NAME
Image::Leptonica::Func::fpix2
VERSION
version 0.04
fpix2.c
fpix2.c
This file has these FPix utilities:
- interconversions with pix, fpix, dpix
- min and max values
- integer scaling
- arithmetic operations
- set all
- border functions
- simple rasterop (source --> dest)
- geometric transforms
Interconversions between Pix, FPix and DPix
FPIX *pixConvertToFPix()
DPIX *pixConvertToDPix()
PIX *fpixConvertToPix()
PIX *fpixDisplayMaxDynamicRange() [useful for debugging]
DPIX *fpixConvertToDPix()
PIX *dpixConvertToPix()
FPIX *dpixConvertToFPix()
Min/max value
l_int32 fpixGetMin()
l_int32 fpixGetMax()
l_int32 dpixGetMin()
l_int32 dpixGetMax()
Integer scaling
FPIX *fpixScaleByInteger()
DPIX *dpixScaleByInteger()
Arithmetic operations
FPIX *fpixLinearCombination()
l_int32 fpixAddMultConstant()
DPIX *dpixLinearCombination()
l_int32 dpixAddMultConstant()
Set all
l_int32 fpixSetAllArbitrary()
l_int32 dpixSetAllArbitrary()
FPix border functions
FPIX *fpixAddBorder()
FPIX *fpixRemoveBorder()
FPIX *fpixAddMirroredBorder()
FPIX *fpixAddContinuedBorder()
FPIX *fpixAddSlopeBorder()
FPix simple rasterop
l_int32 fpixRasterop()
FPix rotation by multiples of 90 degrees
FPIX *fpixRotateOrth()
FPIX *fpixRotate180()
FPIX *fpixRotate90()
FPIX *fpixFlipLR()
FPIX *fpixFlipTB()
FPix affine and projective interpolated transforms
FPIX *fpixAffinePta()
FPIX *fpixAffine()
FPIX *fpixProjectivePta()
FPIX *fpixProjective()
l_int32 linearInterpolatePixelFloat()
Thresholding to 1 bpp Pix
PIX *fpixThresholdToPix()
Generate function from components
FPIX *pixComponentFunction()FUNCTIONS
dpixAddMultConstant
l_int32 dpixAddMultConstant ( DPIX *dpix, l_float64 addc, l_float64 multc )
dpixAddMultConstant()
Input: dpix
addc (use 0.0 to skip the operation)
multc (use 1.0 to skip the operation)
Return: 0 if OK, 1 on error
Notes:
(1) This is an in-place operation.
(2) It can be used to multiply each pixel by a constant,
and also to add a constant to each pixel. Multiplication
is done first.dpixConvertToFPix
FPIX * dpixConvertToFPix ( DPIX *dpix )
dpixConvertToFPix()
Input: dpix
Return: fpix, or null on errordpixConvertToPix
PIX * dpixConvertToPix ( DPIX *dpixs, l_int32 outdepth, l_int32 negvals, l_int32 errorflag )
dpixConvertToPix()
Input: dpixs
outdepth (0, 8, 16 or 32 bpp)
negvals (L_CLIP_TO_ZERO, L_TAKE_ABSVAL)
errorflag (1 to output error stats; 0 otherwise)
Return: pixd, or null on error
Notes:
(1) Use @outdepth = 0 to programmatically determine the
output depth. If no values are greater than 255,
it will set outdepth = 8; otherwise to 16 or 32.
(2) Because we are converting a float to an unsigned int
with a specified dynamic range (8, 16 or 32 bits), errors
can occur. If errorflag == TRUE, output the number
of values out of range, both negative and positive.
(3) If a pixel value is positive and out of range, clip to
the maximum value represented at the outdepth of 8, 16
or 32 bits.dpixGetMax
l_int32 dpixGetMax ( DPIX *dpix, l_float64 *pmaxval, l_int32 *pxmaxloc, l_int32 *pymaxloc )
dpixGetMax()
Input: dpix
&maxval (<optional return> max value)
&xmaxloc (<optional return> x location of max)
&ymaxloc (<optional return> y location of max)
Return: 0 if OK; 1 on errordpixGetMin
l_int32 dpixGetMin ( DPIX *dpix, l_float64 *pminval, l_int32 *pxminloc, l_int32 *pyminloc )
dpixGetMin()
Input: dpix
&minval (<optional return> min value)
&xminloc (<optional return> x location of min)
&yminloc (<optional return> y location of min)
Return: 0 if OK; 1 on errordpixLinearCombination
DPIX * dpixLinearCombination ( DPIX *dpixd, DPIX *dpixs1, DPIX *dpixs2, l_float32 a, l_float32 b )
dpixLinearCombination()
Input: dpixd (<optional>; this can be null, equal to dpixs1, or
different from dpixs1)
dpixs1 (can be == to dpixd)
dpixs2
a, b (multiplication factors on dpixs1 and dpixs2, rsp.)
Return: dpixd always
Notes:
(1) Computes pixelwise linear combination: a * src1 + b * src2
(2) Alignment is to UL corner.
(3) There are 3 cases. The result can go to a new dest,
in-place to dpixs1, or to an existing input dest:
* dpixd == null: (src1 + src2) --> new dpixd
* dpixd == dpixs1: (src1 + src2) --> src1 (in-place)
* dpixd != dpixs1: (src1 + src2) --> input dpixd
(4) dpixs2 must be different from both dpixd and dpixs1.dpixScaleByInteger
DPIX * dpixScaleByInteger ( DPIX *dpixs, l_int32 factor )
dpixScaleByInteger()
Input: dpixs (low resolution, subsampled)
factor (scaling factor)
Return: dpixd (interpolated result), or null on error
Notes:
(1) The width wd of dpixd is related to ws of dpixs by:
wd = factor * (ws - 1) + 1 (and ditto for the height)
We avoid special-casing boundary pixels in the interpolation
by constructing fpixd by inserting (factor - 1) interpolated
pixels between each pixel in fpixs. Then
wd = ws + (ws - 1) * (factor - 1) (same as above)
This also has the advantage that if we subsample by @factor,
throwing out all the interpolated pixels, we regain the
original low resolution dpix.dpixSetAllArbitrary
l_int32 dpixSetAllArbitrary ( DPIX *dpix, l_float64 inval )
dpixSetAllArbitrary()
Input: dpix
val (to set at each pixel)
Return: 0 if OK, 1 on errorfpixAddBorder
FPIX * fpixAddBorder ( FPIX *fpixs, l_int32 left, l_int32 right, l_int32 top, l_int32 bot )
fpixAddBorder()
Input: fpixs
left, right, top, bot (pixels on each side to be added)
Return: fpixd, or null on error
Notes:
(1) Adds border of '0' 32-bit pixelsfpixAddContinuedBorder
FPIX * fpixAddContinuedBorder ( FPIX *fpixs, l_int32 left, l_int32 right, l_int32 top, l_int32 bot )
fpixAddContinuedBorder()
Input: fpixs
left, right, top, bot (pixels on each side to be added)
Return: fpixd, or null on error
Notes:
(1) This adds pixels on each side whose values are equal to
the value on the closest boundary pixel.fpixAddMirroredBorder
FPIX * fpixAddMirroredBorder ( FPIX *fpixs, l_int32 left, l_int32 right, l_int32 top, l_int32 bot )
fpixAddMirroredBorder()
Input: fpixs
left, right, top, bot (pixels on each side to be added)
Return: fpixd, or null on error
Notes:
(1) See pixAddMirroredBorder() for situations of usage.fpixAddMultConstant
l_int32 fpixAddMultConstant ( FPIX *fpix, l_float32 addc, l_float32 multc )
fpixAddMultConstant()
Input: fpix
addc (use 0.0 to skip the operation)
multc (use 1.0 to skip the operation)
Return: 0 if OK, 1 on error
Notes:
(1) This is an in-place operation.
(2) It can be used to multiply each pixel by a constant,
and also to add a constant to each pixel. Multiplication
is done first.fpixAddSlopeBorder
FPIX * fpixAddSlopeBorder ( FPIX *fpixs, l_int32 left, l_int32 right, l_int32 top, l_int32 bot )
fpixAddSlopeBorder()
Input: fpixs
left, right, top, bot (pixels on each side to be added)
Return: fpixd, or null on error
Notes:
(1) This adds pixels on each side whose values have a normal
derivative equal to the normal derivative at the boundary
of fpixs.fpixAffine
FPIX * fpixAffine ( FPIX *fpixs, l_float32 *vc, l_float32 inval )
fpixAffine()
Input: fpixs (8 bpp)
vc (vector of 8 coefficients for projective transformation)
inval (value brought in; typ. 0)
Return: fpixd, or null on errorfpixAffinePta
FPIX * fpixAffinePta ( FPIX *fpixs, PTA *ptad, PTA *ptas, l_int32 border, l_float32 inval )
fpixAffinePta()
Input: fpixs (8 bpp)
ptad (4 pts of final coordinate space)
ptas (4 pts of initial coordinate space)
border (size of extension with constant normal derivative)
inval (value brought in; typ. 0)
Return: fpixd, or null on error
Notes:
(1) If @border > 0, all four sides are extended by that distance,
and removed after the transformation is finished. Pixels
that would be brought in to the trimmed result from outside
the extended region are assigned @inval. The purpose of
extending the image is to avoid such assignments.
(2) On the other hand, you may want to give all pixels that
are brought in from outside fpixs a specific value. In that
case, set @border == 0.fpixConvertToDPix
DPIX * fpixConvertToDPix ( FPIX *fpix )
fpixConvertToDPix()
Input: fpix
Return: dpix, or null on errorfpixConvertToPix
PIX * fpixConvertToPix ( FPIX *fpixs, l_int32 outdepth, l_int32 negvals, l_int32 errorflag )
fpixConvertToPix()
Input: fpixs
outdepth (0, 8, 16 or 32 bpp)
negvals (L_CLIP_TO_ZERO, L_TAKE_ABSVAL)
errorflag (1 to output error stats; 0 otherwise)
Return: pixd, or null on error
Notes:
(1) Use @outdepth = 0 to programmatically determine the
output depth. If no values are greater than 255,
it will set outdepth = 8; otherwise to 16 or 32.
(2) Because we are converting a float to an unsigned int
with a specified dynamic range (8, 16 or 32 bits), errors
can occur. If errorflag == TRUE, output the number
of values out of range, both negative and positive.
(3) If a pixel value is positive and out of range, clip to
the maximum value represented at the outdepth of 8, 16
or 32 bits.fpixDisplayMaxDynamicRange
PIX * fpixDisplayMaxDynamicRange ( FPIX *fpixs )
fpixDisplayMaxDynamicRange()
Input: fpixs
Return: pixd (8 bpp), or null on errorfpixFlipTB
FPIX * fpixFlipTB ( FPIX *fpixd, FPIX *fpixs )
fpixFlipTB()
Input: fpixd (<optional>; can be null, equal to fpixs,
or different from fpixs)
fpixs
Return: fpixd, or null on error
Notes:
(1) This does a top-bottom flip of the image, which is
equivalent to a rotation out of the plane about a
horizontal line through the image center.
(2) There are 3 cases for input:
(a) fpixd == null (creates a new fpixd)
(b) fpixd == fpixs (in-place operation)
(c) fpixd != fpixs (existing fpixd)
(3) For clarity, use these three patterns, respectively:
(a) fpixd = fpixFlipTB(NULL, fpixs);
(b) fpixFlipTB(fpixs, fpixs);
(c) fpixFlipTB(fpixd, fpixs);
(4) If an existing fpixd is not the same size as fpixs, the
image data will be reallocated.fpixGetMax
l_int32 fpixGetMax ( FPIX *fpix, l_float32 *pmaxval, l_int32 *pxmaxloc, l_int32 *pymaxloc )
fpixGetMax()
Input: fpix
&maxval (<optional return> max value)
&xmaxloc (<optional return> x location of max)
&ymaxloc (<optional return> y location of max)
Return: 0 if OK; 1 on errorfpixGetMin
l_int32 fpixGetMin ( FPIX *fpix, l_float32 *pminval, l_int32 *pxminloc, l_int32 *pyminloc )
fpixGetMin()
Input: fpix
&minval (<optional return> min value)
&xminloc (<optional return> x location of min)
&yminloc (<optional return> y location of min)
Return: 0 if OK; 1 on errorfpixLinearCombination
FPIX * fpixLinearCombination ( FPIX *fpixd, FPIX *fpixs1, FPIX *fpixs2, l_float32 a, l_float32 b )
fpixLinearCombination()
Input: fpixd (<optional>; this can be null, equal to fpixs1, or
different from fpixs1)
fpixs1 (can be == to fpixd)
fpixs2
a, b (multiplication factors on fpixs1 and fpixs2, rsp.)
Return: fpixd always
Notes:
(1) Computes pixelwise linear combination: a * src1 + b * src2
(2) Alignment is to UL corner.
(3) There are 3 cases. The result can go to a new dest,
in-place to fpixs1, or to an existing input dest:
* fpixd == null: (src1 + src2) --> new fpixd
* fpixd == fpixs1: (src1 + src2) --> src1 (in-place)
* fpixd != fpixs1: (src1 + src2) --> input fpixd
(4) fpixs2 must be different from both fpixd and fpixs1.fpixProjective
FPIX * fpixProjective ( FPIX *fpixs, l_float32 *vc, l_float32 inval )
fpixProjective()
Input: fpixs (8 bpp)
vc (vector of 8 coefficients for projective transformation)
inval (value brought in; typ. 0)
Return: fpixd, or null on errorfpixProjectivePta
FPIX * fpixProjectivePta ( FPIX *fpixs, PTA *ptad, PTA *ptas, l_int32 border, l_float32 inval )
fpixProjectivePta()
Input: fpixs (8 bpp)
ptad (4 pts of final coordinate space)
ptas (4 pts of initial coordinate space)
border (size of extension with constant normal derivative)
inval (value brought in; typ. 0)
Return: fpixd, or null on error
Notes:
(1) If @border > 0, all four sides are extended by that distance,
and removed after the transformation is finished. Pixels
that would be brought in to the trimmed result from outside
the extended region are assigned @inval. The purpose of
extending the image is to avoid such assignments.
(2) On the other hand, you may want to give all pixels that
are brought in from outside fpixs a specific value. In that
case, set @border == 0.fpixRasterop
l_int32 fpixRasterop ( FPIX *fpixd, l_int32 dx, l_int32 dy, l_int32 dw, l_int32 dh, FPIX *fpixs, l_int32 sx, l_int32 sy )
fpixRasterop()
Input: fpixd (dest fpix)
dx (x val of UL corner of dest rectangle)
dy (y val of UL corner of dest rectangle)
dw (width of dest rectangle)
dh (height of dest rectangle)
fpixs (src fpix)
sx (x val of UL corner of src rectangle)
sy (y val of UL corner of src rectangle)
Return: 0 if OK; 1 on error.
Notes:
(1) This is similiar in structure to pixRasterop(), except
it only allows copying from the source into the destination.
For that reason, no op code is necessary. Additionally,
all pixels are 32 bit words (float values), which makes
the copy very simple.
(2) Clipping of both src and dest fpix are done automatically.
(3) This allows in-place copying, without checking to see if
the result is valid: use for in-place with caution!fpixRemoveBorder
FPIX * fpixRemoveBorder ( FPIX *fpixs, l_int32 left, l_int32 right, l_int32 top, l_int32 bot )
fpixRemoveBorder()
Input: fpixs
left, right, top, bot (pixels on each side to be removed)
Return: fpixd, or null on errorfpixRotate180
FPIX * fpixRotate180 ( FPIX *fpixd, FPIX *fpixs )
fpixRotate180()
Input: fpixd (<optional>; can be null, equal to fpixs,
or different from fpixs)
fpixs
Return: fpixd, or null on error
Notes:
(1) This does a 180 rotation of the image about the center,
which is equivalent to a left-right flip about a vertical
line through the image center, followed by a top-bottom
flip about a horizontal line through the image center.
(2) There are 3 cases for input:
(a) fpixd == null (creates a new fpixd)
(b) fpixd == fpixs (in-place operation)
(c) fpixd != fpixs (existing fpixd)
(3) For clarity, use these three patterns, respectively:
(a) fpixd = fpixRotate180(NULL, fpixs);
(b) fpixRotate180(fpixs, fpixs);
(c) fpixRotate180(fpixd, fpixs);fpixRotate90
FPIX * fpixRotate90 ( FPIX *fpixs, l_int32 direction )
fpixRotate90()
Input: fpixs
direction (1 = clockwise, -1 = counter-clockwise)
Return: fpixd, or null on error
Notes:
(1) This does a 90 degree rotation of the image about the center,
either cw or ccw, returning a new pix.
(2) The direction must be either 1 (cw) or -1 (ccw).fpixRotateOrth
FPIX * fpixRotateOrth ( FPIX *fpixs, l_int32 quads )
fpixRotateOrth()
Input: fpixs
quads (0-3; number of 90 degree cw rotations)
Return: fpixd, or null on errorfpixScaleByInteger
FPIX * fpixScaleByInteger ( FPIX *fpixs, l_int32 factor )
fpixScaleByInteger()
Input: fpixs (low resolution, subsampled)
factor (scaling factor)
Return: fpixd (interpolated result), or null on error
Notes:
(1) The width wd of fpixd is related to ws of fpixs by:
wd = factor * (ws - 1) + 1 (and ditto for the height)
We avoid special-casing boundary pixels in the interpolation
by constructing fpixd by inserting (factor - 1) interpolated
pixels between each pixel in fpixs. Then
wd = ws + (ws - 1) * (factor - 1) (same as above)
This also has the advantage that if we subsample by @factor,
throwing out all the interpolated pixels, we regain the
original low resolution fpix.fpixSetAllArbitrary
l_int32 fpixSetAllArbitrary ( FPIX *fpix, l_float32 inval )
fpixSetAllArbitrary()
Input: fpix
val (to set at each pixel)
Return: 0 if OK, 1 on errorfpixThresholdToPix
PIX * fpixThresholdToPix ( FPIX *fpix, l_float32 thresh )
fpixThresholdToPix()
Input: fpix
thresh
Return: pixd (1 bpp), or null on error
Notes:
(1) For all values of fpix that are <= thresh, sets the pixel
in pixd to 1.linearInterpolatePixelFloat
l_int32 linearInterpolatePixelFloat ( l_float32 *datas, l_int32 w, l_int32 h, l_float32 x, l_float32 y, l_float32 inval, l_float32 *pval )
linearInterpolatePixelFloat()
Input: datas (ptr to beginning of float image data)
wpls (32-bit word/line for this data array)
w, h (of image)
x, y (floating pt location for evaluation)
inval (float value brought in from the outside when the
input x,y location is outside the image)
&val (<return> interpolated float value)
Return: 0 if OK, 1 on error
Notes:
(1) This is a standard linear interpolation function. It is
equivalent to area weighting on each component, and
avoids "jaggies" when rendering sharp edges.pixComponentFunction
FPIX * pixComponentFunction ( PIX *pix, l_float32 rnum, l_float32 gnum, l_float32 bnum, l_float32 rdenom, l_float32 gdenom, l_float32 bdenom )
pixComponentFunction()
Input: pix (32 bpp rgb)
rnum, gnum, bnum (coefficients for numerator)
rdenom, gdenom, bdenom (coefficients for denominator)
Return: fpixd, or null on error
Notes:
(1) This stores a function of the component values of each
input pixel in @fpixd.
(2) The function is a ratio of linear combinations of component values.
There are two special cases for denominator coefficients:
(a) The denominator is 1.0: input 0 for all denominator coefficients
(b) Only one component is used in the denominator: input 1.0
for that denominator component and 0.0 for the other two.
(3) If the denominator is 0, multiply by an arbitrary number that
is much larger than 1. Choose 256 "arbitrarily".pixConvertToDPix
DPIX * pixConvertToDPix ( PIX *pixs, l_int32 ncomps )
pixConvertToDPix()
Input: pix (1, 2, 4, 8, 16 or 32 bpp)
ncomps (number of components: 3 for RGB, 1 otherwise)
Return: dpix, or null on error
Notes:
(1) If colormapped, remove to grayscale.
(2) If 32 bpp and @ncomps == 3, this is RGB; convert to luminance.
In all other cases the src image is treated as having a single
component of pixel values.pixConvertToFPix
FPIX * pixConvertToFPix ( PIX *pixs, l_int32 ncomps )
pixConvertToFPix()
Input: pix (1, 2, 4, 8, 16 or 32 bpp)
ncomps (number of components: 3 for RGB, 1 otherwise)
Return: fpix, or null on error
Notes:
(1) If colormapped, remove to grayscale.
(2) If 32 bpp and @ncomps == 3, this is RGB; convert to luminance.
In all other cases the src image is treated as having a single
component of pixel values.AUTHOR
Zakariyya Mughal <zmughal@cpan.org>
COPYRIGHT AND LICENSE
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.