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Merge pull request #1609 from jeffrbig2/fix_coeffs
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Fix bug in coeff gen on more than 3x downsamples with w and h equal
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nothings authored Feb 13, 2024
2 parents b7cf124 + 2fb057a commit ae721c5
Showing 1 changed file with 39 additions and 21 deletions.
60 changes: 39 additions & 21 deletions stb_image_resize2.h
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
/* stb_image_resize2 - v2.05 - public domain image resizing
/* stb_image_resize2 - v2.06 - public domain image resizing
by Jeff Roberts (v2) and Jorge L Rodriguez
http://github.com/nothings/stb
Expand Down Expand Up @@ -328,7 +328,9 @@
Nathan Reed: warning fixes for 1.0
REVISIONS
2.05 (2024-02-24) fix for 2 pixel to 1 pixel resizes with wrap (thanks Aras)
2.06 (2024-02-10) fix for indentical width/height 3x or more down-scaling
undersampling a single row on rare resize ratios (about 1%)
2.05 (2024-02-07) fix for 2 pixel to 1 pixel resizes with wrap (thanks Aras)
fix for output callback (thanks Julien Koenen)
2.04 (2023-11-17) fix for rare AVX bug, shadowed symbol (thanks Nikola Smiljanic).
2.03 (2023-11-01) ASAN and TSAN warnings fixed, minor tweaks.
Expand Down Expand Up @@ -3394,6 +3396,12 @@ static void stbir__calculate_coefficients_for_gather_downsample( int start, int
}
}

#ifdef STBIR_RENORMALIZE_IN_FLOAT
#define STBIR_RENORM_TYPE float
#else
#define STBIR_RENORM_TYPE double
#endif

static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter_extent_info* filter_info, stbir__scale_info * scale_info, int num_contributors, stbir__contributors* contributors, float * coefficient_group, int coefficient_width )
{
int input_size = scale_info->input_full_size;
Expand All @@ -3415,14 +3423,14 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
for (n = 0; n < end; n++)
{
int i;
float filter_scale, total_filter = 0;
STBIR_RENORM_TYPE filter_scale, total_filter = 0;
int e;

// add all contribs
e = contribs->n1 - contribs->n0;
for( i = 0 ; i <= e ; i++ )
{
total_filter += coeffs[i];
total_filter += (STBIR_RENORM_TYPE) coeffs[i];
STBIR_ASSERT( ( coeffs[i] >= -2.0f ) && ( coeffs[i] <= 2.0f ) ); // check for wonky weights
}

Expand All @@ -3438,10 +3446,11 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
// if the total isn't 1.0, rescale everything
if ( ( total_filter < (1.0f-stbir__small_float) ) || ( total_filter > (1.0f+stbir__small_float) ) )
{
filter_scale = 1.0f / total_filter;
filter_scale = ((STBIR_RENORM_TYPE)1.0) / total_filter;

// scale them all
for (i = 0; i <= e; i++)
coeffs[i] *= filter_scale;
coeffs[i] = (float) ( coeffs[i] * filter_scale );
}
}
++contribs;
Expand Down Expand Up @@ -3562,6 +3571,8 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
filter_info->widest = widest;
}

#undef STBIR_RENORM_TYPE

static int stbir__pack_coefficients( int num_contributors, stbir__contributors* contributors, float * coefficents, int coefficient_width, int widest, int row0, int row1 )
{
#define STBIR_MOVE_1( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint32*)(dest))[0] = ((stbir_uint32*)(src))[0]; }
Expand Down Expand Up @@ -3869,26 +3880,33 @@ static void stbir__calculate_filters( stbir__sampler * samp, stbir__sampler * ot
for (k = gn0 ; k <= gn1 ; k++ )
{
float gc = *g_coeffs++;
if ( ( k > highest_set ) || ( scatter_contributors->n0 > scatter_contributors->n1 ) )

// skip zero and denormals - must skip zeros to avoid adding coeffs beyond scatter_coefficient_width
// (which happens when pivoting from horizontal, which might have dummy zeros)
if ( ( ( gc >= stbir__small_float ) || ( gc <= -stbir__small_float ) ) )
{
if ( ( k > highest_set ) || ( scatter_contributors->n0 > scatter_contributors->n1 ) )
{
// if we are skipping over several contributors, we need to clear the skipped ones
stbir__contributors * clear_contributors = samp->contributors + ( highest_set + filter_pixel_margin + 1);
while ( clear_contributors < scatter_contributors )
{
clear_contributors->n0 = 0;
clear_contributors->n1 = -1;
++clear_contributors;
// if we are skipping over several contributors, we need to clear the skipped ones
stbir__contributors * clear_contributors = samp->contributors + ( highest_set + filter_pixel_margin + 1);
while ( clear_contributors < scatter_contributors )
{
clear_contributors->n0 = 0;
clear_contributors->n1 = -1;
++clear_contributors;
}
}
scatter_contributors->n0 = n;
scatter_contributors->n1 = n;
scatter_coeffs[0] = gc;
highest_set = k;
}
scatter_contributors->n0 = n;
scatter_contributors->n1 = n;
scatter_coeffs[0] = gc;
highest_set = k;
}
else
{
stbir__insert_coeff( scatter_contributors, scatter_coeffs, n, gc );
else
{
stbir__insert_coeff( scatter_contributors, scatter_coeffs, n, gc );
}
STBIR_ASSERT( ( scatter_contributors->n1 - scatter_contributors->n0 + 1 ) <= scatter_coefficient_width );
}
++scatter_contributors;
scatter_coeffs += scatter_coefficient_width;
Expand Down

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