user-0 提问: bilblt的问题

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user: user-1
content: BitBlt 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.   BOOL BitBlt(   HDC hdcDest, // handle to destination device context   int nXDest,  // x-coordinate of destination rectangle's upper-left                 // corner   int nYDest,  // y-coordinate of destination rectangle's upper-left                 // corner   int nWidth,  // width of destination rectangle   int nHeight, // height of destination rectangle   HDC hdcSrc,  // handle to source device context   int nXSrc,   // x-coordinate of source rectangle's upper-left                 // corner   int nYSrc,   // y-coordinate of source rectangle's upper-left                 // corner   DWORD dwRop  // raster operation code );   Parameters hdcDest  Handle to the destination device context.  nXDest  Specifies the logical x-coordinate of the upper-left corner of the destination rectangle.  nYDest  Specifies the logical y-coordinate of the upper-left corner of the destination rectangle.  nWidth  Specifies the logical width of the source and destination rectangles.  nHeight  Specifies the logical height of the source and the destination rectangles.  hdcSrc  Handle to the source device context.  nXSrc  Specifies the logical x-coordinate of the upper-left corner of the source rectangle.  nYSrc  Specifies the logical y-coordinate of the upper-left corner of the source rectangle.  dwRop  Specifies 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: Value Description  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.)  DSTINVERT Inverts the destination rectangle.  MERGECOPY Merges the colors of the source rectangle with the specified pattern 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.  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 specified pattern into the destination bitmap.  PATINVERT Combines the colors of the specified pattern with the colors of the destination rectangle by using the Boolean XOR operator.  PATPAINT Combines the colors of the pattern 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 Values If the function succeeds, the return value is nonzero.  If the function fails, the return value is zero.   Windows NT: To get extended error information, callGetLastError.   Remarks 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, StretchBlt.   BitBlt returns an error if the source and destination device contexts represent different devices.   ICM: No color management is performed when blits occur.   Windows CE: In Windows CE version 1.0, the dwRop parameter can only be assigned the following values:  SRCCOPY  SRCAND  SRCPAINT   SRCINVERT   In Windows CE version 2.0, the dwRop parameter can be any ROP3.   QuickInfo   Windows NT: Requires version 3.1 or later.   Windows: Requires Windows 95 or later.   Windows CE: Requires version 1.0 or later.   Header: Declared in wingdi.h.   Import Library: Use gdi32.lib.  See Also Bitmaps Overview, Bitmap Functions

user: user-1
content: Setting a Breakpoint on a Message Received by a Windows Function You can set message breakpoints to stop the debugger when a particular WndProc function message is received.  Note   Message breakpoints work only on x86- or Pentium-based systems.  To set a breakpoint on a message   From the Edit menu, click Breakpoints.  The Breakpoints dialog box appears.  Click the Messages tab.   In the Break At WndProc text box, type the name of the Windows function.  If you are setting a breakpoint during a debug session, the list contains the exported functions in your project.   In the Set One Breakpoint For Each Message To Watch list box, select the message.   To set another breakpoint, press ENTER, and then repeat steps 3 and 4.  The Breakpoints list displays the currently active breakpoints.  Click OK to set the breakpoints.  Note If you interrupt execution while Windows or other system code is running, the results can be unpredictable.

user: user-0
content: 你运行一下呗，那个函数本来设置的是窗口左上角的一部分就是那个图标。然后整个客户区显示的多是那个图标。 如果说，他所选取的位置一直是相对于窗口的，那应该客户区显示的一直是那个图标。 如果说，他所选取的位置是相对于桌面的，那也应该那个位置有什么显示什么，但实际不是这样啊，比如说我要最大化在还原，那那个位置就还是那个图标了，但是显示的是一片空白。 你运行一下改变一下窗口的大小就知道了，我可能说不太明白。

user: user-2
content: 就是说，bitblt的拷贝源 就是  桌面上窗口系统图片所显示的位置的东西，  如果它被什么覆盖了， 拿  就 直接把 覆盖后的效果  拷贝到    拷贝先（这边应该是客户区）  因此，就是你说描述的效果吧  但是 最大化，就没了  是什么意思？ 最大化， 你的系统图片不是还在  显示器显示范围内吗