I written a VB.Net program that intercept RENDER_PATH and RENDER_TEXT events generated by iText7 module.

I have written a little code to find location of TEXT.

    Dim ascent As LineSegment = t.GetAscentLine()
    Dim descent As LineSegment = t.GetDescentLine()

    Dim initX As Single = descent.GetStartPoint().Get(0)
    Dim initY As Single = descent.GetStartPoint().Get(1)
    Dim endX As Single = ascent.GetEndPoint().Get(0)
    Dim endY As Single = ascent.GetEndPoint().Get(1)

For specific PDF page, all values returned by GetStartPoint() and GetEndPoint() are between 20 and 600.

To find PATH values, I have writte following code

   Private Sub RenderPath(render As PathRenderInfo)
        For Each sp As Subpath In render.GetPath().GetSubpaths()
            Console.WriteLine(render.GetPath().ToString())
            For Each segment In sp.GetSegments()
                Console.WriteLine("  " & segment.ToString())
                Select Case segment.GetType().FullName
                    Case "iText.Kernel.Geom.Line"
                        Dim oLine As iText.Kernel.Geom.Line = segment
                        Dim oList As List(Of Point) = oLine.GetBasePoints()
                        Dim n = 0
                        For Each p In oList
                            Console.WriteLine("    p" & CStr(n) & ".x: " & CStr(oList(n).GetX()))
                            Console.WriteLine("    p" & CStr(n) & ".y: " & CStr(oList(n).GetY()))
                            n  = 1
                        Next
                        Console.WriteLine("    width: " & CStr(oList(0).GetX() - oList(1).GetX()))
                        Console.WriteLine("    height: " & CStr(oList(0).GetY() - oList(1).GetY()))
                    Case "iText.Kernel.Geom.BezierCurve"
                    Case Else
                        Dim i0 = 0
                End Select
            Next
        Next
    End Sub

All location's values returned by GetX() and GetY() functions are now between ... 200 and 6000 !

Why PATH location's values seems to be 10 times greater that TEXT location's values ?

Is that normal or is that a BUG ?

In iText7, what are dimensions of TEXT locations and dimensions of PATH segments ?

CodePudding user response：

In iText7, what are dimensions of TEXT locations and dimensions of PATH segments ?

Indeed, the coordinates returned by TextRenderInfo and those returned by PathRenderInfo differ:

• Coordinates returned by TextRenderInfo are given in the default user space coordinates of the given page, i.e. all active transformations are already accounted for.

• Coordinates returned by PathRenderInfo, on the other hand, are given in the current user space coordinates - current when the path is constructed and drawn. To transform these coordinates into default user space coordinates, you have to apply the CTM (current transformation matrix) to the path. You can retrieve the CTM using the GetCTM method of the path render info object.

That different render info classes return coordinates in conceptually different coordinate system probably isn't intuitive and should be made clearer.

In case of your document page the CTM appears to be a scaling transformation by a factor of 0.1.