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Tradução
Original

Método Graphics.DrawImage (Image, Rectangle, Int32, Int32, Int32, Int32, GraphicsUnit, ImageAttributes, Graphics.DrawImageAbort, IntPtr)

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

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

public void DrawImage(
	Image image,
	Rectangle destRect,
	int srcX,
	int srcY,
	int srcWidth,
	int srcHeight,
	GraphicsUnit srcUnit,
	ImageAttributes imageAttrs,
	Graphics..::.DrawImageAbort callback,
	IntPtr callbackData
)

Parâmetros

image
Tipo: System.Drawing.Image
Image to draw.
destRect
Tipo: System.Drawing.Rectangle
Rectangle structure that specifies the location and size of the drawn image. The image is scaled to fit the rectangle.
srcX
Tipo: System.Int32
The x-coordinate of the upper-left corner of the portion of the source image to draw.
srcY
Tipo: System.Int32
The y-coordinate of the upper-left corner of the portion of the source image to draw.
srcWidth
Tipo: System.Int32
Width of the portion of the source image to draw.
srcHeight
Tipo: System.Int32
Height of the portion of the source image to draw.
srcUnit
Tipo: System.Drawing.GraphicsUnit
Member of the GraphicsUnit enumeration that specifies the units of measure used to determine the source rectangle.
imageAttrs
Tipo: System.Drawing.Imaging.ImageAttributes
ImageAttributes that specifies recoloring and gamma information for the image object.
callback
Tipo: 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.
callbackData
Tipo: System.IntPtr
Value specifying additional data for the Graphics.DrawImageAbort delegate to use when checking whether to stop execution of the DrawImage method.

ExceçãoCondição
ArgumentNullException

image é null.

The srcX, srcY, srcWidth, and srcHeight parameters specify a rectangular portion, of the image object to draw. The rectangle is relative to the upper-left corner of the source image. This portion is scaled to fit inside the rectangle specified by the destRect 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 Paint 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 destination rectangle in which to draw the image.

  • Creates a source 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 destination rectangle 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 destination rectangle, the position locates the image on the screen, and the size of the source rectangle and the size and shape of the destination rectangle determines the scaling 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.


// Define DrawImageAbort callback method.
private bool DrawImageCallback6(IntPtr callBackData)
{

    // Test for call that passes callBackData parameter.
    if(callBackData==IntPtr.Zero)
    {

        // If no callBackData passed, abort DrawImage method.
        return true;
    }
    else
    {

        // If callBackData passed, continue DrawImage method.
        return false;
    }
}
private void DrawImageRect4IntAtrribAbortData(PaintEventArgs e)
{

    // Create callback method.
    Graphics.DrawImageAbort imageCallback
        = new Graphics.DrawImageAbort(DrawImageCallback6);
    IntPtr imageCallbackData = new IntPtr(1);

    // Create image.
    Image newImage = Image.FromFile("SampImag.jpg");

    // Create rectangle for displaying original image.
    Rectangle destRect1 = new Rectangle(100, 25, 450, 150);

    // Create coordinates of rectangle for source image.
    int x = 50;
    int y = 50;
    int width = 150;
    int height = 150;
    GraphicsUnit units = GraphicsUnit.Pixel;

    // Draw original image to screen.
    e.Graphics.DrawImage(newImage, destRect1, x, y, width, height, units);

    // Create rectangle for adjusted image.
    Rectangle destRect2 = new Rectangle(100, 175, 450, 150);

    // Create image attributes and set large gamma.
    ImageAttributes imageAttr = new ImageAttributes();
    imageAttr.SetGamma(4.0F);
    try
    {
        checked
        {

            // Draw adjusted image to screen.
            e.Graphics.DrawImage(
                newImage,
                destRect2,
                x, y,
                width, height,
                units,
                imageAttr,
                imageCallback,
                imageCallbackData);
        }
    }
    catch (Exception ex)
    {
        e.Graphics.DrawString(
            ex.ToString(),
            new Font("Arial", 8),
            Brushes.Black,
            new PointF(0, 0));
    }
}


Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

o.NET Framework e.NET Compact Framework não oferecem suporte a todas as versões de cada plataforma. Para obter uma lista de versões suportadas, consulte Requisitos de sistema do .NET framework.

.NET Framework

Compatível com: 3.5, 3.0, 2.0, 1.1, 1.0

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