''
'' 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.Collections.Generic
Imports System.Linq
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 to use the GammaCorrectionEffect.
Public Class GammaCorrection
    Function GenerateImage(
        ByVal pixelSize As Size,
        ByVal dpi As Single,
        ByVal opaque As Boolean,
        Optional ByVal sampleParams As String() = Nothing) As GcBitmap
 
        opaque = False
        Dim bmp = New GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi)
        Using origBmp = New GcBitmap()
            '' Load a sample photo:
            Dim imagePath = Path.Combine("Resources", "ImagesBis", "butterfly.jpg")
            Using stm = New FileStream(imagePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.RandomAccess)
                origBmp.Load(stm)
            End Using
 
            origBmp.SetAlphaTo255()
            origBmp.Opaque = False
 
            '' 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)
                '' Copy the resized original into 4 quadrants of the resulting bitmap:
                bmp.BitBlt(sizedBmp, 0, 0)
                bmp.BitBlt(sizedBmp, w, 0)
                bmp.BitBlt(sizedBmp, 0, h)
                bmp.BitBlt(sizedBmp, w, h)
            End Using
 
            '' Keep the pixels in top left quadrant intact,
            '' apply effects to the other 3 quadrants:
            Dim lineh = 2
            bmp.ApplyEffect(GammaCorrectionEffect.Get(5), New Rectangle(w + lineh, 0, w - lineh, h - lineh))
            bmp.ApplyEffect(GammaCorrectionEffect.Get(0.5F), New Rectangle(0, h + lineh, w - lineh, h - lineh))
            bmp.ApplyEffect(GammaCorrectionEffect.Get(0.1F), New Rectangle(w + lineh, h + lineh, w - lineh, h - lineh))
 
            '' Add borders between the quadrants, and captions for each:
            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(Color.Gray, lineh * 2))
                g.DrawLine(0, h, w * 2, h, New GCDRAW.Pen(Color.Gray, lineh * 2))
                Dim tf = New TextFormat() With {.Font = fnt, .FontSize = 18, .ForeColor = foreColor, .BackColor = backColor, .FontBold = True}
                Dim th = g.MeasureString("QWERTY", tf).Height
                g.DrawString(" Original image ", tf, New PointF(0, h - th + lineh))
                g.DrawString(" Gamma Correction 5 ", tf, New PointF(w + lineh, h - th + lineh))
                g.DrawString(" Gamma Correction 0.5 ", tf, New PointF(0, h * 2 + lineh - th + lineh))
                g.DrawString(" Gamma Correction 0.1 ", tf, New PointF(w + lineh, h * 2 + lineh - th + lineh))
            End Using
        End Using
        Return bmp
    End Function
End Class