AISFormat.mesa
Last changed by Maureen Stone, 8-Oct-81 11:31:05
Last changed by Doug Wyatt, 13-Aug-81 15:41:02
Definition of AIS (Array of Intensity Samples) file format
AISFormat: DEFINITIONS = {
aisPassword: INTEGER = -31574;
aisWordsPerPage: CARDINAL = 1024;
unused: INTEGER = -1; -- for unused values in Placement and Photometry parts
Header:
TYPE =
MACHINE
DEPENDENT
RECORD [
password: INTEGER, attributeLength: CARDINAL];
PartType:
TYPE =
MACHINE
DEPENDENT {nil(0),
raster(1), placement(2), photometry(3), comment(4), (77B)};
PartHeader: TYPE = MACHINE DEPENDENT RECORD[type: PartType, length: [0..1777B]];
CodingType: TYPE = MACHINE DEPENDENT {uca(1)};
RasterPart:
TYPE =
MACHINE
DEPENDENT
RECORD [
part(0): PartHeader,
scanCount(1): CARDINAL,
scanLength(2): CARDINAL,
scanDir(3): CARDINAL,
samplesPerPixel(4): CARDINAL,
coding(5:0..79):
SELECT codingType(5): CodingType
FROM
uca => [
-- Uncompressed array
bitsPerSample(6): CARDINAL,
wordsPerScanLine(7): CARDINAL,
scanLinesPerBlock(8): INTEGER, -- -1 means no blocking
paddingPerBlock(9): CARDINAL -- in words
],
ENDCASE
];
PlacementPart:
TYPE =
MACHINE
DEPENDENT
RECORD [
part: PartHeader,
xLeft: INTEGER,
yBottom: INTEGER,
xWidth: INTEGER,
yHeight: INTEGER
];
PhotometryPart:
TYPE =
MACHINE
DEPENDENT
RECORD [
part: PartHeader,
signal: SignalType,
sense: Sense,
scaleType: ScaleType,
pointA: Point,
pointB: Point,
pointC: Point,
spotType: SpotType,
spotWidth: INTEGER, -- in units of 100*(width in pixels)
spotLength: INTEGER, -- in units of 100*(length in scanlines)
sampleMin: INTEGER,
sampleMax: INTEGER,
histogramLength: INTEGER,
followed by Histogram if histogramLength is not 0 or -1
histogram: SEQUENCE COMPUTED CARDINAL OF INTEGER
];
SignalType:
TYPE =
MACHINE
DEPENDENT {blackAndWhite(0),
red(1), blue(2), green(3), cyan(4), magenta(5), yellow(6), x(7), y(8),
RGB(100), CMY(101), CMYB(102), Yxy(103),
comments(177776B), undefined(177777B)};
Sense:
TYPE =
MACHINE
DEPENDENT {largerIsLighter(0), largerIsDarker(1),
undefined(177777B)};
ScaleType:
TYPE =
MACHINE
DEPENDENT {reflectance(1), density(2),
comments(177776B), undefined(177777B)};
Point: TYPE = MACHINE DEPENDENT RECORD [sample: INTEGER, level: INTEGER];
SpotType:
TYPE =
MACHINE
DEPENDENT {rectangular(1), circular(2),
comments(177776B), undefined(177777B)};
CommentPart:
TYPE =
MACHINE
DEPENDENT
RECORD [
part: PartHeader,
chars: PACKED SEQUENCE COMPUTED CARDINAL OF CHARACTER
];
Comment string is chars[1..LOOPHOLE[chars[0],CARDINAL]]
}.