PictureEdit.ImageEditorDialogShowing Event

Fires when the Editor dialog is about to be opened. Allows you to customize the dialog and its graphic commands.

Namespace: DevExpress.XtraEditors

Assembly: DevExpress.XtraEditors.v24.1.dll

NuGet Package: DevExpress.Win.Navigation

Declaration

C#

[DXCategory("Events")]
public event ImageEditorDialogShowingEventHandler ImageEditorDialogShowing

VB.NET

<DXCategory("Events")>
Public Event ImageEditorDialogShowing As ImageEditorDialogShowingEventHandler

Event Data

The ImageEditorDialogShowing event's data class is DevExpress.XtraEditors.ImageEditor.ImageEditorDialogShowingEventArgs.

Remarks

The PictureEdit control supports basic edit operations on an image in a separate Editor dialog (see the RepositoryItemPictureEdit.ShowEditMenuItem property and PictureEdit.ShowImageEditorDialog method).

The ImageEditorDialogShowing event fires when the Editor dialog is about to be opened. It allows you to do the following:

• Prevent the dialog from being opened - Set the Cancel event parameter to true.
• Customize the form (dialog) - You can access this form with the Form event parameter.
• Access the image that is about to be customized (see the Image parameter).
• Customize graphic commands in the Editor’s main toolbar.

• Specify custom aspect ratios for crop operations (the CustomizeCropOptions event).

  

  Use the event’s Commands collection to add new and remove existing graphic commands (DevExpress.XtraEditors.ImageEditor.IGraphicCommand objects). After your ImageEditorDialogShowing event handler is complete, the Editor dialog creates buttons in the main toolbar. Each button corresponds to a graphic command in the Commands collection.

Example - Add Watermarks tool to the Image Editor

This example shows how to extend the editor with custom graphic commands that add watermarks to the current image.

The steps to add a WatermarkCommand (and other commands) to the image editor are as follows.

1. Create a new class (WatermarkGraphicOperation) that performs an operation on an image. The operation must be a BaseCachedGraphicOperation descendant. Users can undo and redo BaseCachedGraphicOperations while the image editor is active.

2. You can allow users to specify the operation’s settings in custom controls before the operation is applied. Create a panel with controls and implement the IToolSettingsControl interface for the panel. The IToolSettingsControl.GetOperation method must return the customized graphic operation (WatermarkGraphicOperation).

   This example creates a user control (WatermarkToolControl) with controls to enter the watermark-related settings:

   • a TextEditor to enter the watermark text
   • a ColorEditor to specify the font color
   • a SpinEditor to enter the font size
   • a CheckEditor to allow the watermark text to be repeated throughout the image.

3. Handle the PictureEdit.ImageEditorDialogShowing event to add custom commands (buttons) to the editor’s main toolbar.

   In the example two commands are added:

   • WatermarkPreset - Invokes the WatermarkGraphicOperation with predefined settings.
   • WatermarkCommand - Displays the WatermarkToolControl in which users can specify custom watermark settings and then apply the WatermarkGraphicOperation.

Note

A complete code sample project is available on GitHub at How to add custom graphic operations (watermarks) to the built-in editor dialog for a PictureEdit control.

C#

void PictureEdit1_ImageEditorDialogShowing(object sender, ImageEditorDialogShowingEventArgs e) {
    e.Commands.Insert(0, new WatermarkCommand() { Image = svgImageCollection1[0] });
    e.Commands.Insert(1, new WatermarkPreset() { Image = svgImageCollection1[1] });
}

public class WatermarkCommand : IGraphicCommand {
    public virtual SvgImage Image {
        get;
        set;
    }
    public virtual string ToolTip {
        get { return "Add Watermark"; }
    }
    public virtual void Execute(ImageEditorControl editorControl) {
        editorControl.SetActiveTool(new WatermarkToolControl());
    }
}

public class WatermarkPreset : WatermarkCommand {
    public override string ToolTip {
        get { return "Watermark Preset"; }
    }
    public override void Execute(ImageEditorControl editorControl) {
        // Perform the WatermarkGraphicOperation operation in code, using the EditController. Users can undo this operation while the Image Editor is active.
        editorControl.EditController.DoOperation(new WatermarkGraphicOperation("devexpress.com", Color.LightBlue, 15, true));
    }
}

public partial class WatermarkToolControl : XtraUserControl, IToolSettingsControl {
    public event EventHandler Changed;

    public WatermarkToolControl() {
        InitializeComponent();

        teText.TextChanged += (s, e) => RaiseChanged();
        cpeColor.EditValueChanged += (s, e) => RaiseChanged();
        seFontSize.EditValueChanged += (s, e) => RaiseChanged();
        ceRepeat.CheckedChanged += (s, e) => RaiseChanged();
    }
    protected override void OnLoad(EventArgs e) {
        base.OnLoad(e);
        teText.Text = "devexpress.com";
        cpeColor.Color = Color.FromArgb(180, Color.Silver);
        seFontSize.Value = 30;
        ceRepeat.Checked = true;
    }
    void RaiseChanged() {
        if(Changed != null)
            Changed(this, EventArgs.Empty);
    }
    public BaseGraphicOperation GetOperation() {
        return new WatermarkGraphicOperation(teText.Text, cpeColor.Color, (int)seFontSize.Value, ceRepeat.Checked);
    }
}

public class WatermarkGraphicOperation : BaseCachedGraphicOperation {
    public string Text { get; protected set; }
    public Color Color { get; protected set; }
    public bool Repeat { get; protected set; }
    public int FontSize { get; protected set; }

    public WatermarkGraphicOperation(String text, Color color, int fontSize, bool repeat) {
        this.Text = text;
        this.FontSize = fontSize;
        this.Color = color;
        this.Repeat = repeat;
    }
    public override Image Apply(Image input) {
        Image newImg = new Bitmap(input);
        if(!String.IsNullOrEmpty(Text)) {
            using(Graphics g = Graphics.FromImage(newImg)) {
                g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
                using(Font font = new Font("Tahoma", FontSize)) {
                    using(SolidBrush brush = new SolidBrush(this.Color)) {
                        if(this.Repeat) {
                            float centerX = ((float)newImg.Width / 2);
                            float centerY = ((float)newImg.Height / 2);
                            g.TranslateTransform(centerX, centerY);
                            g.RotateTransform(-45);
                            g.TranslateTransform(-centerX, -centerY);
                            Size textSize = g.MeasureString(Text, font).ToSize();
                            int max = Math.Max(newImg.Width, newImg.Height);
                            int start = -Math.Abs(newImg.Width - newImg.Height);
                            for(int y = start; y < max; y += textSize.Height + 64) {
                                for(int x = start - (textSize.Width / 2); x < max; x += textSize.Width + 64) {
                                    g.DrawString(Text, font, brush, new PointF(x, y));
                                }
                            }
                        } else {
                            RectangleF rect = new RectangleF(0, 0, input.Width, input.Height);
                            using(StringFormat format = new StringFormat()) {
                                format.Alignment = StringAlignment.Center;
                                format.LineAlignment = StringAlignment.Center;
                                g.DrawString(Text, font, brush, rect, format);
                            }
                        }
                    }
                }
            }
        }
        return newImg;
    }
}

VB.NET

Private Sub PictureEdit1_ImageEditorDialogShowing(sender As Object, e As DevExpress.XtraEditors.ImageEditor.ImageEditorDialogShowingEventArgs) Handles PictureEdit1.ImageEditorDialogShowing
    e.Commands.Insert(0, New WatermarkCommand() With {
        .Image = SvgImageCollection1(0)
    })
    e.Commands.Insert(1, New WatermarkPreset() With {
        .Image = SvgImageCollection1(1)
    })
End Sub

Public Class WatermarkCommand
    Inherits IGraphicCommand

    Public Overridable Property Image As SvgImage

    Public Overridable ReadOnly Property ToolTip As String
        Get
            Return "Add Watermark"
        End Get
    End Property

    Public Overridable Sub Execute(ByVal editorControl As ImageEditorControl)
        editorControl.SetActiveTool(New WatermarkToolControl())
    End Sub
End Class

Public Class WatermarkPreset
    Inherits WatermarkCommand

    Public Overrides ReadOnly Property ToolTip As String
        Get
            Return "Watermark Preset"
        End Get
    End Property

    Public Overrides Sub Execute(ByVal editorControl As ImageEditorControl)
        editorControl.EditController.DoOperation(New WatermarkGraphicOperation("devexpress.com", Color.LightBlue, 15, True))
    End Sub
End Class

Public Partial Class WatermarkToolControl
    Inherits XtraUserControl
    Implements IToolSettingsControl

    Public Event Changed As EventHandler

    Public Sub New()
        InitializeComponent()
        teText.TextChanged += Function(s, e) RaiseChanged()
        cpeColor.EditValueChanged += Function(s, e) RaiseChanged()
        seFontSize.EditValueChanged += Function(s, e) RaiseChanged()
        ceRepeat.CheckedChanged += Function(s, e) RaiseChanged()
    End Sub

    Protected Overrides Sub OnLoad(ByVal e As EventArgs)
        MyBase.OnLoad(e)
        teText.Text = "devexpress.com"
        cpeColor.Color = Color.FromArgb(180, Color.Silver)
        seFontSize.Value = 30
        ceRepeat.Checked = True
    End Sub

    Private Sub RaiseChanged()
        RaiseEvent Changed(Me, EventArgs.Empty)
    End Sub

    Public Function GetOperation() As BaseGraphicOperation
        Return New WatermarkGraphicOperation(teText.Text, cpeColor.Color, CInt(seFontSize.Value), ceRepeat.Checked)
    End Function
End Class

Public Class WatermarkGraphicOperation
    Inherits BaseCachedGraphicOperation

    Public Property Text As String
    Public Property Color As Color
    Public Property Repeat As Boolean
    Public Property FontSize As Integer

    Public Sub New(ByVal text As String, ByVal color As Color, ByVal fontSize As Integer, ByVal repeat As Boolean)
        Me.Text = text
        Me.FontSize = fontSize
        Me.Color = color
        Me.Repeat = repeat
    End Sub

    Public Overrides Function Apply(ByVal input As Image) As Image
        Dim newImg As Image = New Bitmap(input)

        If Not String.IsNullOrEmpty(Text) Then

            Using g As Graphics = Graphics.FromImage(newImg)
                g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias

                Using font As Font = New Font("Tahoma", FontSize)

                    Using brush As SolidBrush = New SolidBrush(Me.Color)

                        If Me.Repeat Then
                            Dim centerX As Single = (CSng(newImg.Width) / 2)
                            Dim centerY As Single = (CSng(newImg.Height) / 2)
                            g.TranslateTransform(centerX, centerY)
                            g.RotateTransform(-45)
                            g.TranslateTransform(-centerX, -centerY)
                            Dim textSize As Size = g.MeasureString(Text, font).ToSize()
                            Dim max As Integer = Math.Max(newImg.Width, newImg.Height)
                            Dim start As Integer = -Math.Abs(newImg.Width - newImg.Height)
                            Dim y As Integer = start

                            While y < max
                                Dim x As Integer = start - (textSize.Width / 2)

                                While x < max
                                    g.DrawString(Text, font, brush, New PointF(x, y))
                                    x += textSize.Width + 64
                                End While

                                y += textSize.Height + 64
                            End While
                        Else
                            Dim rect As RectangleF = New RectangleF(0, 0, input.Width, input.Height)

                            Using format As StringFormat = New StringFormat()
                                format.Alignment = StringAlignment.Center
                                format.LineAlignment = StringAlignment.Center
                                g.DrawString(Text, font, brush, rect, format)
                            End Using
                        End If
                    End Using
                End Using
            End Using
        End If

        Return newImg
    End Function
End Class

Example - Add custom aspect ratios to the Image Editor’s Crop tool

You can handle the PictureEdit.ImageEditorDialogShowing (or RepositoryItemPictureEdit.ImageEditorDialogShowing) event to customize the settings of the Image Editor dialog. Subscribe to the CustomizeCropOptions event (available from the e.Form event parameter) to change the list of aspect ratios for the Image Editor’s crop operations. The following image shows the default crop options.

The code below removes the default aspect ratios and adds “16:9” and “4:3” aspect ratios to this list.

C#

void pictureEdit1_ImageEditorDialogShowing(object sender, DevExpress.XtraEditors.ImageEditor.ImageEditorDialogShowingEventArgs e) {
    e.Form.CustomizeCropOptions += CustomizeCropOptions;
}

void CustomizeCropOptions(object sender, CustomizeCropOptionsEventArgs e) {
    var widescreen = new AspectRatioInfo(1.777f, "16:9");
    var standard = new AspectRatioInfo(1.333f, "4:3");
    e.AspectRatios.Clear();
    e.AspectRatios.Add(widescreen);
    e.AspectRatios.Add(standard);
    e.DefaultAspectRatio = widescreen;
}

VB.NET

Private Sub PictureEdit1_ImageEditorDialogShowing(sender As Object, e As DevExpress.XtraEditors.ImageEditor.ImageEditorDialogShowingEventArgs) Handles PictureEdit1.ImageEditorDialogShowing
    AddHandler e.Form.CustomizeCropOptions, AddressOf CustomizeCropOptions
End Sub

Private Sub CustomizeCropOptions(ByVal sender As Object, ByVal e As CustomizeCropOptionsEventArgs)
    Dim widescreen = New AspectRatioInfo(1.777F, "16:9")
    Dim standard = New AspectRatioInfo(1.333F, "4:3")
    e.AspectRatios.Clear()
    e.AspectRatios.Add(widescreen)
    e.AspectRatios.Add(standard)
    e.DefaultAspectRatio = widescreen
End Sub

See the following demo for a complete example: Picture Edit - Edit Image module in the XtraEditors MainDemo

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the ImageEditorDialogShowing event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

winforms-pictureedit-add-custom-graphic-operation-watermark/CS/WatermarkDemo/WatermarkDemo/Form1.cs#L18

    InitializeComponent();
    pictureEdit1.ImageEditorDialogShowing += PictureEdit1_ImageEditorDialogShowing;
}

VB.NET

winforms-pictureedit-add-custom-graphic-operation-watermark/VB/WatermarkDemo/WatermarkDemo/Form1.vb#L20

    InitializeComponent()
    AddHandler pictureEdit1.ImageEditorDialogShowing, AddressOf PictureEdit1_ImageEditorDialogShowing
End Sub