/* * Image Scaling Functions (4 tap) * Copyright (c) 2005 David A. Schleef * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "vs_image.h" #include "vs_scanline.h" #include "vs_4tap.h" #include #include #define SHIFT 10 #define MAX(a,b) (((a) > (b)) ? (a) : (b)) #define MIN(a,b) (((a) < (b)) ? (a) : (b)) #define CLAMP(x,a,b) MAX(MIN((x),(b)),(a)) #ifndef M_PI #define M_PI 3.14159265358979323846 #endif #ifdef WIN32 #define rint(x) (floor((x)+0.5)) #endif static int16_t vs_4tap_taps[256][4]; static double vs_4tap_func (double x) { #if 0 if (x < -1) return 0; if (x > 1) return 0; if (x < 0) return 1 + x; return 1 - x; #endif #if 0 if (x == 0) return 1; return sin (M_PI * x) / (M_PI * x) * (1 - 0.25 * x * x); #endif #if 1 if (x == 0) return 1; return sin (M_PI * x) / (M_PI * x); #endif } void vs_4tap_init (void) { int i; double a, b, c, d; double sum; for (i = 0; i < 256; i++) { a = vs_4tap_func (-1 - i / 256.0); b = vs_4tap_func (0 - i / 256.0); c = vs_4tap_func (1 - i / 256.0); d = vs_4tap_func (2 - i / 256.0); sum = a + b + c + d; vs_4tap_taps[i][0] = rint ((1 << SHIFT) * (a / sum)); vs_4tap_taps[i][1] = rint ((1 << SHIFT) * (b / sum)); vs_4tap_taps[i][2] = rint ((1 << SHIFT) * (c / sum)); vs_4tap_taps[i][3] = rint ((1 << SHIFT) * (d / sum)); } } void vs_scanline_resample_4tap_Y (uint8_t * dest, uint8_t * src, int n, int src_width, int *xacc, int increment) { int i; int j; int acc; int x; int y; acc = *xacc; for (i = 0; i < n; i++) { j = acc >> 16; x = (acc & 0xff00) >> 8; if (j - 1 >= 0 && j + 2 < src_width) { y = vs_4tap_taps[x][0] * src[MAX (j - 1, 0)]; y += vs_4tap_taps[x][1] * src[j]; y += vs_4tap_taps[x][2] * src[j + 1]; y += vs_4tap_taps[x][3] * src[j + 2]; } else { y = vs_4tap_taps[x][0] * src[CLAMP (j - 1, 0, src_width - 1)]; y += vs_4tap_taps[x][1] * src[CLAMP (j, 0, src_width - 1)]; y += vs_4tap_taps[x][2] * src[CLAMP (j + 1, 0, src_width - 1)]; y += vs_4tap_taps[x][3] * src[CLAMP (j + 2, 0, src_width - 1)]; } y += (1 << (SHIFT - 1)); dest[i] = CLAMP (y >> SHIFT, 0, 255); acc += increment; } *xacc = acc; } void vs_scanline_merge_4tap_Y (uint8_t * dest, uint8_t * src1, uint8_t * src2, uint8_t * src3, uint8_t * src4, int n, int acc) { int i; int y; int a, b, c, d; acc = (acc >> 8) & 0xff; a = vs_4tap_taps[acc][0]; b = vs_4tap_taps[acc][1]; c = vs_4tap_taps[acc][2]; d = vs_4tap_taps[acc][3]; for (i = 0; i < n; i++) { y = a * src1[i]; y += b * src2[i]; y += c * src3[i]; y += d * src4[i]; y += (1 << (SHIFT - 1)); dest[i] = CLAMP (y >> SHIFT, 0, 255); } } void vs_image_scale_4tap_Y (const VSImage * dest, const VSImage * src, uint8_t * tmpbuf) { int yacc; int y_increment; int x_increment; int i; int j; int xacc; int k; if (dest->height == 1) y_increment = 0; else y_increment = ((src->height - 1) << 16) / (dest->height - 1); if (dest->width == 1) x_increment = 0; else x_increment = ((src->width - 1) << 16) / (dest->width - 1); k = 0; for (i = 0; i < 4; i++) { xacc = 0; vs_scanline_resample_4tap_Y (tmpbuf + i * dest->width, src->pixels + i * src->stride, dest->width, src->width, &xacc, x_increment); } yacc = 0; for (i = 0; i < dest->height; i++) { uint8_t *t0, *t1, *t2, *t3; j = yacc >> 16; while (j > k) { k++; if (k + 3 < src->height) { xacc = 0; vs_scanline_resample_4tap_Y (tmpbuf + ((k + 3) & 3) * dest->width, src->pixels + (k + 3) * src->stride, dest->width, src->width, &xacc, x_increment); } } t0 = tmpbuf + (CLAMP (j - 1, 0, src->height - 1) & 3) * dest->width; t1 = tmpbuf + (CLAMP (j, 0, src->height - 1) & 3) * dest->width; t2 = tmpbuf + (CLAMP (j + 1, 0, src->height - 1) & 3) * dest->width; t3 = tmpbuf + (CLAMP (j + 2, 0, src->height - 1) & 3) * dest->width; vs_scanline_merge_4tap_Y (dest->pixels + i * dest->stride, t0, t1, t2, t3, dest->width, yacc & 0xffff); yacc += y_increment; } } void vs_scanline_resample_4tap_RGBA (uint8_t * dest, uint8_t * src, int n, int src_width, int *xacc, int increment) { int i; int j; int acc; int x; int y; int off; acc = *xacc; for (i = 0; i < n; i++) { j = acc >> 16; x = (acc & 0xffff) >> 8; for (off = 0; off < 4; off++) { if (j - 1 >= 0 && j + 2 < src_width) { y = vs_4tap_taps[x][0] * src[MAX ((j - 1) * 4 + off, 0)]; y += vs_4tap_taps[x][1] * src[j * 4 + off]; y += vs_4tap_taps[x][2] * src[(j + 1) * 4 + off]; y += vs_4tap_taps[x][3] * src[(j + 2) * 4 + off]; } else { y = vs_4tap_taps[x][0] * src[CLAMP ((j - 1) * 4 + off, 0, 4 * (src_width - 1) + off)]; y += vs_4tap_taps[x][1] * src[CLAMP (j * 4 + off, 0, 4 * (src_width - 1) + off)]; y += vs_4tap_taps[x][2] * src[CLAMP ((j + 1) * 4 + off, 0, 4 * (src_width - 1) + off)]; y += vs_4tap_taps[x][3] * src[CLAMP ((j + 2) * 4 + off, 0, 4 * (src_width - 1) + off)]; } y += (1 << (SHIFT - 1)); dest[i * 4 + off] = CLAMP (y >> SHIFT, 0, 255); } acc += increment; } *xacc = acc; } void vs_scanline_merge_4tap_RGBA (uint8_t * dest, uint8_t * src1, uint8_t * src2, uint8_t * src3, uint8_t * src4, int n, int acc) { int i; int y; int off; int a, b, c, d; acc = (acc >> 8) & 0xff; a = vs_4tap_taps[acc][0]; b = vs_4tap_taps[acc][1]; c = vs_4tap_taps[acc][2]; d = vs_4tap_taps[acc][3]; for (i = 0; i < n; i++) { for (off = 0; off < 4; off++) { y = a * src1[i * 4 + off]; y += b * src2[i * 4 + off]; y += c * src3[i * 4 + off]; y += d * src4[i * 4 + off]; y += (1 << (SHIFT - 1)); dest[i * 4 + off] = CLAMP (y >> SHIFT, 0, 255); } } } void vs_image_scale_4tap_RGBA (const VSImage * dest, const VSImage * src, uint8_t * tmpbuf) { int yacc; int y_increment; int x_increment; int i; int j; int xacc; int k; if (dest->height == 1) y_increment = 0; else y_increment = ((src->height - 1) << 16) / (dest->height - 1); if (dest->width == 1) x_increment = 0; else x_increment = ((src->width - 1) << 16) / (dest->width - 1); k = 0; for (i = 0; i < 4; i++) { xacc = 0; vs_scanline_resample_4tap_RGBA (tmpbuf + i * dest->stride, src->pixels + i * src->stride, dest->width, src->width, &xacc, x_increment); } yacc = 0; for (i = 0; i < dest->height; i++) { uint8_t *t0, *t1, *t2, *t3; j = yacc >> 16; while (j > k) { k++; if (k + 3 < src->height) { xacc = 0; vs_scanline_resample_4tap_RGBA (tmpbuf + ((k + 3) & 3) * dest->stride, src->pixels + (k + 3) * src->stride, dest->width, src->width, &xacc, x_increment); } } t0 = tmpbuf + (CLAMP (j - 1, 0, src->height - 1) & 3) * dest->stride; t1 = tmpbuf + (CLAMP (j, 0, src->height - 1) & 3) * dest->stride; t2 = tmpbuf + (CLAMP (j + 1, 0, src->height - 1) & 3) * dest->stride; t3 = tmpbuf + (CLAMP (j + 2, 0, src->height - 1) & 3) * dest->stride; vs_scanline_merge_4tap_RGBA (dest->pixels + i * dest->stride, t0, t1, t2, t3, dest->width, yacc & 0xffff); yacc += y_increment; } } void vs_scanline_resample_4tap_RGB (uint8_t * dest, uint8_t * src, int n, int src_width, int *xacc, int increment) { int i; int j; int acc; int x; int y; int off; acc = *xacc; for (i = 0; i < n; i++) { j = acc >> 16; x = (acc & 0xffff) >> 8; for (off = 0; off < 3; off++) { if (j - 1 >= 0 && j + 2 < src_width) { y = vs_4tap_taps[x][0] * src[MAX ((j - 1) * 3 + off, 0)]; y += vs_4tap_taps[x][1] * src[j * 3 + off]; y += vs_4tap_taps[x][2] * src[(j + 1) * 3 + off]; y += vs_4tap_taps[x][3] * src[(j + 2) * 3 + off]; } else { y = vs_4tap_taps[x][0] * src[CLAMP ((j - 1) * 3 + off, 0, 3 * (src_width - 1) + off)]; y += vs_4tap_taps[x][1] * src[CLAMP (j * 3 + off, 0, 3 * (src_width - 1) + off)]; y += vs_4tap_taps[x][2] * src[CLAMP ((j + 1) * 3 + off, 0, 3 * (src_width - 1) + off)]; y += vs_4tap_taps[x][3] * src[CLAMP ((j + 2) * 3 + off, 0, 3 * (src_width - 1) + off)]; } y += (1 << (SHIFT - 1)); dest[i * 3 + off] = CLAMP (y >> SHIFT, 0, 255); } acc += increment; } *xacc = acc; } void vs_scanline_merge_4tap_RGB (uint8_t * dest, uint8_t * src1, uint8_t * src2, uint8_t * src3, uint8_t * src4, int n, int acc) { int i; int y; int off; int a, b, c, d; acc = (acc >> 8) & 0xff; a = vs_4tap_taps[acc][0]; b = vs_4tap_taps[acc][1]; c = vs_4tap_taps[acc][2]; d = vs_4tap_taps[acc][3]; for (i = 0; i < n; i++) { for (off = 0; off < 3; off++) { y = a * src1[i * 3 + off]; y += b * src2[i * 3 + off]; y += c * src3[i * 3 + off]; y += d * src4[i * 3 + off]; y += (1 << (SHIFT - 1)); dest[i * 3 + off] = CLAMP (y >> SHIFT, 0, 255); } } } void vs_image_scale_4tap_RGB (const VSImage * dest, const VSImage * src, uint8_t * tmpbuf) { int yacc; int y_increment; int x_increment; int i; int j; int xacc; int k; if (dest->height == 1) y_increment = 0; else y_increment = ((src->height - 1) << 16) / (dest->height - 1); if (dest->width == 1) x_increment = 0; else x_increment = ((src->width - 1) << 16) / (dest->width - 1); k = 0; for (i = 0; i < 4; i++) { xacc = 0; vs_scanline_resample_4tap_RGB (tmpbuf + i * dest->stride, src->pixels + i * src->stride, dest->width, src->width, &xacc, x_increment); } yacc = 0; for (i = 0; i < dest->height; i++) { uint8_t *t0, *t1, *t2, *t3; j = yacc >> 16; while (j > k) { k++; if (k + 3 < src->height) { xacc = 0; vs_scanline_resample_4tap_RGB (tmpbuf + ((k + 3) & 3) * dest->stride, src->pixels + (k + 3) * src->stride, dest->width, src->width, &xacc, x_increment); } } t0 = tmpbuf + (CLAMP (j - 1, 0, src->height - 1) & 3) * dest->stride; t1 = tmpbuf + (CLAMP (j, 0, src->height - 1) & 3) * dest->stride; t2 = tmpbuf + (CLAMP (j + 1, 0, src->height - 1) & 3) * dest->stride; t3 = tmpbuf + (CLAMP (j + 2, 0, src->height - 1) & 3) * dest->stride; vs_scanline_merge_4tap_RGB (dest->pixels + i * dest->stride, t0, t1, t2, t3, dest->width, yacc & 0xffff); yacc += y_increment; } }