dynamically creating a text image

Dhillon · Apr 28, 2012

The code below dynamically creates a text image. I modified the code from: http://asp101.com/articles/john/textimage/default.asp The problem is that width of each character is different, which means the width of the image is hard to calculate. Is there a way to make an image just as big as needed? Right now it makes long words images too wide. Thank you Aaron <%@ Page Language="VB" Debug="True" Trace="True" %> <%@ Import Namespace="System.Drawing" %> <%@ Import Namespace="System.Drawing.Imaging" %> <%@ Import Namespace="System.Drawing.Text" %>  <% ' Declare Vars Dim objBMP As System.Drawing.Bitmap Dim objGraphics As System.Drawing.Graphics Dim objFont As System.Drawing.Font Dim objColor As System.Drawing.Color Dim TextStr As String = Request.QueryString("TextStr") Dim FontName, myFontStyle As String Dim myFontSize As Integer Dim ImageHeight, ImageWidth As Integer If Len(Request.QueryString("FontSize")) = 0 then myFontSize = 8 else myFontSize = Request.QueryString("FontSize") End if TextStr = Replace(TextStr, " ", VBCRLF) If Len(TextStr) = 0 then TextStr = "line 1" & VBCRLF & "line 2" & VBCRLF & "line 3" End if FontName = Request.QueryString("FontName") If Len(FontName) = 0 then FontName = "Arial" End If Dim FontColor As String FontColor = Replace(Request.QueryString("FontColor"), "Hex:", "#") If Len(FontColor) = 0 then FontColor = "black" End If Dim myBrush As SolidBrush = New SolidBrush(ColorTranslator.FromHtml(FontColor)) ' Configure font to use for text myFontStyle = Request.QueryString("FontStyle") Select Case LCase(myFontStyle) Case "bold" objFont = New Font(FontName, myFontSize, FontStyle.Bold) Case "italic" objFont = New Font(FontName, myFontSize, FontStyle.Italic) Case "strikeout" objFont = New Font(FontName, myFontSize, FontStyle.Strikeout) Case "underline" objFont = New Font(FontName, myFontSize, FontStyle.Underline) Case Else objFont = New Font(FontName, myFontSize, FontStyle.Regular) End select ' Create new image - bitmap ' width, height 'ImageHeight = (InStrCount(TextStr, VBCRLF) + 1) * (myFontSize*2) 'ImageWidth = Len(TextStr)*((myFontSize-1)*2) ImageHeight = ((InStrCount(TextStr, VBCRLF) + 1) * objFont.Height) + 2 ' Counts how many line breaks to calculate the height ImageWidth = Len(TextStr)*((myFontSize-1)*2) ' Can't calculate this correctlly 'ImageWidth = Len(TextStr)* objFont. objBMP = New Bitmap(ImageWidth, ImageHeight) 'objBMP = New Bitmap(Len(TextStr)*16, 20) ' Create a graphics object to work with from the BMP objGraphics = System.Drawing.Graphics.FromImage(objBMP) ' Fill the image with background color objGraphics.Clear(Color.White) ' Set anti-aliasing for text to make it better looking objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias objGraphics.DrawString(TextStr, objFont, myBrush, 3, 3) ' Set the content type and return the image Response.ContentType = "image/GIF" objBMP.Save(Response.OutputStream, ImageFormat.Gif) ' Kill our objects objFont.Dispose() objGraphics.Dispose() objBMP.Dispose() %> You could loop through the pixels of the image and figure out where the black pixels stop being used. I assume that you are doing this as a one time shot (not constantly displaying dynamic images on your site!) This is pretty processor intensive. Pseudo code follows: intRightmostBlackPixel = 0 intBottommostBlackPixel = 0 intTempColorValue = http://aspmessageboard.com/archive/index.php/0 For intYCoordinate = 1 To ImageHeight For intXCoordinate = 1 To ImageWidth intTempColorValue = 0 intTempColorValue = intTempColorValue + GetRedValue(intXCoordinate, intYCoordinate) intTempColorValue = intTempColorValue + GetGreenValue(intXCoordinate, intYCoordinate) intTempColorValue = intTempColorValue + GetBlueValue(intXCoordinate, intYCoordinate) If intTempColorValue 3 < 128 Then ' The pixel is black If intYCoordinate > intBottommostBlackPixel Then intBottommostBlackPixel = intYCoordinate End If If intXCoordinate > intRightmostBlackPixel Then intRightmostBlackPixel = intXCoordinate End If End If Next Next Image.Crop(intRightmostBlackPixel + intMargin, intBottommostBlackPixel + intMargin)There is a MeasureString function! ' ========================= Dim objFont As Font Dim objSize As SizeF Dim objBitmap As Bitmap Dim intWidth As Integer Dim intHeight As Integer intWidth = 0 intHeight = 0 objFont = New Font("Arial", 28) objBitmap = New Bitmap(1, 1, PixelFormat.Format32bppPArgb) objSize = Graphics.FromImage(objBitmap).MeasureString("Your Text Here", objFont) intWidth = objSize.Width intHeight = objSize.Height That is exactly what I was looking for!! Works good. Thank you Aaron

dynamically creating a text image

Dhillon

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