import type { Predicate } from "@thi.ng/api" ; import { assert } from "@thi.ng/errors/assert" ; import { unsupported } from "@thi.ng/errors/unsupported" ; import { GRAY16 } from "@thi.ng/pixel/format/gray16" ; import { GRAY8 } from "@thi.ng/pixel/format/gray8" ; import { RGB888 } from "@thi.ng/pixel/format/rgb888" ; import { intBuffer } from "@thi.ng/pixel/int" ; const isLinebreak = ( c ) => c === 0xa ; const isWS = ( c ) => c === 0x20 || ( c >= 9 && c <= 13 ) ; const readUntil = ( src , i , end = isLinebreak ) : [ string , number ] => { let res = "" ; for ( ; i < src . length ; i ++ ) { let c = src [ i ] ; if ( end ( c ) ) { i ++ ; break ; } res += String . fromCharCode ( c ) ; } return [ res , i ] ; } ; const readComments = ( src , acc , i ) => { while ( src [ i ] === 0x23 ) { const [ comment , j ] = readUntil ( src , i ) ; assert ( j !== i , `EOF reached` ) ; acc . push ( comment . substr ( 1 ) . trim ( ) ) ; i = j ; } return i ; } ; param src export const parseHeader = ( src ) => { let type ; let sw , sh ; let norm ; let max ; const comments = [ ] ; let i = readComments ( src , comments , 0 ) ; [ type , i ] = readUntil ( src , i ) ; i = readComments ( src , comments , i ) ; [ sw , i ] = readUntil ( src , i , isWS ) ; [ sh , i ] = readUntil ( src , i , isWS ) ; const width = parseInt ( sw ) ; const height = parseInt ( sh ) ; assert ( width > 0 && height > 0 , `invalid NetPBM header` ) ; if ( type === "P5" || type === "P6" ) { [ norm , i ] = readUntil ( src , i ) ; max = parseInt ( norm ) ; } return { type , width , height , max , start : i , comments , } ; } ; /**
 * Takes a PBM/PGM/PPM file as byte array and parses it into a
 *  {@link @thi.ng/pixel#IntBuffer} of corresponding format.
 *
 *  remarks Depending on header information, the following rules apply:
 *
 * - only binary NetPBM formats are supported (P4,P5,P6 types)
 * - 1bit PBM (P4) =>  readPBM * - grayscale PGM (P5) =>  readPGM8 or  readPGM16 * - 24bit RGB (P6) =>  readPPM *
 * Function will throw an error if image is of any other type or header is
 * corrupt otherwise. Any embedded comments will be discarded.
 *
 *  param src export const read = ( src ) => { const { type , width , height , max , start } = parseHeader ( src ) ; switch ( type ) { case "P4" : return readPBM ( src , start , width , height ) ; case "P5" : return max ! < 0x100 ? readPGM8 ( src , start , width , height , max ) : readPGM16 ( src , start , width , height , max ) ; case "P6" : return readPPM ( src , start , width , height , max ) ; default : unsupported ( `PBM type: ${ type }` ) ; } } ; /**
 * Reads pixels from given 1bit PBM file byte buffer, starting at index `i` and
 * returns  {@link @thi.ng/pixel#IntBuffer} in `GRAY8` format (due to current
 * lack of true 1bit format).
 *
 *  param src param i param width param height export const readPBM = ( src , i , width , height ) => { const buf = intBuffer ( width , height , GRAY8 ) ; const data = buf . data ; const w1 = width - 1 ; for ( let y = 0 , j = 0 ; y < height ; y ++ ) { for ( let x = 0 ; x < width ; x ++ , j ++ ) { data [ j ] = src [ i ] & ( 1 << ( ~ x & 7 ) ) ? 0 : 0xff ; if ( ( x & 7 ) === 7 || x === w1 ) i ++ ; } } return buf ; } ; /**
 * Reads pixels from given 8bit PGM file byte buffer, starting at index `i` and
 * returns  {@link @thi.ng/pixel#IntBuffer} in `GRAY8` format. If needed,
 * pixel values are rescaled given `max` value defined in PGM header (MUST
 * be <= 0xff).
 *
 *  remarks param src param i param width param height param max export const readPGM8 = ( src , i , width , height , max = 0xff ) => { const buf = intBuffer ( width , height , GRAY8 ) ; const data = buf . data ; if ( max === 0xff ) { data . set ( src . subarray ( i ) ) ; } else { max = 0xff / max ; for ( let j = 0 , n = data . length ; j < n ; i ++ , j ++ ) { data [ j ] = ( src [ i ] * max ) | 0 ; } } return buf ; } ; /**
 * Reads pixels from given 16bit PGM file byte buffer, starting at index `i` and
 * returns  {@link @thi.ng/pixel#IntBuffer} in `GRAY16` format. Pixel values
 * are rescaled given `max` value defined in PGM header (MUST be <= 0xffff).
 *
 *  remarks param src param i param width param height param max export const readPGM16 = ( src , i , width , height , max = 0xffff ) => { const buf = intBuffer ( width , height , GRAY16 ) ; const data = buf . data ; max = 0xffff / max ; for ( let j = 0 , n = data . length ; j < n ; i += 2 , j ++ ) { data [ j ] = ( ( ( src [ i ] << 8 ) | src [ i + 1 ] ) * max ) | 0 ; } return buf ; } ; /**
 * Reads pixels from given 24bit PPM file byte buffer, starting at index `i` and
 * returns  {@link @thi.ng/pixel#IntBuffer} in `RGB888` format. Color channel
 * values are rescaled given `max` value defined in PGM header (MUST be <=
 * 0xff).
 *
 *  remarks param src param i param width param height param max export const readPPM = ( src , i , width , height , max = 0xff ) => { const buf = intBuffer ( width , height , RGB888 ) ; const data = buf . data ; assert ( max <= 0xff , `unsupported max value: ${ max }` ) ; if ( max === 0xff ) { for ( let j = 0 , n = data . length ; j < n ; i += 3 , j ++ ) { data [ j ] = ( src [ i ] << 16 ) | ( src [ i + 1 ] << 8 ) | src [ i + 2 ] ; } } else { max = 0xff / max ; for ( let j = 0 , n = data . length ; j < n ; i += 3 , j ++ ) { data [ j ] = ( ( src [ i ] * max ) << 16 ) | ( ( src [ i + 1 ] * max ) << 8 ) | ( src [ i + 2 ] * max ) ; } } return buf ; } ;