RichTextBox Images Quality Loss
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Answers
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Hello Everyone,
This is an example i made of creating a Metafile from an image on your hard drive and pasting it into a RichTextBox. This method will produce a much better quality image than just pasting a standard bitmap image into your RichTextBox. You can re-size the image to the size of a postal stamp or to the size of the whole RichTextBox without making your image look blurry and discolored. I commented the AddImageToRtb sub that i wrote so it should be fairly easy for anyone to understand the steps i took to do this. I don`t claim this to be a prize winning masterpiece but, it works pretty good.
I also want to say Thanks Again to JohnWein for helping point me in the rite direction for doing this and for the helpful link he provided to the ClipboardMetafileHelper code which contains the PutEnhMetafileOnClipboard function i used in this example.
You can test this example by creating a new Windows Form Application project and placing 2 Buttons and 1 RichTextBox onto the Form. Button1 will allow you to select an image from your hard drive to add to the RichTextBox. Button2 will allow you to save your Rich Text File to your hard drive. Have Fun!!!
Imports System.Drawing.Imaging Imports System.Runtime.InteropServices Public Class Form1 <DllImport("user32.dll", EntryPoint:="OpenClipboard")> Private Shared Function OpenClipboard(ByVal hWnd As IntPtr) As Boolean End Function <DllImport("user32.dll", EntryPoint:="EmptyClipboard")> Private Shared Function EmptyClipboard() As Boolean End Function <DllImport("user32.dll", EntryPoint:="SetClipboardData")> Private Shared Function SetClipboardData(ByVal uFormat As Integer, ByVal hWnd As IntPtr) As IntPtr End Function <DllImport("user32.dll", EntryPoint:="CloseClipboard")> Private Shared Function CloseClipboard() As Boolean End Function <DllImport("gdi32.dll", EntryPoint:="CopyEnhMetaFileA")> Private Shared Function CopyEnhMetaFile(ByVal hemfSrc As IntPtr, ByVal hNULL As IntPtr) As IntPtr End Function <DllImport("gdi32.dll", EntryPoint:="DeleteEnhMetaFile")> Private Shared Function DeleteEnhMetaFile(ByVal hemfSrc As IntPtr) As Boolean End Function 'I do not claim to have written the PutEnhMetafileOnClipboard function. 'For more information on this function and why it is needed refer to http://support.microsoft.com/kb/323530/en-us Private Shared Function PutEnhMetafileOnClipboard(ByVal hWnd As IntPtr, ByVal mf As Metafile) As Boolean Dim bResult As New Boolean() bResult = False Dim hEMF, hEMF2 As IntPtr hEMF = mf.GetHenhmetafile() ' invalidates mf If Not hEMF.Equals(New IntPtr(0)) Then hEMF2 = CopyEnhMetaFile(hEMF, New IntPtr(0)) If Not hEMF2.Equals(New IntPtr(0)) Then If OpenClipboard(hWnd) Then If EmptyClipboard() Then Dim hRes As IntPtr hRes = SetClipboardData(14, hEMF2) ' 14 == CF_ENHMETAFILE bResult = hRes.Equals(hEMF2) CloseClipboard() End If End If End If DeleteEnhMetaFile(hEMF) End If Return bResult End Function Private Sub AddImageToRtb(ByVal imgPathName As String) 'Create a bitmap of the image you want to draw to the metafile Dim bm As New Bitmap(imgPathName) 'Create a graphics object of the Form and get its hdc handle Dim me_grx As Graphics = Me.CreateGraphics() Dim me_hdc As IntPtr = me_grx.GetHdc() 'Create a new metafile the same size as the image and create a graphics object for it Dim emf As New Metafile("Tmp.emf", me_hdc, New Rectangle(0, 0, bm.Width, bm.Height), MetafileFrameUnit.Pixel) Dim emf_gr As Graphics = Graphics.FromImage(emf) 'Draw the bitmap image onto the new metafile emf_gr.DrawImage(bm, 0, 0) 'Dispose the bitmap and the metafile graphics object emf_gr.Dispose() bm.Dispose() 'Copy the new metafile to the clipboard PutEnhMetafileOnClipboard(Me.Handle, emf) 'Paste the new metafile in the RichTextBox RichTextBox1.Paste() 'Dispose the rest of the objects we created me_grx.ReleaseHdc(me_hdc) me_grx.Dispose() emf.Dispose() End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim ofd As New OpenFileDialog ofd.Title = "Add Image..." ofd.Filter = "Images|*.jpg;*.bmp;*.png" ofd.Multiselect = False If ofd.ShowDialog = DialogResult.OK Then AddImageToRtb(ofd.FileName) End If ofd.Dispose() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Dim sfd As New SaveFileDialog sfd.Title = "Save File..." sfd.FileName = "Untitled" sfd.DefaultExt = "rtf" sfd.AddExtension = True If sfd.ShowDialog = DialogResult.OK Then RichTextBox1.SaveFile(sfd.FileName, RichTextBoxStreamType.RichText) End If sfd.Dispose() End Sub End Class
EDIT : Updated code so that no temporary images are saved on the hard drive. Again thanks to JohnWein`s help with this.
- Edited by IronRazerz Wednesday, January 15, 2014 2:17 AM
- Marked as answer by Carl Andersson Wednesday, January 15, 2014 4:10 PM
All replies
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I have heard about metafile. But how do i make one from an image?
Well there's a few issues with the possible solution I wanted to propose.
First when an image is pasted into a RichTextBox from the clip board and is then resized its actual image size apparently does not change. Because after the clip board is cleared and the image in the RichTextBox is sized much smaller it can be copied back to the clip board and its size in the clip board is the same as it was when the image was first pasted into the RichTextBox from the clip board.
The only changes I saw were changes to the images metadata, I guess it is called, which I suppose pertains to how the RichTextBox displays the image.
In the image below the top picture is an image pasted into a RichTextBox before resizing. The same image is in the PictureBox to the right of the RichTextBox which was resized smaller using "graphicsHandle.InterpolationMode = InterpolationMode.HighQualityBicubic". The bottom picture in the image below is the image in the RichTextBox resized to approximately the same size as the image in the PictureBox. You can see the loss of quality in the RichTextBox image.
Below is the "metadata" of the top pictures RichTextBox image followed by the "metadata" of the bottom pictures RichTextBox image. You can see how the picw, pich, picwgoal and pichgoal values changed. It may not be too difficult to figure how to use those values (I haven't really looked at them yet) with an actual bitmap to adjust the bitmaps size and replace the image in the RichTextBox with a high quality interpolated bitmap.
{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fnil\fcharset0 Microsoft Sans Serif;}} \uc1\pard\f0\fs29{\pict\wmetafile8\picw8148\pich6931\picwgoal4619\pichgoal3929 {\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fnil\fcharset0 Microsoft Sans Serif;}} \uc1\pard\f0\fs29{\pict\wmetafile8\picw2514\pich2275\picwgoal1425\pichgoal1290The issue I see is that if you downsize the image in the RTB and replace it with a high quality image then the new high quality image will be whatever size it is instead of the original size of the original image pasted into the RTB. So if you attempt to resize the small image larger there will be loss at some point. If the original image pasted into the RTB were still available though then it could always be used when resizing occurs to enlarge or reduce a copy of it. Then replace the image in the RTB after it is resized.
So basically when an image is pasted into an RTB save a copy of it to a list(of Image) or something. Then read its metadata and store it. If it is resized wait until the resizing is done, read its new metadata, figure out what size the original image was, enlarge or decrease its size according to the metadata before and after values and replace it with a new bitmap image copied to the clipboard for pasting into the RTB.
And be able to do this for multiple images in an RTB. I would guess something in an RTB images metadata can denote it from another RTB image.
So maybe sometime tomorrow I may end up being able to do it or maybe not.
Please BEWARE that I have NO EXPERIENCE and NO EXPERTISE and probably onset of DEMENTIA which may affect my answers! Also, I've been told by an expert, that when you post an image it clutters up the thread and mysteriously, over time, the link to the image will somehow become "unstable" or something to that effect. :) I can only surmise that is due to Global Warming of the threads.
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Ok now, i use this code for addin my images right now:
OpenImage.ShowDialog() If OpenImage.FileName = "" Then Else Dim img As Image = Image.FromFile(OpenImage.FileName) Dim orgData = Clipboard.GetDataObject Clipboard.SetImage(img) Me.RichTextBox1.Paste() Clipboard.SetDataObject(orgData) End IfAnd when i resize the image it gets like this:
Programs such as WordPad using something like(if i understood it right):
- Create a EMF file from the image
- Convert it to WMF.
- Convert the bytes to hexademicals.
Programs like WordPad is using an convertion to make the image correct in resize.
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Ok now, i use this code for addin my images right now:
OpenImage.ShowDialog() If OpenImage.FileName = "" Then Else Dim img As Image = Image.FromFile(OpenImage.FileName) Dim orgData = Clipboard.GetDataObject Clipboard.SetImage(img) Me.RichTextBox1.Paste() Clipboard.SetDataObject(orgData) End IfAnd when i resize the image it gets like this:
Programs such as WordPad using something like(if i understood it right):
- Create a EMF file from the image
- Convert it to WMF.
- Convert the bytes to hexademicals.
Programs like WordPad is using an convertion to make the image correct in resize.
Just construct a metafile and draw your image to it. Copy the metafile to the Clipboard and paste to your rich text box. I don't know how to make it any simpler. -
Hello Everyone,
This is an example i made of creating a Metafile from an image on your hard drive and pasting it into a RichTextBox. This method will produce a much better quality image than just pasting a standard bitmap image into your RichTextBox. You can re-size the image to the size of a postal stamp or to the size of the whole RichTextBox without making your image look blurry and discolored. I commented the AddImageToRtb sub that i wrote so it should be fairly easy for anyone to understand the steps i took to do this. I don`t claim this to be a prize winning masterpiece but, it works pretty good.
I also want to say Thanks Again to JohnWein for helping point me in the rite direction for doing this and for the helpful link he provided to the ClipboardMetafileHelper code which contains the PutEnhMetafileOnClipboard function i used in this example.
You can test this example by creating a new Windows Form Application project and placing 2 Buttons and 1 RichTextBox onto the Form. Button1 will allow you to select an image from your hard drive to add to the RichTextBox. Button2 will allow you to save your Rich Text File to your hard drive. Have Fun!!!
Imports System.Drawing.Imaging Imports System.Runtime.InteropServices Public Class Form1 <DllImport("user32.dll", EntryPoint:="OpenClipboard")> Private Shared Function OpenClipboard(ByVal hWnd As IntPtr) As Boolean End Function <DllImport("user32.dll", EntryPoint:="EmptyClipboard")> Private Shared Function EmptyClipboard() As Boolean End Function <DllImport("user32.dll", EntryPoint:="SetClipboardData")> Private Shared Function SetClipboardData(ByVal uFormat As Integer, ByVal hWnd As IntPtr) As IntPtr End Function <DllImport("user32.dll", EntryPoint:="CloseClipboard")> Private Shared Function CloseClipboard() As Boolean End Function <DllImport("gdi32.dll", EntryPoint:="CopyEnhMetaFileA")> Private Shared Function CopyEnhMetaFile(ByVal hemfSrc As IntPtr, ByVal hNULL As IntPtr) As IntPtr End Function <DllImport("gdi32.dll", EntryPoint:="DeleteEnhMetaFile")> Private Shared Function DeleteEnhMetaFile(ByVal hemfSrc As IntPtr) As Boolean End Function 'I do not claim to have written the PutEnhMetafileOnClipboard function. 'For more information on this function and why it is needed refer to http://support.microsoft.com/kb/323530/en-us Private Shared Function PutEnhMetafileOnClipboard(ByVal hWnd As IntPtr, ByVal mf As Metafile) As Boolean Dim bResult As New Boolean() bResult = False Dim hEMF, hEMF2 As IntPtr hEMF = mf.GetHenhmetafile() ' invalidates mf If Not hEMF.Equals(New IntPtr(0)) Then hEMF2 = CopyEnhMetaFile(hEMF, New IntPtr(0)) If Not hEMF2.Equals(New IntPtr(0)) Then If OpenClipboard(hWnd) Then If EmptyClipboard() Then Dim hRes As IntPtr hRes = SetClipboardData(14, hEMF2) ' 14 == CF_ENHMETAFILE bResult = hRes.Equals(hEMF2) CloseClipboard() End If End If End If DeleteEnhMetaFile(hEMF) End If Return bResult End Function Private Sub AddImageToRtb(ByVal imgPathName As String) 'Create a bitmap of the image you want to draw to the metafile Dim bm As New Bitmap(imgPathName) 'Create a graphics object of the Form and get its hdc handle Dim me_grx As Graphics = Me.CreateGraphics() Dim me_hdc As IntPtr = me_grx.GetHdc() 'Create a new metafile the same size as the image and create a graphics object for it Dim emf As New Metafile("Tmp.emf", me_hdc, New Rectangle(0, 0, bm.Width, bm.Height), MetafileFrameUnit.Pixel) Dim emf_gr As Graphics = Graphics.FromImage(emf) 'Draw the bitmap image onto the new metafile emf_gr.DrawImage(bm, 0, 0) 'Dispose the bitmap and the metafile graphics object emf_gr.Dispose() bm.Dispose() 'Copy the new metafile to the clipboard PutEnhMetafileOnClipboard(Me.Handle, emf) 'Paste the new metafile in the RichTextBox RichTextBox1.Paste() 'Dispose the rest of the objects we created me_grx.ReleaseHdc(me_hdc) me_grx.Dispose() emf.Dispose() End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim ofd As New OpenFileDialog ofd.Title = "Add Image..." ofd.Filter = "Images|*.jpg;*.bmp;*.png" ofd.Multiselect = False If ofd.ShowDialog = DialogResult.OK Then AddImageToRtb(ofd.FileName) End If ofd.Dispose() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Dim sfd As New SaveFileDialog sfd.Title = "Save File..." sfd.FileName = "Untitled" sfd.DefaultExt = "rtf" sfd.AddExtension = True If sfd.ShowDialog = DialogResult.OK Then RichTextBox1.SaveFile(sfd.FileName, RichTextBoxStreamType.RichText) End If sfd.Dispose() End Sub End Class
EDIT : Updated code so that no temporary images are saved on the hard drive. Again thanks to JohnWein`s help with this.
- Edited by IronRazerz Wednesday, January 15, 2014 2:17 AM
- Marked as answer by Carl Andersson Wednesday, January 15, 2014 4:10 PM
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That is kind of like giving your car a new paint job before taking it to the demolition derby. haha. :)
Please BEWARE that I have NO EXPERIENCE and NO EXPERTISE and probably onset of DEMENTIA which may affect my answers! Also, I've been told by an expert, that when you post an image it clutters up the thread and mysteriously, over time, the link to the image will somehow become "unstable" or something to that effect. :) I can only surmise that is due to Global Warming of the threads.
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I know you ended this thread but I said I would post the code for my solution even if you found another solution.
How this works.
When an image is to be resized then left click in the middle of the image. This will add its RTF metadata to a list(Of string) for its current size according to the metadata as the list(Of Strings) first entry. It also brings up the images resizing things (the little squares for resizing the image).
When the image is finished being resized then left click in the middle of the image. This will add its new RTF metadata to the list(Of String) as the last entry.
If you want to replace the RTB's resized image with a good quality image then after the left click, with the cursor still on the image then right click. A MessageBox will ask if you want to replace the RTB image with a high quality resize of it.
Anyhow if you continually reduce the size of the image it works fine. However if you want to enlarge a reduced sized image the quality gets poorer and poorer the larger it gets. Therefore the image in the RTB should be deleted and reloaded which may not be possible depending on how the image was placed in the clipboard (like from some website where you forgot the location of the image or something).
If you want to increase the original images size it seems to work fine up to some point I would guess when the quality starts becoming poorer. Although you can continually reduce the size of an enlarged image with no apparent loss of quality if the enlarged image looked good after the last enlargement.
I also tested it by placing an image at the top of the RTB and below that adding some words then adding the image again and adding some more words. Then reducing the size of the image between the words to make sure this would not affect the image in the top of the RTB and it appeared to work fine.
And you don't need the PictureBox. It's just there for testing purposes. You could use a Bitmap to hold the image instead I believe.
Option Strict On Imports System.Runtime.InteropServices Imports System.Drawing.Drawing2D Public Class Form1 ' For question in thread http://social.msdn.microsoft.com/Forums/en-US/355bfc59-cd0a-4e81-984e-9f066fd3a897/richtextbox-images-quality-loss?forum=vbgeneral ' NOTE: Using Clipboard.Clear causes the app to malfunction at some point or Visual Studio to quit working if app is running ' in debugger. And Visual Studio will not work again until the PC is rebooted. <DllImport("user32.dll")> _ Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr End Function Private Const WM_COPY = &H301 Dim RTBMetaInfo As New List(Of String) Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load Me.CenterToScreen() End Sub Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click Clipboard.SetImage(Image.FromFile("C:\Users\John\Desktop\Hydrofoil.Bmp")) RichTextBox1.Paste() End Sub Private Sub RichTextBox1_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles RichTextBox1.MouseDown If e.Button = Windows.Forms.MouseButtons.Left Then If RichTextBox1.SelectionType = RichTextBoxSelectionTypes.Object And RichTextBox1.SelectedRtf.Contains("\pict\wmetafile8\") Then Dim Temp As String = RichTextBox1.SelectedRtf.ToString Dim TempR As Integer = 0 Dim Count As Integer = 0 For i = 0 To Temp.Count - 1 If Temp(i) = ChrW(10) Then Count += 1 If Count = 2 Then TempR = i Exit For End If End If Next Temp = Temp.Remove(TempR, Temp.Count - TempR) RTBMetaInfo.Add(Temp) If My.Computer.FileSystem.FileExists("C:\Users\John\Desktop\RTBMetaInfo.Txt") Then My.Computer.FileSystem.DeleteFile("C:\Users\John\Desktop\RTBMetaInfo.Txt") End If For Each Item In RTBMetaInfo My.Computer.FileSystem.WriteAllText("C:\Users\John\Desktop\RTBMetaInfo.Txt", Item & vbCrLf, True) Next End If End If If e.Button = Windows.Forms.MouseButtons.Right Then If RichTextBox1.SelectionType = RichTextBoxSelectionTypes.Object And RichTextBox1.SelectedRtf.Contains("\pict\wmetafile8\") Then If MessageBox.Show("Do you want to convert this image?", "Convert Image", MessageBoxButtons.OKCancel) = Windows.Forms.DialogResult.OK Then SendMessage(RichTextBox1.Handle, WM_COPY, IntPtr.Zero, IntPtr.Zero) Label1.Text = "Image properties before resize were" & vbCrLf & RTBMetaInfo(0) Label2.Text = "Image properties after resize are" & vbCrLf & RTBMetaInfo(RTBMetaInfo.Count - 1) Dim Temp1Split() As String = RTBMetaInfo(0).Split("\"c) Dim Temp2Split() As String = RTBMetaInfo(RTBMetaInfo.Count - 1).Split("\"c) Dim Temp1 As String = Temp1Split(Temp1Split.Count - 2) & "^" & Temp1Split(Temp1Split.Count - 1) & "^" & Temp2Split(Temp2Split.Count - 2) & "^" & Temp2Split(Temp2Split.Count - 1) Temp1 = Temp1.Replace("picwgoal", "") Temp1 = Temp1.Replace("pichgoal", "") Dim Temp3Split() As String = Temp1.Split("^"c) Dim Width1 As Integer = CInt(Temp3Split(0)) Dim Width2 As Integer = CInt(Temp3Split(2)) Dim Height1 As Integer = CInt(Temp3Split(1)) Dim Height2 As Integer = CInt(Temp3Split(3)) Dim Width3 As Integer = CInt((100 / Width1) * Width2) Dim Height3 As Integer = CInt((100 / Height1) * Height2) Label3.Text = "Original width and height were " & Width1.ToString & " " & Height1.ToString & vbCrLf & _ "and resized width and height are " & Width2.ToString & " " & Height2.ToString & vbCrLf & _ "so the new sizes width is approximately " & Width3.ToString & "% of the original width" & vbCrLf & _ "and the new sizes height is approximately " & Height3.ToString & "% of the original height." Dim Img As New Bitmap(Clipboard.GetImage) Dim newImage As Image = New Bitmap(CInt((Clipboard.GetImage.Width / 100) * Width3), CInt((Clipboard.GetImage.Height / 100) * Height3)) Using graphicsHandle As Graphics = Graphics.FromImage(newImage) graphicsHandle.InterpolationMode = InterpolationMode.HighQualityBicubic graphicsHandle.DrawImage(Img, 0, 0, CInt((Clipboard.GetImage.Width / 100) * Width3), CInt((Clipboard.GetImage.Height / 100) * Height3)) End Using PictureBox1.Width = newImage.Width PictureBox1.Height = newImage.Height PictureBox1.Image = newImage Img.Dispose() SendKeys.Send("{Delete}") Clipboard.SetImage(PictureBox1.Image) RichTextBox1.Paste() RTBMetaInfo.Clear() Else RTBMetaInfo.Clear() End If End If End If End Sub End Class
Please BEWARE that I have NO EXPERIENCE and NO EXPERTISE and probably onset of DEMENTIA which may affect my answers! Also, I've been told by an expert, that when you post an image it clutters up the thread and mysteriously, over time, the link to the image will somehow become "unstable" or something to that effect. :) I can only surmise that is due to Global Warming of the threads.
- Edited by Mr. Monkeyboy Sunday, January 19, 2014 7:49 PM 5555
