'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports GrapeCity.Documents.PdfImports GrapeCity.Documents.TextImports GrapeCity.Documents.DrawingImports GCDRAW = GrapeCity.Documents.Drawing
Public Class InterpolationModes    Public Function CreatePDF(ByVal stream As Stream) As Integer        ' Small image of a QRCode that will be enlarged in PDFs that are then saved as JPEGs:        Using image = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "QRCode-57x57.png"))            ' Create 4 PDFs, each is one page on which the small image is enlarged,            ' save each PDF as JPEG with different interpolation modes specified in SaveAsImageOptions:            Dim tmpNearestNeighbor = Path.GetTempFileName()            MakePDF(image, InterpolationMode.NearestNeighbor).SaveAsJpeg(tmpNearestNeighbor, Nothing,                New SaveAsImageOptions() With {.InterpolationMode = InterpolationMode.NearestNeighbor})            Dim tmpLinear = Path.GetTempFileName()            MakePDF(image, InterpolationMode.Linear).SaveAsJpeg(tmpLinear, Nothing,                New SaveAsImageOptions() With {.InterpolationMode = InterpolationMode.Linear})            Dim tmpCubic = Path.GetTempFileName()            MakePDF(image, InterpolationMode.Cubic).SaveAsJpeg(tmpCubic, Nothing,                New SaveAsImageOptions() With {.InterpolationMode = InterpolationMode.Cubic})            Dim tmpDownscale = Path.GetTempFileName()            MakePDF(image, InterpolationMode.Downscale).SaveAsJpeg(tmpDownscale, Nothing,                New SaveAsImageOptions() With {.InterpolationMode = InterpolationMode.Downscale})
            ' Draw each JPEG at its natural size onto a page of the resulting PDF:            Dim pageCount As Integer = 0            Using imgNearestNeighbor = GCDRAW.Image.FromFile(tmpNearestNeighbor),                  imgLinear = GCDRAW.Image.FromFile(tmpLinear),                  imgCubic = GCDRAW.Image.FromFile(tmpCubic),                  imgDownscale = GCDRAW.Image.FromFile(tmpDownscale)                Dim doc = New GcPdfDocument()                Dim page = doc.NewPage()                page.Graphics.DrawImage(imgNearestNeighbor, page.Bounds, Nothing, ImageAlign.Default)                page = doc.NewPage()                page.Graphics.DrawImage(imgLinear, page.Bounds, Nothing, ImageAlign.Default)                page = doc.NewPage()                page.Graphics.DrawImage(imgCubic, page.Bounds, Nothing, ImageAlign.Default)                page = doc.NewPage()                page.Graphics.DrawImage(imgDownscale, page.Bounds, Nothing, ImageAlign.Default)                ' Save the resulting PDF:                doc.Save(stream)                pageCount = doc.Pages.Count            End Using            ' Cleanup:            File.Delete(tmpNearestNeighbor)            File.Delete(tmpLinear)            File.Delete(tmpCubic)            File.Delete(tmpDownscale)
            '' Done:            Return pageCount        End Using    End Function
    ' InterpolationMode parameter here is only to show in the resulting PDF,    ' GcPdfGraphics only supports InterpolationMode.NearestNeighbor:    Public Function MakePDF(ByVal image As GCDRAW.Image, ByVal imode As InterpolationMode) As GcPdfDocument        Dim tfCaption = New TextFormat() With {            .Font = StandardFonts.Times,            .FontSize = 20        }        Dim tf = New TextFormat() With {            .Font = StandardFonts.Times,            .FontSize = 18        }
        Dim doc = New GcPdfDocument()        Dim page = doc.NewPage()        Dim g = page.Graphics
        Dim xpad = 36        Dim ypad = 36        Dim ip = New PointF(xpad, ypad)        g.DrawString($"SaveAsImageOptions.InterpolationMode is {imode}", tfCaption, ip)        ip.Y *= 2.5F
        ' Draw the original with the original size:        g.DrawImage(image, New RectangleF(ip.X, ip.Y, image.Width, image.Height), Nothing, ImageAlign.Default)        g.DrawString($"⟵ Original image ({image.Width} by {image.Height} pixels)", tf, New PointF(ip.X * 2 + image.Width, ip.Y))        ip.Y += image.Height + ypad
        ' Enlarge the original small image by a factor of 8:        Dim f = 8        Dim twidth As Integer = image.Width * f        Dim theight As Integer = image.Height * f
        ' Draw the enlarged image:        g.DrawImage(image, New RectangleF(ip.X, ip.Y, twidth, theight), Nothing, ImageAlign.StretchImage)        g.DrawString($"Image enlarged to {twidth} by {theight} pixels:", tf, New PointF(ip.X, ip.Y - ypad))
        Return doc    End FunctionEnd Class