From VFXPedia

Contents 1 CrosshairControl 1.1 Description 1.2 Attributes 1.3 Example 1.4 Tips for CrossHairControl (edit)

CrosshairControl

Description

The crosshair control is an preview control that shows a crosshair to represent the position of Point value. The crosshair is added to an Input by setting the INPID_PreviewControl attribute of an input to "CrosshairControl" in the AddInput function's attribute table.

Attributes

CHC_Style

string : Determines the appearance of the crosshair control. Can be set to "NormalCross", "DiagonalCross", "Rectangle", or "Circle".

.

Example

The FuseTransform.Fuse example found at Example Fuses is a good example of the CrossHair control.

The following example is a very simplified Fuse which uses a crosshair control to transform an image.

FuRegisterClass("SampleOffset", CT_Tool, {
	REGS_Category = "Fuses\\Samples",
	REGS_OpIconString = "SOf",
	REGS_OpDescription = "SampleOffset",
	})
 
function Create()
	InCenter = self:AddInput("Center", "Center", {
		LINKID_DataType = "Point",
		INPID_InputControl = "OffsetControl",
		INPID_PreviewControl = "CrosshairControl",
		})
 
	InImage = self:AddInput("Input", "Input", {
		LINKID_DataType = "Image",
		LINK_Main = 1,
		})
 
	OutImage = self:AddOutput("Output", "Output", {
		LINKID_DataType = "Image",
		LINK_Main = 1,
		})				
		
end
 
function Process(req) 
	local img     = InImage:GetValue(req)
	local center  = InCenter:GetValue(req)
	
	out = img:Transform(nil, { 
		XF_XOffset = center.X, 
		XF_YOffset = center.Y, 
		XF_XAxis = 0.5,
		XF_YAxis = 0.5,
		XF_XSize = 1, 
		XF_YSize = 1, 
		XF_Angle = 0, 
		XF_EdgeMode = "Black",
		})
	
	OutImage:Set(req, out)
end

Tips for CrossHairControl (edit)

There are attributes that apply to all preview controls. PCD_OffsetX and PCD_OffsetY will shift the crosshair in the viewer by the specified distance. This is useful if you want a pivot crosshair to follow the translation crosshair (as is the case with Fusion's transform tool). To implement this behavior, you need to update those attributes in the NotifyChanged() event handler.