DrawText

  • 项目

This function draws formatted text in the specified rectangle. DrawText formats the text according to the specified format method.

int DrawText(
  HDC hDC, 
  LPCTSTR lpString, 
  int nCount, 
  LPRECT lpRect, 
  UNIT uFormat
);

Parameters

  • hDC
    [in] Handle to the device context.
  • lpString
    [in] Long pointer to the string that you want to draw. If the nCount parameter is –1, you must specify a null-terminated string.
  • nCount
    [in] Integer that specifies the number of characters in the string. If nCount is –1, DrawText assumes that the lpString parameter is a pointer to a null-terminated string and computes the character count automatically.
  • lpRect
    [in] Long pointer to a RECT structure that contains the rectangle, in logical coordinates, in which you want to format the text.
  • uFormat
    [in] Unsigned integer that specifies the method of formatting the text. The following table shows the possible values that you can combine to create a value for this parameter.
    Value Description
    DT_BOTTOM Justifies the text to the bottom of the rectangle. You must combine this value with DT_SINGLELINE.
    DT_CALCRECT Determines the width and height of the rectangle. If the rectangle includes multiple lines of text, DrawText uses the width of the rectangle pointed to by the lpRect parameter and extends the base of the rectangle to bound the last line of text. If the rectangle includes only one line of text, DrawText modifies the right side of the rectangle so that it bounds the last character in the line. In either case, DrawText returns the height of the formatted text but does not draw the text.

    Before calling DrawText, an application must set the right and bottom members of the RECT structure pointed to by lpRect. These members are updated with the call to DrawText.
    DT_CENTER Centers text horizontally in the rectangle.
    DT_EXPANDTABS Expands tab characters. The default number of characters per tab is eight.
    DT_INTERNAL Uses the system font to calculate text metrics.
    DT_LEFT Aligns text to the left.
    DT_NOCLIP Draws without clipping. DrawText is somewhat faster when DT_NOCLIP is used.
    DT_NOPREFIX Turns off processing of prefix characters. Normally, DrawText interprets the mnemonic-prefix character & as a directive to underscore the character that follows, and the mnemonic-prefix characters && as a directive to print a single &. By specifying DT_NOPREFIX, this processing is turned off.
    DT_RIGHT Aligns text to the right.
    DT_SINGLELINE Displays text on a single line only. Carriage returns and linefeeds do not break the line.
    DT_TABSTOP Sets tab stops. Bits 8–15, which form the high-order byte of the low-order word, of the uFormat parameter specify the number of characters for each tab. The default number of characters per tab is eight. You cannot use the DT_CALCRECT, DT_EXTERNALLEADING, DT_INTERNAL, DT_NOCLIP, and DT_NOPREFIX values with the DT_TABSTOP value.
    DT_TOP Top-justifies text. You must combine this value with DT_SINGLELINE.
    DT_VCENTER Centers text vertically. You must combine this value with DT_SINGLELINE.
    DT_WORDBREAK Breaks words. DrawText automatically breaks lines between words if a word would extend past the edge of the rectangle specified by the lpRect parameter. A carriage return-linefeed sequence also breaks the line.

Return Values

The height of the text indicates success. Zero indicates failure. To get extended error information, call GetLastError.

Remarks

The DrawText function uses the selected font, text color, and background color for the device context to draw the text. Unless you specify the DT_NOCLIP value, DrawText clips the text so that it does not appear outside the specified rectangle. DrawText assumes that all formatting has multiple lines unless you specify the DT_SINGLELINE format.

If the selected font is too large for the specified rectangle, the DrawText function does not attempt to substitute a smaller font.

For Windows CE 2.10 and later, line breaking is supported for the Chinese, Korean, and Japanese languages.

Requirements

OS Versions: Windows CE 1.0 and later.
Header: Windows.h.
Link Library: Coredll.lib.

See Also

ExtTextOut | RECT

Last updated on Wednesday, April 13, 2005

© 2005 Microsoft Corporation. All rights reserved.