Inserting images from memory
TX Text Control offers various functions to insert images from physical files in many supported formats. Sometimes, however, it is necessary that images are inserted from memory.
The Microsoft .NET Framework ships with many options to import, manipulate and export images. This sample illustrates how to insert a System.Drawing.Image into the current document of TX Text Control.
The secret here, is actually quite simple: We use the RTF format to load the image. The System.Drawing.Image is saved as a JPEG, converted into a hex string and embedded into an RTF string that is valid according to the RTF specifications. This document can be loaded using the Selection.Load method.
Private Sub InsertImageFromMemory(ByVal image As System.Drawing.Image, ByVal _
AsFixedImage As Boolean, ByVal tx As TXTextControl.TextControl)
Dim stream As New System.IO.MemoryStream
Dim buffer() As Byte
Dim RTFString As String
Dim ImageString As New System.Text.StringBuilder
image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg)
buffer = stream.ToArray()
For Each nbyte As Byte In buffer
ImageString.Append(nbyte.ToString("x2"))
Next
RTFString = "{\rtf1" + vbCr
If AsFixedImage = True Then RTFString += "{\shp{\*\shpinst\shpfhdr0\ _
shpbxcolumn\shpbypara\shpwr2\shpwrk0\shpfblwtxt0\shplid1025{\sp _
{\sn shapeType}{\sv 75}}{\sp{\sn dxWrapDistLeft}{\sv 0}}{\sp _
{\sn dxWrapDistRight}{\sv 0}}{\sp{\sn pib}{\sv "
RTFString += "{\pict\jpegblip\picscalex100\picscaley100" + vbCr
RTFString += ImageString.ToString()
RTFString += "}}"
If AsFixedImage = True Then RTFString += "\par}"
tx.Selection.Load(RTFString, TXTextControl.StringStreamType.RichTextFormat)
End Sub
This function allows the image to be inserted as a character or fixed anchored at a paragraph. It is called like this:
Dim myImage As System.Drawing.Image = System.Drawing.Image.FromFile("Blue hills.png")
InsertImageFromMemory(myImage, False, TextControl1)
Using this technique, it is possible to import image formats that are not directly supported by TX Text Control.
You can download the fully functional sample project for Visual Basic .NET to test this sample application for yourself. The minimum requirements for this sample application are TX Text Control .NET for Windows Forms trial version and Visual Studio .NET 2003.
