1a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Copyright 2012 Google Inc. All Rights Reserved. 2a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 30406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Use of this source code is governed by a BSD-style license 40406ce1417f76f2034833414dcecc9f56253640cVikas Arora// that can be found in the COPYING file in the root of the source 50406ce1417f76f2034833414dcecc9f56253640cVikas Arora// tree. An additional intellectual property rights grant can be found 60406ce1417f76f2034833414dcecc9f56253640cVikas Arora// in the file PATENTS. All contributing project authors may 70406ce1417f76f2034833414dcecc9f56253640cVikas Arora// be found in the AUTHORS file in the root of the source tree. 8a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// ----------------------------------------------------------------------------- 9a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 10a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Rescaling functions 11a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 12a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Author: Skal (pascal.massimino@gmail.com) 13a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 14a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#include <assert.h> 15a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#include <stdlib.h> 16a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#include "./rescaler.h" 17a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 18a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 19a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 20a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#if defined(__cplusplus) || defined(c_plusplus) 21a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraextern "C" { 22a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#endif 23a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 24a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#define RFIX 30 250406ce1417f76f2034833414dcecc9f56253640cVikas Arora#define MULT_FIX(x, y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX) 26a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 27a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, 28a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora uint8_t* const dst, int dst_width, int dst_height, 29a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int dst_stride, int num_channels, int x_add, int x_sub, 30a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int y_add, int y_sub, int32_t* const work) { 31a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->x_expand = (src_width < dst_width); 32a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->src_width = src_width; 33a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->src_height = src_height; 34a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->dst_width = dst_width; 35a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->dst_height = dst_height; 36a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->dst = dst; 37a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->dst_stride = dst_stride; 38a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->num_channels = num_channels; 39a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora // for 'x_expand', we use bilinear interpolation 40a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add - x_sub; 41a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub; 42a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->y_accum = y_add; 43a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->y_add = y_add; 44a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->y_sub = y_sub; 45a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->fx_scale = (1 << RFIX) / x_sub; 46a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->fy_scale = (1 << RFIX) / y_sub; 47a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->fxy_scale = wrk->x_expand ? 48a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora ((int64_t)dst_height << RFIX) / (x_sub * src_height) : 49a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora ((int64_t)dst_height << RFIX) / (x_add * src_height); 50a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->irow = work; 51a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->frow = work + num_channels * dst_width; 52a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 53a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 54a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid WebPRescalerImportRow(WebPRescaler* const wrk, 55a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const uint8_t* const src, int channel) { 56a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int x_stride = wrk->num_channels; 57a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int x_out_max = wrk->dst_width * wrk->num_channels; 58a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int x_in = channel; 59a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int x_out; 60a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int accum = 0; 61a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora if (!wrk->x_expand) { 62a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int sum = 0; 63a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (x_out = channel; x_out < x_out_max; x_out += x_stride) { 64a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora accum += wrk->x_add; 65a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (; accum > 0; accum -= wrk->x_sub) { 66a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora sum += src[x_in]; 67a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora x_in += x_stride; 68a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 69a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora { // Emit next horizontal pixel. 70a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int32_t base = src[x_in]; 71a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int32_t frac = base * (-accum); 72a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora x_in += x_stride; 73a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->frow[x_out] = (sum + base) * wrk->x_sub - frac; 74a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora // fresh fractional start for next pixel 75a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora sum = (int)MULT_FIX(frac, wrk->fx_scale); 76a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 77a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 78a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } else { // simple bilinear interpolation 79a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int left = src[channel], right = src[channel]; 80a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (x_out = channel; x_out < x_out_max; x_out += x_stride) { 81a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora if (accum < 0) { 82a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora left = right; 83a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora x_in += x_stride; 84a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora right = src[x_in]; 85a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora accum += wrk->x_add; 86a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 87a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum; 88a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora accum -= wrk->x_sub; 89a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 90a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 91a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora // Accumulate the new row's contribution 92a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (x_out = channel; x_out < x_out_max; x_out += x_stride) { 93a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->irow[x_out] += wrk->frow[x_out]; 94a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 95a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 96a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 97a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorauint8_t* WebPRescalerExportRow(WebPRescaler* const wrk) { 98a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora if (wrk->y_accum <= 0) { 99a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int x_out; 100a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora uint8_t* const dst = wrk->dst; 101a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int32_t* const irow = wrk->irow; 102a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int32_t* const frow = wrk->frow; 103a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int yscale = wrk->fy_scale * (-wrk->y_accum); 104a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int x_out_max = wrk->dst_width * wrk->num_channels; 105a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 106a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (x_out = 0; x_out < x_out_max; ++x_out) { 107a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int frac = (int)MULT_FIX(frow[x_out], yscale); 108a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale); 109a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255; 110a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora irow[x_out] = frac; // new fractional start 111a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 112a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->y_accum += wrk->y_add; 113a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->dst += wrk->dst_stride; 114a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return dst; 115a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } else { 116a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return NULL; 117a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 118a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 119a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 120a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#undef MULT_FIX 121a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#undef RFIX 122a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 123a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 124a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// all-in-one calls 125a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 126a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint WebPRescalerImport(WebPRescaler* const wrk, int num_lines, 127a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const uint8_t* src, int src_stride) { 128a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int total_imported = 0; 129a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora while (total_imported < num_lines && wrk->y_accum > 0) { 130a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int channel; 131a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora for (channel = 0; channel < wrk->num_channels; ++channel) { 132a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora WebPRescalerImportRow(wrk, src, channel); 133a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 134a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora src += src_stride; 135a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora ++total_imported; 136a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora wrk->y_accum -= wrk->y_sub; 137a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 138a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return total_imported; 139a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 140a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 141a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint WebPRescalerExport(WebPRescaler* const rescaler) { 142a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int total_exported = 0; 143a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora while (WebPRescalerHasPendingOutput(rescaler)) { 144a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora WebPRescalerExportRow(rescaler); 145a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora ++total_exported; 146a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora } 147a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return total_exported; 148a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 149a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 150a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 151a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 152a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#if defined(__cplusplus) || defined(c_plusplus) 153a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} // extern "C" 154a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#endif 155