typedef struct tagTEXTXFORM {
short txfHeight;
short txfWidth;
short txfEscapement;
short txfOrientation;
short txfWeight;
char txfItalic;
char txfUnderline;
char txfStrikeOut;
char txfOutPrecision;
char txfClipPrecision;
short txfAccelerator;
short txfOverhang;
} TEXTXFORM;
The TEXTXFORM structure contains information describing the actual appearance of text as displayed by the device. The StrBlt and ExtTextOut functions check the the TEXTXFORM structure to determine what additional actions are required to generate the desired text from the specified physical font.
txfHeight
Specifies the height of characters (ascent + descent) in device units.
txfWidth
Specifies the width in device units of the bounding box of the letter “X.”
txfEscapement
Specifies the angle in tenths of a degree counterclockwise from the x-axis of the vector passing through the origin of all the characters in the string.
txfOrientation
Specifies the angle in tenths of a degree counterclockwise from the x-axis of the baseline of the character.
txfWeight
Specifies the weight of the font ranging from 1 to 1000, with 400 being the value for the standard font.
txfItalic
Specifies whether the font is to be italic. If the low bit is set, the font is to be italic. All the other bits must be zero.
txfUnderline
Specifies whether the font is to be underlined. If the low bit is set, the font is to be underlined. All the other bits must be zero.
txfStrikeOut
Specifies whether to strike out the font. If the low bit is set, the font is to be struck out. All the other bits must be zero.
txfOutPrecision
Specifies the required output precision for text. This member can have one of the following values.
| Value | Meaning |
| OUT_DEFAULT_PRECIS (0x00) | Chooses a reasonable font. |
| OUT_STRING_PRECIS (0x01) | Chooses the font whose size (height and width) most closely matches the requested size. The driver may disregard the requested orientation and escapement, but other attributes must match. |
| OUT_CHARACTER_PRECIS (0x02) | Chooses the font whose size (height and width) most closely matches the requested size. The driver may disregard the requested orientation, but other attributes must match. |
| OUT_STROKE_PRECIS (0x03) | Chooses a font whose attributes exactly match the requested attributes. |
txfClipPrecision
Specifies the required clipping precision for text. This member can have one of the following values.
| Value | Meaning |
| CLIP_DEFAULT_PRECIS (0x00) | Chooses a reasonable font. |
| CLIP_CHARACTER_PRECIS (0x01) | Chooses a font that allows clipping of individual characters. The driver must be able to clip a character if any portion of it lies outside the clipping rectangle. |
| CLIP_STROKE_PRECIS (0x02) | Chooses a font that allows clipping of portions of a character. The driver must be able to clip any portion of a character that lies outside the clipping rectangle. |
txfAccelerator
Specifies the requested text modifications using the same format as the the dpText member in the GDIINFO structure. Each bit in this member is set if the corresponding ability is required to modify the physical font into the requested font.
txfOverhang
Specifies same information as the tmOverhang member in the TEXTMETRIC structure. This member is set by the device for device-realized fonts and is in device units. GDI uses additional overhang if it makes the font bold.
Although most of the members in the TEXTXFORM structure correspond to the members in the LFONT structure, these members may not always exactly match. For example, if the logical font specified a 19-unit font at string precision and the closest available was a 9-unit font on a device capable of doubling, then the txfHeight member in the structure is 18.
A driver should check the dpText member in its GDIINFO structure to determine whether the driver can carry out the requested text modifications. In particular, the driver should check the bitwise difference between the txfAccelerator member and the dpText member to determine what abilities it should simulate. If the driver can not carry out the modifications, GDI is responsible for simulating the required modifications.
EngineRealizeFont, ExtTextOut, StrBlt