' File name:  Mstr.vb
' Location: See Matrox Example Launcher in the MIL Control Center
' Synopsis:  This program uses the String Reader module to define a font 
'            from an image containing a mosaic of Quebec license plates.
'            Two String Models are then defined and parameterized to read 
'            only some valid Quebec license plates.
'            A license plate reading is then performed in a target image 
'            of a car on the road.
' Copyright (C) Matrox Electronic Systems Ltd., 1992-2020.
' All Rights Reserved
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Text

Imports Matrox.MatroxImagingLibrary

Namespace MStr
    Friend Class Program
        ' MIL image file specifications.
        Private Const IMAGE_FILE_DEFINITION As String = MIL.M_IMAGE_PATH & "QcPlates.mim"
        Private Const IMAGE_FILE_TO_READ As String = MIL.M_IMAGE_PATH & "LicPlate.mim"

        ' String containing all characters used for font definition.
        Private Const TEXT_DEFINITION As String = "AVS300CVK781JNK278 EBX380QKN918HCC839 YRH900ZQR756977AMQ GPK742389EYE569ESQ"

        ' Font normalization size Y.
        Private Const NORMALIZATION_SIZE_Y As Integer = 20

        ' Max size of plate string.
        Private Const STRING_MAX_SIZE As Integer = 32

        Shared Sub Main(ByVal args() As String)
            Dim MilApplication As MIL_ID = MIL.M_NULL ' Application identifier.
            Dim MilSystem As MIL_ID = MIL.M_NULL ' System identifier.
            Dim MilDisplay As MIL_ID = MIL.M_NULL ' Display identifier.
            Dim MilImage As MIL_ID = MIL.M_NULL ' Image buffer identifier.
            Dim MilOverlayImage As MIL_ID = MIL.M_NULL ' Overlay image.
            Dim MilStrContext As MIL_ID = MIL.M_NULL ' String context identifier.
            Dim MilStrResult As MIL_ID = MIL.M_NULL ' String result buffer identifier.
            Dim NumberOfStringRead As MIL_INT = 0 ' Total number of strings to read.
            Dim Score As Double = 0.0
            Dim StringResult As New StringBuilder(STRING_MAX_SIZE + 1) ' String of characters read.
            Dim Time As Double = 0.0 ' Time variable.

            ' Print module name.
            Console.Write(Constants.vbLf + "STRING READER MODULE:" + Constants.vbLf)
            Console.Write("---------------------" + Constants.vbLf + Constants.vbLf)

            ' Allocate defaults
            MIL.MappAllocDefault(MIL.M_DEFAULT, MilApplication, MilSystem, MilDisplay, CType(MIL.M_NULL, IntPtr), CType(MIL.M_NULL, IntPtr))

            ' Restore the font definition image
            MIL.MbufRestore(IMAGE_FILE_DEFINITION, MilSystem, MilImage)

            ' Display the image and prepare for overlay annotations.
            MIL.MdispSelect(MilDisplay, MilImage)
            MIL.MdispControl(MilDisplay, MIL.M_OVERLAY, MIL.M_ENABLE)
            MIL.MdispInquire(MilDisplay, MIL.M_OVERLAY_ID, MilOverlayImage)

            ' Allocate a new empty String Reader context.
            MIL.MstrAlloc(MilSystem, MIL.M_FONT_BASED, MIL.M_DEFAULT, MilStrContext)

            ' Allocate a new empty String Reader result buffer.
            MIL.MstrAllocResult(MilSystem, MIL.M_DEFAULT, MilStrResult)

            MIL.MstrControl(MilStrContext, MIL.M_CONTEXT, MIL.M_ENCODING, MIL.M_UNICODE)

            ' Add a new empty user defined font to the context.
            MIL.MstrControl(MilStrContext, MIL.M_CONTEXT, MIL.M_FONT_ADD, MIL.M_USER_DEFINED)

            ' Add user-defined characters from the license plate mosaic image. 
            ' Note that the string that identifies the character values to associate with the 
            ' character representations (TEXT_DEFINITION) includes repeated character values 
            ' (e.g. 'E'); each instance of a repeated character value causes the character 
            ' representation associated with this value to be overwritten.

            ' Draw all the characters in the font in the overlay image. 
            ' Note that since M_ORIGINAL is specified, characters are drawn at the location 
            ' from which they were originally extracted from the license plate mosaic image.
            ' This allows you to see which character representation was used for a repeated 
            ' character value in TEXT_DEFINITION.
            MIL.MstrDraw(MIL.M_DEFAULT, MilStrContext, MilOverlayImage, MIL.M_DRAW_CHAR, MIL.M_FONT_INDEX(0), MIL.M_ORIGINAL)

            ' Normalize the characters of the font to an appropriate size.

            ' Add 2 new empty strings models to the context for the 2 valid types of 
            ' plates (3 letters followed by 3 numbers or 3 numbers followed by 3 letters)
            ' Note that the read time increases with the number of strings in the context.
            MIL.MstrControl(MilStrContext, MIL.M_CONTEXT, MIL.M_STRING_ADD, MIL.M_USER_DEFINED)
            MIL.MstrControl(MilStrContext, MIL.M_CONTEXT, MIL.M_STRING_ADD, MIL.M_USER_DEFINED)

            ' Set number of strings to read.
            MIL.MstrControl(MilStrContext, MIL.M_CONTEXT, MIL.M_STRING_NUMBER, 1)

            ' Set number of expected characters for all string models to 6 characters.
            MIL.MstrControl(MilStrContext, MIL.M_STRING_INDEX(MIL.M_ALL), MIL.M_STRING_SIZE_MIN, 6)
            MIL.MstrControl(MilStrContext, MIL.M_STRING_INDEX(MIL.M_ALL), MIL.M_STRING_SIZE_MAX, 6)

            ' Set default constraint to uppercase letter for all string models
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(0), MIL.M_DEFAULT, MIL.M_LETTER + MIL.M_UPPERCASE, IntPtr.Zero)
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(1), MIL.M_DEFAULT, MIL.M_LETTER + MIL.M_UPPERCASE, IntPtr.Zero)

            ' Set constraint of 3 last characters to digit for the first string model
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(0), 3, MIL.M_DIGIT, IntPtr.Zero)
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(0), 4, MIL.M_DIGIT, IntPtr.Zero)
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(0), 5, MIL.M_DIGIT, IntPtr.Zero)

            ' Set constraint of 3 first characters to digit for the second string model
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(1), 0, MIL.M_DIGIT, IntPtr.Zero)
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(1), 1, MIL.M_DIGIT, IntPtr.Zero)
            MIL.MstrSetConstraint(MilStrContext, MIL.M_STRING_INDEX(1), 2, MIL.M_DIGIT, IntPtr.Zero)

            ' Pause to show the font definition.
            Console.Write("This program has defined a font with this Quebec plates mosaic image." + Constants.vbLf)
            Console.Write("Press <Enter> to continue." + Constants.vbLf + Constants.vbLf)

            ' Clear the display overlay.
            MIL.MdispControl(MilDisplay, MIL.M_OVERLAY_CLEAR, MIL.M_DEFAULT)

            ' Load image to read into image buffer.
            MIL.MbufLoad(IMAGE_FILE_TO_READ, MilImage)

            ' Preprocess the String Reader context.
            MIL.MstrPreprocess(MilStrContext, MIL.M_DEFAULT)

            ' Dummy first call for bench measure purpose only (bench stabilization, cache effect, etc...). This first call is NOT required by the application.
            MIL.MstrRead(MilStrContext, MilImage, MilStrResult)

            ' Reset the timer.

            ' Perform the read operation on the specified target image.
            MIL.MstrRead(MilStrContext, MilImage, MilStrResult)

            ' Read the time.

            ' Get number of strings read and show the result.
            MIL.MstrGetResult(MilStrResult, MIL.M_GENERAL, MIL.M_STRING_NUMBER + MIL.M_TYPE_MIL_INT, NumberOfStringRead)
            If NumberOfStringRead >= 1 Then
                Console.Write("The license plate was read successfully ({0:#.##} ms)" + Constants.vbLf + Constants.vbLf, Time * 1000)

                ' Draw read result.
                MIL.MgraColor(MIL.M_DEFAULT, MIL.M_COLOR_BLUE)
                MIL.MstrDraw(MIL.M_DEFAULT, MilStrResult, MilOverlayImage, MIL.M_DRAW_STRING, MIL.M_ALL, MIL.M_DEFAULT)
                MIL.MgraColor(MIL.M_DEFAULT, MIL.M_COLOR_GREEN)
                MIL.MstrDraw(MIL.M_DEFAULT, MilStrResult, MilOverlayImage, MIL.M_DRAW_STRING_BOX, MIL.M_ALL, MIL.M_DEFAULT)

                ' Print the read result.
                Console.Write(" String                  Score" + Constants.vbLf)
                Console.Write(" -----------------------------------" + Constants.vbLf)
                MIL.MstrGetResult(MilStrResult, 0, MIL.M_STRING + MIL.M_TYPE_TEXT_CHAR, StringResult)
                MIL.MstrGetResult(MilStrResult, 0, MIL.M_STRING_SCORE, Score)
                Console.Write(" {0}                  {1:0.0}" + Constants.vbLf, StringResult.ToString(), Score)
                Console.Write("Error: Plate was not read." + Constants.vbLf)
            End If

            ' Pause to show results.
            Console.Write(Constants.vbLf + "Press <Enter> to end." + Constants.vbLf + Constants.vbLf)

            ' Free all allocations.

            ' Free defaults.
            MIL.MappFreeDefault(MilApplication, MilSystem, MilDisplay, MIL.M_NULL, MIL.M_NULL)
        End Sub
    End Class
End Namespace