Microsoft Foundation Classes (mfc.hlp) (
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CDC::BitBlt
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──Microsoft Foundation Classes──────────────────────────────────────────────
BOOL BitBlt( int x, int y, int nWidth, int nHeight, CDC* pSrcDC,
int xSrc, int ySrc, DWORD dwRop );
Parameter Description
<x> Specifies the logical x-coordinate of the upper-left corner
of the destination rectangle.
<y> Specifies the logical y-coordinate of the upper-left corner
of the destination rectangle.
<nWidth> Specifies the width (in logical units) of the destination
rectangle and source bitmap.
<nHeight> Specifies the height (in logical units) of the destination
rectangle and source bitmap.
<pSrcDC> Pointer to a CDC object that identifies the device context
from which the bitmap will be copied. It must be NULL if
<dwRop> specifies a raster operation that does not include a
source.
<xSrc> Specifies the logical x-coordinate of the upper-left corner
of the source bitmap.
<ySrc> Specifies the logical y-coordinate of the upper-left corner
of the source bitmap.
<dwRop> Specifies the raster operation to be performed.
Raster-operation codes define how the graphics device
interface (GDI) combines colors in output operations that
involve a current brush, a possible source bitmap, and a
destination bitmap. The following lists raster-operation
codes for <dwRop>:
Code Description
BLACKNESS Turns all output black.
DSTINVERT Inverts the destination bitmap.
MERGECOPY Combines the pattern and the source bitmap
using the Boolean AND operator.
MERGEPAINT Combines the inverted source bitmap with the
destination bitmap using the Boolean OR
operator.
NOTSRCCOPY Copies the inverted source bitmap to the
destination.
NOTSRCERASE Inverts the result of combining the
destination and source bitmaps using the
Boolean OR operator.
PATCOPY Copies the pattern to the destination bitmap.
PATINVERT Combines the destination bitmap with the
pattern using the Boolean XOR operator.
PATPAINT Combines the inverted source bitmap with the
pattern using the Boolean OR operator.
Combines the result of this operation with the
destination bitmap using the Boolean OR
operator.
SRCAND Combines pixels of the destination and source
bitmaps using the Boolean AND operator.
SRCCOPY Copies the source bitmap to the destination
bitmap.
SRCERASE Inverts the desination bitmap and combines the
result with the source bitmap using the
Boolean AND operator.
SRCINVERT Combines pixels of the destination and source
bitmaps using the Boolean XOR operator.
SRCPAINT Combines pixels of the destination and source
bitmaps using the Boolean OR operator.
WHITENESS Turns all output white.
For a complete list of raster-operation codes, see the
Windows Software Development Kit documentation.
Remarks
Copies a bitmap from the source device context to this current device
context.
The application can align the windows or client areas on byte boundaries
to ensure that the BitBlt operations occur on byte-aligned rectangles.
(Set the CS_BYTEALIGNWINDOW or CS_BYTEALIGNCLIENT flags when you
register the window classes.)
BitBlt operations on byte-aligned rectangles are considerably faster
than BitBlt operations on rectangles that are not byte aligned. If you
want to specify class styles such as byte-alignment or your own device
context, you will have to register a window class rather than relying on
the Foundation classes to do it for you. Use the Foundation global
function ◄AfxRegisterWndClass►.
GDI transforms <nWidth> and <nHeight>, once by using the destination
display context, and once by using the source display context. If the
resulting extents do not match, GDI uses the Windows StretchBlt function
to compress or stretch the source bitmap as necessary.
If destination, source, and pattern bitmaps do not have the same color
format, the BitBlt function converts the source and pattern bitmaps to
match the destination. The foreground and background colors of the
destination are used in the conversion.
Note that not all device contexts support BitBlt. To check whether a
given device context does support BitBlt, use GetDeviceCaps.
Return Value
TRUE if the bitmap is drawn; otherwise FALSE.
See Also
◄CDC::GetDeviceCaps►, ◄CDC::PatBlt►, ◄CDC::SetTextColor►,
◄CDC::StretchBlt►, ◄::StretchDIBits►, ◄::BitBlt►
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