Indexing.vb
- ''
- '' 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
-