X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=qemu%2Fpixman%2Fpixman%2Fpixman-filter.c;fp=qemu%2Fpixman%2Fpixman%2Fpixman-filter.c;h=b2bf53fed147b7cffab3c74f8922376ceac14977;hb=e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb;hp=0000000000000000000000000000000000000000;hpb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;p=kvmfornfv.git diff --git a/qemu/pixman/pixman/pixman-filter.c b/qemu/pixman/pixman/pixman-filter.c new file mode 100644 index 000000000..b2bf53fed --- /dev/null +++ b/qemu/pixman/pixman/pixman-filter.c @@ -0,0 +1,350 @@ +/* + * Copyright 2012, Red Hat, Inc. + * Copyright 2012, Soren Sandmann + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + * + * Author: Soren Sandmann + */ +#include +#include +#include +#include +#include +#ifdef HAVE_CONFIG_H +#include +#endif +#include "pixman-private.h" + +typedef double (* kernel_func_t) (double x); + +typedef struct +{ + pixman_kernel_t kernel; + kernel_func_t func; + double width; +} filter_info_t; + +static double +impulse_kernel (double x) +{ + return (x == 0.0)? 1.0 : 0.0; +} + +static double +box_kernel (double x) +{ + return 1; +} + +static double +linear_kernel (double x) +{ + return 1 - fabs (x); +} + +static double +gaussian_kernel (double x) +{ +#define SQRT2 (1.4142135623730950488016887242096980785696718753769480) +#define SIGMA (SQRT2 / 2.0) + + return exp (- x * x / (2 * SIGMA * SIGMA)) / (SIGMA * sqrt (2.0 * M_PI)); +} + +static double +sinc (double x) +{ + if (x == 0.0) + return 1.0; + else + return sin (M_PI * x) / (M_PI * x); +} + +static double +lanczos (double x, int n) +{ + return sinc (x) * sinc (x * (1.0 / n)); +} + +static double +lanczos2_kernel (double x) +{ + return lanczos (x, 2); +} + +static double +lanczos3_kernel (double x) +{ + return lanczos (x, 3); +} + +static double +nice_kernel (double x) +{ + return lanczos3_kernel (x * 0.75); +} + +static double +general_cubic (double x, double B, double C) +{ + double ax = fabs(x); + + if (ax < 1) + { + return ((12 - 9 * B - 6 * C) * ax * ax * ax + + (-18 + 12 * B + 6 * C) * ax * ax + (6 - 2 * B)) / 6; + } + else if (ax >= 1 && ax < 2) + { + return ((-B - 6 * C) * ax * ax * ax + + (6 * B + 30 * C) * ax * ax + (-12 * B - 48 * C) * + ax + (8 * B + 24 * C)) / 6; + } + else + { + return 0; + } +} + +static double +cubic_kernel (double x) +{ + /* This is the Mitchell-Netravali filter. + * + * (0.0, 0.5) would give us the Catmull-Rom spline, + * but that one seems to be indistinguishable from Lanczos2. + */ + return general_cubic (x, 1/3.0, 1/3.0); +} + +static const filter_info_t filters[] = +{ + { PIXMAN_KERNEL_IMPULSE, impulse_kernel, 0.0 }, + { PIXMAN_KERNEL_BOX, box_kernel, 1.0 }, + { PIXMAN_KERNEL_LINEAR, linear_kernel, 2.0 }, + { PIXMAN_KERNEL_CUBIC, cubic_kernel, 4.0 }, + { PIXMAN_KERNEL_GAUSSIAN, gaussian_kernel, 6 * SIGMA }, + { PIXMAN_KERNEL_LANCZOS2, lanczos2_kernel, 4.0 }, + { PIXMAN_KERNEL_LANCZOS3, lanczos3_kernel, 6.0 }, + { PIXMAN_KERNEL_LANCZOS3_STRETCHED, nice_kernel, 8.0 }, +}; + +/* This function scales @kernel2 by @scale, then + * aligns @x1 in @kernel1 with @x2 in @kernel2 and + * and integrates the product of the kernels across @width. + * + * This function assumes that the intervals are within + * the kernels in question. E.g., the caller must not + * try to integrate a linear kernel ouside of [-1:1] + */ +static double +integral (pixman_kernel_t kernel1, double x1, + pixman_kernel_t kernel2, double scale, double x2, + double width) +{ + /* If the integration interval crosses zero, break it into + * two separate integrals. This ensures that filters such + * as LINEAR that are not differentiable at 0 will still + * integrate properly. + */ + if (x1 < 0 && x1 + width > 0) + { + return + integral (kernel1, x1, kernel2, scale, x2, - x1) + + integral (kernel1, 0, kernel2, scale, x2 - x1, width + x1); + } + else if (x2 < 0 && x2 + width > 0) + { + return + integral (kernel1, x1, kernel2, scale, x2, - x2) + + integral (kernel1, x1 - x2, kernel2, scale, 0, width + x2); + } + else if (kernel1 == PIXMAN_KERNEL_IMPULSE) + { + assert (width == 0.0); + return filters[kernel2].func (x2 * scale); + } + else if (kernel2 == PIXMAN_KERNEL_IMPULSE) + { + assert (width == 0.0); + return filters[kernel1].func (x1); + } + else + { + /* Integration via Simpson's rule */ +#define N_SEGMENTS 128 +#define SAMPLE(a1, a2) \ + (filters[kernel1].func ((a1)) * filters[kernel2].func ((a2) * scale)) + + double s = 0.0; + double h = width / (double)N_SEGMENTS; + int i; + + s = SAMPLE (x1, x2); + + for (i = 1; i < N_SEGMENTS; i += 2) + { + double a1 = x1 + h * i; + double a2 = x2 + h * i; + + s += 2 * SAMPLE (a1, a2); + + if (i >= 2 && i < N_SEGMENTS - 1) + s += 4 * SAMPLE (a1, a2); + } + + s += SAMPLE (x1 + width, x2 + width); + + return h * s * (1.0 / 3.0); + } +} + +static pixman_fixed_t * +create_1d_filter (int *width, + pixman_kernel_t reconstruct, + pixman_kernel_t sample, + double scale, + int n_phases) +{ + pixman_fixed_t *params, *p; + double step; + double size; + int i; + + size = scale * filters[sample].width + filters[reconstruct].width; + *width = ceil (size); + + p = params = malloc (*width * n_phases * sizeof (pixman_fixed_t)); + if (!params) + return NULL; + + step = 1.0 / n_phases; + + for (i = 0; i < n_phases; ++i) + { + double frac = step / 2.0 + i * step; + pixman_fixed_t new_total; + int x, x1, x2; + double total; + + /* Sample convolution of reconstruction and sampling + * filter. See rounding.txt regarding the rounding + * and sample positions. + */ + + x1 = ceil (frac - *width / 2.0 - 0.5); + x2 = x1 + *width; + + total = 0; + for (x = x1; x < x2; ++x) + { + double pos = x + 0.5 - frac; + double rlow = - filters[reconstruct].width / 2.0; + double rhigh = rlow + filters[reconstruct].width; + double slow = pos - scale * filters[sample].width / 2.0; + double shigh = slow + scale * filters[sample].width; + double c = 0.0; + double ilow, ihigh; + + if (rhigh >= slow && rlow <= shigh) + { + ilow = MAX (slow, rlow); + ihigh = MIN (shigh, rhigh); + + c = integral (reconstruct, ilow, + sample, 1.0 / scale, ilow - pos, + ihigh - ilow); + } + + total += c; + *p++ = (pixman_fixed_t)(c * 65536.0 + 0.5); + } + + /* Normalize */ + p -= *width; + total = 1 / total; + new_total = 0; + for (x = x1; x < x2; ++x) + { + pixman_fixed_t t = (*p) * total + 0.5; + + new_total += t; + *p++ = t; + } + + if (new_total != pixman_fixed_1) + *(p - *width / 2) += (pixman_fixed_1 - new_total); + } + + return params; +} + +/* Create the parameter list for a SEPARABLE_CONVOLUTION filter + * with the given kernels and scale parameters + */ +PIXMAN_EXPORT pixman_fixed_t * +pixman_filter_create_separable_convolution (int *n_values, + pixman_fixed_t scale_x, + pixman_fixed_t scale_y, + pixman_kernel_t reconstruct_x, + pixman_kernel_t reconstruct_y, + pixman_kernel_t sample_x, + pixman_kernel_t sample_y, + int subsample_bits_x, + int subsample_bits_y) +{ + double sx = fabs (pixman_fixed_to_double (scale_x)); + double sy = fabs (pixman_fixed_to_double (scale_y)); + pixman_fixed_t *horz = NULL, *vert = NULL, *params = NULL; + int subsample_x, subsample_y; + int width, height; + + subsample_x = (1 << subsample_bits_x); + subsample_y = (1 << subsample_bits_y); + + horz = create_1d_filter (&width, reconstruct_x, sample_x, sx, subsample_x); + vert = create_1d_filter (&height, reconstruct_y, sample_y, sy, subsample_y); + + if (!horz || !vert) + goto out; + + *n_values = 4 + width * subsample_x + height * subsample_y; + + params = malloc (*n_values * sizeof (pixman_fixed_t)); + if (!params) + goto out; + + params[0] = pixman_int_to_fixed (width); + params[1] = pixman_int_to_fixed (height); + params[2] = pixman_int_to_fixed (subsample_bits_x); + params[3] = pixman_int_to_fixed (subsample_bits_y); + + memcpy (params + 4, horz, + width * subsample_x * sizeof (pixman_fixed_t)); + memcpy (params + 4 + width * subsample_x, vert, + height * subsample_y * sizeof (pixman_fixed_t)); + +out: + free (horz); + free (vert); + + return params; +}