''
'' This code is part of Document Solutions for Imaging demos.
'' Copyright (c) MESCIUS inc. All rights reserved.
''
Imports System.IO
Imports System.Drawing
Imports System.Numerics
Imports GrapeCity.Documents.Drawing
Imports GrapeCity.Documents.Text
Imports GrapeCity.Documents.Imaging
Imports GCTEXT = GrapeCity.Documents.Text
Imports GCDRAW = GrapeCity.Documents.Drawing

'' This sample demonstrates how convert full color RGB
'' to 4 BPP and 8 BPP indexed images.
Public Class Indexing
    Function GenerateImage(
        ByVal pixelSize As Size,
        ByVal dpi As Single,
        ByVal opaque As Boolean,
        Optional ByVal sampleParams As String() = Nothing) As GcBitmap

        Dim bmp = New GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi)
        Using origBmp = New GcBitmap()
            '' Load a sample photo:
            Dim imagePath = Path.Combine("Resources", "Images", "maple.jpg")
            Using stm = New FileStream(imagePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.RandomAccess)
                origBmp.Load(stm)
            End Using

            origBmp.SetAlphaTo255()
            origBmp.Opaque = opaque

            '' Resize the original photo so we can place 4 samples of it
            '' on the resulting bitmap:
            Dim w = pixelSize.Width / 2
            Dim h = pixelSize.Height / 2
            Using sizedBmp = origBmp.Resize(w, h, InterpolationMode.Cubic),
                ib4bpp = sizedBmp.ToIndexed4bppBitmap(DitheringMethod.JarvisJudiceNinke),
                ib8bpp = sizedBmp.ToIndexed8bppBitmap(DitheringMethod.JarvisJudiceNinke),
                b4bpp = ib4bpp.ToGcBitmap(),
                b8bpp = ib8bpp.ToGcBitmap()
                '' Copy the original And indexed images into 4 quadrants of the resulting bitmap:
                bmp.BitBlt(sizedBmp, 0, 0)
                b4bpp.Opaque = opaque
                bmp.BitBlt(b4bpp, w, 0)
                b8bpp.Opaque = opaque
                bmp.BitBlt(b8bpp, 0, h)
                bmp.BitBlt(sizedBmp, w, h)
            End Using

            '' Add borders between the quadrants, And captions for each:
            Dim lineh = 2
            Using g = bmp.CreateGraphics(Nothing)
                Dim foreColor = Color.Yellow
                Dim backColor = Color.Blue
                Dim fnt = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "cour.ttf"))
                g.DrawLine(w, 0, w, h * 2, New GCDRAW.Pen(foreColor, lineh * 2))
                g.DrawLine(0, h, w * 2, h, New GCDRAW.Pen(foreColor, lineh * 2))
                Dim tf = New TextFormat() With {.Font = fnt, .FontSize = 18, .ForeColor = foreColor, .BackColor = backColor, .FontBold = True}
                g.DrawString(" Original image ", tf, New PointF(0, 0))
                g.DrawString(" Indexed 4 bits per pixel ", tf, New PointF(w + lineh, 0))
                g.DrawString(" Indexed 8 bits per pixel ", tf, New PointF(0, h + lineh))
                g.DrawString(" Original image ", tf, New PointF(w + lineh, h + lineh))
            End Using
            Return bmp
        End Using
    End Function
End Class