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make coefficients ints

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This commit is contained in:
homm 2016-05-03 12:23:16 +02:00
parent 342e6f213b
commit e13297b396
1 changed files with 37 additions and 45 deletions
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82
libImaging/Resample.c
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@ -38,8 +38,6 @@ static inline float lanczos_filter(float x)
return 0.0; return 0.0;
} }
static struct filter LANCZOS = { lanczos_filter, 3.0 };
static inline float bilinear_filter(float x) static inline float bilinear_filter(float x)
{ {
if (x < 0.0) if (x < 0.0)
@ -49,8 +47,6 @@ static inline float bilinear_filter(float x)
return 0.0; return 0.0;
} }
static struct filter BILINEAR = { bilinear_filter, 1.0 };
static inline float bicubic_filter(float x) static inline float bicubic_filter(float x)
{ {
/* https://en.wikipedia.org/wiki/Bicubic_interpolation#Bicubic_convolution_algorithm */ /* https://en.wikipedia.org/wiki/Bicubic_interpolation#Bicubic_convolution_algorithm */
@ -65,45 +61,41 @@ static inline float bicubic_filter(float x)
#undef a #undef a
} }
static struct filter LANCZOS = { lanczos_filter, 3.0 };
static struct filter BILINEAR = { bilinear_filter, 1.0 };
static struct filter BICUBIC = { bicubic_filter, 2.0 }; static struct filter BICUBIC = { bicubic_filter, 2.0 };
static inline UINT8 clip8(float in)
/* 8 bits for result. Filter can have negative areas.
In one cases the sum of the coefficients will be negative,
in the other it will be more than 1.0. That is why we need
two extra bits for overflow and int type. */
#define PRECISION_BITS (32 - 8 - 2)
static inline UINT8 clip8(int in)
{ {
int out = (int) in; if (in >= (1 << PRECISION_BITS << 8))
if (out >= 255)
return 255; return 255;
if (out <= 0) if (in <= 0)
return 0; return 0;
return (UINT8) out; return (UINT8) (in >> PRECISION_BITS);
} }
/* This is work around bug in GCC prior 4.9 in 64-bit mode.
GCC generates code with partial dependency which 3 times slower.
See: http://stackoverflow.com/a/26588074/253146 */
#if defined(__x86_64__) && defined(__SSE__) && ! defined(__NO_INLINE__) && \
! defined(__clang__) && defined(GCC_VERSION) && (GCC_VERSION < 40900)
static float __attribute__((always_inline)) i2f(int v) {
float x;
__asm__("xorps %0, %0; cvtsi2ss %1, %0" : "=X"(x) : "r"(v) );
return x;
}
#else
static float inline i2f(int v) { return (float) v; }
#endif
Imaging Imaging
ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp) ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
{ {
ImagingSectionCookie cookie; ImagingSectionCookie cookie;
Imaging imOut; Imaging imOut;
float support, scale, filterscale; float support, scale, filterscale;
float center, ww, ss, ss0, ss1, ss2, ss3; float center, ww, ss;
int ss0, ss1, ss2, ss3;
int xx, yy, x, kmax, xmin, xmax; int xx, yy, x, kmax, xmin, xmax;
int *xbounds; int *xbounds;
float *k, *kk, *kw; int *k, *kk;
float *kw;
/* prepare for horizontal stretch */ /* prepare for horizontal stretch */
filterscale = scale = (float) imIn->xsize / xsize; filterscale = scale = (float) imIn->xsize / xsize;
@ -118,7 +110,7 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
kmax = (int) ceil(support) * 2 + 1; kmax = (int) ceil(support) * 2 + 1;
// check for overflow // check for overflow
if (xsize > SIZE_MAX / (kmax * sizeof(float))) if (xsize > SIZE_MAX / (kmax * sizeof(int)))
return (Imaging) ImagingError_MemoryError(); return (Imaging) ImagingError_MemoryError();
// sizeof(int) should be greater than 0 as well // sizeof(int) should be greater than 0 as well
@ -126,7 +118,7 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
return (Imaging) ImagingError_MemoryError(); return (Imaging) ImagingError_MemoryError();
/* coefficient buffer */ /* coefficient buffer */
kk = malloc(xsize * kmax * sizeof(float)); kk = malloc(xsize * kmax * sizeof(int));
if ( ! kk) if ( ! kk)
return (Imaging) ImagingError_MemoryError(); return (Imaging) ImagingError_MemoryError();
@ -162,7 +154,7 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
k = &kk[xx * kmax]; k = &kk[xx * kmax];
for (x = 0; x < xmax - xmin; x++) { for (x = 0; x < xmax - xmin; x++) {
if (ww != 0.0) if (ww != 0.0)
k[x] = kw[x] / ww; k[x] = (int) floor(0.5 + kw[x] / ww * (1 << PRECISION_BITS));
} }
xbounds[xx * 2 + 0] = xmin; xbounds[xx * 2 + 0] = xmin;
xbounds[xx * 2 + 1] = xmax; xbounds[xx * 2 + 1] = xmax;
@ -186,10 +178,10 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
xmin = xbounds[xx * 2 + 0]; xmin = xbounds[xx * 2 + 0];
xmax = xbounds[xx * 2 + 1]; xmax = xbounds[xx * 2 + 1];
k = &kk[xx * kmax]; k = &kk[xx * kmax];
ss = 0.5; ss0 = 0;
for (x = xmin; x < xmax; x++) for (x = xmin; x < xmax; x++)
ss += i2f(imIn->image8[yy][x]) * k[x - xmin]; ss0 += ((UINT8) imIn->image8[yy][x]) * k[x - xmin];
imOut->image8[yy][xx] = clip8(ss); imOut->image8[yy][xx] = clip8(ss0);
} }
} else { } else {
switch(imIn->type) { switch(imIn->type) {
@ -200,10 +192,10 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
xmin = xbounds[xx * 2 + 0]; xmin = xbounds[xx * 2 + 0];
xmax = xbounds[xx * 2 + 1]; xmax = xbounds[xx * 2 + 1];
k = &kk[xx * kmax]; k = &kk[xx * kmax];
ss0 = ss1 = 0.5; ss0 = ss1 = 0;
for (x = xmin; x < xmax; x++) { for (x = xmin; x < xmax; x++) {
ss0 += i2f((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin]; ss0 += ((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin];
ss1 += i2f((UINT8) imIn->image[yy][x*4 + 3]) * k[x - xmin]; ss1 += ((UINT8) imIn->image[yy][x*4 + 3]) * k[x - xmin];
} }
imOut->image[yy][xx*4 + 0] = clip8(ss0); imOut->image[yy][xx*4 + 0] = clip8(ss0);
imOut->image[yy][xx*4 + 3] = clip8(ss1); imOut->image[yy][xx*4 + 3] = clip8(ss1);
@ -213,11 +205,11 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
xmin = xbounds[xx * 2 + 0]; xmin = xbounds[xx * 2 + 0];
xmax = xbounds[xx * 2 + 1]; xmax = xbounds[xx * 2 + 1];
k = &kk[xx * kmax]; k = &kk[xx * kmax];
ss0 = ss1 = ss2 = 0.5; ss0 = ss1 = ss2 = 0;
for (x = xmin; x < xmax; x++) { for (x = xmin; x < xmax; x++) {
ss0 += i2f((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin]; ss0 += ((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin];
ss1 += i2f((UINT8) imIn->image[yy][x*4 + 1]) * k[x - xmin]; ss1 += ((UINT8) imIn->image[yy][x*4 + 1]) * k[x - xmin];
ss2 += i2f((UINT8) imIn->image[yy][x*4 + 2]) * k[x - xmin]; ss2 += ((UINT8) imIn->image[yy][x*4 + 2]) * k[x - xmin];
} }
imOut->image[yy][xx*4 + 0] = clip8(ss0); imOut->image[yy][xx*4 + 0] = clip8(ss0);
imOut->image[yy][xx*4 + 1] = clip8(ss1); imOut->image[yy][xx*4 + 1] = clip8(ss1);
@ -228,12 +220,12 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
xmin = xbounds[xx * 2 + 0]; xmin = xbounds[xx * 2 + 0];
xmax = xbounds[xx * 2 + 1]; xmax = xbounds[xx * 2 + 1];
k = &kk[xx * kmax]; k = &kk[xx * kmax];
ss0 = ss1 = ss2 = ss3 = 0.5; ss0 = ss1 = ss2 = ss3 = 0;
for (x = xmin; x < xmax; x++) { for (x = xmin; x < xmax; x++) {
ss0 += i2f((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin]; ss0 += ((UINT8) imIn->image[yy][x*4 + 0]) * k[x - xmin];
ss1 += i2f((UINT8) imIn->image[yy][x*4 + 1]) * k[x - xmin]; ss1 += ((UINT8) imIn->image[yy][x*4 + 1]) * k[x - xmin];
ss2 += i2f((UINT8) imIn->image[yy][x*4 + 2]) * k[x - xmin]; ss2 += ((UINT8) imIn->image[yy][x*4 + 2]) * k[x - xmin];
ss3 += i2f((UINT8) imIn->image[yy][x*4 + 3]) * k[x - xmin]; ss3 += ((UINT8) imIn->image[yy][x*4 + 3]) * k[x - xmin];
} }
imOut->image[yy][xx*4 + 0] = clip8(ss0); imOut->image[yy][xx*4 + 0] = clip8(ss0);
imOut->image[yy][xx*4 + 1] = clip8(ss1); imOut->image[yy][xx*4 + 1] = clip8(ss1);
@ -250,7 +242,7 @@ ImagingResampleHorizontal(Imaging imIn, int xsize, struct filter *filterp)
k = &kk[xx * kmax]; k = &kk[xx * kmax];
ss = 0.0; ss = 0.0;
for (x = xmin; x < xmax; x++) for (x = xmin; x < xmax; x++)
ss += i2f(IMAGING_PIXEL_I(imIn, x, yy)) * k[x - xmin]; ss += (IMAGING_PIXEL_I(imIn, x, yy)) * k[x - xmin];
IMAGING_PIXEL_I(imOut, xx, yy) = (int) ss; IMAGING_PIXEL_I(imOut, xx, yy) = (int) ss;
} }
break; break;