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gd_interpolation.c
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/*
* The two pass scaling function is based on:
* Filtered Image Rescaling
* Based on Gems III
* - Schumacher general filtered image rescaling
* (pp. 414-424)
* by Dale Schumacher
*
* Additional changes by Ray Gardener, Daylon Graphics Ltd.
* December 4, 1999
*
* Ported to libgd by Pierre Joye. Support for multiple channels
* added (argb for now).
*
* Initial sources code is avaibable in the Gems Source Code Packages:
* http://www.acm.org/pubs/tog/GraphicsGems/GGemsIII.tar.gz
*
*/
/*
Summary:
- Horizontal filter contributions are calculated on the fly,
as each column is mapped from src to dst image. This lets
us omit having to allocate a temporary full horizontal stretch
of the src image.
- If none of the src pixels within a sampling region differ,
then the output pixel is forced to equal (any of) the source pixel.
This ensures that filters do not corrupt areas of constant color.
- Filter weight contribution results, after summing, are
rounded to the nearest pixel color value instead of
being casted to ILubyte (usually an int or char). Otherwise,
artifacting occurs.
*/
/*
Additional functions are available for simple rotation or up/downscaling.
downscaling using the fixed point implementations are usually much faster
than the existing gdImageCopyResampled while having a similar or better
quality.
For image rotations, the optimized versions have a lazy antialiasing for
the edges of the images. For a much better antialiased result, the affine
function is recommended.
*/
/*
TODO:
- Optimize pixel accesses and loops once we have continuous buffer
- Add scale support for a portion only of an image (equivalent of copyresized/resampled)
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <gd.h>
#include "gdhelpers.h"
#ifdef _MSC_VER
# pragma optimize("t", on)
# include <emmintrin.h>
#endif
#ifndef HAVE_FLOORF
# define HAVE_FLOORF 0
#endif
#if HAVE_FLOORF == 0
# ifndef floorf
/* float floorf(float x);*/
# define floorf(x) ((float)(floor(x)))
# endif
#endif
#ifndef MIN
#define MIN(a,b) ((a)<(b)?(a):(b))
#endif
#define MIN3(a,b,c) ((a)<(b)?(MIN(a,c)):(MIN(b,c)))
#ifndef MAX
#define MAX(a,b) ((a)<(b)?(b):(a))
#endif
#define MAX3(a,b,c) ((a)<(b)?(MAX(b,c)):(MAX(a,c)))
#define CLAMP(x, low, high) (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
/* only used here, let do a generic fixed point integers later if required by other
part of GD */
typedef long gdFixed;
/* Integer to fixed point */
#define gd_itofx(x) (long)((unsigned long)(x) << 8)
/* Float to fixed point */
#define gd_ftofx(x) (long)((x) * 256)
/* Double to fixed point */
#define gd_dtofx(x) (long)((x) * 256)
/* Fixed point to integer */
#define gd_fxtoi(x) ((x) >> 8)
/* Fixed point to float */
# define gd_fxtof(x) ((float)(x) / 256)
/* Fixed point to double */
#define gd_fxtod(x) ((double)(x) / 256)
/* Multiply a fixed by a fixed */
#define gd_mulfx(x,y) (((x) * (y)) >> 8)
/* Divide a fixed by a fixed */
#define gd_divfx(x,y) ((long)((unsigned long)(x) << 8) / (y))
typedef struct
{
double *Weights; /* Normalized weights of neighboring pixels */
int Left,Right; /* Bounds of source pixels window */
} ContributionType; /* Contirbution information for a single pixel */
typedef struct
{
ContributionType *ContribRow; /* Row (or column) of contribution weights */
unsigned int WindowSize, /* Filter window size (of affecting source pixels) */
LineLength; /* Length of line (no. or rows / cols) */
} LineContribType;
/* Each core filter has its own radius */
#define DEFAULT_FILTER_BICUBIC 3.0
#define DEFAULT_FILTER_BOX 0.5
#define DEFAULT_FILTER_GENERALIZED_CUBIC 0.5
#define DEFAULT_FILTER_RADIUS 1.0
#define DEFAULT_LANCZOS8_RADIUS 8.0
#define DEFAULT_LANCZOS3_RADIUS 3.0
#define DEFAULT_HERMITE_RADIUS 1.0
#define DEFAULT_BOX_RADIUS 0.5
#define DEFAULT_TRIANGLE_RADIUS 1.0
#define DEFAULT_BELL_RADIUS 1.5
#define DEFAULT_CUBICSPLINE_RADIUS 2.0
#define DEFAULT_MITCHELL_RADIUS 2.0
#define DEFAULT_COSINE_RADIUS 1.0
#define DEFAULT_CATMULLROM_RADIUS 2.0
#define DEFAULT_QUADRATIC_RADIUS 1.5
#define DEFAULT_QUADRATICBSPLINE_RADIUS 1.5
#define DEFAULT_CUBICCONVOLUTION_RADIUS 3.0
#define DEFAULT_GAUSSIAN_RADIUS 1.0
#define DEFAULT_HANNING_RADIUS 1.0
#define DEFAULT_HAMMING_RADIUS 1.0
#define DEFAULT_SINC_RADIUS 1.0
#define DEFAULT_WELSH_RADIUS 1.0
enum GD_RESIZE_FILTER_TYPE{
FILTER_DEFAULT = 0,
FILTER_BELL,
FILTER_BESSEL,
FILTER_BLACKMAN,
FILTER_BOX,
FILTER_BSPLINE,
FILTER_CATMULLROM,
FILTER_COSINE,
FILTER_CUBICCONVOLUTION,
FILTER_CUBICSPLINE,
FILTER_HERMITE,
FILTER_LANCZOS3,
FILTER_LANCZOS8,
FILTER_MITCHELL,
FILTER_QUADRATIC,
FILTER_QUADRATICBSPLINE,
FILTER_TRIANGLE,
FILTER_GAUSSIAN,
FILTER_HANNING,
FILTER_HAMMING,
FILTER_SINC,
FILTER_WELSH,
FILTER_CALLBACK = 999
};
typedef enum GD_RESIZE_FILTER_TYPE gdResizeFilterType;
static double KernelBessel_J1(const double x)
{
double p, q;
register long i;
static const double
Pone[] =
{
0.581199354001606143928050809e+21,
-0.6672106568924916298020941484e+20,
0.2316433580634002297931815435e+19,
-0.3588817569910106050743641413e+17,
0.2908795263834775409737601689e+15,
-0.1322983480332126453125473247e+13,
0.3413234182301700539091292655e+10,
-0.4695753530642995859767162166e+7,
0.270112271089232341485679099e+4
},
Qone[] =
{
0.11623987080032122878585294e+22,
0.1185770712190320999837113348e+20,
0.6092061398917521746105196863e+17,
0.2081661221307607351240184229e+15,
0.5243710262167649715406728642e+12,
0.1013863514358673989967045588e+10,
0.1501793594998585505921097578e+7,
0.1606931573481487801970916749e+4,
0.1e+1
};
p = Pone[8];
q = Qone[8];
for (i=7; i >= 0; i--)
{
p = p*x*x+Pone[i];
q = q*x*x+Qone[i];
}
return (double)(p/q);
}
static double KernelBessel_P1(const double x)
{
double p, q;
register long i;
static const double
Pone[] =
{
0.352246649133679798341724373e+5,
0.62758845247161281269005675e+5,
0.313539631109159574238669888e+5,
0.49854832060594338434500455e+4,
0.2111529182853962382105718e+3,
0.12571716929145341558495e+1
},
Qone[] =
{
0.352246649133679798068390431e+5,
0.626943469593560511888833731e+5,
0.312404063819041039923015703e+5,
0.4930396490181088979386097e+4,
0.2030775189134759322293574e+3,
0.1e+1
};
p = Pone[5];
q = Qone[5];
for (i=4; i >= 0; i--)
{
p = p*(8.0/x)*(8.0/x)+Pone[i];
q = q*(8.0/x)*(8.0/x)+Qone[i];
}
return (double)(p/q);
}
static double KernelBessel_Q1(const double x)
{
double p, q;
register long i;
static const double
Pone[] =
{
0.3511751914303552822533318e+3,
0.7210391804904475039280863e+3,
0.4259873011654442389886993e+3,
0.831898957673850827325226e+2,
0.45681716295512267064405e+1,
0.3532840052740123642735e-1
},
Qone[] =
{
0.74917374171809127714519505e+4,
0.154141773392650970499848051e+5,
0.91522317015169922705904727e+4,
0.18111867005523513506724158e+4,
0.1038187585462133728776636e+3,
0.1e+1
};
p = Pone[5];
q = Qone[5];
for (i=4; i >= 0; i--)
{
p = p*(8.0/x)*(8.0/x)+Pone[i];
q = q*(8.0/x)*(8.0/x)+Qone[i];
}
return (double)(p/q);
}
static double KernelBessel_Order1(double x)
{
double p, q;
if (x == 0.0)
return (0.0f);
p = x;
if (x < 0.0)
x=(-x);
if (x < 8.0)
return (p*KernelBessel_J1(x));
q = (double)sqrt(2.0f/(M_PI*x))*(double)(KernelBessel_P1(x)*(1.0f/sqrt(2.0f)*(sin(x)-cos(x)))-8.0f/x*KernelBessel_Q1(x)*
(-1.0f/sqrt(2.0f)*(sin(x)+cos(x))));
if (p < 0.0f)
q = (-q);
return (q);
}
static double filter_bessel(const double x)
{
if (x == 0.0f)
return (double)(M_PI/4.0f);
return (KernelBessel_Order1((double)M_PI*x)/(2.0f*x));
}
static double filter_blackman(const double x)
{
return (0.42f+0.5f*(double)cos(M_PI*x)+0.08f*(double)cos(2.0f*M_PI*x));
}
/**
* Bicubic interpolation kernel (a=-1):
\verbatim
/
| 1-2|t|**2+|t|**3 , if |t| < 1
h(t) = | 4-8|t|+5|t|**2-|t|**3 , if 1<=|t|<2
| 0 , otherwise
\
\endverbatim
* ***bd*** 2.2004
*/
static double filter_bicubic(const double t)
{
const double abs_t = (double)fabs(t);
const double abs_t_sq = abs_t * abs_t;
if (abs_t<1) return 1-2*abs_t_sq+abs_t_sq*abs_t;
if (abs_t<2) return 4 - 8*abs_t +5*abs_t_sq - abs_t_sq*abs_t;
return 0;
}
/**
* Generalized cubic kernel (for a=-1 it is the same as BicubicKernel):
\verbatim
/
| (a+2)|t|**3 - (a+3)|t|**2 + 1 , |t| <= 1
h(t) = | a|t|**3 - 5a|t|**2 + 8a|t| - 4a , 1 < |t| <= 2
| 0 , otherwise
\
\endverbatim
* Often used values for a are -1 and -1/2.
*/
static double filter_generalized_cubic(const double t)
{
const double a = -DEFAULT_FILTER_GENERALIZED_CUBIC;
double abs_t = (double)fabs(t);
double abs_t_sq = abs_t * abs_t;
if (abs_t < 1) return (a + 2) * abs_t_sq * abs_t - (a + 3) * abs_t_sq + 1;
if (abs_t < 2) return a * abs_t_sq * abs_t - 5 * a * abs_t_sq + 8 * a * abs_t - 4 * a;
return 0;
}
#ifdef FUNCTION_NOT_USED_YET
/* CubicSpline filter, default radius 2 */
static double filter_cubic_spline(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x < 1.0 ) {
const double x2 = x*x;
return (0.5 * x2 * x - x2 + 2.0 / 3.0);
}
if (x < 2.0) {
return (pow(2.0 - x, 3.0)/6.0);
}
return 0;
}
#endif
#ifdef FUNCTION_NOT_USED_YET
/* CubicConvolution filter, default radius 3 */
static double filter_cubic_convolution(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
const double x2 = x1 * x1;
const double x2_x = x2 * x;
if (x <= 1.0) return ((4.0 / 3.0)* x2_x - (7.0 / 3.0) * x2 + 1.0);
if (x <= 2.0) return (- (7.0 / 12.0) * x2_x + 3 * x2 - (59.0 / 12.0) * x + 2.5);
if (x <= 3.0) return ( (1.0/12.0) * x2_x - (2.0 / 3.0) * x2 + 1.75 * x - 1.5);
return 0;
}
#endif
static double filter_box(double x) {
if (x < - DEFAULT_FILTER_BOX)
return 0.0f;
if (x < DEFAULT_FILTER_BOX)
return 1.0f;
return 0.0f;
}
static double filter_catmullrom(const double x)
{
if (x < -2.0)
return(0.0f);
if (x < -1.0)
return(0.5f*(4.0f+x*(8.0f+x*(5.0f+x))));
if (x < 0.0)
return(0.5f*(2.0f+x*x*(-5.0f-3.0f*x)));
if (x < 1.0)
return(0.5f*(2.0f+x*x*(-5.0f+3.0f*x)));
if (x < 2.0)
return(0.5f*(4.0f+x*(-8.0f+x*(5.0f-x))));
return(0.0f);
}
#ifdef FUNCTION_NOT_USED_YET
static double filter_filter(double t)
{
/* f(t) = 2|t|^3 - 3|t|^2 + 1, -1 <= t <= 1 */
if(t < 0.0) t = -t;
if(t < 1.0) return((2.0 * t - 3.0) * t * t + 1.0);
return(0.0);
}
#endif
#ifdef FUNCTION_NOT_USED_YET
/* Lanczos8 filter, default radius 8 */
static double filter_lanczos8(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
#define R DEFAULT_LANCZOS8_RADIUS
if ( x == 0.0) return 1;
if ( x < R) {
return R * sin(x*M_PI) * sin(x * M_PI/ R) / (x * M_PI * x * M_PI);
}
return 0.0;
#undef R
}
#endif
#ifdef FUNCTION_NOT_USED_YET
/* Lanczos3 filter, default radius 3 */
static double filter_lanczos3(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
#define R DEFAULT_LANCZOS3_RADIUS
if ( x == 0.0) return 1;
if ( x < R)
{
return R * sin(x*M_PI) * sin(x * M_PI / R) / (x * M_PI * x * M_PI);
}
return 0.0;
#undef R
}
#endif
/* Hermite filter, default radius 1 */
static double filter_hermite(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x < 1.0) return ((2.0 * x - 3) * x * x + 1.0 );
return 0.0;
}
/* Trangle filter, default radius 1 */
static double filter_triangle(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x < 1.0) return (1.0 - x);
return 0.0;
}
/* Bell filter, default radius 1.5 */
static double filter_bell(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x < 0.5) return (0.75 - x*x);
if (x < 1.5) return (0.5 * pow(x - 1.5, 2.0));
return 0.0;
}
/* Mitchell filter, default radius 2.0 */
static double filter_mitchell(const double x)
{
#define KM_B (1.0f/3.0f)
#define KM_C (1.0f/3.0f)
#define KM_P0 (( 6.0f - 2.0f * KM_B ) / 6.0f)
#define KM_P2 ((-18.0f + 12.0f * KM_B + 6.0f * KM_C) / 6.0f)
#define KM_P3 (( 12.0f - 9.0f * KM_B - 6.0f * KM_C) / 6.0f)
#define KM_Q0 (( 8.0f * KM_B + 24.0f * KM_C) / 6.0f)
#define KM_Q1 ((-12.0f * KM_B - 48.0f * KM_C) / 6.0f)
#define KM_Q2 (( 6.0f * KM_B + 30.0f * KM_C) / 6.0f)
#define KM_Q3 (( -1.0f * KM_B - 6.0f * KM_C) / 6.0f)
if (x < -2.0)
return(0.0f);
if (x < -1.0)
return(KM_Q0-x*(KM_Q1-x*(KM_Q2-x*KM_Q3)));
if (x < 0.0f)
return(KM_P0+x*x*(KM_P2-x*KM_P3));
if (x < 1.0f)
return(KM_P0+x*x*(KM_P2+x*KM_P3));
if (x < 2.0f)
return(KM_Q0+x*(KM_Q1+x*(KM_Q2+x*KM_Q3)));
return(0.0f);
}
#ifdef FUNCTION_NOT_USED_YET
/* Cosine filter, default radius 1 */
static double filter_cosine(const double x)
{
if ((x >= -1.0) && (x <= 1.0)) return ((cos(x * M_PI) + 1.0)/2.0);
return 0;
}
#endif
/* Quadratic filter, default radius 1.5 */
static double filter_quadratic(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x <= 0.5) return (- 2.0 * x * x + 1);
if (x <= 1.5) return (x * x - 2.5* x + 1.5);
return 0.0;
}
static double filter_bspline(const double x)
{
if (x>2.0f) {
return 0.0f;
} else {
double a, b, c, d;
/* Was calculated anyway cause the "if((x-1.0f) < 0)" */
const double xm1 = x - 1.0f;
const double xp1 = x + 1.0f;
const double xp2 = x + 2.0f;
if ((xp2) <= 0.0f) a = 0.0f; else a = xp2*xp2*xp2;
if ((xp1) <= 0.0f) b = 0.0f; else b = xp1*xp1*xp1;
if (x <= 0) c = 0.0f; else c = x*x*x;
if ((xm1) <= 0.0f) d = 0.0f; else d = xm1*xm1*xm1;
return (0.16666666666666666667f * (a - (4.0f * b) + (6.0f * c) - (4.0f * d)));
}
}
#ifdef FUNCTION_NOT_USED_YET
/* QuadraticBSpline filter, default radius 1.5 */
static double filter_quadratic_bspline(const double x1)
{
const double x = x1 < 0.0 ? -x1 : x1;
if (x <= 0.5) return (- x * x + 0.75);
if (x <= 1.5) return (0.5 * x * x - 1.5 * x + 1.125);
return 0.0;
}
#endif
static double filter_gaussian(const double x)
{
/* return(exp((double) (-2.0 * x * x)) * sqrt(2.0 / M_PI)); */
return (double)(exp(-2.0f * x * x) * 0.79788456080287f);
}
static double filter_hanning(const double x)
{
/* A Cosine windowing function */
return(0.5 + 0.5 * cos(M_PI * x));
}
static double filter_hamming(const double x)
{
/* should be
(0.54+0.46*cos(M_PI*(double) x));
but this approximation is sufficient */
if (x < -1.0f)
return 0.0f;
if (x < 0.0f)
return 0.92f*(-2.0f*x-3.0f)*x*x+1.0f;
if (x < 1.0f)
return 0.92f*(2.0f*x-3.0f)*x*x+1.0f;
return 0.0f;
}
static double filter_power(const double x)
{
const double a = 2.0f;
if (fabs(x)>1) return 0.0f;
return (1.0f - (double)fabs(pow(x,a)));
}
static double filter_sinc(const double x)
{
/* X-scaled Sinc(x) function. */
if (x == 0.0) return(1.0);
return (sin(M_PI * (double) x) / (M_PI * (double) x));
}
#ifdef FUNCTION_NOT_USED_YET
static double filter_welsh(const double x)
{
/* Welsh parabolic windowing filter */
if (x < 1.0)
return(1 - x*x);
return(0.0);
}
#endif
/* Copied from upstream's libgd */
static inline int _color_blend (const int dst, const int src)
{
const int src_alpha = gdTrueColorGetAlpha(src);
if( src_alpha == gdAlphaOpaque ) {
return src;
} else {
const int dst_alpha = gdTrueColorGetAlpha(dst);
if( src_alpha == gdAlphaTransparent ) return dst;
if( dst_alpha == gdAlphaTransparent ) {
return src;
} else {
register int alpha, red, green, blue;
const int src_weight = gdAlphaTransparent - src_alpha;
const int dst_weight = (gdAlphaTransparent - dst_alpha) * src_alpha / gdAlphaMax;
const int tot_weight = src_weight + dst_weight;
alpha = src_alpha * dst_alpha / gdAlphaMax;
red = (gdTrueColorGetRed(src) * src_weight
+ gdTrueColorGetRed(dst) * dst_weight) / tot_weight;
green = (gdTrueColorGetGreen(src) * src_weight
+ gdTrueColorGetGreen(dst) * dst_weight) / tot_weight;
blue = (gdTrueColorGetBlue(src) * src_weight
+ gdTrueColorGetBlue(dst) * dst_weight) / tot_weight;
return ((alpha << 24) + (red << 16) + (green << 8) + blue);
}
}
}
static inline int getPixelOverflowTC(gdImagePtr im, const int x, const int y, const int bgColor)
{
if (gdImageBoundsSafe(im, x, y)) {
const int c = im->tpixels[y][x];
if (c == im->transparent) {
return bgColor == -1 ? gdTrueColorAlpha(0, 0, 0, 127) : bgColor;
}
return c;
} else {
return bgColor;
}
}
#define colorIndex2RGBA(c) gdTrueColorAlpha(im->red[(c)], im->green[(c)], im->blue[(c)], im->alpha[(c)])
#define colorIndex2RGBcustomA(c, a) gdTrueColorAlpha(im->red[(c)], im->green[(c)], im->blue[(c)], im->alpha[(a)])
static inline int getPixelOverflowPalette(gdImagePtr im, const int x, const int y, const int bgColor)
{
if (gdImageBoundsSafe(im, x, y)) {
const int c = im->pixels[y][x];
if (c == im->transparent) {
return bgColor == -1 ? gdTrueColorAlpha(0, 0, 0, 127) : bgColor;
}
return colorIndex2RGBA(c);
} else {
return bgColor;
}
}
static int getPixelInterpolateWeight(gdImagePtr im, const double x, const double y, const int bgColor)
{
/* Closest pixel <= (xf,yf) */
int sx = (int)(x);
int sy = (int)(y);
const double xf = x - (double)sx;
const double yf = y - (double)sy;
const double nxf = (double) 1.0 - xf;
const double nyf = (double) 1.0 - yf;
const double m1 = xf * yf;
const double m2 = nxf * yf;
const double m3 = xf * nyf;
const double m4 = nxf * nyf;
/* get color values of neighbouring pixels */
const int c1 = im->trueColor == 1 ? getPixelOverflowTC(im, sx, sy, bgColor) : getPixelOverflowPalette(im, sx, sy, bgColor);
const int c2 = im->trueColor == 1 ? getPixelOverflowTC(im, sx - 1, sy, bgColor) : getPixelOverflowPalette(im, sx - 1, sy, bgColor);
const int c3 = im->trueColor == 1 ? getPixelOverflowTC(im, sx, sy - 1, bgColor) : getPixelOverflowPalette(im, sx, sy - 1, bgColor);
const int c4 = im->trueColor == 1 ? getPixelOverflowTC(im, sx - 1, sy - 1, bgColor) : getPixelOverflowPalette(im, sx, sy - 1, bgColor);
int r, g, b, a;
if (x < 0) sx--;
if (y < 0) sy--;
/* component-wise summing-up of color values */
if (im->trueColor) {
r = (int)(m1*gdTrueColorGetRed(c1) + m2*gdTrueColorGetRed(c2) + m3*gdTrueColorGetRed(c3) + m4*gdTrueColorGetRed(c4));
g = (int)(m1*gdTrueColorGetGreen(c1) + m2*gdTrueColorGetGreen(c2) + m3*gdTrueColorGetGreen(c3) + m4*gdTrueColorGetGreen(c4));
b = (int)(m1*gdTrueColorGetBlue(c1) + m2*gdTrueColorGetBlue(c2) + m3*gdTrueColorGetBlue(c3) + m4*gdTrueColorGetBlue(c4));
a = (int)(m1*gdTrueColorGetAlpha(c1) + m2*gdTrueColorGetAlpha(c2) + m3*gdTrueColorGetAlpha(c3) + m4*gdTrueColorGetAlpha(c4));
} else {
r = (int)(m1*im->red[(c1)] + m2*im->red[(c2)] + m3*im->red[(c3)] + m4*im->red[(c4)]);
g = (int)(m1*im->green[(c1)] + m2*im->green[(c2)] + m3*im->green[(c3)] + m4*im->green[(c4)]);
b = (int)(m1*im->blue[(c1)] + m2*im->blue[(c2)] + m3*im->blue[(c3)] + m4*im->blue[(c4)]);
a = (int)(m1*im->alpha[(c1)] + m2*im->alpha[(c2)] + m3*im->alpha[(c3)] + m4*im->alpha[(c4)]);
}
r = CLAMP(r, 0, 255);
g = CLAMP(g, 0, 255);
b = CLAMP(b, 0, 255);
a = CLAMP(a, 0, gdAlphaMax);
return gdTrueColorAlpha(r, g, b, a);
}
/**
* Function: getPixelInterpolated
* Returns the interpolated color value using the default interpolation
* method. The returned color is always in the ARGB format (truecolor).
*
* Parameters:
* im - Image to set the default interpolation method
* y - X value of the ideal position
* y - Y value of the ideal position
* method - Interpolation method <gdInterpolationMethod>
*
* Returns:
* GD_TRUE if the affine is rectilinear or GD_FALSE
*
* See also:
* <gdSetInterpolationMethod>
*/
int getPixelInterpolated(gdImagePtr im, const double x, const double y, const int bgColor)
{
const int xi=(int)((x) < 0 ? x - 1: x);
const int yi=(int)((y) < 0 ? y - 1: y);
int yii;
int i;
double kernel, kernel_cache_y;
double kernel_x[12], kernel_y[4];
double new_r = 0.0f, new_g = 0.0f, new_b = 0.0f, new_a = 0.0f;
/* These methods use special implementations */
if (im->interpolation_id == GD_BILINEAR_FIXED || im->interpolation_id == GD_BICUBIC_FIXED || im->interpolation_id == GD_NEAREST_NEIGHBOUR) {
return -1;
}
if (im->interpolation_id == GD_WEIGHTED4) {
return getPixelInterpolateWeight(im, x, y, bgColor);
}
if (im->interpolation_id == GD_NEAREST_NEIGHBOUR) {
if (im->trueColor == 1) {
return getPixelOverflowTC(im, xi, yi, bgColor);
} else {
return getPixelOverflowPalette(im, xi, yi, bgColor);
}
}
if (im->interpolation) {
for (i=0; i<4; i++) {
kernel_x[i] = (double) im->interpolation((double)(xi+i-1-x));
kernel_y[i] = (double) im->interpolation((double)(yi+i-1-y));
}
} else {
return -1;
}
/*
* TODO: use the known fast rgba multiplication implementation once
* the new formats are in place
*/
for (yii = yi-1; yii < yi+3; yii++) {
int xii;
kernel_cache_y = kernel_y[yii-(yi-1)];
if (im->trueColor) {
for (xii=xi-1; xii<xi+3; xii++) {
const int rgbs = getPixelOverflowTC(im, xii, yii, bgColor);
kernel = kernel_cache_y * kernel_x[xii-(xi-1)];
new_r += kernel * gdTrueColorGetRed(rgbs);
new_g += kernel * gdTrueColorGetGreen(rgbs);
new_b += kernel * gdTrueColorGetBlue(rgbs);
new_a += kernel * gdTrueColorGetAlpha(rgbs);
}
} else {
for (xii=xi-1; xii<xi+3; xii++) {
const int rgbs = getPixelOverflowPalette(im, xii, yii, bgColor);
kernel = kernel_cache_y * kernel_x[xii-(xi-1)];
new_r += kernel * gdTrueColorGetRed(rgbs);
new_g += kernel * gdTrueColorGetGreen(rgbs);
new_b += kernel * gdTrueColorGetBlue(rgbs);
new_a += kernel * gdTrueColorGetAlpha(rgbs);
}
}
}
new_r = CLAMP(new_r, 0, 255);
new_g = CLAMP(new_g, 0, 255);
new_b = CLAMP(new_b, 0, 255);
new_a = CLAMP(new_a, 0, gdAlphaMax);
return gdTrueColorAlpha(((int)new_r), ((int)new_g), ((int)new_b), ((int)new_a));
}
static inline LineContribType * _gdContributionsAlloc(unsigned int line_length, unsigned int windows_size)
{
unsigned int u = 0;
LineContribType *res;
size_t weights_size;
if (overflow2(windows_size, sizeof(double))) {
return NULL;
} else {
weights_size = windows_size * sizeof(double);
}
res = (LineContribType *) gdMalloc(sizeof(LineContribType));
if (!res) {
return NULL;
}
res->WindowSize = windows_size;
res->LineLength = line_length;
if (overflow2(line_length, sizeof(ContributionType))) {
gdFree(res);
return NULL;
}
res->ContribRow = (ContributionType *) gdMalloc(line_length * sizeof(ContributionType));
if (res->ContribRow == NULL) {
gdFree(res);
return NULL;
}
for (u = 0 ; u < line_length ; u++) {
res->ContribRow[u].Weights = (double *) gdMalloc(weights_size);
if (res->ContribRow[u].Weights == NULL) {
unsigned int i;
for (i=0;i<u;i++) {
gdFree(res->ContribRow[i].Weights);
}
gdFree(res->ContribRow);
gdFree(res);
return NULL;
}
}
return res;
}
static inline void _gdContributionsFree(LineContribType * p)
{
unsigned int u;
for (u = 0; u < p->LineLength; u++) {
gdFree(p->ContribRow[u].Weights);
}
gdFree(p->ContribRow);
gdFree(p);
}
static inline LineContribType *_gdContributionsCalc(unsigned int line_size, unsigned int src_size, double scale_d, const interpolation_method pFilter)
{
double width_d;
double scale_f_d = 1.0;
const double filter_width_d = DEFAULT_BOX_RADIUS;
int windows_size;
unsigned int u;
LineContribType *res;
if (scale_d < 1.0) {
width_d = filter_width_d / scale_d;
scale_f_d = scale_d;
} else {
width_d= filter_width_d;
}
windows_size = 2 * (int)ceil(width_d) + 1;
res = _gdContributionsAlloc(line_size, windows_size);
if (res == NULL) {
return NULL;
}
for (u = 0; u < line_size; u++) {
const double dCenter = (double)u / scale_d;
/* get the significant edge points affecting the pixel */
register int iLeft = MAX(0, (int)floor (dCenter - width_d));
int iRight = MIN((int)ceil(dCenter + width_d), (int)src_size - 1);
double dTotalWeight = 0.0;
int iSrc;
/* Cut edge points to fit in filter window in case of spill-off */
if (iRight - iLeft + 1 > windows_size) {
if (iLeft < ((int)src_size - 1 / 2)) {
iLeft++;
} else {
iRight--;
}
}
res->ContribRow[u].Left = iLeft;
res->ContribRow[u].Right = iRight;
for (iSrc = iLeft; iSrc <= iRight; iSrc++) {
dTotalWeight += (res->ContribRow[u].Weights[iSrc-iLeft] = scale_f_d * (*pFilter)(scale_f_d * (dCenter - (double)iSrc)));
}
if (dTotalWeight < 0.0) {
_gdContributionsFree(res);
return NULL;
}
if (dTotalWeight > 0.0) {
for (iSrc = iLeft; iSrc <= iRight; iSrc++) {
res->ContribRow[u].Weights[iSrc-iLeft] /= dTotalWeight;
}
}
}
return res;
}
static inline void _gdScaleRow(gdImagePtr pSrc, unsigned int src_width, gdImagePtr dst, unsigned int dst_width, unsigned int row, LineContribType *contrib)
{
int *p_src_row = pSrc->tpixels[row];
int *p_dst_row = dst->tpixels[row];
unsigned int x;
for (x = 0; x < dst_width - 1; x++) {
register unsigned char r = 0, g = 0, b = 0, a = 0;
const int left = contrib->ContribRow[x].Left;
const int right = contrib->ContribRow[x].Right;
int i;
/* Accumulate each channel */
for (i = left; i <= right; i++) {
const int left_channel = i - left;
r += (unsigned char)(contrib->ContribRow[x].Weights[left_channel] * (double)(gdTrueColorGetRed(p_src_row[i])));
g += (unsigned char)(contrib->ContribRow[x].Weights[left_channel] * (double)(gdTrueColorGetGreen(p_src_row[i])));
b += (unsigned char)(contrib->ContribRow[x].Weights[left_channel] * (double)(gdTrueColorGetBlue(p_src_row[i])));
a += (unsigned char)(contrib->ContribRow[x].Weights[left_channel] * (double)(gdTrueColorGetAlpha(p_src_row[i])));
}
p_dst_row[x] = gdTrueColorAlpha(r, g, b, a);
}
}
static inline int _gdScaleHoriz(gdImagePtr pSrc, unsigned int src_width, unsigned int src_height, gdImagePtr pDst, unsigned int dst_width, unsigned int dst_height)
{
unsigned int u;
LineContribType * contrib;
/* same width, just copy it */
if (dst_width == src_width) {
unsigned int y;
for (y = 0; y < src_height - 1; ++y) {
memcpy(pDst->tpixels[y], pSrc->tpixels[y], src_width);
}
}
contrib = _gdContributionsCalc(dst_width, src_width, (double)dst_width / (double)src_width, pSrc->interpolation);
if (contrib == NULL) {
return 0;
}
/* Scale each row */
for (u = 0; u < dst_height - 1; u++) {
_gdScaleRow(pSrc, src_width, pDst, dst_width, u, contrib);
}
_gdContributionsFree (contrib);
return 1;
}
static inline void _gdScaleCol (gdImagePtr pSrc, unsigned int src_width, gdImagePtr pRes, unsigned int dst_width, unsigned int dst_height, unsigned int uCol, LineContribType *contrib)
{
unsigned int y;
for (y = 0; y < dst_height - 1; y++) {
register unsigned char r = 0, g = 0, b = 0, a = 0;
const int iLeft = contrib->ContribRow[y].Left;
const int iRight = contrib->ContribRow[y].Right;
int i;
/* Accumulate each channel */
for (i = iLeft; i <= iRight; i++) {
const int pCurSrc = pSrc->tpixels[i][uCol];
const int i_iLeft = i - iLeft;
r += (unsigned char)(contrib->ContribRow[y].Weights[i_iLeft] * (double)(gdTrueColorGetRed(pCurSrc)));
g += (unsigned char)(contrib->ContribRow[y].Weights[i_iLeft] * (double)(gdTrueColorGetGreen(pCurSrc)));
b += (unsigned char)(contrib->ContribRow[y].Weights[i_iLeft] * (double)(gdTrueColorGetBlue(pCurSrc)));
a += (unsigned char)(contrib->ContribRow[y].Weights[i_iLeft] * (double)(gdTrueColorGetAlpha(pCurSrc)));
}
pRes->tpixels[y][uCol] = gdTrueColorAlpha(r, g, b, a);