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BitBlt Function

The BitBlt function performs a bit-block transfer of the color data corresponding to a rectangle of pixels from the specified source device context into a destination device context.

Syntax

BOOL BitBlt(
  __in  HDC hdcDest,
  __in  int nXDest,
  __in  int nYDest,
  __in  int nWidth,
  __in  int nHeight,
  __in  HDC hdcSrc,
  __in  int nXSrc,
  __in  int nYSrc,
  __in  DWORD dwRop
);

Parameters

hdcDest [in]

A handle to the destination device context.

nXDest [in]

The x-coordinate, in logical units, of the upper-left corner of the destination rectangle.

nYDest [in]

The y-coordinate, in logical units, of the upper-left corner of the destination rectangle.

nWidth [in]

The width, in logical units, of the source and destination rectangles.

nHeight [in]

The height, in logical units, of the source and the destination rectangles.

hdcSrc [in]

A handle to the source device context.

nXSrc [in]

The x-coordinate, in logical units, of the upper-left corner of the source rectangle.

nYSrc [in]

The y-coordinate, in logical units, of the upper-left corner of the source rectangle.

dwRop [in]

A raster-operation code. These codes define how the color data for the source rectangle is to be combined with the color data for the destination rectangle to achieve the final color.

The following list shows some common raster operation codes.

ValueMeaning
BLACKNESS

Fills the destination rectangle using the color associated with index 0 in the physical palette. (This color is black for the default physical palette.)

CAPTUREBLT

Includes any windows that are layered on top of your window in the resulting image. By default, the image only contains your window. Note that this generally cannot be used for printing device contexts.

DSTINVERT

Inverts the destination rectangle.

MERGECOPY

Merges the colors of the source rectangle with the brush currently selected in hdcDest, by using the Boolean AND operator.

MERGEPAINT

Merges the colors of the inverted source rectangle with the colors of the destination rectangle by using the Boolean OR operator.

NOMIRRORBITMAP

Prevents the bitmap from being mirrored.

NOTSRCCOPY

Copies the inverted source rectangle to the destination.

NOTSRCERASE

Combines the colors of the source and destination rectangles by using the Boolean OR operator and then inverts the resultant color.

PATCOPY

Copies the brush currently selected in hdcDest, into the destination bitmap.

PATINVERT

Combines the colors of the brush currently selected in hdcDest, with the colors of the destination rectangle by using the Boolean XOR operator.

PATPAINT

Combines the colors of the brush currently selected in hdcDest, with the colors of the inverted source rectangle by using the Boolean OR operator. The result of this operation is combined with the colors of the destination rectangle by using the Boolean OR operator.

SRCAND

Combines the colors of the source and destination rectangles by using the Boolean AND operator.

SRCCOPY

Copies the source rectangle directly to the destination rectangle.

SRCERASE

Combines the inverted colors of the destination rectangle with the colors of the source rectangle by using the Boolean AND operator.

SRCINVERT

Combines the colors of the source and destination rectangles by using the Boolean XOR operator.

SRCPAINT

Combines the colors of the source and destination rectangles by using the Boolean OR operator.

WHITENESS

Fills the destination rectangle using the color associated with index 1 in the physical palette. (This color is white for the default physical palette.)

 

Return Value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

BitBlt only does clipping on the destination DC.

If a rotation or shear transformation is in effect in the source device context, BitBlt returns an error. If other transformations exist in the source device context (and a matching transformation is not in effect in the destination device context), the rectangle in the destination device context is stretched, compressed, or rotated, as necessary.

If the color formats of the source and destination device contexts do not match, the BitBlt function converts the source color format to match the destination format.

When an enhanced metafile is being recorded, an error occurs if the source device context identifies an enhanced-metafile device context.

Not all devices support the BitBlt function. For more information, see the RC_BITBLT raster capability entry in the GetDeviceCaps function as well as the following functions: MaskBlt, PlgBlt, and StretchBlt.

BitBlt returns an error if the source and destination device contexts represent different devices. To transfer data between DCs for different devices, convert the memory bitmap to a DIB by calling GetDIBits. To display the DIB to the second device, call SetDIBits or StretchDIBits.

ICM: No color management is performed when blits occur.

Examples

For an example, see Capturing an Image.

Requirements

Minimum supported client

Windows 2000 Professional

Minimum supported server

Windows 2000 Server

Header

Wingdi.h (include Windows.h)

Library

Gdi32.lib

DLL

Gdi32.dll

See Also

Bitmaps Overview
Bitmap Functions
GetDeviceCaps
GetDIBits
MaskBlt
PlgBlt
SetDIBits
StretchBlt
StretchDIBits

 

 

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Build date: 5/4/2010

Community ContentAdd
A few notes
Note well that if you have a resulting BitMap image that contains more and more black space (image is shifted down or right), it may be because you are using nXDest instead of nXSrc for your starting offset.  If you want to grab an offset from the screen, you use nXSrc.  Just experiment with them until you get the right one. $0$0 $0 $0Also note that there are more efficient ways to get the screen capture: http://www.codeproject.com/KB/dialog/screencap.aspx (LGPL)$0 $0$0 $0 $0Also note that for me, disabling "Enable desktop composition" in my system properties -> advanced -> Performance Options -> Visual effects made this method call *much* faster.  There may be other tweaks that matter as well, speed-wise.$0
CAPTUREBLT not needed when Aero is on

If Aero is activce BitBlt() will capture transparent windows even if the CAPTUREBLT flag isn't set. This is nice as the CAPTUREBLT flag causes the mouse to disapear during the BitBlt()

dwRop Values
From wingdi.h:

#define BLACKNESS 0x42
#define DSTINVERT 0x550009
#define MERGECOPY 0xC000CA
#define MERGEPAINT 0xBB0226
#define NOTSRCCOPY 0x330008
#define NOTSRCERASE 0x1100A6
#define PATCOPY 0xF00021
#define PATINVERT 0x5A0049
#define PATPAINT 0xFB0A09
#define SRCAND 0x8800C6
#define SRCCOPY 0xCC0020
#define SRCERASE 0x440328
#define SRCINVERT 0x660046
#define SRCPAINT 0xEE0086
#define WHITENESS 0xFF0062
C# syntax
[DllImport("gdi32.dll", CharSet=CharSet.Auto, SetLastError=true, ExactSpelling=true)]
public static extern bool BitBlt(IntPtr hDC, int x, int y, int nWidth, int nHeight, IntPtr hSrcDC, int xSrc, int ySrc, int dwRop);
vb.net syntax
<DllImport("gdi32.dll", CharSet:=CharSet.Auto, SetLastError:=True, ExactSpelling:=True)> _
Public Shared Function BitBlt(ByVal hDC As IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hSrcDC As HandleRef, ByVal xSrc As Integer, ByVal ySrc As Integer, ByVal dwRop As Integer) As Boolean
End Function
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