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// Copyright 2014 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Rescaling functions
//
// Author: Skal (pascal.massimino@gmail.com)
#include <assert.h>
#include "src/dsp/dsp.h"
#include "src/utils/rescaler_utils.h"
//------------------------------------------------------------------------------
// Implementations of critical functions ImportRow / ExportRow
#define ROUNDER (WEBP_RESCALER_ONE >> 1)
#define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
#define MULT_FIX_FLOOR(x, y) (((uint64_t)(x) * (y)) >> WEBP_RESCALER_RFIX)
//------------------------------------------------------------------------------
// Row import
void WebPRescalerImportRowExpand_C(WebPRescaler* const wrk,
const uint8_t* src) {
const int x_stride = wrk->num_channels;
const int x_out_max = wrk->dst_width * wrk->num_channels;
int channel;
assert(!WebPRescalerInputDone(wrk));
assert(wrk->x_expand);
for (channel = 0; channel < x_stride; ++channel) {
int x_in = channel;
int x_out = channel;
// simple bilinear interpolation
int accum = wrk->x_add;
int left = src[x_in];
int right = (wrk->src_width > 1) ? src[x_in + x_stride] : left;
x_in += x_stride;
while (1) {
wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
x_out += x_stride;
if (x_out >= x_out_max) break;
accum -= wrk->x_sub;
if (accum < 0) {
left = right;
x_in += x_stride;
assert(x_in < wrk->src_width * x_stride);
right = src[x_in];
accum += wrk->x_add;
}
}
assert(wrk->x_sub == 0 /* <- special case for src_width=1 */ || accum == 0);
}
}
void WebPRescalerImportRowShrink_C(WebPRescaler* const wrk,
const uint8_t* src) {
const int x_stride = wrk->num_channels;
const int x_out_max = wrk->dst_width * wrk->num_channels;
int channel;
assert(!WebPRescalerInputDone(wrk));
assert(!wrk->x_expand);
for (channel = 0; channel < x_stride; ++channel) {
int x_in = channel;
int x_out = channel;
uint32_t sum = 0;
int accum = 0;
while (x_out < x_out_max) {
uint32_t base = 0;
accum += wrk->x_add;
while (accum > 0) {
accum -= wrk->x_sub;
assert(x_in < wrk->src_width * x_stride);
base = src[x_in];
sum += base;
x_in += x_stride;
}
{ // Emit next horizontal pixel.
const rescaler_t frac = base * (-accum);
wrk->frow[x_out] = sum * wrk->x_sub - frac;
// fresh fractional start for next pixel
sum = (int)MULT_FIX(frac, wrk->fx_scale);
}
x_out += x_stride;
}
assert(accum == 0);
}
}
//------------------------------------------------------------------------------
// Row export
void WebPRescalerExportRowExpand_C(WebPRescaler* const wrk) {
int x_out;
uint8_t* const dst = wrk->dst;
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(wrk->y_expand);
assert(wrk->y_sub != 0);
if (wrk->y_accum == 0) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const uint32_t J = frow[x_out];
const int v = (int)MULT_FIX(J, wrk->fy_scale);
dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
}
} else {
const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
const uint32_t A = (uint32_t)(WEBP_RESCALER_ONE - B);
for (x_out = 0; x_out < x_out_max; ++x_out) {
const uint64_t I = (uint64_t)A * frow[x_out]
+ (uint64_t)B * irow[x_out];
const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
const int v = (int)MULT_FIX(J, wrk->fy_scale);
dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
}
}
}
void WebPRescalerExportRowShrink_C(WebPRescaler* const wrk) {
int x_out;
uint8_t* const dst = wrk->dst;
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
if (yscale) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const uint32_t frac = (uint32_t)MULT_FIX_FLOOR(frow[x_out], yscale);
const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
irow[x_out] = frac; // new fractional start
}
} else {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(irow[x_out], wrk->fxy_scale);
dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
irow[x_out] = 0;
}
}
}
#undef MULT_FIX_FLOOR
#undef MULT_FIX
#undef ROUNDER
//------------------------------------------------------------------------------
// Main entry calls
void WebPRescalerImportRow(WebPRescaler* const wrk, const uint8_t* src) {
assert(!WebPRescalerInputDone(wrk));
if (!wrk->x_expand) {
WebPRescalerImportRowShrink(wrk, src);
} else {
WebPRescalerImportRowExpand(wrk, src);
}
}
void WebPRescalerExportRow(WebPRescaler* const wrk) {
if (wrk->y_accum <= 0) {
assert(!WebPRescalerOutputDone(wrk));
if (wrk->y_expand) {
WebPRescalerExportRowExpand(wrk);
} else if (wrk->fxy_scale) {
WebPRescalerExportRowShrink(wrk);
} else { // special case
int i;
assert(wrk->src_height == wrk->dst_height && wrk->x_add == 1);
assert(wrk->src_width == 1 && wrk->dst_width <= 2);
for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) {
wrk->dst[i] = wrk->irow[i];
wrk->irow[i] = 0;
}
}
wrk->y_accum += wrk->y_add;
wrk->dst += wrk->dst_stride;
++wrk->dst_y;
}
}
//------------------------------------------------------------------------------
WebPRescalerImportRowFunc WebPRescalerImportRowExpand;
WebPRescalerImportRowFunc WebPRescalerImportRowShrink;
WebPRescalerExportRowFunc WebPRescalerExportRowExpand;
WebPRescalerExportRowFunc WebPRescalerExportRowShrink;
extern void WebPRescalerDspInitSSE2(void);
extern void WebPRescalerDspInitMIPS32(void);
extern void WebPRescalerDspInitMIPSdspR2(void);
extern void WebPRescalerDspInitMSA(void);
extern void WebPRescalerDspInitNEON(void);
WEBP_DSP_INIT_FUNC(WebPRescalerDspInit) {
#if !defined(WEBP_REDUCE_SIZE)
#if !WEBP_NEON_OMIT_C_CODE
WebPRescalerExportRowExpand = WebPRescalerExportRowExpand_C;
WebPRescalerExportRowShrink = WebPRescalerExportRowShrink_C;
#endif
WebPRescalerImportRowExpand = WebPRescalerImportRowExpand_C;
WebPRescalerImportRowShrink = WebPRescalerImportRowShrink_C;
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
if (VP8GetCPUInfo(kSSE2)) {
WebPRescalerDspInitSSE2();
}
#endif
#if defined(WEBP_USE_MIPS32)
if (VP8GetCPUInfo(kMIPS32)) {
WebPRescalerDspInitMIPS32();
}
#endif
#if defined(WEBP_USE_MIPS_DSP_R2)
if (VP8GetCPUInfo(kMIPSdspR2)) {
WebPRescalerDspInitMIPSdspR2();
}
#endif
#if defined(WEBP_USE_MSA)
if (VP8GetCPUInfo(kMSA)) {
WebPRescalerDspInitMSA();
}
#endif
}
#if defined(WEBP_USE_NEON)
if (WEBP_NEON_OMIT_C_CODE ||
(VP8GetCPUInfo != NULL && VP8GetCPUInfo(kNEON))) {
WebPRescalerDspInitNEON();
}
#endif
assert(WebPRescalerExportRowExpand != NULL);
assert(WebPRescalerExportRowShrink != NULL);
assert(WebPRescalerImportRowExpand != NULL);
assert(WebPRescalerImportRowShrink != NULL);
#endif // WEBP_REDUCE_SIZE
}
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