Screen handling

[britlion]

Slenkar: Perhaps these are useful for setting colours?

They both paint a rectangle in the specified colours - one needs ink/paper/bright/flash separately, the second takes the attribute byte directly.

Code:

SUB WindowPaint(x as uByte,y as uByte, width as uByte, height as uByte, inkCol as ubyte, paperCol as uByte, isBright as uByte, isFlash as uByte)
paint(x,y,width,height,(isFlash<<7+isBright<<6+paperCol<<3+inkCol))
END SUB

Code:

SUB paint (x as uByte,y as uByte, width as uByte, height as uByte, attribute as ubyte)
    asm
    ld      a,(IX+7)   ;ypos
    rrca
    rrca
    rrca               ; Multiply by 32
    ld      l,a        ; Pass to L
    and     3          ; Mask with 00000011
    add     a,88       ; 88 * 256 = 22528 - start of attributes. Change this if you are working with a buffer or somesuch.
    ld      h,a        ; Put it in the High Byte
    ld      a,l        ; We get y value *32
    and     224        ; Mask with 11100000
    ld      l,a        ; Put it in L
    ld      a,(IX+5)   ; xpos
    add     a,l        ; Add it to the Low byte
    ld      l,a        ; Put it back in L, and we're done. HL=Address.
    
    push HL            ; save address
    LD A, (IX+13)      ; attribute
    LD DE,32
    LD c,(IX+11)       ; height
    
    BLPaintHeightLoop:
    LD b,(IX+9)        ; width
    
    BLPaintWidthLoop:
    LD (HL),a          ; paint a character
    INC L              ; Move to the right (Note that we only would have to inc H if we are crossing from the right edge to the left, and we shouldn't be needing to do that)
    DJNZ BLPaintWidthLoop
    
    BLPaintWidthExitLoop:
    POP HL             ; recover our left edge
    DEC C
    JR Z, BLPaintHeightExitLoop
    
    ADD HL,DE          ; move 32 down
    PUSH HL            ; save it again
    JP BLPaintHeightLoop

    BLPaintHeightExitLoop:
    
end asm
END SUB