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-rw-r--r--media/libwebp/utils/rescaler_utils.c146
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diff --git a/media/libwebp/utils/rescaler_utils.c b/media/libwebp/utils/rescaler_utils.c
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+// Copyright 2012 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 <stdlib.h>
+#include <string.h>
+#include "../dsp/dsp.h"
+#include "./rescaler_utils.h"
+
+//------------------------------------------------------------------------------
+
+void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
+ uint8_t* const dst,
+ int dst_width, int dst_height, int dst_stride,
+ int num_channels, rescaler_t* const work) {
+ const int x_add = src_width, x_sub = dst_width;
+ const int y_add = src_height, y_sub = dst_height;
+ wrk->x_expand = (src_width < dst_width);
+ wrk->y_expand = (src_height < dst_height);
+ wrk->src_width = src_width;
+ wrk->src_height = src_height;
+ wrk->dst_width = dst_width;
+ wrk->dst_height = dst_height;
+ wrk->src_y = 0;
+ wrk->dst_y = 0;
+ wrk->dst = dst;
+ wrk->dst_stride = dst_stride;
+ wrk->num_channels = num_channels;
+
+ // for 'x_expand', we use bilinear interpolation
+ wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add;
+ wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub;
+ if (!wrk->x_expand) { // fx_scale is not used otherwise
+ wrk->fx_scale = WEBP_RESCALER_FRAC(1, wrk->x_sub);
+ }
+ // vertical scaling parameters
+ wrk->y_add = wrk->y_expand ? y_add - 1 : y_add;
+ wrk->y_sub = wrk->y_expand ? y_sub - 1 : y_sub;
+ wrk->y_accum = wrk->y_expand ? wrk->y_sub : wrk->y_add;
+ if (!wrk->y_expand) {
+ // This is WEBP_RESCALER_FRAC(dst_height, x_add * y_add) without the cast.
+ // Its value is <= WEBP_RESCALER_ONE, because dst_height <= wrk->y_add, and
+ // wrk->x_add >= 1;
+ const uint64_t ratio =
+ (uint64_t)dst_height * WEBP_RESCALER_ONE / (wrk->x_add * wrk->y_add);
+ if (ratio != (uint32_t)ratio) {
+ // When ratio == WEBP_RESCALER_ONE, we can't represent the ratio with the
+ // current fixed-point precision. This happens when src_height ==
+ // wrk->y_add (which == src_height), and wrk->x_add == 1.
+ // => We special-case fxy_scale = 0, in WebPRescalerExportRow().
+ wrk->fxy_scale = 0;
+ } else {
+ wrk->fxy_scale = (uint32_t)ratio;
+ }
+ wrk->fy_scale = WEBP_RESCALER_FRAC(1, wrk->y_sub);
+ } else {
+ wrk->fy_scale = WEBP_RESCALER_FRAC(1, wrk->x_add);
+ // wrk->fxy_scale is unused here.
+ }
+ wrk->irow = work;
+ wrk->frow = work + num_channels * dst_width;
+ memset(work, 0, 2 * dst_width * num_channels * sizeof(*work));
+
+ WebPRescalerDspInit();
+}
+
+int WebPRescalerGetScaledDimensions(int src_width, int src_height,
+ int* const scaled_width,
+ int* const scaled_height) {
+ assert(scaled_width != NULL);
+ assert(scaled_height != NULL);
+ {
+ int width = *scaled_width;
+ int height = *scaled_height;
+
+ // if width is unspecified, scale original proportionally to height ratio.
+ if (width == 0) {
+ width = (src_width * height + src_height / 2) / src_height;
+ }
+ // if height is unspecified, scale original proportionally to width ratio.
+ if (height == 0) {
+ height = (src_height * width + src_width / 2) / src_width;
+ }
+ // Check if the overall dimensions still make sense.
+ if (width <= 0 || height <= 0) {
+ return 0;
+ }
+
+ *scaled_width = width;
+ *scaled_height = height;
+ return 1;
+ }
+}
+
+//------------------------------------------------------------------------------
+// all-in-one calls
+
+int WebPRescaleNeededLines(const WebPRescaler* const wrk, int max_num_lines) {
+ const int num_lines = (wrk->y_accum + wrk->y_sub - 1) / wrk->y_sub;
+ return (num_lines > max_num_lines) ? max_num_lines : num_lines;
+}
+
+int WebPRescalerImport(WebPRescaler* const wrk, int num_lines,
+ const uint8_t* src, int src_stride) {
+ int total_imported = 0;
+ while (total_imported < num_lines && !WebPRescalerHasPendingOutput(wrk)) {
+ if (wrk->y_expand) {
+ rescaler_t* const tmp = wrk->irow;
+ wrk->irow = wrk->frow;
+ wrk->frow = tmp;
+ }
+ WebPRescalerImportRow(wrk, src);
+ if (!wrk->y_expand) { // Accumulate the contribution of the new row.
+ int x;
+ for (x = 0; x < wrk->num_channels * wrk->dst_width; ++x) {
+ wrk->irow[x] += wrk->frow[x];
+ }
+ }
+ ++wrk->src_y;
+ src += src_stride;
+ ++total_imported;
+ wrk->y_accum -= wrk->y_sub;
+ }
+ return total_imported;
+}
+
+int WebPRescalerExport(WebPRescaler* const rescaler) {
+ int total_exported = 0;
+ while (WebPRescalerHasPendingOutput(rescaler)) {
+ WebPRescalerExportRow(rescaler);
+ ++total_exported;
+ }
+ return total_exported;
+}
+
+//------------------------------------------------------------------------------