diff options
Diffstat (limited to 'converter/pbm/pbmtomrf.c')
| -rw-r--r-- | converter/pbm/pbmtomrf.c | 160 |
1 files changed, 110 insertions, 50 deletions
diff --git a/converter/pbm/pbmtomrf.c b/converter/pbm/pbmtomrf.c index 186e95f5..e7b7fcc9 100644 --- a/converter/pbm/pbmtomrf.c +++ b/converter/pbm/pbmtomrf.c @@ -13,81 +13,139 @@ #include "pm_c_util.h" #include "pbm.h" -static int bitbox; -static int bitsleft; -static FILE *bit_out; + +typedef struct bitOut { + int bitbox; + int bitsleft; + FILE * fileP; +} bitOut; + static void -bit_init(FILE * const out) { - bitbox = 0; - bitsleft = 8; - bit_out = out; +bit_init(struct bitOut * const bitOutP, + FILE * const ofP) { + + bitOutP->bitbox = 0; + bitOutP->bitsleft = 8; + bitOutP->fileP = ofP; } static void -bit_output(int const bit) { - --bitsleft; - bitbox |= (bit << bitsleft); - if (bitsleft == 0) { - fputc(bitbox, bit_out); - bitbox = 0; - bitsleft = 8; +bit_output(struct bitOut * const bitOutP, + int const bit) { + + --bitOutP->bitsleft; + bitOutP->bitbox |= (bit << bitOutP->bitsleft); + if (bitOutP->bitsleft == 0) { + fputc(bitOutP->bitbox, bitOutP->fileP); + bitOutP->bitbox = 0; + bitOutP->bitsleft = 8; } } static void -bit_flush(void) { +bit_flush(struct bitOut * const bitOutP) { /* there are never 0 bits left outside of bit_output, but * if 8 bits are left here there's nothing to flush, so * only do it if bitsleft!=8. */ - if (bitsleft != 8) { - bitsleft = 1; - bit_output(0); /* yes, really. This will always work. */ + if (bitOutP->bitsleft != 8) { + bitOutP->bitsleft = 1; + bit_output(bitOutP, 0); /* yes, really. This will always work. */ } } -static void -doSquare(unsigned char * const image, - int const ox, - int const oy, - int const w, - int const size) { - - unsigned int y; +static void +determineBlackWhiteOrMix(const unsigned char * const image, + unsigned int const ulCol, + unsigned int const ulRow, + unsigned int const imageWidth, + unsigned int const size, + bool * const oneColorP, + int * const colorP) { +/*---------------------------------------------------------------------------- + Determine whether a square within 'image' is all white, all black, + or a mix. +-----------------------------------------------------------------------------*/ + unsigned int rowOfSquare; unsigned int t; - /* check square to see if it's all black or all white. */ + for (rowOfSquare = 0, t = 0; rowOfSquare < size; ++rowOfSquare) { + unsigned int colOfSquare; + for (colOfSquare = 0; colOfSquare < size; ++colOfSquare) { + unsigned int rowOfImage = ulRow + rowOfSquare; + unsigned int colOfImage = ulCol + colOfSquare; - t = 0; - for (y = 0; y < size; ++y) { - unsigned int x; - for (x = 0; x < size; ++x) - t += image[(oy+y)*w + ox + x]; + t += image[rowOfImage * imageWidth + colOfImage]; + } } /* if the total's 0, it's black. if it's size*size, it's white. */ - if (t == 0 || t == size*size) { - if (size != 1) /* (it's implicit when size is 1, of course) */ - bit_output(1); /* all same color */ - bit_output(t?1:0); - return; - } - - /* otherwise, if our square is greater than 1x1, we need to recurse. */ - if(size > 1) { - bit_output(0); /* not all same */ - doSquare(image, ox, oy, w, size>>1); - doSquare(image, ox+size, oy, w, size>>1); - doSquare(image, ox, oy+size, w, size>>1); - doSquare(image, ox+size, oy+size, w, size>>1); + if (t == 0) { + *oneColorP = TRUE; + *colorP = 0; + } else if (t == SQR(size)) { + *oneColorP = TRUE; + *colorP = 1; + } else + *oneColorP = FALSE; +} + + + +static void +doSquare(bitOut * const bitOutP, + const unsigned char * const image, + unsigned int const ulCol, + unsigned int const ulRow, + unsigned int const imageWidth, + unsigned int const size) { +/*---------------------------------------------------------------------------- + Do a square of side 'size', whose upper left corner is at (ulCol, ulRow). + This is a square within 'image', which is a concatenation of rows + 'imageWidth' pixels wide, one byte per pixel. + + Write the pixel values out to the bit stream *bitOutP, in MRF format. +-----------------------------------------------------------------------------*/ + if (size == 1) { + /* The fact that it is all one color is implied because the square is + just one pixel; no bit goes in MRF output to state that. + */ + bit_output(bitOutP, image[ulRow * imageWidth + ulCol] ? 1 : 0); + } else { + bool oneColor; + int color; + + determineBlackWhiteOrMix(image, ulCol, ulRow, imageWidth, size, + &oneColor, &color); + + if (oneColor) { + bit_output(bitOutP, 1); /* all same color */ + bit_output(bitOutP, color); + } else { + /* Square is not all the same color, so recurse. Do each + of the four quadrants of this square individually. + */ + unsigned int const quadSize = size/2; + + bit_output(bitOutP, 0); /* not all same color */ + + doSquare(bitOutP, image, ulCol, ulRow, + imageWidth, quadSize); + doSquare(bitOutP, image, ulCol + quadSize, ulRow, + imageWidth, quadSize); + doSquare(bitOutP, image, ulCol, ulRow + quadSize, + imageWidth, quadSize); + doSquare(bitOutP, image, ulCol + quadSize, ulRow + quadSize, + imageWidth, quadSize); + } } } @@ -241,7 +299,7 @@ readPbmImage(FILE * const ifP, pm_error("Ridiculously large, unprocessable image: %u cols x %u rows", cols, rows); - image = calloc(w64*h64*64*64,1); + image = calloc(w64*h64*64*64, 1); if (image == NULL) pm_error("Unable to get memory for raster"); @@ -274,6 +332,8 @@ outputMrf(FILE * const ofP, unsigned int const w64 = (cols + 63) / 64; unsigned int const h64 = (rows + 63) / 64; + bitOut bitOut; + unsigned int row; fprintf(ofP, "MRF1"); @@ -283,14 +343,14 @@ outputMrf(FILE * const ofP, /* now recursively check squares. */ - bit_init(ofP); + bit_init(&bitOut, ofP); for (row = 0; row < h64; ++row) { unsigned int col; for (col = 0; col < w64; ++col) - doSquare(image, col*64, row*64, w64*64, 64); + doSquare(&bitOut, image, col*64, row*64, w64*64, 64); } - bit_flush(); + bit_flush(&bitOut); } |