Graphics.DrawImage Method (Image, PointF(), RectangleF, GraphicsUnit, ImageAttributes, Graphics.DrawImageAbort, Int32)


Draws the specified portion of the specified Image at the specified location and with the specified size.

Namespace:   System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

Public Sub DrawImage (
	image As Image,
	destPoints As PointF(),
	srcRect As RectangleF,
	srcUnit As GraphicsUnit,
	imageAttr As ImageAttributes,
	callback As Graphics.DrawImageAbort,
	callbackData As Integer


Type: System.Drawing.Image

Image to draw.

Type: System.Drawing.PointF()

Array of three PointF structures that define a parallelogram.

Type: System.Drawing.RectangleF

RectangleF structure that specifies the portion of the image object to draw.

Type: System.Drawing.GraphicsUnit

Member of the GraphicsUnit enumeration that specifies the units of measure used by the srcRect parameter.

Type: System.Drawing.Imaging.ImageAttributes

ImageAttributes that specifies recoloring and gamma information for the image object.

Type: System.Drawing.Graphics.DrawImageAbort

Graphics.DrawImageAbort delegate that specifies a method to call during the drawing of the image. This method is called frequently to check whether to stop execution of the DrawImage method according to application-determined criteria.

Type: System.Int32

Value specifying additional data for the Graphics.DrawImageAbort delegate to use when checking whether to stop execution of the DrawImage method.

Exception Condition

image is null.

The destPoints parameter specifies three points of a parallelogram. The three PointF structures represent the upper-left, upper-right, and lower-left corners of the parallelogram. The fourth point is extrapolated from the first three to form a parallelogram.

The srcRect parameter specifies a rectangular portion of the image object to draw. This portion is scaled and sheared to fit inside the parallelogram specified by the destPoints parameter.

This overload with the callback and callbackData parameters provides the means to stop the drawing of an image once it starts according to criteria and data determined by the application. For example, an application could start drawing a large image and the user might scroll the image off the screen, in which case the application could stop the drawing.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the PaPaint event handler. The code first defines a callback method for the Graphics.DrawImageAbort delegate; the definition is simplistic and merely tests to see whether the DrawImage method calls it with a null callBackData parameter. The main body of the example performs the following actions:

  • Creates an instance of the Graphics.DrawImageAbort callback method.

  • Creates an image from a JPEG file SampImag.jpg in the folder of the example.

  • Creates points that define a parallelogram in which to draw the image.

  • Creates a rectangle to select the portion of the image to draw.

  • Sets the graphics drawing unit to pixel.

  • Draws the original image to the screen.

  • Creates an additional parallelogram in which to draw an adjusted image.

  • Creates and sets the attributes of the adjusted image to have a larger-than-usual gamma value.

  • Draws the adjusted image to the screen.

For the original, unadjusted parallelogram, the position locates the image on the screen, and the size of the rectangle and the size and shape of the parallelogram determines the scaling and shearing of the drawn image.

Because this example uses an overload that passes a callBackData parameter, the Graphics.DrawImageAbort callback returns false, which causes the DrawImage method to continue, and the example draws the adjusted image to the screen.

Private Function DrawImageCallback4(ByVal callBackData As IntPtr) As Boolean

    ' Test for call that passes callBackData parameter.
    If callBackData.Equals(IntPtr.Zero) Then

        ' If no callBackData passed, abort DrawImage method.
        Return True

        ' If callBackData passed, continue DrawImage method.
        Return False
    End If
End Function
Private Sub DrawImageParaFRectAttribAbortData(ByVal e As PaintEventArgs)

    ' Create callback method.
    Dim imageCallback As New _
    Graphics.DrawImageAbort(AddressOf DrawImageCallback4)
    Dim imageCallbackData As Integer = 1

    ' Create image.
    Dim newImage As Image = Image.FromFile("SampImag.jpg")

    ' Create parallelogram for drawing original image.
    Dim ulCorner1 As New PointF(100.0F, 100.0F)
    Dim urCorner1 As New PointF(325.0F, 100.0F)
    Dim llCorner1 As New PointF(150.0F, 250.0F)
    Dim destPara1 As PointF() = {ulCorner1, urCorner1, llCorner1}

    ' Create rectangle for source image.
    Dim srcRect As New RectangleF(50.0F, 50.0F, 150.0F, 150.0F)
    Dim units As GraphicsUnit = GraphicsUnit.Pixel

    ' Create parallelogram for drawing adjusted image.
    Dim ulCorner2 As New PointF(325.0F, 100.0F)
    Dim urCorner2 As New PointF(550.0F, 100.0F)
    Dim llCorner2 As New PointF(375.0F, 250.0F)
    Dim destPara2 As PointF() = {ulCorner2, urCorner2, llCorner2}

    ' Draw original image to screen.
    e.Graphics.DrawImage(newImage, destPara1, srcRect, units)

    ' Create image attributes and set large gamma.
    Dim imageAttr As New ImageAttributes

        ' Draw adjusted image to screen.
        e.Graphics.DrawImage(newImage, destPara2, srcRect, units, _
        imageAttr, imageCallback, imageCallbackData)
    Catch ex As Exception
        e.Graphics.DrawString(ex.ToString(), New Font("Arial", 8), _
        Brushes.Black, New PointF(0, 0))
    End Try
End Sub

.NET Framework
Available since 1.1
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