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The GDIINFO structure describes the graphics capabilities of a given device.
typedef struct _GDIINFO {
ULONG ulVersion;
ULONG ulTechnology;
ULONG ulHorzSize;
ULONG ulVertSize;
ULONG ulHorzRes;
ULONG ulVertRes;
ULONG cBitsPixel;
ULONG cPlanes;
ULONG ulNumColors;
ULONG flRaster;
ULONG ulLogPixelsX;
ULONG ulLogPixelsY;
ULONG flTextCaps;
ULONG ulDACRed;
ULONG ulDACGreen;
ULONG ulDACBlue;
ULONG ulAspectX;
ULONG ulAspectY;
ULONG ulAspectXY;
LONG xStyleStep;
LONG yStyleStep;
LONG denStyleStep;
POINTL ptlPhysOffset;
SIZEL szlPhysSize;
ULONG ulNumPalReg;
COLORINFO ciDevice;
ULONG ulDevicePelsDPI;
ULONG ulPrimaryOrder;
ULONG ulHTPatternSize;
ULONG ulHTOutputFormat;
ULONG flHTFlags;
ULONG ulVRefresh;
ULONG ulBltAlignment;
ULONG ulPanningHorzRes;
ULONG ulPanningVertRes;
ULONG xPanningAlignment;
ULONG yPanningAlignment;
ULONG cxHTPat;
ULONG cyHTPat;
LPBYTE pHTPatA;
LPBYTE pHTPatB;
LPBYTE pHTPatC;
ULONG flShadeBlend;
ULONG ulPhysicalPixelCharacteristics;
ULONG ulPhysicalPixelGamma;
} GDIINFO, *PGDIINFO;
The high-order 16 bits must be set to zero. Bits 8 through 15 specify the version number of the Microsoft operating system for which the driver is designed. The high-order 4 bits of this range specify the major number of the version, the low-order 4 bits contain the minor number of the version. The low-order 8 bits of ulVersion specify the version number of the display driver; this value should be incremented for each release of the display driver binary file.
The Display program in Control Panel indicates the version number contained in ulVersion, along with other driver-specific information.
| Value | Meaning |
|---|---|
| DT_CHARSTREAM | Device fonts only |
| DT_PLOTTER | Vector plotter |
| DT_RASCAMERA | Raster camera |
| DT_RASDISPLAY | Raster display |
| DT_RASPRINTER | Raster printer |
For printers, this member should be set to the printer's resolution in dpi.
For displays, this member must be set to 96.
For printers, this member should be set to the printer's resolution in dpi.
For displays, this member must be set to 96.
Because the physical dot size for most printers is larger than the measured dot size, GDI uses this value to approximate how many physical dots can be placed, based on the cell size (pattern size). A log regression is then performed to determine what is most linear; that is, where the dots should be placed for the best coverage to optimize the overlapped device pixels coverage (dot gain).
For displays, this member should be set to zero.
| Flag | Meaning |
|---|---|
| PRIMARY_ORDER_ABC | Device output order is RGB or CMY. Red or cyan is in the least significant bits; blue or yellow is in the most significant bits. |
| PRIMARY_ORDER_ACB | Device output order is RBG or CYM. Red or cyan is in the least significant bits; green or magenta is in the most significant bits. |
| PRIMARY_ORDER_BAC | Device output order is GRB or MCY. Green or magenta is in the least significant bits; blue or yellow is in the most significant bits. |
| PRIMARY_ORDER_BCA | Device output order is GBR or MYC. Green or magenta is in the least significant bits; red or cyan is in the most significant bits. |
| PRIMARY_ORDER_CBA | Device output order is BGR or YMC. Blue or yellow is in the least significant bits; red or cyan is in the most significant bits. |
| PRIMARY_ORDER_CAB | Device output order is BRG or YCM. Blue or yellow is in the least significant bits; green or magenta is in the most significant bits. |
HT_PATSIZE_2x2
HT_PATSIZE_2x2_M
HT_PATSIZE_4x4
HT_PATSIZE_4x4_M
HT_PATSIZE_6x6
HT_PATSIZE_6x6_M
HT_PATSIZE_8x8
HT_PATSIZE_8x8_M
HT_PATSIZE_10x10
HT_PATSIZE_10x10_M
HT_PATSIZE_12x12
HT_PATSIZE_12x12_M
HT_PATSIZE_14x14
HT_PATSIZE_14x14_M
HT_PATSIZE_16x16
HT_PATSIZE_16x16_M
HT_PATSIZE_SUPERCELL
HT_PATSIZE_SUPERCELL_M
HT_PATSIZE_USER
HT_PATSIZE_MAX_INDEX
HT_PATSIZE_DEFAULT
HT_FORMAT_1BPP
HT_FORMAT_4BPP
HT_FORMAT_4BPP_IRGB
HT_FORMAT_8BPP
HT_FORMAT_16BPP
HT_FORMAT_24BPP
HT_FORMAT_32BPP
| Flag | Meaning |
|---|---|
| HT_FLAG_8BPP_CMY332_MASK | Flag used to clear the upper eight bits of flHTFlags (bits 24 to 31). The MAKE_CMY332_MASK macro can then be used to set these bits with 8-bit-per-pixel CMY mode ink level information. See Using GDI 8-Bit-Per-Pixel CMY Mask Modes for more information. |
| HT_FLAG_ADDITIVE_PRIMS | Device primaries are additive. |
| HT_FLAG_DO_DEVCLR_XFORM | Requests GDI to perform generic color correction. |
| HT_FLAG_HAS_BLACK_DYE | Device has separate black dye. |
| HT_FLAG_HIGH_INK_ABSORPTION HT_FLAG_HIGHER_INK_ABSORPTION HT_FLAG_HIGHEST_INK_ABSORPTION |
Paper in device absorbs more than normal amount of ink, so GDI should render less ink to paper. These flags indicate the relative amount of ink absorption, with HT_FLAG_HIGHER_INK_ABSORPTION denoting more absorption than HT_FLAG_HIGH_INK_ABSORPTION, but less than HT_FLAG_HIGHEST_INK_ABSORPTION. |
| HT_FLAG_INK_ABSORPTION_IDX0 HT_FLAG_INK_ABSORPTION_IDX1 HT_FLAG_INK_ABSORPTION_IDX2 HT_FLAG_INK_ABSORPTION_IDX3 |
Flags used to define HT_FLAG_HIGH/HIGHER/HIGHEST_INK_ABSORPTION and HT_FLAG_LOW/LOWER/LOWEST_INK_ABSORPTION. |
| HT_FLAG_INK_HIGH_ABSORPTION | Flag used to define HT_FLAG_HIGH/HIGHER/HIGHEST_INK_ABSORPTION. |
| HT_FLAG_INVERT_8BPP_BITMASK_IDX | GDI halftone should render 8-bit-per-pixel ask mode surface bitmap using a CMY_INVERTED mode palette. See Using GDI 8-Bit-Per-Pixel CMY Mask Modes for CMY_INVERTED mode palette description and requirements. |
| HT_FLAG_LOW_INK_ABSORPTION HT_FLAG_LOWER_INK_ABSORPTION HT_FLAG_LOWEST_INK_ABSORPTION |
Paper in device absorbs less than normal amount of ink, so GDI should render more ink to paper. These flags indicate the relative amount of ink absorption, with HT_FLAG_LOWER_INK_ABSORPTION denoting less absorption than HT_FLAG_LOW_INK_ABSORPTION, but more than HT_FLAG_LOWEST_INK_ABSORPTION. |
| HT_FLAG_NORMAL_INK_ABSORPTION | Paper in device absorbs normal amount of ink. |
| HT_FLAG_OUTPUT_CMY | Device uses CMY primaries rather than RGB primaries. This flag value applies only to 1 bpp and 4 bpp destination surfaces. |
| HT_FLAG_PRINT_DRAFT_MODE | Disables GDI's antialiasing code. |
| HT_FLAG_SQUARE_DEVICE_PEL | Device pixel is square rather than round (displays only — printers require rounded pixels). |
| HT_FLAG_USE_8BPP_BITMASK | Device uses monochrome printing. |
The Display program in Control Panel displays the refresh rate contained in the ulVRefresh member.
This value is used by the system to determine the default alignment for window positions and is also used to set the initial full-drag default during setup. A value of zero indicates that full-drag should be on by default; any value other than zero indicates that full-drag should be off by default.
The ulPhysicalPixelCharacteristics member must be set to one of the values shown in the following table:
| Value | Meaning |
|---|---|
| PPC_DEFAULT | Display device physical pixel information is unknown. |
| PPC_BGR_ORDER_HORIZONTAL_STRIPES | Physical color fragments on the display device are arranged, from top to bottom, in rows of blue, green, and red color fragments. |
| PPC_BGR_ORDER_VERTICAL_STRIPES | Physical color fragments on the display device are arranged, from left to right, in columns of blue, green, and red color fragments. |
| PPC_RGB_ORDER_HORIZONTAL_STRIPES | Physical color fragments on the display device are arranged, from top to bottom, in rows of red, green, and blue color fragments. |
| PPC_RGB_ORDER_VERTICAL_STRIPES | Physical color fragments on the display device are arranged, from left to right, in columns of red, green, and blue color fragments. |
| PPC_UNDEFINED | Display device physical pixel information is known but cannot be expressed as one of the given enumerations. The enumerations are currently applicable to an LCD-based monitor. The driver should set ulPhysicalPixelCharacteristics to PPC_UNDEFINED when either of the following conditions is met. (This list is not comprehensive, but covers the most common conditions.)
|
| Value | Meaning |
|---|---|
| PPG_DEFAULT | The driver has no knowledge of the gamma for the device. |
| PPG_SRGB | The device uses an sRGB gamma. |
Declared in winddi.h. Include winddi.h.
GDI zero-initializes this structure before calling the driver-supplied DrvEnablePDEV function.
The xStyleStep, yStyleStep, and denStyleStep members define how a cosmetic line style should advance as it draws each pixel of a cosmetic line. The amount advanced along the style for each pixel is defined as a fraction that depends on whether the line is x-styled or y-styled. If the line is x-styled, the style advances by the fractional amount dx/D for each pixel moved in the x direction. Otherwise the style advances by dy/D for each pixel moved in the y direction.
The dots in the predefined line style PS_DOT are each one unit long. If the driver defines xStyleStep as one and denStyleStep as 5, then a dotted horizontal line consists of 5-pixels-on followed by 5-pixels-off, repeated.
Each of these three numbers must be less than 65536, even though the caps members are LONG values. These style steps are defined by the driver to ensure that the dots and dashes in a line are a pleasing size on the output device. The horizontal and vertical steps can be different to correct for non trivial aspect ratios. For example, on an EGA display, whose pixels are 33 percent higher than they are wide, you can set:
pdevcaps->xStyleStep = 3; // For an EGA pdevcaps->yStyleStep = 4; pdevcaps->denStyleStep = 12;
In this case, horizontal dotted lines are 4-pixels-on, 4-pixels-off, because the style advances by 3/12 or 1/4 for each pixel. Vertical dotted lines are 3-pixels-on/3-pixels-off.
Styled lines look better if both the x and y style steps divide evenly into the style denominator, as they do in the preceding example. This gives dashes and dots that are always the same length.
GDI needs this information so that its bitmap functions can emulate exactly what the device does on its own surface. Applications can access this information to determine exactly which pixels will be turned on for styled lines. Refer also to Styled Cosmetic Lines.
The halftone-related members, cxHTPat, cyHTPat, pHTPatA, pHTPatB, and pHTPatC, can be used in an OEM Unidrv rendering plug-in to define a custom halftone pattern consisting of either one or three colors. These members are checked only if the ulHTPatternSize member is set to HT_PATSIZE_USER. In this case an OEM can use these members to define a custom halftone pattern, based on data stored in a resource file or generated by an OEM customization module. The cxHTPat and cyHTPat members define the size of each of the three two-dimensional halftone pattern arrays. The pHTPatA, pHTPatB, and pHTPatC members point to the respective pattern arrays for each color. If only one pattern array is used, pHTPatA points to it, and the other two pointers are set to NULL.
Each byte threshold at a particular location in a halftone dither pattern determines whether the pixel at the corresponding output plane location will be on or off. A zero threshold value at a particular location in the pattern array indicates that the corresponding pixel location is ignored (is black). Threshold values from 1 to 255 provide the dither pattern with 255 levels of gray; if the pixel value in the output plane is greater than or equal to the threshold value for that location, the pixel is turned on. A pixel value less than its corresponding threshold value causes its pixel to be turned off in the output plane. See Customized Halftoning in Customizing Microsoft's Printer Drivers for more information.
CIECHROMA, COLORINFO, DrvBitBlt, DrvCopyBits, DrvEnablePDEV, DrvTextOut