-- PressFontFormat.mesa
-- modified by Michael Plass on August 11, 1982 8:43 am
-- modified by Maureen Stone 30-Dec-81 17:14:31
-- modified by Geschke on November 5, 1979  4:42 PM

DIRECTORY
    Mopcodes;


PressFontFormat: DEFINITIONS =
BEGIN

Byte: TYPE = [0..377B];

-- the IndexHeader corresponds to Structure IX pp5 Font Formats Manual.

IndexHeader: TYPE = MACHINE DEPENDENT RECORD[
    type: IndexType,
    length: [0..4096)
    ];
    --length in words, counting this one

IndexType: TYPE = MACHINE DEPENDENT {
    end,name,splines,chars,widths,
    unassigned1,unassigned2,unassigned3,unassigned4,
     unassigned5,unassigned6,unassigned7,unassigned8,
     unassigned9,unassigned10,unassigned11};

bcplMaxLength: CARDINAL = 255;
BcplSTRING: TYPE = MACHINE DEPENDENT RECORD[
    body: PACKED ARRAY[0..bcplMaxLength] OF CHARACTER
        --body[0] is the length of the string
    ];

-- The RawIndex corresponds to the five kinds of index entries.
-- EndSegment, NameSegment, SplineSegment, CharacterSegment, and WidthSegment.

RawIndex: TYPE = MACHINE DEPENDENT RECORD
  [hdr: IndexHeader,
   variantPart: SELECT COMPUTED IndexType FROM
      end => NULL,
      name =>
        [
        fill: Byte,
        code: FontCode, -- local, unique name for font
        fontname: BcplSTRING
        ],
      splines, widths =>
        [
        family: FontCode,
        face: FaceType,
        bc, ec: CHARACTER,                        -- first and last character
        size: CARDINAL,                            -- Font size (10 micron units)
        rotation: CARDINAL,                        -- Rotation (anti clockwise)
        startaddress: bcplLONGPOINTER,        -- Starting address of data part
        length: bcplLONGCARDINAL                -- Length of data part
        ],
      chars =>
        [
        family: FontCode,
        face: FaceType,
        bc, ec: CHARACTER,                        -- first and last character
        size: CARDINAL,                            -- Font size (10 micron units)
        rotation: CARDINAL,                        -- Rotation (anti clockwise)
        startaddress: bcplLONGPOINTER,        -- Starting address of data part
        length: bcplLONGCARDINAL,                -- Length of data part
        resolutionx: CARDINAL,                    -- 10*(number of bits/inch)
        resolutiony: CARDINAL                    -- ditto
        ],
      ENDCASE
  ];

FontCode: TYPE = Byte;
FaceType: TYPE = Byte;
FaceWeight: TYPE = {L,M,B};
FaceSlant: TYPE = {I,R};
FaceWidth: TYPE = {C,R,E};

CharBboxDesc: TYPE = LONG DESCRIPTOR FOR ARRAY OF BoundingBox;
CharDirDesc: TYPE = LONG DESCRIPTOR FOR ARRAY OF bcplLONGPOINTER;

BoundingBox: TYPE = MACHINE DEPENDENT RECORD[
    xwidth, ywidth: bcplFraction,
    BBox, BBoy: INTEGER, BBdx, BBdy: CARDINAL];


--  BCPL data structures for spline definitions

SplineDataDesc: TYPE = LONG DESCRIPTOR FOR ARRAY OF BcplSplineData;
SplineDirDesc: TYPE = CharDirDesc;

BcplSplineData: TYPE = MACHINE DEPENDENT RECORD[
    xwidth, ywidth, bbox, bboy, rightx, topy: BcplREAL];

missingCharValueBits: bcplLONGCARDINAL = [highhalf: 0, lowhalf: 177777B]; 
missingCharValue: BcplREAL = LOOPHOLE[missingCharValueBits];

SplineCommandCode: TYPE = MACHINE DEPENDENT {
    MoveTo, DrawTo, DrawCurve, NewObject, EndDefinition
    };

BcplSplineCommand: TYPE = MACHINE DEPENDENT RECORD
  [type: BcplCommandCode,
   variantPart: SELECT OVERLAID SplineCommandCode FROM
      MoveTo, DrawTo => [x,y: BcplREAL],
      DrawCurve => [x0,y0, x1,y1, x2,y2: BcplREAL],
      NewObject, EndDefinition => NULL,
      ENDCASE
  ];

BcplREAL: TYPE = MACHINE DEPENDENT RECORD[
    sign: [0..1], exp: [0..377B], sigbit: [0..1], topmantissa: [0..77B],
    restofmantissa: [0..177777B]];

BcplCommandCode: TYPE = INTEGER;
moveToCode: BcplCommandCode = 1;
drawToCode: BcplCommandCode = 2;
drawCurveCode: BcplCommandCode = 3;
newObjectCode: BcplCommandCode = -1;
endSplineCode: BcplCommandCode = -2;

-- BCPL data structures for width definitions

BcplWidthSegment: TYPE = MACHINE DEPENDENT RECORD[
    FBBox, FBBoy, FBBdx, FBBdy: CARDINAL,
    XWidthFixed, YWidthFixed: BOOLEAN,
    fill: PACKED ARRAY [0..14) OF BOOLEAN,
    widthData: ARRAY [0..0) OF CARDINAL
    ];

--  converting from the doubleword world of Mesa to BCPL and conversely

LongCardinalFromBcplLongPointer: PROCEDURE [bp: bcplLONGPOINTER] RETURNS [p: LONG CARDINAL] =
    MACHINE CODE BEGIN Mopcodes.zEXCH; END;

MesaToBcplLongCardinal: PROCEDURE [c: LONG CARDINAL] RETURNS [bc: bcplLONGCARDINAL] =
    MACHINE CODE BEGIN Mopcodes.zEXCH; END;

BcplToMesaLongCardinal: PROCEDURE [bc: bcplLONGCARDINAL] RETURNS [c: LONG CARDINAL] =
    MACHINE CODE BEGIN Mopcodes.zEXCH; END;

MesaToBcplFraction: PROCEDURE [f: Fraction] RETURNS [bf: bcplFraction] =
    MACHINE CODE BEGIN Mopcodes.zEXCH; END;

BcplToMesaFraction: PROCEDURE [bf: bcplFraction] RETURNS [f: Fraction] =
    MACHINE CODE BEGIN Mopcodes.zEXCH; END;


bcplLONGPOINTER: TYPE = MACHINE DEPENDENT RECORD[
    highhalf, lowhalf: WORD];

bcplLONGCARDINAL: TYPE = MACHINE DEPENDENT RECORD[
    highhalf, lowhalf: WORD];

bcplFraction: TYPE = MACHINE DEPENDENT RECORD[
    integerpart, fractionpart: WORD];

Fraction: TYPE = LONG INTEGER;

RasterPointer: TYPE = LONG POINTER TO RasterDimension;
RasterDimension: TYPE = MACHINE DEPENDENT RECORD[height: [0..77B], width: [0..1777B]];

-- The private record structure for the font reader, for those who want to dig into the bits for themselves.

CharRepresentation: TYPE = {raster, outline, widthsOnly};
FontPrivateRec: PUBLIC TYPE = RECORD [
base: LONG POINTER,  -- For checking against handle.base
descriptors: SELECT rep: CharRepresentation FROM
raster => [
indexEntry: LONG POINTER TO chars RawIndex,
dataDesc: CharBboxDesc,
dirDesc: CharDirDesc,
rasterStart, rasterEnd: LONG CARDINAL
],
outline => [
indexEntry: LONG POINTER TO splines RawIndex,
dataDesc: SplineDataDesc,
dirDesc: SplineDirDesc,
commandStart, commandEnd: LONG CARDINAL
],
widthsOnly => [
indexEntry: LONG POINTER TO widths RawIndex,
widthSeg: LONG POINTER TO BcplWidthSegment,
xWidthDesc: LONG DESCRIPTOR FOR ARRAY OF CARDINAL,
yWidthDesc: LONG DESCRIPTOR FOR ARRAY OF CARDINAL
],
ENDCASE
];


END.

Michael Plass on August 5, 1982 8:41 am. Extracted from BcplFontFileDefs.