GreDrawBits

GreDrawBits draws a rectangle of bits.

Simulation support

This function is simulated by a handling routine in Revision 2.0 (or higher) of the graphics engine and can be hooked by the presentation driver.

Syntax

GreDrawBits(hdc, pBitmap, pInfo, cPoints, paptlPoint, lRop, flOptions, pInstance, lFunction)

Parameters

hdc (HDC) - input

Device context handle.

pBitmap (PBYTE) - input

Pointer to bit map data.

Pointer to the pel data of the bit map. This data is stored in the order that the coordinates appear on a display screen, that is, the pel in the lower-left corner is the first in the bit map. Pels are scanned to the right, and upward, from that position. The bits of the first pel are stored beginning with the most significant bits of the first byte. The data for pels in each scan line is packed together tightly. However, all scan lines are padded at the end so that each one begins on a ULONG boundary. That is, three bytes of pel data will hold one 24-bit pel, three 8-bit pels, six 4-bit pels, or twenty-four 1-bit pels. If those three bytes are the only pel data for that scan line, one more byte of zeros would be required to pad the line to a ULONG boundary.

pInfo (PBITMAPINFO) - input

Pointer to data structure defining the new bit map. Pointer to either a BITMAPINFO or a BITMAPINFO2 structure:

cPoints (LONG) - input

Number of (X, Y) pairs in paptlPoint.

This count must be set to 4.

The operation is determined by comparing the sizes of the two rectangles:

Target<Source Compress the source rectangle into the target rectangle. The flOptions flags determine how eliminated rows and columns should be handled.

Target=Source Copy between equal rectangles.

Target>Source Stretch the source rectangle into the target rectangle. In this case, the call can be passed to the GreBitblt routine in the graphics engine.

paptlPoint (PPOINTL) - input

Pointer to an array of (X, Y) coordinate pairs.

A pointer to a block of (X, Y) coordinate pairs that define the target and source rectangles. The coordinates, which can be passed as a pair of RECTL structures, define the bottom-left and top-right corners of the target and source rectangles (see "cPoints" above for more information): (xTgtBL, yTgtBL), (xTgtTR, yTgtTR), (xSrcBL, ySrcBL), (xSrcTR, ySrcTR)

When the source rectangle is totally or partially outside the source bit map (or device), the operation is implementation-dependent for that area, that is, the user must decide what to do.

Note

When BBO_TARGWORLD is set, the target rectangle is inclusive at all boundaries. The source is noninclusive.

When BBO_TARGWORLD is not set, the rectangles are noninclusive. That is, they include the left and lower boundaries in device units but not the top and right boundaries. When the bottom-left corner of a rectangle maps to the same device pel as the top-right corner, that rectangle is considered to be empty.

lRop (LONG) - input

Raster operation code.

The low-order byte represents a mix value in the range, hex 00 - hex FF. Raster operation code values and the mix-bit table are defined in the Presentation Manager Programming Reference. The handling routine uses lRop to determine the operations to perform on pattern, source, and target to get the required mix.

In addition to the raster operation values defined at the API, the presentation driver must support ROP_GRAY (hex 000080CA). This value is used to shade the text for menu items that are not currently selectable. When ROP_GRAY is set, the handling routine overpaints the foreground pattern using the current pattern and the background pattern color (background pels for the pattern are not changed). For the PATSYM_HALFTONE pattern, this overpaints the background pattern color onto alternate pels, leaving those in between unchanged.

flOptions (ULONG) - input

Specified treatment of eliminated lines and columns.

Option flags:

BBO_OR Stretch and compress, as necessary, ORing any eliminated rows and columns. Used for White on Black.

BBO_AND Stretch and compress, as necessary, ANDing any eliminated rows and columns. Used for Black on White.

BBO_IGNORE Stretch and compress, as necessary, IGNORing any eliminated rows and columns. Used for color.

BBO_TARGWORLD The target rectangle is defined in world coordinates in the target PS. When this option is specified, the target rectangle is transformed to device coordinates. Where any shear or rotation has occurred, the target rectangle must be converted to an upright rectangle that bounds the transformed figure. This rectangle is then used as the target for the operation. No inversion of the image takes place.

BBO_COLORS The source color map is defined in terms of indexes into the destination color map instead of RGB values.

BBO_PAL_COLORS The color values in BITMAPINFOHEADER2 are not colors; they are indexes into the currently realized palette.

BBO_NO_COLOR_INFO No color information is associated with the source. The source bit map should be copied directly to the destination without translating the pels. This option must be supported if the device supports palette management.

BBO_DITHER Use an enhanced stretching algorithm when stretching a bit map.

BLTMODE_SRC_BITMAP hdcSrc is a bit map handle. The bit map must not be currently selected into a device context. If this flag is not set, hdcSrc is a DC handle.

BLTMODE_ATTRS_PRES If set, the pBattrs parameter is present. This option can be ORed with any of the options above.

Note

Flags 15-31 are not used by the system; they are reserved for use by the presentation driver.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

High-order WORD=flags; low-order WORD=NGreDrawBits.

Returns

rc (ULONG) - returns

Return Codes.

On completion, the handling routine must return a LONG integer (cHits) indicating, where appropriate, whether correlation hits were detected:

GPI_OK Successful

GPI_HITS Successful with correlation hit (returned by the display driver when the correlation flag is ON, and a hit is detected)

GPI_ERROR Error

Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:

• PMERR_BASE_ERROR
• PMERR_HDC_BUSY
• PMERR_INCORRECT_DC_TYPE
• PMERR_INV_BITBLT_MIX
• PMERR_INV_BITBLT_STYLE
• PMERR_INV_COORDINATE
• PMERR_INV_HDC
• PMERR_INV_LENGTH_OR_COUNT
• PMERR_INV_RECT

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.

Sample

#define INCL_GRE_BITMAPS
#include <os2.h>

HDC            hdc;         /*  Device context handle. */
PBYTE          pBitmap;     /*  Pointer to bit map data. */
PBITMAPINFO    pInfo;
LONG           cPoints;     /*  Number of (X, Y) pairs in paptlPoint. */
PPOINTL        paptlPoint;  /*  Pointer to an array of (X, Y) coordinate pairs. */
LONG           lRop;        /*  Raster operation code. */
ULONG          flOptions;
PVOID          pInstance;   /*  Pointer to instance data. */
ULONG          lFunction;
ULONG          rc;          /*  Return Codes. */

rc = GreDrawBits(hdc, pBitmap, pInfo, cPoints,
       paptlPoint, lRop, flOptions, pInstance, lFunction);