Transforms.vb
''
'' This code is part of GrapeCity Documents for PDF samples.
'' Copyright (c) GrapeCity, Inc. All rights reserved.
''
Imports System.IO
Imports System.Drawing
Imports System.Numerics
Imports GrapeCity.Documents.Pdf
Imports GrapeCity.Documents.Text
Imports GrapeCity.Documents.Drawing

'' Shows how to use graphics transformations (GcPdfGraphics.Transform property).
Public Class Transforms
    '' Helper method drawing a filled box with text:
    Private Sub DrawBox(ByVal text As String, ByVal g As GcGraphics, ByVal box As RectangleF)
        g.FillRectangle(box, Color.FromArgb(80, 0, 184, 204))
        g.DrawRectangle(box, Color.FromArgb(0, 193, 213), 1)
        box.Inflate(-6, -6)
        g.DrawString(text, New TextFormat() With {.Font = StandardFonts.Times, .FontSize = 14}, box)
    End Sub

    Function CreatePDF(ByVal stream As Stream) As Integer
        Const baseTxt = "Text drawn at (0,36) in a 4""x2"" box"
        Dim doc = New GcPdfDocument()
        Dim page = doc.NewPage()
        Dim g = page.Graphics
        Dim box = New RectangleF(0, 36, 72 * 4, 72 * 2)
        '' #1:
        DrawBox($"Box 1: {baseTxt}, no transformations.", g, box)
        ''
        Dim translate0 = Matrix3x2.CreateTranslation(72 * 1, 72 * 4)
        Dim scale0 = Matrix3x2.CreateScale(0.5F)

        '' Transforms are applied in order from last to first.

        '' #2:
        g.Transform =
            scale0 *
            translate0
        DrawBox($"Box 2: {baseTxt}, translated by (1"",4"") and scaled by 0.5.", g, box)
        '' #3:
        g.Transform =
            translate0 *
            scale0
        DrawBox($"Box 3: {baseTxt}, scaled by 0.5 and translated by (1"",4"").", g, box)
        ''
        Dim translate1 = Matrix3x2.CreateTranslation(72 * 3, 72 * 5)
        Dim scale1 = Matrix3x2.CreateScale(0.7F)
        Dim rotate0 = Matrix3x2.CreateRotation((-70 * Math.PI) / 180.0F) '' 70 degrees CCW
        '' #4:
        g.Transform =
            rotate0 *
            translate1 *
            scale1
        DrawBox($"Box 4: {baseTxt}, scaled by 0.7, translated by (3"",5""), and rotated 70 degrees counterclockwise.", g, box)
        '' #5:
        g.Transform =
            Matrix3x2.CreateTranslation(36, 72) *
            g.Transform
        DrawBox($"Box 5: {baseTxt}, applied current transform (Box 4), and translated by (1/2"",1"").", g, box)
        '' #6:
        g.Transform =
            Matrix3x2.CreateSkew((-45 * Math.PI) / 180.0F, (20 * Math.PI) / 180.0F) *
            Matrix3x2.CreateTranslation(72 * 3, 72 * 7)
        DrawBox($"Box 6: {baseTxt}, translated by (3"",7""), and skewed -45 degrees on axis X and 20 degrees on axis Y.", g, box)
        '' #7:
        g.Transform =
            Matrix3x2.CreateRotation(Math.PI) *
            Matrix3x2.CreateTranslation(page.Size.Width - 72, page.Size.Height - 72)
        DrawBox($"Box 7: {baseTxt}, translated by (7.5"",10""), and rotated by 180 degrees.", g, box)
        '' We can remove any transformations on a graphics like so:
        g.Transform = Matrix3x2.Identity
        ''
        '' Done:
        doc.Save(stream)
        Return doc.Pages.Count
    End Function
End Class