static List<Brush> CaptchaBrushes = null;
public static FileStreamResult CreateCaptcha(string captcha)
{
if (CaptchaBrushes == null)
{
CaptchaBrushes = new List<Brush>();
CaptchaBrushes.Add(Brushes.White);
CaptchaBrushes.Add(Brushes.Gold);
CaptchaBrushes.Add(Brushes.LightSkyBlue);
CaptchaBrushes.Add(Brushes.LimeGreen);
CaptchaBrushes.Add(Brushes.AliceBlue);
CaptchaBrushes.Add(Brushes.AntiqueWhite);
CaptchaBrushes.Add(Brushes.BurlyWood);
CaptchaBrushes.Add(Brushes.Silver);
}
int width = 90;
int height = 45;
//https://stackoverflow.com/questions/61365732/cannot-access-a-closed-stream-when-returning-filestreamresult-from-c-sharp-netc
//Using statements close and unload the variable from memory set in the using statement which is why you are getting an error trying to access a closed memory stream.You don't need to use a using statement if you are just going to return the result at the end.
//這個 memory stream 不用關閉或 dispose
var ms = new MemoryStream();
// 釋放所有在 GDI+ 所佔用的記憶體空間 ( 非常重要!! )
using (Bitmap _bmp = new Bitmap(width, height))
using (Graphics _graphics = Graphics.FromImage(_bmp))
using (Font _font = new Font("Courier New", 24, FontStyle.Bold)) // _font 設定要出現在圖片上的文字字型、大小與樣式
{
// (封裝 GDI+ 繪圖介面) 所有繪圖作業都需透過 Graphics 物件進行操作
_graphics.Clear(Color.Black);
// 如果想啟用「反鋸齒」功能，可以將以下這行取消註解
//_graphics.TextRenderingHint = TextRenderingHint.AntiAlias;
// 將亂碼字串「繪製」到之前產生的 Graphics 「繪圖板」上
var x = 10;
for(var i = 0; i < captcha.Length; i++)
{
_graphics.DrawString(captcha.Substring(i, 1), _font, CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], x, Su.MathUtil.GetRandomInt(15));
x += 10 + Su.MathUtil.GetRandomInt(10);
}
// 畫線
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
Su.MathUtil.GetRandomInt(0, Convert.ToInt32((width * 0.9 / 2))), 0, Su.MathUtil.GetRandomInt(Convert.ToInt32(width / 2), Convert.ToInt32(width * 1.9 / 2)), height);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
Su.MathUtil.GetRandomInt(Convert.ToInt32(width / 2), Convert.ToInt32(width * 1.9 / 2)), 0, Su.MathUtil.GetRandomInt(0, Convert.ToInt32((width * 0.9 / 2))), height);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
0,
Su.MathUtil.GetRandomInt(height / 2),
width,
height / 2 + Su.MathUtil.GetRandomInt(height / 2)
);
_graphics.DrawLine(new Pen(CaptchaBrushes[Su.MathUtil.GetRandomInt(CaptchaBrushes.Count)], 1),
0,
height / 2 + Su.MathUtil.GetRandomInt(height / 2),
width,
Su.MathUtil.GetRandomInt(height / 2)
);
_bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
}
ms.Seek(0, SeekOrigin.Begin);
// Controller 的型別為 FileResult
return new FileStreamResult(ms, "image/jpeg")
{ FileDownloadName = $"{DateTime.Now.Ymdhmsf()}.jpg" };
}
namespace Web.Controllers
{
public class CaptchaController : Controller
{
[Route("captcha")]
public async Task<FileStreamResult> Index()
{
//產生 Captcha 並存入 Session 之中。目前是四位數字
string captcha = (await Ah.ReGetAsync<object>("api/kol/create-captcha-code")).ToString();
//產生圖檔並回傳 FileStreamResult
return Su.Wu.CreateCaptcha(captcha);
}
}
}
Imports System.Drawing.Printing
Namespace X
Partial Public Class PrintSomething
Dim PD As PrintDocumentDim ppc As New Printing.PreviewPrintController()
Dim TotalPage As Int32 = 0
''' <summary>
''' 第幾次列印, 用來控制寫出的圖檔
''' </summary>
''' <remarks></remarks>
Dim PrintCount As Int32 = 1Dim PageCount As Int32 = 1
:
:
:
Sub New(ByVal oPM As DB.PackingListMain, ByVal dtDetail As DataTable, dtUsedCoupon As DataTable)
'初始化資料
:
:
:
End SubSub InitPrintDocument()
'在這裡設定 PrintDocument 的紙張, 印表機, 邊界, 橫印或直印PD = New PrintDocument
:
:
:End Sub
Sub print()
InitPrintDocument()PD.PrintController = ppc
' 第一次先把列印結果存在 Printing.PreviewPrintController 中
AddHandler PD.PrintPage, AddressOf GeneratePreview'再來儲存圖片
AddHandler PD.EndPrint, AddressOf SaveImagePD.Print()
End Sub
Dim ppi() As Printing.PreviewPageInfo
Dim PrintPage As Int32 = 0Sub SaveImage(ByVal sender As Object, ByVal ev As PrintEventArgs)
PrintDebug("Save Image Start, " & Now.ToString("yyyy-MM-dd HH:mm:ss.fff"))
'把圖檔存起來
Dim TF As String = Now.ToString("yyyyMMddHHmmss") ' DB.SysConfig.Path.LocalDataRoot
Dim PathLocal As String = "C:\PrintLog\" & TF.Substring(0, 4) & "-" & TF.Substring(4, 2) & "\"
Dim PathPackingListSheetImage As String = DB.SysConfig.PackingListSheetImage & TF.Substring(0, 4) & "-" & TF.Substring(4, 2) & "\"System.IO.Directory.CreateDirectory(PathLocal)
System.IO.Directory.CreateDirectory(PathPackingListSheetImage)Dim LatestImages As String = ""
ppi = ppc.GetPreviewPageInfo()For x As Integer = 0 To ppi.Length - 1
Dim Filename As String = TF & "_" & Me.oPM.Id & "_" & x & ".png"ppi(x).Image.Save(PathLocal & Filename, System.Drawing.Imaging.ImageFormat.Png)
Next
'把圖檔印出來
For x As Integer = 0 To ppi.Length - 1
'建立新的 PrintDocument
InitPrintDocument()If CST.WebConfig.Server_NAME = "測試主機" Then
UW.WU.DebugWriteLine("PrinterName: " & Me.PD.PrinterSettings.PrinterName)
UW.WU.DebugWriteLine("PaperSize: " & PD.DefaultPageSettings.PaperSize.PaperName)PD.DocumentName = "PackingList"
PD.PrinterSettings.PrintFileName = "C:\PDF\PackingList" & Now.ToString("yyyyMMddHHmmss") & "_" & PrintPage & ".prn"
PD.PrinterSettings.PrintToFile = True'PD.PrinterSettings.
End If'很奇怪, 這裡不會分頁, 所以要一張一張印
AddHandler PD.PrintPage, AddressOf pd_PrintPage2
PD.Print()
PrintPage += 1Next
End SubPrivate Sub pd_PrintPage2(ByVal sender As Object, ByVal ev As PrintPageEventArgs)
'很奇怪, 這裡不會分頁, 所以要一張一張印
ev.Graphics.DrawImage(ppi(PrintPage).Image, 0, 0)
ev.HasMorePages = False
End Sub
Private Sub GeneratePreview(ByVal sender As Object, ByVal ev As PrintPageEventArgs)
' 列印內容
End SubEnd Class
End ClassEnd Namespace