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CDC::GrayString

Visual Studio 2012

Draws dimmed (gray) text at the given location by writing the text in a memory bitmap, dimming the bitmap, and then copying the bitmap to the display.

virtual BOOL GrayString( 
   CBrush* pBrush, 
   BOOL ( CALLBACK* lpfnOutput )( HDC, LPARAM, int ), 
   LPARAM lpData, 
   int nCount, 
   int x, 
   int y, 
   int nWidth, 
   int nHeight 
);

Parameters

pBrush: Identifies the brush to be used for dimming (graying).
lpfnOutput: Specifies the procedure-instance address of the application-supplied callback function that will draw the string. For more information, see the description of the Windows OutputFunc callback function. If this parameter is NULL, the system uses the Windows TextOut function to draw the string, and lpData is assumed to be a long pointer to the character string to be output.
lpData: Specifies a far pointer to data to be passed to the output function. If lpfnOutput is NULL, lpData must be a long pointer to the string to be output.
nCount: Specifies the number of characters to be output. If this parameter is 0, GrayString calculates the length of the string (assuming that lpData is a pointer to the string). If nCount is –1 and the function pointed to by lpfnOutput returns 0, the image is shown but not dimmed.
x: Specifies the logical x-coordinate of the starting position of the rectangle that encloses the string.
y: Specifies the logical y-coordinate of the starting position of the rectangle that encloses the string.
nWidth: Specifies the width (in logical units) of the rectangle that encloses the string. If nWidth is 0, GrayString calculates the width of the area, assuming lpData is a pointer to the string.
nHeight: Specifies the height (in logical units) of the rectangle that encloses the string. If nHeight is 0, GrayString calculates the height of the area, assuming lpData is a pointer to the string.

Return Value

Nonzero if the string is drawn, or 0 if either the TextOut function or the application-supplied output function returned 0, or if there was insufficient memory to create a memory bitmap for dimming.

Remarks

The function dims the text regardless of the selected brush and background. The GrayString member function uses the currently selected font. The MM_TEXT mapping mode must be selected before using this function.

An application can draw dimmed (grayed) strings on devices that support a solid gray color without calling the GrayString member function. The system color COLOR_GRAYTEXT is the solid-gray system color used to draw disabled text. The application can call the GetSysColor Windows function to retrieve the color value of COLOR_GRAYTEXT. If the color is other than 0 (black), the application can call the SetTextColor member function to set the text color to the color value and then draw the string directly. If the retrieved color is black, the application must call GrayString to dim (gray) the text.

If lpfnOutput is NULL, GDI uses the Windows TextOut function, and lpData is assumed to be a far pointer to the character to be output. If the characters to be output cannot be handled by the TextOut member function (for example, the string is stored as a bitmap), the application must supply its own output function.

Also note that all callback functions must trap Microsoft Foundation exceptions before returning to Windows, since exceptions cannot be thrown across callback boundaries. For more information about exceptions, see the article Exceptions.

The callback function passed to GrayString must use the __stdcall calling convention and must be exported with __declspec.

When the framework is in preview mode, a call to the GrayString member function is translated to a TextOut call, and the callback function is not called.

Requirements

Header: afxwin.h

Reference

CDC Class

Hierarchy Chart

GetSysColor

CDC::SetTextColor

CDC::TextOut

GrayString

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