SaveGraphicsState Method (GdPicturePDF)

In This Topic

Saves the current graphics state on the graphics state stack. You can use the GdPicturePDF.RestoreGraphicsState method to reset the previously defined graphics state. Please note that GdPicturePDF.SaveGraphicsState and following GdPicturePDF.RestoreGraphicsState calls need to be applied on the same page, in other words changing the current page between these two calls causes incorrect behavior of the graphics state.

The graphics on a PDF page are described by a sequence of draw operators, graphics state operators, and marked-content operators. The graphics state operators change the graphics state (set the line width, dash pattern, fill color, font size etc) and the result of draw operators are affected by the graphics state. Please see also the GdPicturePDF.ResetGraphicsState method for more details.

Syntax

Visual Basic
C#
Delphi
JScript
Managed Extensions for C++
C++/CLI

'Declaration
 
Public Function SaveGraphicsState() As GdPictureStatus

public GdPictureStatus SaveGraphicsState()

public function SaveGraphicsState(): GdPictureStatus;

public function SaveGraphicsState() : GdPictureStatus;

public: GdPictureStatus SaveGraphicsState();

public:
GdPictureStatus SaveGraphicsState();

Return Value

A member of the GdPictureStatus enumeration. If the method has been successfully followed, then the return value is GdPictureStatus.OK.

We strongly recommend always checking this status first.

Remarks

This method is only allowed for use with non-encrypted documents.

Be aware that changing the current page between calls to GdPicturePDF.SaveGraphicsState and GdPicturePDF.RestoreGraphicsState methods causes incorrect behavior of the graphics state. According to the PDF Reference, Section "Graphics State", the graphics state parameters are initialized to their default values at the beginning of each page.

Example

How to correctly save and restore graphics state to draw various rectangles onto the newly created PDF document.

VB.NET
C#

Dim caption As String = "Example: SaveGraphicsState"
Dim gdpicturePDF As New GdPicturePDF()
Dim status As GdPictureStatus = gdpicturePDF.NewPDF()
If status = GdPictureStatus.OK Then
    gdpicturePDF.SetOrigin(PdfOrigin.PdfOriginTopLeft)
    gdpicturePDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitMillimeter)
    'This is the font only used to describe the drawn rectangles.
    Dim fontName As String = gdpicturePDF.AddStandardFont(PdfStandardFont.PdfStandardFontHelvetica)
    If gdpicturePDF.GetStat() = GdPictureStatus.OK Then
        If (gdpicturePDF.NewPage(210, 297) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.ResetGraphicsState() = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetLineWidth(0.5F) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetLineColor(0, 0, 255) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 255, 255) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawRectangle(10, 10, 40, 20, True, True) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawText(fontName, 15, 15, "1. rectangle") = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 255, 255) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SaveGraphicsState() = GdPictureStatus.OK) AndAlso 'Saving the graphics state.
           (gdpicturePDF.SaveGraphicsState() = GdPictureStatus.OK) AndAlso 'Saving the graphics state again.
           (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, 150, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetLineColor(255, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(128, 0, 128) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawRectangle(10, 10, 40, 20, True, True) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawText(fontName, 15, 15, "2. rectangle") = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.RestoreGraphicsState() = GdPictureStatus.OK) AndAlso 'Restoring the preceding graphics state.
           (gdpicturePDF.AddTransformationMatrix(1, 0.1F, 0, 1, 150, -100) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetLineColor(0, 128, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(173, 255, 47) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawRectangle(10, 10, 40, 20, True, True) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawText(fontName, 15, 15, "3. rectangle") = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.RestoreGraphicsState() = GdPictureStatus.OK) AndAlso 'Restoring the initial graphics state.
           (gdpicturePDF.DrawRectangle(10, 80, 40, 20, True, True) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawText(fontName, 15, 85, "4. rectangle") = GdPictureStatus.OK) AndAlso '1. and 4. rectangle use the same colors.
           (gdpicturePDF.AddTransformationMatrix(1, 0.1F, 0.1F, 1, 100, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetLineColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(255, 255, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawRectangle(10, 80, 40, 20, True, True) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.SetFillColor(0, 0, 0) = GdPictureStatus.OK) AndAlso
           (gdpicturePDF.DrawText(fontName, 15, 85, "5. rectangle") = GdPictureStatus.OK) Then
            status = gdpicturePDF.SaveToFile("test_GraphicState.pdf")
            If status = GdPictureStatus.OK Then
                MessageBox.Show("The example has been followed successfully and the file has been saved.", caption)
            Else
                MessageBox.Show("The example has been followed successfully, but the file can't be saved. Status: " + status.ToString(), caption)
            End If
        Else
            MessageBox.Show("The example has not been followed successfully." + vbCrLf + "The last known status is " + gdpicturePDF.GetStat().ToString(), caption)
        End If
    Else
        MessageBox.Show("The AddStandardFont() method has failed with the status: " + status.ToString(), caption)
    End If
Else
    MessageBox.Show("The NewPDF() method has failed with the status: " + status.ToString(), caption)
End If
gdpicturePDF.Dispose()

string caption = "Example: SaveGraphicsState";
GdPicturePDF gdpicturePDF = new GdPicturePDF();
GdPictureStatus status = gdpicturePDF.NewPDF();
if (status == GdPictureStatus.OK)
{
    gdpicturePDF.SetOrigin(PdfOrigin.PdfOriginTopLeft);
    gdpicturePDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitMillimeter);
    //This is the font only used to describe the drawn rectangles.
    string fontName = gdpicturePDF.AddStandardFont(PdfStandardFont.PdfStandardFontHelvetica);
    if (gdpicturePDF.GetStat() == GdPictureStatus.OK)
    {
        if ((gdpicturePDF.NewPage(210, 297) == GdPictureStatus.OK) &&
            (gdpicturePDF.ResetGraphicsState() == GdPictureStatus.OK) &&
            (gdpicturePDF.SetLineWidth(0.5f) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetLineColor(0, 0, 255) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 255, 255) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawRectangle(10, 10, 40, 20, true, true) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawText(fontName, 15, 15, "1. rectangle") == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 255, 255) == GdPictureStatus.OK) &&
            (gdpicturePDF.SaveGraphicsState() == GdPictureStatus.OK) && //Saving the graphics state.
            (gdpicturePDF.SaveGraphicsState() == GdPictureStatus.OK) && //Saving the graphics state again.
            (gdpicturePDF.AddTransformationMatrix(1, 0, 0, 1, 150, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetLineColor(255, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(128, 0, 128) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawRectangle(10, 10, 40, 20, true, true) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawText(fontName, 15, 15, "2. rectangle") == GdPictureStatus.OK) &&
            (gdpicturePDF.RestoreGraphicsState() == GdPictureStatus.OK) && //Restoring the preceding graphics state.
            (gdpicturePDF.AddTransformationMatrix(1, 0.1f, 0, 1, 150, -100) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetLineColor(0, 128, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(173, 255, 47) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawRectangle(10, 10, 40, 20, true, true) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawText(fontName, 15, 15, "3. rectangle") == GdPictureStatus.OK) &&
            (gdpicturePDF.RestoreGraphicsState() == GdPictureStatus.OK) && //Restoring the initial graphics state.
            (gdpicturePDF.DrawRectangle(10, 80, 40, 20, true, true) == GdPictureStatus.OK) && //1. and 4. rectangle use the same colors.
            (gdpicturePDF.SetFillColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawText(fontName, 15, 85, "4. rectangle") == GdPictureStatus.OK) &&
            (gdpicturePDF.AddTransformationMatrix(1, 0.1f, 0.1f, 1, 100, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetLineColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(255, 255, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawRectangle(10, 80, 40, 20, true, true) == GdPictureStatus.OK) &&
            (gdpicturePDF.SetFillColor(0, 0, 0) == GdPictureStatus.OK) &&
            (gdpicturePDF.DrawText(fontName, 15, 85, "5. rectangle") == GdPictureStatus.OK))
        {
            status = gdpicturePDF.SaveToFile("test_GraphicState.pdf");
            if (status == GdPictureStatus.OK)
                MessageBox.Show("The example has been followed successfully and the file has been saved.", caption);
            else
                MessageBox.Show("The example has been followed successfully, but the file can't be saved. Status: " + status.ToString(), caption);
        }
        else
            MessageBox.Show("The example has not been followed successfully.\nThe last known status is " + gdpicturePDF.GetStat().ToString(), caption);
    }
    else
        MessageBox.Show("The AddStandardFont() method has failed with the status: " + status.ToString(), caption);
}
else
    MessageBox.Show("The NewPDF() method has failed with the status: " + status.ToString(), caption);
gdpicturePDF.Dispose();

Reference

GdPicturePDF Class
GdPicturePDF Members
RestoreGraphicsState Method
ResetGraphicsState Method
AddTransformationMatrix Method