'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.ImagingImports GCTEXT = GrapeCity.Documents.Text
'' This sample demonstrates how to resize (downscale) an existing image'' to create a thumbnail, using different interpolation modes.Public Class DownscaleImage    Function GenerateImage(        ByVal pixelSize As Size,        ByVal dpi As Single,        ByVal opaque As Boolean,        Optional ByVal sampleParams As String() = Nothing) As GcBitmap
        Dim origImagePath = Path.Combine("Resources", "Images", "minerva.jpg")        '' Create and fill the target bitmap:        Dim targetBmp = New GcBitmap(pixelSize.Width, pixelSize.Height, True, dpi, dpi)        Using g = targetBmp.CreateGraphics(Color.FromArgb(&HFF004D99))            '' creating a graphics with a fill color does what we need        End Using        Const fontSize = 16, fpad = 4, xpad = 10, ypad = 3        Dim tf = New TextFormat With            {                .ForeColor = Color.FromArgb(&HFFFFCC00),                .Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeSerif.ttf")),                .FontSize = fontSize            }        Using origBmp = New GcBitmap()            Using stm = New FileStream(origImagePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, FileOptions.RandomAccess)                origBmp.Load(stm)            End Using
            '' Bitwise copy the original image with the original size:            targetBmp.BitBlt(origBmp, 0, 0)            Using g = targetBmp.CreateGraphics(Nothing)                g.DrawString($"Original image ({origBmp.Width} by {origBmp.Height} pixels)", tf, New PointF(fpad, origBmp.Height + fpad))            End Using            Dim dx = origBmp.Width + xpad
            '' Scale down the image using the various interpolation modes,            '' and render those on the right of the original:            Dim f = (origBmp.Height - ypad * 3) / origBmp.Height / 4            Dim twidth = Math.Round(origBmp.Width * f)            Dim theight = Math.Round(origBmp.Height * f)
            ''            Dim drawCaption As Action(Of String, Single, Single) =            Sub(caption, x, y)                Using g = targetBmp.CreateGraphics(Nothing)                    g.DrawString(caption, tf, New PointF(x + twidth + fpad, y + fpad))                End Using            End Sub
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.NearestNeighbor)                targetBmp.BitBlt(bmp, dx, 0)            End Using            drawCaption("InterpolationMode.NearestNeighbor", dx, 0)
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Linear)                targetBmp.BitBlt(bmp, dx, theight + ypad)            End Using            drawCaption("InterpolationMode.Linear", dx, theight + ypad)
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Cubic)                targetBmp.BitBlt(bmp, dx, (theight + ypad) * 2)            End Using            drawCaption("InterpolationMode.Cubic", dx, (theight + ypad) * 2)
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Downscale)                targetBmp.BitBlt(bmp, dx, (theight + ypad) * 3)            End Using            drawCaption("InterpolationMode.Downscale", dx, (theight + ypad) * 3)        End Using        Return targetBmp    End FunctionEnd Class