计算机科学论坛--Direct3D中的字体与文本显示

使用ID3DXFont对象绘制二维文本

创建了ID3DXFont对象后，就可以使用其接口函数ID3DXFont::DrawText()在指定位置绘制二维文本，该函数支持ANSI和双字节字符串，声明如下：

Draws formatted text. This method supports ANSI and Unicode strings.

INT DrawText( LPD3DXSPRITE pSprite, LPCTSTR pString, INT Count, LPRECT pRect, DWORD Format, D3DCOLOR Color);
Parameters
pSprite
[in] Pointer to an ID3DXSprite object that contains the string. Can be NULL, in which case Direct3D will render the string with its own sprite object. To improve efficiency, a sprite object should be specified if ID3DXFont::DrawText is to be called more than once in a row.
pString
[in] Pointer to a string to draw.If the Count parameter is -1, the string must be null-terminated.
Count
[in] Specifies the number of characters in the string. If Count is -1, then the pString parameter is assumed to be a pointer to a null-terminated string and ID3DXFont::DrawText computes the character count automatically.
pRect
[in] Pointer to a RECT structure that contains the rectangle, in logical coordinates, in which the text is to be formatted. As with any RECT object, the coordinate value of the rectangle's right side must be greater than that of its left side. Likewise, the coordinate value of the bottom must be greater than that of the top.
Format
[in] Specifies the method of formatting the text. It can be any combination of the following values:
DT_BOTTOM
Justifies the text to the bottom of the rectangle. This value must be combined with DT_SINGLELINE.
DT_CALCRECT
Determines the width and height of the rectangle. If there are multiple lines of text, ID3DXFont::DrawText uses the width of the rectangle pointed to by the pRect parameter and extends the base of the rectangle to bound the last line of text. If there is only one line of text, ID3DXFont::DrawText modifies the right side of the rectangle so that it bounds the last character in the line. In either case, ID3DXFont::DrawText returns the height of the formatted text but does not draw the text.
DT_CENTER
Centers text horizontally in the rectangle.
DT_EXPANDTABS
Expands tab characters. The default number of characters per tab is eight.
DT_LEFT
Aligns text to the left.
DT_NOCLIP
Draws without clipping. ID3DXFont::DrawText is somewhat faster when DT_NOCLIP is used.
DT_RIGHT
Aligns text to the right.
DT_RTLREADING
Displays text in right-to-left reading order for bidirectional text when a Hebrew or Arabic font is selected. The default reading order for all text is left-to-right.
DT_SINGLELINE
Displays text on a single line only. Carriage returns and line feeds do not break the line.
DT_TOP
Top-justifies text.
DT_VCENTER
Centers text vertically (single line only).
DT_WORDBREAK
Breaks words. Lines are automatically broken between words if a word would extend past the edge of the rectangle specified by the pRect parameter. A carriage return/line feed sequence also breaks the line.
Color
[in] Color of the text. For more information, see D3DCOLOR.
Return Values
If the function succeeds, the return value is the height of the text in logical units. If DT_VCENTER or DT_BOTTOM is specified, the return value is the offset from pRect (top to the bottom) of the drawn text. If the function fails, the return value is zero.

Remarks
The parameters of this method are very similar to those of the GDI DrawText function.

This method supports both ANSI and Unicode strings.

This method must be called inside a IDirect3DDevice9::BeginScene ... IDirect3DDevice9::EndScene block. The only exception is when an application calls ID3DXFont::DrawText with DT_CALCRECT to calculate the size of a given block of text.

Unless the DT_NOCLIP format is used, this method clips the text so that it does not appear outside the specified rectangle. All formatting is assumed to have multiple lines unless the DT_SINGLELINE format is specified.

If the selected font is too large for the rectangle, this method does not attempt to substitute a smaller font.

This method supports only fonts whose escapement and orientation are both zero.

示例代码如下：

g_device->BeginScene();

DWORD format = DT_SINGLELINE | DT_NOCLIP | DT_CENTER | DT_VCENTER;
g_font->DrawText(NULL, g_text, (INT) strlen(g_text), &g_client_rect, format, 0xFFFFFF00);

g_device->EndScene();

*树形目录（最近20个回帖）	顶端
主题： Direct3D中的字体与文本显示(2565字) －卷积内核，2008年11月25日
回复： [B]ID3DXFont其他相关接口函数[/B]函数ID3DXFont::GetDevice(..(4873字) －卷积内核，2008年11月25日
回复：使用ID3DXFont对象绘制二维文本创建了ID3DXFont对象后，就可以使用其接口函数ID..(4391字) －卷积内核，2008年11月25日


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