SDLine
SDLine is a preclipped line rendering routine. It processes line operations onto a destination linear address. SDLine is the default when OS2_PM_DRV_ENABLE: QueryDeviceSurface does not hook the pfnLine function directly.
Syntax
SDLine(pInput, pOutput);
Parameters
- pInput (PLINEINFO) - input
- Pointer to LINEINFO data structure.
- ulLength
- Length of the LINEINFO data structure.
- ulType
- Defines line type.
- LINE_SOLID : Line will be solid in Foreground color.
- LINE_INVISIBLE : Line is not drawn.
- LINE_ALTERNATE : Line will be alternating Foreground and Background color; ignores style.
- ulStyleMask
- A 32-bit style mask.
- cLines
- Count of lines to be drawn.
- ulFGColor
- Line Foreground color.
- ulBGColor
- Line Background color.
- usForeROP
- Line Foreground mix.
- usBackROP
- Line Background mix.
- pDstBmapInfo
- Destination surface (BMAPINFO).
- alpkLinePack
- Array of line details information.
- ulStyleStep
- The value to be added to ulStyleValue on each pel stepped along the line style's direction.
- ulStyleValue
- The style value at the current pel. It is composed of an error value and a mask position, as follows:
┌───────────────┬───────────────┬───────────────┬───────────────┐ │high word │3 bits │5 bits │8 bits │ ├───────────────┼───────────────┼───────────────┼───────────────┤ │not used │not used │mask pos │error value │ └───────────────┴───────────────┴───────────────┴───────────────┘
- ulFlags
- Miscellaneous flags used for the LINEPACK data structure.
- LINE_DO_FIRST_PEL Draws the first pel.
- LINE_DIR_Y_POSITIVE Indicates line direction is bottom-to-top.
- LINE_HORIZONTAL Indicates line is horizontal. No Bresenham algorithm.
- LINE_X_MAJOR Line is XMAJOR.
- LINE_DIR_X_POSITIVE Indicates line direction is right-to-left.
- LINE_VERTICAL Indicates line is vertical. No Bresenham algorithm.
- LINE_STYLE_X_MAJOR Line style is XMAJOR.
- LINE_DO_LAST_PEL Draws the last pel.
- ulAbsDeltaX
- Clipped Bresenham Delta X, absolute (ptlStart.x - ptlEnd.x).
- ulAbsDeltaY
- Clipped Bresenham Delta Y, absolute (ptlStart.y - ptlEnd.y).
- ptlClipStart
- Pointer to location where device performs the Bresenham algorithm. Sets only the pels from ptlClipStart to ptlClipEnd, inclusive.
- ptlClipEnd
- Ending location for Bresenham algorithm (see previous parameter, ptlClipStart).
- ptlStart
- Pointer to starting location for line. The device can perform the Bresenham algorithm from ptlStart or ptlClipStart.
- ptlEnd
- Ending location for line.
- lClipStartError
- The standard Bresenham error at the clipped start point. This error is calculated from the initial error at the start point and the error increments for major step and diagonal step. The initial error and the error increments are as follows:
- MAX
- Maximum (ulAbsDeltaX, ulAbsDeltaY)
- MIN
- Minimum (ulAbsDeltaX, ulAbsDeltaY)
- Major Increment
- Increment to the error for stepping along the major axis:
2 * MIN.
- Diagonal Increment
- Increment to the error for stepping along the major and minor axes:
2 * MIN - 2 * MAX.
- Initial Error
- Error at the start point:
2 * MIN - MAX, if LINE_DIR_X_POSITIVE is On 2 * MIN - MAX - 1, if LINE_DIR_Y_POSITIVE is Off.
- Horizontal and vertical lines. The line is drawn from the clipped start to clipped end. The lClipStartError will not be given.
- First pel consideration. Set the first pel at the ptlStart (not ptlClipStart) only if LINE_DO_FIRST_PEL is set and the first pel is not clipped.
- Last pel consideration. Set the last pel at the ptlEnd (not ptlClipEnd) only if LINE_DO_LAST_PEL is set and the last pel is not clipped.
- Styling. Lines are styled using the ulStyleMask, ulStyleStep and ulStyleValue.
- Error Value
- Error value at the current pel.
- Mask Position
- Bit position of the ulStyleMask.
- If this bit is on, set the current pel to the ulFGColor through usForeROP; otherwise, set the current pel to the ulBGColor through usBackROP.
- prclBounds
- Bounding rect of the clipped line.
- pOutput (PVOID) - input
- Reserved.
Returns
- rc (ULONG) - returns
- Return codes.
Valid values are:
RC_SUCCESS RC_ERROR
Remarks
Simulation support: This function is simulated by a handling routine in Revision 2.X of the graphics engine.
Example Code
#include <os2.h> PLINEINFO pInput; /* Pointer to LINEINFO data structure. */ PVOID pOutput; /* Reserved. */ ULONG rc; /* Return codes. */ rc = SDLine(pInput, pOutput);
Related Functions
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