.TH "PPK Overview" 3 "24th December 2000"
.SH "Data Structures"
.PP
A simplified view of
the main data structures is illustrated below.
Note that each array member pp_\fIxxx\fP in the PPK_Printer structure has a
corresponding structure member named pp_Num\fIxxx\fP which gives the number of
items in the array (e.g. pp_PaperTypes and pp_NumPaperTypes).
These members are not shown, for brevity.
.sp
'\" This picture shows interesting bits of PPK_Env and PPK_Printer,
'\" and a little of how they link together.
'\"
'\" picture begins {
.ce
\fBFig 1:\fP Main Data Structures
.PS
down
#
# The main data struct
#

sx = 0.7
sy = 0.7

"PPK_Env" at (-sx,0.3)

move to (-sx, 0.1)

dy = 0.18
boxwid = 2 * sx
boxht =  dy

NumPrinters:	box invis
NumCopies:	box invis
Printers:	box invis
Page:		box invis
UserSettings:	box invis
PrintProgress:	box invis
IoCallBack:	box invis
	"pe_NumPrinters" ljust at NumPrinters.w
	"pe_NumCopies" ljust at NumCopies.w
	"pe_Printers" ljust at Printers.w
	"pe_Page" ljust at Page.w
	"pe_UserSettings" ljust at UserSettings.w
	"pe_PrintProgress" ljust at PrintProgress.w
	"pe_IoCallBack" ljust at IoCallBack.w

boxht =  7 * dy + dy/2

P: box at (-sx -0.1,-sy + dy)

move to P.ne + (1.5,0)
"PPK_Printer" at Here
move to Here + (0,-0.3)

boxwid = 2 * sx
boxht =  dy

ModelNumber:	box invis
Aliases:	box invis
Tables:		box invis
Resolutions:	box invis
PaperSizes:	box invis
PaperTypes:	box invis
Settings:	box invis
Media:		box invis
	"pp_ModelNumber" ljust at ModelNumber.w
	"pp_Aliases[]" ljust at Aliases.w
	"pp_Tables[]" ljust at Tables.w
	"pp_Resolutions[]" ljust at Resolutions.w
	"pp_PaperSizes[]" ljust at PaperSizes.w
	"pp_PaperTypes[]" ljust at PaperTypes.w
	"pp_Settings[]" ljust at Settings.w
	"pp_Media" ljust at Media.w

boxht =  8 * dy + dy/2
P2: box at PaperSizes + (-0.1, 0.1)


#
# The sizes array
#
    boxwid = 0.5
    move to last box.e + (1.0,0)
Sz: [
	A: box height 0.2  "size0"
	B: box height 0.2  "size1"
	C: box height 0.4  "..."
    ]
spline -> right from PaperSizes.e - (0.3,0) to last [].A.nw
down

gap = 1.0

move to last [].A.ne + (gap,0)

#
# The aliases array
#
    boxwid = 0.6
Al: [
	A: box height 0.2  "alias0"
	B: box height 0.2  "alias1"
	C: box height 0.4  "..."
    ]
spline -> right from Aliases.e - (0.3,0) to last [].A.nw

spline -> right from Printers.e - (0.3,0) to P2.nw

down
.PE
'\" picture ends }
'\" =============================
.SH "Pixel Formats"
.PP
The PPK supports the pixel formats used by the XXX.
Specifically,
it supports these formats:
.IP "\(bu" 4
1 byte grayscale.
.IP "\(bu" 4
2 byte RGBA.
5 bits each of red, blue, green,
and a single bit for alpha transparency (`on' means opaque).
The colors are assumed to be pre-multiplied (i.e. the
transparency bit is simply ignored).
.IP "\(bu" 4
3 byte RGB.
Tightly packed.
.IP "\(bu" 4
4 byte RGBA.
1 byte each of red, blue, green,
and alpha transparency (255 means fully opaque).
The colors are assumed to be pre-multiplied (i.e. the
transparency byte is simply ignored).