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6.9 Horizontal line

Name:

»Horizontal line«

Line-A number:

$A004

Syntax:

See 'Bindings for horizontal_line'

Description:

This Line-A function draws a horizontal line. The following Line-A variables are used:

Variable

Meaning

X-coordinate of the first end-point

Y-coordinate of the line

X-coordinate of the second end-point

fg_bp_1

Bit value of the first plane for the colour that should be used for filling

fg_bp_2

Bit value of the second plane (only low or medium resolution)

fg_bp_3

Bit value of the third plane (only low resolution)

fg_bp_4

Bit value of the fourth plane (only low resolution)

patptr

Pointer to a field with 16-bit line patterns

patmsk

Number of line patterns - 1. Depending on the Y-coordinate, one pattern will now be chosen from the field of line patterns. The index of the line pattern used may be calculated with (y mod (patmsk + 1)). By specifying several line patterns and using multiple calls of this function for consecutive lines, it is easy to draw complex patterns as well.

wrt_mode

Writing mode; the following modes are possible:

REPLACE 0	Replace
TRANS 1	Transparent (OR)
XOR 2	Inverse (XOR)
INVERS 3	Inverse Transparent (XOR with not(LN_MASK))

multifill

0 specifies that only the first colour plane is to be drawn, a value >0 that all colour planes are to be drawn

Note: This function is used internally for the area fill routines.

The binding from TC passes the line pattern, writing mode and colour not to the horizontal_line function, but uses separate functions set_fg_bp, set_wrt_mode and set_pattern for setting the parameters in the Line-A parameter block.

Return value:

The function does not return a result.

Availability:

All TOS versions.

6.9.1 Bindings for horizontal_line

Pure-C:

void horizontal_line( int16_t x1, int16_t y1, int16_t x2 );

Assembler:

movem.l   D0-D2/A0-A2,-(A7)  ; Save registers
move.l    pParamblk,A0       ; Pointer parameter block LINEA
move.w    x1,(38,A0)         ; First X-coordinate in LINEA.x1
move.w    y1,(40,A0)         ; First Y-coordinate in LINEA.y1
move.w    x2,(42,A0)         ; Second X-coordinate in LINEA.x2
move.w    colbit0,(24,A0)    ; Bit for first plane in LINEA.fg_bp_1
move.w    colbit1,(26,A0)    ; Bit for first plane in LINEA.fg_bp_2
move.w    colbit2,(28,A0)    ; Bit for first plane in LINEA.fg_bp_3
move.w    colbit3,(30,A0)    ; Bit for first plane in LINEA.fg_bp_4
move.w    wmode,(36,A0)      ; Writing mode in LINEA.wrt_mode
move.w    patptr,(46,A0)     ; Line pattern in LINEA.patptr
move.w    patmsk,(50,A0)     ; Number patterns in LINEA.patmsk
move.w    mfill,(52,A0)      ; Writing mode in LINEA.multifill
dc.w      $A004              ; Line-A opcode
movem.l   (A7)+,D0-D2/A0-A2  ; Restore registers