Image::Leptonica::Func::runlength
version 0.04
runlength.c
runlength.c Label pixels by membership in runs PIX *pixStrokeWidthTransform() static PIX *pixFindMinRunsOrthogonal() PIX *pixRunlengthTransform() Find runs along horizontal and vertical lines l_int32 pixFindHorizontalRuns() l_int32 pixFindVerticalRuns() Compute runlength-to-membership transform on a line l_int32 runlengthMembershipOnLine() Make byte position LUT l_int32 makeMSBitLocTab()
l_int32 * makeMSBitLocTab ( l_int32 bitval )
makeMSBitLocTab() Input: bitval (either 0 or 1) Return: table (giving, for an input byte, the MS bit location, starting at 0 with the MSBit in the byte), or null on error. Notes: (1) If bitval == 1, it finds the leftmost ON pixel in a byte; otherwise if bitval == 0, it finds the leftmost OFF pixel. (2) If there are no pixels of the indicated color in the byte, this returns 8.
l_int32 pixFindHorizontalRuns ( PIX *pix, l_int32 y, l_int32 *xstart, l_int32 *xend, l_int32 *pn )
pixFindHorizontalRuns() Input: pix (1 bpp) y (line to traverse) xstart (returns array of start positions for fg runs) xend (returns array of end positions for fg runs) &n (<return> the number of runs found) Return: 0 if OK; 1 on error Notes: (1) This finds foreground horizontal runs on a single scanline. (2) To find background runs, use pixInvert() before applying this function. (3) The xstart and xend arrays are input. They should be of size w/2 + 1 to insure that they can hold the maximum number of runs in the raster line.
l_int32 pixFindVerticalRuns ( PIX *pix, l_int32 x, l_int32 *ystart, l_int32 *yend, l_int32 *pn )
pixFindVerticalRuns() Input: pix (1 bpp) x (line to traverse) ystart (returns array of start positions for fg runs) yend (returns array of end positions for fg runs) &n (<return> the number of runs found) Return: 0 if OK; 1 on error Notes: (1) This finds foreground vertical runs on a single scanline. (2) To find background runs, use pixInvert() before applying this function. (3) The ystart and yend arrays are input. They should be of size h/2 + 1 to insure that they can hold the maximum number of runs in the raster line.
PIX * pixRunlengthTransform ( PIX *pixs, l_int32 color, l_int32 direction, l_int32 depth )
pixRunlengthTransform() Input: pixs (1 bpp) color (0 for white runs, 1 for black runs) direction (L_HORIZONTAL_RUNS, L_VERTICAL_RUNS) depth (8 or 16 bpp) Return: pixd (8 or 16 bpp), or null on error Notes: (1) The dest Pix is 8 or 16 bpp, with the pixel values equal to the runlength in which it is a member. The length is clipped to the max pixel value if necessary. (2) The color determines if we're labelling white or black runs. (3) A pixel that is not a member of the chosen color gets value 0; it belongs to a run of length 0 of the chosen color. (4) To convert for maximum dynamic range, either linear or log, use pixMaxDynamicRange().
PIX * pixStrokeWidthTransform ( PIX *pixs, l_int32 color, l_int32 depth, l_int32 nangles )
pixStrokeWidthTransform() Input: pixs (1 bpp) color (0 for white runs, 1 for black runs) depth (of pixd: 8 or 16 bpp) nangles (2, 4, 6 or 8) Return: pixd (8 or 16 bpp), or null on error Notes: (1) The dest Pix is 8 or 16 bpp, with the pixel values equal to the stroke width in which it is a member. The values are clipped to the max pixel value if necessary. (2) The color determines if we're labelling white or black strokes. (3) A pixel that is not a member of the chosen color gets value 0; it belongs to a width of length 0 of the chosen color. (4) This chooses, for each dest pixel, the minimum of sets of runlengths through each pixel. Here are the sets: nangles increment set ------- --------- -------------------------------- 2 90 {0, 90} 4 45 {0, 45, 90, 135} 6 30 {0, 30, 60, 90, 120, 150} 8 22.5 {0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5} (5) Runtime scales linearly with (nangles - 2).
l_int32 runlengthMembershipOnLine ( l_int32 *buffer, l_int32 size, l_int32 depth, l_int32 *start, l_int32 *end, l_int32 n )
runlengthMembershipOnLine() Input: buffer (into which full line of data is placed) size (full size of line; w or h) depth (8 or 16 bpp) start (array of start positions for fg runs) end (array of end positions for fg runs) n (the number of runs) Return: 0 if OK; 1 on error Notes: (1) Converts a set of runlengths into a buffer of runlength membership values. (2) Initialization of the array gives pixels that are not within a run the value 0.
Zakariyya Mughal <zmughal@cpan.org>
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Image::Leptonica, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Image::Leptonica
CPAN shell
perl -MCPAN -e shell install Image::Leptonica
For more information on module installation, please visit the detailed CPAN module installation guide.