show DWG file thumbnail image

[Coolmo]

Brilliant, brilliant, brilliant!! I knew there was some sort of bit by bit code out there that worked!! This did the trick (with a few modifications to fit my code) I basically understand NONE of it but figured enough out as to where to place the STRUCTURE and such and then simply passed my filename to the bitmap object. Thanks to all who have contributed! Thank you so much!

[Jeff H]

What do you not understand I will explain it if need be

[Coolmo]

What do you not understand I will explain it if need be

Actually... I need to invert the colors of the bitmap object before it's passed to the picturebox to correct the "white washout" but all the code I found seems to not like "indexed" bitmaps. Any ideas on how to invert the colors? Remember, I'm NOT using the thumbnailviewer class download but the bit by bit version of the code posted. Since I now have the extracted bitmap thumbnail from the drawing file saved as a System.Drawing.Bitmap, shouldn't there be an easy way to invert the colors? Actually, and easy way was found but once again an error occurs stating you can't change the pixels of an indexed bitmap... or something like that.

Much appreciation (you have no idea how long I've searched for all of this)

[Kerry Brown]

Actually, and easy way was found but once again an error occurs stating you can't change the pixels of an indexed bitmap... or something like that.

What was the code you tried ??

and what was the actual error message. ?

[Jeff H]

You cn set the picture box background to be black and I added a little code so you did not have to look at the whole file path

Now that Kerry stop by at least you got someone who knows what their doing.

In the picture you can see how to set some settings to change Auto, zoom, center etc..
I know you can improve the images unlike AutoCAD's API, luckily there is a ton of info for .NET

 Private Shared folderName As String = ""
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Fbd.ShowDialog = Windows.Forms.DialogResult.OK Then
            folderName = Fbd.SelectedPath
            lstbxFiles.Items.Clear()
            For Each fName In Directory.GetFiles(folderName, "*.dwg")
                Me.lstbxFiles.Items.Add(Path.GetFileNameWithoutExtension(fName))
            Next
        End If
    End Sub

    Private Sub lstbxFiles_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstbxFiles.SelectedIndexChanged
        Dim db As Database = New Database(False, False)
        Dim fname As String = lstbxFiles.SelectedItem.ToString()
        db.ReadDwgFile(folderName & "\" & fname & ".dwg", FileOpenMode.OpenForReadAndReadShare, False, "")

        Dim tmbNail As Bitmap = db.ThumbnailBitmap
        picBox.Image = tmbNail
    End Sub

[Jeff H]

This saves them to file but one of the overloads is a memory stream if it is easer to use a png or gif or whatever then you could probably paint the picture box

db.ThumbnailBitmap.Save.("C:\AcadImages\Doc.Png",System.Drawing.Imaging.ImageFormat.Png)
or
db.ThumbnailBitmap.Save.("C:\AcadImages\Doc.Png",System.Drawing.Imaging.ImageFormat.Gif)

[Coolmo]

What was the code you tried ??

and what was the actual error message. ?

I used this code right after the system.drawing.bitmap was created and just before I passed it to the picturebox:
(without this code the image shows with no errors)

        Dim x As Integer
        Dim y As Integer
        For x = 0 To image.Width - 1 Step 1
            For y = 0 To image.Height - 1 Step 1
                Dim clr As Color = image.GetPixel(x, y)
                Dim clr2 As Color
                If InvertAlpha Then
                    clr2 = Color.FromArgb(255 - clr.A, 255 - clr.R, 255 - clr.G, 255 - clr.B)
                Else
                    clr2 = Color.FromArgb(clr.A, 255 - clr.R, 255 - clr.G, 255 - clr.B)
                End If
                image.SetPixel(x, y, clr2)
            Next
        Next

and got the error "SetPixel is not supported for images with indexed pixel formats"

I did take out the "InvertAlpha" stuff. The way I read the web site I got this from seemed to indicate that this was an optional setting for whether or not you wanted to invert the image and since I always want to.. I took it out.

[Kerry Brown]

The way I read the web site I got this from seemed to indicate < ... >

And the reference is ??

[Coolmo]

Sorry. A Google search for "Drawing.bitmap invert colors" comes up with:

http://www.dreamincode.net/code/snippet2056.htm

[Kerry Brown]

The code you posted ... was that in-line or a public function ?