Depois de ter tentado por mais de duas horas, posso dizer com segurança que todo o método mencionado até agora não funciona em navegadores ou no IE, mesmo em versões de navegadores ...
Por exemplo (resposta com mais votos):
filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=0.083); /* IE6,IE7 */
-ms-filter: "progid:DXImageTransform.Microsoft.BasicImage(rotation=0.083)"; /* IE8 */
gira duas vezes no IE9, uma vez para o filtro e uma vez para -ms-filter, então ...
Todos os outros métodos mencionados também não funcionam, pelo menos não se você tiver que definir nenhuma altura / largura fixa da célula do cabeçalho da tabela (com cor de plano de fundo), onde deve ajustar automaticamente o tamanho do elemento mais alto.
Então, para elaborar a geração de imagens do lado do servidor proposta por Nathan Long, que é realmente o único método de trabalho universal, aqui está o meu código VB.NET para um manipulador genérico (* .ashx):
Imports System.Web
Imports System.Web.Services
Public Class GenerateImage
Implements System.Web.IHttpHandler
Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
'context.Response.ContentType = "text/plain"
'context.Response.Write("Hello World!")
context.Response.ContentType = "image/png"
Dim strText As String = context.Request.QueryString("text")
Dim strRotate As String = context.Request.QueryString("rotate")
Dim strBGcolor As String = context.Request.QueryString("bgcolor")
Dim bRotate As Boolean = True
If String.IsNullOrEmpty(strText) Then
strText = "No Text"
End If
Try
If Not String.IsNullOrEmpty(strRotate) Then
bRotate = System.Convert.ToBoolean(strRotate)
End If
Catch ex As Exception
End Try
'Dim img As System.Drawing.Image = GenerateImage(strText, "Arial", bRotate)
'Dim img As System.Drawing.Image = CreateBitmapImage(strText, bRotate)
' Generic error in GDI+
'img.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png)
'Dim bm As System.Drawing.Bitmap = New System.Drawing.Bitmap(img)
'bm.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png)
Using msTempOutputStream As New System.IO.MemoryStream
'Dim img As System.Drawing.Image = GenerateImage(strText, "Arial", bRotate)
Using img As System.Drawing.Image = CreateBitmapImage(strText, bRotate, strBGcolor)
img.Save(msTempOutputStream, System.Drawing.Imaging.ImageFormat.Png)
msTempOutputStream.Flush()
context.Response.Buffer = True
context.Response.ContentType = "image/png"
context.Response.BinaryWrite(msTempOutputStream.ToArray())
End Using ' img
End Using ' msTempOutputStream
End Sub ' ProcessRequest
Private Function CreateBitmapImage(strImageText As String) As System.Drawing.Image
Return CreateBitmapImage(strImageText, True)
End Function ' CreateBitmapImage
Private Function CreateBitmapImage(strImageText As String, bRotate As Boolean) As System.Drawing.Image
Return CreateBitmapImage(strImageText, bRotate, Nothing)
End Function
Private Function InvertMeAColour(ColourToInvert As System.Drawing.Color) As System.Drawing.Color
Const RGBMAX As Integer = 255
Return System.Drawing.Color.FromArgb(RGBMAX - ColourToInvert.R, RGBMAX - ColourToInvert.G, RGBMAX - ColourToInvert.B)
End Function
Private Function CreateBitmapImage(strImageText As String, bRotate As Boolean, strBackgroundColor As String) As System.Drawing.Image
Dim bmpEndImage As System.Drawing.Bitmap = Nothing
If String.IsNullOrEmpty(strBackgroundColor) Then
strBackgroundColor = "#E0E0E0"
End If
Dim intWidth As Integer = 0
Dim intHeight As Integer = 0
Dim bgColor As System.Drawing.Color = System.Drawing.Color.LemonChiffon ' LightGray
bgColor = System.Drawing.ColorTranslator.FromHtml(strBackgroundColor)
Dim TextColor As System.Drawing.Color = System.Drawing.Color.Black
TextColor = InvertMeAColour(bgColor)
'TextColor = Color.FromArgb(102, 102, 102)
' Create the Font object for the image text drawing.
Using fntThisFont As New System.Drawing.Font("Arial", 11, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel)
' Create a graphics object to measure the text's width and height.
Using bmpInitialImage As New System.Drawing.Bitmap(1, 1)
Using gStringMeasureGraphics As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmpInitialImage)
' This is where the bitmap size is determined.
intWidth = CInt(gStringMeasureGraphics.MeasureString(strImageText, fntThisFont).Width)
intHeight = CInt(gStringMeasureGraphics.MeasureString(strImageText, fntThisFont).Height)
' Create the bmpImage again with the correct size for the text and font.
bmpEndImage = New System.Drawing.Bitmap(bmpInitialImage, New System.Drawing.Size(intWidth, intHeight))
' Add the colors to the new bitmap.
Using gNewGraphics As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmpEndImage)
' Set Background color
'gNewGraphics.Clear(Color.White)
gNewGraphics.Clear(bgColor)
gNewGraphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias
gNewGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias
''''
'gNewGraphics.TranslateTransform(bmpEndImage.Width, bmpEndImage.Height)
'gNewGraphics.RotateTransform(180)
'gNewGraphics.RotateTransform(0)
'gNewGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.SystemDefault
gNewGraphics.DrawString(strImageText, fntThisFont, New System.Drawing.SolidBrush(TextColor), 0, 0)
gNewGraphics.Flush()
If bRotate Then
'bmpEndImage = rotateImage(bmpEndImage, 90)
'bmpEndImage = RotateImage(bmpEndImage, New PointF(0, 0), 90)
'bmpEndImage.RotateFlip(RotateFlipType.Rotate90FlipNone)
bmpEndImage.RotateFlip(System.Drawing.RotateFlipType.Rotate270FlipNone)
End If ' bRotate
End Using ' gNewGraphics
End Using ' gStringMeasureGraphics
End Using ' bmpInitialImage
End Using ' fntThisFont
Return bmpEndImage
End Function ' CreateBitmapImage
' http://msdn.microsoft.com/en-us/library/3zxbwxch.aspx
' http://msdn.microsoft.com/en-us/library/7e1w5dhw.aspx
' http://www.informit.com/guides/content.aspx?g=dotnet&seqNum=286
' http://road-blogs.blogspot.com/2011/01/rotate-text-in-ssrs.html
Public Shared Function GenerateImage_CrappyOldReportingServiceVariant(ByVal strText As String, ByVal strFont As String, bRotate As Boolean) As System.Drawing.Image
Dim bgColor As System.Drawing.Color = System.Drawing.Color.LemonChiffon ' LightGray
bgColor = System.Drawing.ColorTranslator.FromHtml("#E0E0E0")
Dim TextColor As System.Drawing.Color = System.Drawing.Color.Black
'TextColor = System.Drawing.Color.FromArgb(255, 0, 0, 255)
If String.IsNullOrEmpty(strFont) Then
strFont = "Arial"
Else
If strFont.Trim().Equals(String.Empty) Then
strFont = "Arial"
End If
End If
'Dim fsFontStyle As System.Drawing.FontStyle = System.Drawing.FontStyle.Regular
Dim fsFontStyle As System.Drawing.FontStyle = System.Drawing.FontStyle.Bold
Dim fontFamily As New System.Drawing.FontFamily(strFont)
Dim iFontSize As Integer = 8 '//Change this as needed
' vice-versa, because 270° turn
'Dim height As Double = 2.25
Dim height As Double = 4
Dim width As Double = 1
' width = 10
' height = 10
Dim bmpImage As New System.Drawing.Bitmap(1, 1)
Dim iHeight As Integer = CInt(height * 0.393700787 * bmpImage.VerticalResolution) 'y DPI
Dim iWidth As Integer = CInt(width * 0.393700787 * bmpImage.HorizontalResolution) 'x DPI
bmpImage = New System.Drawing.Bitmap(bmpImage, New System.Drawing.Size(iWidth, iHeight))
'// Create the Font object for the image text drawing.
'Dim MyFont As New System.Drawing.Font("Arial", iFontSize, fsFontStyle, System.Drawing.GraphicsUnit.Point)
'// Create a graphics object to measure the text's width and height.
Dim MyGraphics As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bmpImage)
MyGraphics.Clear(bgColor)
Dim stringFormat As New System.Drawing.StringFormat()
stringFormat.FormatFlags = System.Drawing.StringFormatFlags.DirectionVertical
'stringFormat.FormatFlags = System.Drawing.StringFormatFlags.DirectionVertical Or System.Drawing.StringFormatFlags.DirectionRightToLeft
Dim solidBrush As New System.Drawing.SolidBrush(TextColor)
Dim pointF As New System.Drawing.PointF(CSng(iWidth / 2 - iFontSize / 2 - 2), 5)
Dim font As New System.Drawing.Font(fontFamily, iFontSize, fsFontStyle, System.Drawing.GraphicsUnit.Point)
MyGraphics.TranslateTransform(bmpImage.Width, bmpImage.Height)
MyGraphics.RotateTransform(180)
MyGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.SystemDefault
MyGraphics.DrawString(strText, font, solidBrush, pointF, stringFormat)
MyGraphics.ResetTransform()
MyGraphics.Flush()
'If Not bRotate Then
'bmpImage.RotateFlip(System.Drawing.RotateFlipType.Rotate90FlipNone)
'End If
Return bmpImage
End Function ' GenerateImage
ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
Get
Return False
End Get
End Property ' IsReusable
End Class
Note que se você acha que esta parte
Using msTempOutputStream As New System.IO.MemoryStream
'Dim img As System.Drawing.Image = GenerateImage(strText, "Arial", bRotate)
Using img As System.Drawing.Image = CreateBitmapImage(strText, bRotate, strBGcolor)
img.Save(msTempOutputStream, System.Drawing.Imaging.ImageFormat.Png)
msTempOutputStream.Flush()
context.Response.Buffer = True
context.Response.ContentType = "image/png"
context.Response.BinaryWrite(msTempOutputStream.ToArray())
End Using ' img
End Using ' msTempOutputStream
pode ser substituído por
img.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png)
porque funciona no servidor de desenvolvimento, você se engana ao assumir que o mesmo código não lançaria uma exceção GDI + genérica se você implantá-lo em um servidor IIS 6 do Windows 2003 ...
use-o assim:
<img alt="bla" src="GenerateImage.ashx?no_cache=123&text=Hello%20World&rotate=true" />
