to the Viewport's ToneOperatorParameters property. You may also need to call UpdateDisplay(). 

[AVCPlugins]

I tried reassigning the ToneOperatorParameters object. Immediately afterward, all its values ​​revert to their original values. I see this in step-by-step debugging.  And my command calls Regen at the end – this has no effect.

public static void
SetExposure(this Viewport ts, double value)
{
if (ts is null || ts.IsErased || ts.ObjectId.IsNull || double.IsNaN(value)) return;
try
{
if (value < -6) value = -6;
if (value > 21) value = 21;
using Autodesk.AutoCAD.GraphicsInterface.ToneOperatorParameters tp = ts.ToneOperatorParameters;
if (tp.ExistsProp("Exposure") && value != (double)tp.GetProp("Exposure"))
{
tp.SetProp("Exposure", value);
ts.ToneOperatorParameters = tp;
}
}
catch { Debug.Print("Viewport.Exposure error"); }
}

[ActivistInvestor]

After you assign a value to the property, try issuing the REGEN3 command. 

[essam-salah]

hi

---

@AVCPlugins wrote:

I tried reassigning the ToneOperatorParameters object. Immediately afterward, all its values ​​revert to their original values. I see this in step-by-step debugging.  And my command calls Regen at the end – this has no effect.

public static void
SetExposure(this Viewport ts, double value)
{
if (ts is null || ts.IsErased || ts.ObjectId.IsNull || double.IsNaN(value)) return;
try
{
if (value < -6) value = -6;
if (value > 21) value = 21;
using Autodesk.AutoCAD.GraphicsInterface.ToneOperatorParameters tp = ts.ToneOperatorParameters;
if (tp.ExistsProp("Exposure") && value != (double)tp.GetProp("Exposure"))
{
tp.SetProp("Exposure", value);
ts.ToneOperatorParameters = tp;
}
}
catch { Debug.Print("Viewport.Exposure error"); }
}

---

have you checked to commit the outer or any open transction?

also have tried to call viewport.UpdateDisplay(); after setting viewportToneOperatorParameters ?

[ActivistInvestor]

If the Viewport you're modifying is not the active viewport, Regen will not work. the REGENALL command might.