summaryrefslogtreecommitdiff
path: root/drivers/webp/utils/rescaler.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/webp/utils/rescaler.c')
-rw-r--r--drivers/webp/utils/rescaler.c176
1 files changed, 83 insertions, 93 deletions
diff --git a/drivers/webp/utils/rescaler.c b/drivers/webp/utils/rescaler.c
index 9825dcbc5f..00c9300bfb 100644
--- a/drivers/webp/utils/rescaler.c
+++ b/drivers/webp/utils/rescaler.c
@@ -1,8 +1,10 @@
// Copyright 2012 Google Inc. All Rights Reserved.
//
-// This code is licensed under the same terms as WebM:
-// Software License Agreement: http://www.webmproject.org/license/software/
-// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
+// 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
@@ -11,124 +13,116 @@
#include <assert.h>
#include <stdlib.h>
+#include <string.h>
+#include "../dsp/dsp.h"
#include "./rescaler.h"
//------------------------------------------------------------------------------
-#if defined(__cplusplus) || defined(c_plusplus)
-extern "C" {
-#endif
-
-#define RFIX 30
-#define MULT_FIX(x,y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX)
-
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, int x_add, int x_sub,
- int y_add, int y_sub, int32_t* const work) {
+ 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 - x_sub;
+ wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add;
wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub;
- wrk->y_accum = y_add;
- wrk->y_add = y_add;
- wrk->y_sub = y_sub;
- wrk->fx_scale = (1 << RFIX) / x_sub;
- wrk->fy_scale = (1 << RFIX) / y_sub;
- wrk->fxy_scale = wrk->x_expand ?
- ((int64_t)dst_height << RFIX) / (x_sub * src_height) :
- ((int64_t)dst_height << RFIX) / (x_add * src_height);
+ 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.
+ const uint64_t ratio =
+ (uint64_t)dst_height * WEBP_RESCALER_ONE / (wrk->x_add * wrk->y_add);
+ if (ratio != (uint32_t)ratio) {
+ // We can't represent the ratio with the current fixed-point precision.
+ // => 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));
-void WebPRescalerImportRow(WebPRescaler* const wrk,
- const uint8_t* const src, int channel) {
- const int x_stride = wrk->num_channels;
- const int x_out_max = wrk->dst_width * wrk->num_channels;
- int x_in = channel;
- int x_out;
- int accum = 0;
- if (!wrk->x_expand) {
- int sum = 0;
- for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
- accum += wrk->x_add;
- for (; accum > 0; accum -= wrk->x_sub) {
- sum += src[x_in];
- x_in += x_stride;
- }
- { // Emit next horizontal pixel.
- const int32_t base = src[x_in];
- const int32_t frac = base * (-accum);
- x_in += x_stride;
- wrk->frow[x_out] = (sum + base) * wrk->x_sub - frac;
- // fresh fractional start for next pixel
- sum = (int)MULT_FIX(frac, wrk->fx_scale);
- }
- }
- } else { // simple bilinear interpolation
- int left = src[channel], right = src[channel];
- for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
- if (accum < 0) {
- left = right;
- x_in += x_stride;
- right = src[x_in];
- accum += wrk->x_add;
- }
- wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
- accum -= wrk->x_sub;
- }
- }
- // Accumulate the new row's contribution
- for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
- wrk->irow[x_out] += wrk->frow[x_out];
- }
+ WebPRescalerDspInit();
}
-uint8_t* WebPRescalerExportRow(WebPRescaler* const wrk) {
- if (wrk->y_accum <= 0) {
- int x_out;
- uint8_t* const dst = wrk->dst;
- int32_t* const irow = wrk->irow;
- const int32_t* const frow = wrk->frow;
- const int yscale = wrk->fy_scale * (-wrk->y_accum);
- const int x_out_max = wrk->dst_width * wrk->num_channels;
+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;
- for (x_out = 0; x_out < x_out_max; ++x_out) {
- const int frac = (int)MULT_FIX(frow[x_out], yscale);
- const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
- dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
- irow[x_out] = frac; // new fractional start
+ // if width is unspecified, scale original proportionally to height ratio.
+ if (width == 0) {
+ width = (src_width * height + src_height / 2) / src_height;
}
- wrk->y_accum += wrk->y_add;
- wrk->dst += wrk->dst_stride;
- return dst;
- } else {
- return NULL;
+ // 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;
}
}
-#undef MULT_FIX
-#undef RFIX
-
//------------------------------------------------------------------------------
// 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 && wrk->y_accum > 0) {
- int channel;
- for (channel = 0; channel < wrk->num_channels; ++channel) {
- WebPRescalerImportRow(wrk, src, channel);
+ 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;
@@ -146,7 +140,3 @@ int WebPRescalerExport(WebPRescaler* const rescaler) {
}
//------------------------------------------------------------------------------
-
-#if defined(__cplusplus) || defined(c_plusplus)
-} // extern "C"
-#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-13 02:08:39 +0000