[Cyan]<Cedar6.0>Imager>ImagerSample.mesa!5

ImagerSample.mesa

Doug Wyatt, May 28, 1985 11:47:19 am PDT

Michael Plass, June 3, 1985 11:11:41 am PDT

DIRECTORY

Basics USING [bitsPerWord, LongNumber, RawWords],

ImagerTransformation USING [Transformation],

PrincOps USING [SrcFunc, DstFunc]

;

ImagerSample: CEDAR DEFINITIONS

~ BEGIN

Transformation: TYPE ~ ImagerTransformation.Transformation;

Sample buffers

Sample: TYPE ~ WORD;

maxBitsPerSample: NAT ~ Basics.bitsPerWord;

RawSamples: TYPE ~ Basics.RawWords;

UnsafeSamples: TYPE ~ LONG POINTER TO RawSamples;

SampleBuffer: TYPE ~ REF SampleBufferRep;

SampleBufferRep: TYPE ~ RECORD [

iSize, jSize: NAT,

samples: SEQUENCE size: NAT OF Sample

];

NewBuffer: PROC [iSize, jSize: NAT, scratch: SampleBuffer ← NIL] RETURNS [SampleBuffer];

ObtainScratchBuffer: PROC [iSize, jSize: NAT] RETURNS [SampleBuffer];

ReleaseScratchBuffer: PROC [buffer: SampleBuffer];

DoWithScratchBuffer: PROC [iSize, jSize: NAT, action: PROC [SampleBuffer]];

GetSample: PROC [buffer: SampleBuffer, i, j: NAT] RETURNS [Sample];

PutSample: PROC [buffer: SampleBuffer, i, j: NAT, sample: Sample];

GetPointer: PROC [buffer: SampleBuffer, i, j, count: NAT] RETURNS [UnsafeSamples];

SampleBuffer operations

UnsafeAdd: UNSAFE PROC [src1, src2, dst: UnsafeSamples, count: NAT];

FOR k: NAT IN[0..count) DO dst[k] ← src1[k]+src2[k] ENDLOOP;

UnsafeSub: UNSAFE PROC [src1, src2, dst: UnsafeSamples, count: NAT];

FOR k: NAT IN[0..count) DO dst[k] ← src1[k]-src2[k] ENDLOOP;

UnsafeLookup: UNSAFE PROC [tbl, src, dst: UnsafeSamples, count: NAT];

FOR k: NAT IN[0..count) DO dst[k] ← tbl[src[k]] ENDLOOP;

AddSamples: PROC [samples: SampleBuffer, si, sj: NAT ← 0,
buffer: SampleBuffer, bi, bj: NAT ← 0, count: NAT];

FOR k: NAT IN[0..count) DO

buffer.PutSample[bi, bj+k, buffer.GetSample[bi, bj+k]+samples.GetSample[si, sj+k]]

ENDLOOP;

SubSamples: PROC [samples: SampleBuffer, si, sj: NAT ← 0,
buffer: SampleBuffer, bi, bj: NAT ← 0, count: NAT];

FOR k: NAT IN[0..count) DO

buffer.PutSample[bi, bj+k, buffer.GetSample[bi, bj+k]-samples.GetSample[si, sj+k]]

ENDLOOP;

LookupSamples: PROC [table: SampleBuffer, samples: SampleBuffer, si, sj: NAT ← 0,
buffer: SampleBuffer, bi, bj: NAT ← 0, count: NAT];

FOR k: NAT IN[0..count) DO

buffer.PutSample[bi, bj+k, table.GetSample[0, samples.GetSample[si, sj+k]]]

ENDLOOP;

LookupPixels: PROC [tables: SampleBuffer, pixels: SampleBuffer, pj: NAT ← 0,
buffer: SampleBuffer, bi, bj: NAT ← 0, count: NAT];

FOR k: NAT IN[0..count) DO

sum: Sample ← 0;

FOR i: NAT IN[0..tables.iSize) DO

sum ← sum+tables.GetSample[i, pixels.GetSample[i, pj+k]];

ENDLOOP;

buffer.PutSample[bi, bj+k, sum];

ENDLOOP;

Packing and unpacking

BitsPerSample: TYPE ~ [0..maxBitsPerSample];

UnsafeGetF: UNSAFE PROC [samples: UnsafeSamples, count: NAT, s, f: NAT ← 0,
base: LONG POINTER, wordsPerLine: NAT, bitsPerSample: BitsPerSample];

samples[k] ← array[s, f+k], for k IN[0..count)

UnsafePutF: UNSAFE PROC [samples: UnsafeSamples, count: NAT, s, f: NAT ← 0,
base: LONG POINTER, wordsPerLine: NAT, bitsPerSample: BitsPerSample, srcFunc: PrincOps.SrcFunc ← null, dstFunc: PrincOps.DstFunc ← null];

array[s, f+k] ← Func[array[s, f+k], samples[k]], for k IN[0..count)

UnsafePutFSign: UNSAFE PROC [samples: UnsafeSamples, count: NAT, s, f: NAT ← 0,
base: LONG POINTER, wordsPerLine: NAT];

bitArray[s, f+k] ← SignBit[samples[k]], for k IN[0..count). Useful for halftoning.

UnsafeGetS: UNSAFE PROC [samples: UnsafeSamples, count: NAT, s, f: NAT ← 0,
base: LONG POINTER, wordsPerLine: NAT, bitsPerSample: BitsPerSample];

samples[k] ← array[s+k, f], for k IN[0..count)

UnsafePutS: UNSAFE PROC [samples: UnsafeSamples, count: NAT, s, f: NAT ← 0,
base: LONG POINTER, wordsPerLine: NAT, bitsPerSample: BitsPerSample, srcFunc: PrincOps.SrcFunc ← null, dstFunc: PrincOps.DstFunc ← null];

array[s+k, f] ← Func[array[s+k, f], samples[k]], for k IN[0..count)

Sampling

Sampler: TYPE ~ REF SamplerRep;

SamplerRep: TYPE ~ RECORD [

base: LONG POINTER ← NIL, -- source base address

wordsPerLine: CARDINAL ← 0, -- source words per scan line

bitsPerSample: BitsPerSample ← 0, -- source bits per sample

sSize: CARDINAL ← 0, -- source size in slow (scan line) direction

fSize: CARDINAL ← 0, -- source size in fast (pixel) direction

sMin: CARDINAL ← 0, -- source origin in slow (scan line) direction

fMin: CARDINAL ← 0, -- source origin in fast (pixel) direction

sfDelta: Basics.LongNumber ← [lc[0]], -- source delta s for destination f increment

ffDelta: Basics.LongNumber ← [lc[0]], -- source delta f for destination f increment

ssDelta: Basics.LongNumber ← [lc[0]], -- source delta s for destination s increment

fsDelta: Basics.LongNumber ← [lc[0]], -- source delta f for destination s increment

sSource: Basics.LongNumber ← [lc[0]], -- initial source s (corresponding to sDest, fDest)

fSource: Basics.LongNumber ← [lc[0]], -- initial source f (corresponding to sDest, fDest)

sDest: CARDINAL ← 0, -- initial destination s

fDest: CARDINAL ← 0 -- initial destination f

];

SetSamplerIncrements: PROC [sampler: Sampler, m: Transformation];

Sets sfDelta, ffDelta, ssDelta, fsDelta.

SetSamplerPosition: PROC [sampler: Sampler, m: Transformation, s, f: CARDINAL];

Sets initial destination position.

GetPointSamples: PROC [sampler: Sampler, s, f: CARDINAL,
buffer: SampleBuffer, bi, bj: NAT ← 0, count: NAT];

buffer[bi, bj+k] ← <sample for destination>[s, f+k], for k IN[0..count)

GetInterpolatedSamples: PROC [sampler: Sampler, s, f: CARDINAL,
buffer: SampleBuffer, i, j: NAT ← 0, count: NAT];

Similar to GetPointSamples, but interpolates four surrounding samples to get result.

END.