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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.
// -----------------------------------------------------------------------------
//
// WebPPicture tools: copy, crop, rescaling and view.
//
// Author: Skal (pascal.massimino@gmail.com)
#include "src/webp/encode.h"
#if !defined(WEBP_REDUCE_SIZE)
#include <assert.h>
#include <stdlib.h>
#include "src/enc/vp8i_enc.h"
#include "src/utils/rescaler_utils.h"
#include "src/utils/utils.h"
#define HALVE(x) (((x) + 1) >> 1)
// Grab the 'specs' (writer, *opaque, width, height...) from 'src' and copy them
// into 'dst'. Mark 'dst' as not owning any memory.
static void PictureGrabSpecs(const WebPPicture* const src,
WebPPicture* const dst) {
assert(src != NULL && dst != NULL);
*dst = *src;
WebPPictureResetBuffers(dst);
}
//------------------------------------------------------------------------------
// Adjust top-left corner to chroma sample position.
static void SnapTopLeftPosition(const WebPPicture* const pic,
int* const left, int* const top) {
if (!pic->use_argb) {
*left &= ~1;
*top &= ~1;
}
}
// Adjust top-left corner and verify that the sub-rectangle is valid.
static int AdjustAndCheckRectangle(const WebPPicture* const pic,
int* const left, int* const top,
int width, int height) {
SnapTopLeftPosition(pic, left, top);
if ((*left) < 0 || (*top) < 0) return 0;
if (width <= 0 || height <= 0) return 0;
if ((*left) + width > pic->width) return 0;
if ((*top) + height > pic->height) return 0;
return 1;
}
int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) {
if (src == NULL || dst == NULL) return 0;
if (src == dst) return 1;
PictureGrabSpecs(src, dst);
if (!WebPPictureAlloc(dst)) return 0;
if (!src->use_argb) {
WebPCopyPlane(src->y, src->y_stride,
dst->y, dst->y_stride, dst->width, dst->height);
WebPCopyPlane(src->u, src->uv_stride, dst->u, dst->uv_stride,
HALVE(dst->width), HALVE(dst->height));
WebPCopyPlane(src->v, src->uv_stride, dst->v, dst->uv_stride,
HALVE(dst->width), HALVE(dst->height));
if (dst->a != NULL) {
WebPCopyPlane(src->a, src->a_stride,
dst->a, dst->a_stride, dst->width, dst->height);
}
} else {
WebPCopyPlane((const uint8_t*)src->argb, 4 * src->argb_stride,
(uint8_t*)dst->argb, 4 * dst->argb_stride,
4 * dst->width, dst->height);
}
return 1;
}
int WebPPictureIsView(const WebPPicture* picture) {
if (picture == NULL) return 0;
if (picture->use_argb) {
return (picture->memory_argb_ == NULL);
}
return (picture->memory_ == NULL);
}
int WebPPictureView(const WebPPicture* src,
int left, int top, int width, int height,
WebPPicture* dst) {
if (src == NULL || dst == NULL) return 0;
// verify rectangle position.
if (!AdjustAndCheckRectangle(src, &left, &top, width, height)) return 0;
if (src != dst) { // beware of aliasing! We don't want to leak 'memory_'.
PictureGrabSpecs(src, dst);
}
dst->width = width;
dst->height = height;
if (!src->use_argb) {
dst->y = src->y + top * src->y_stride + left;
dst->u = src->u + (top >> 1) * src->uv_stride + (left >> 1);
dst->v = src->v + (top >> 1) * src->uv_stride + (left >> 1);
dst->y_stride = src->y_stride;
dst->uv_stride = src->uv_stride;
if (src->a != NULL) {
dst->a = src->a + top * src->a_stride + left;
dst->a_stride = src->a_stride;
}
} else {
dst->argb = src->argb + top * src->argb_stride + left;
dst->argb_stride = src->argb_stride;
}
return 1;
}
//------------------------------------------------------------------------------
// Picture cropping
int WebPPictureCrop(WebPPicture* pic,
int left, int top, int width, int height) {
WebPPicture tmp;
if (pic == NULL) return 0;
if (!AdjustAndCheckRectangle(pic, &left, &top, width, height)) return 0;
PictureGrabSpecs(pic, &tmp);
tmp.width = width;
tmp.height = height;
if (!WebPPictureAlloc(&tmp)) return 0;
if (!pic->use_argb) {
const int y_offset = top * pic->y_stride + left;
const int uv_offset = (top / 2) * pic->uv_stride + left / 2;
WebPCopyPlane(pic->y + y_offset, pic->y_stride,
tmp.y, tmp.y_stride, width, height);
WebPCopyPlane(pic->u + uv_offset, pic->uv_stride,
tmp.u, tmp.uv_stride, HALVE(width), HALVE(height));
WebPCopyPlane(pic->v + uv_offset, pic->uv_stride,
tmp.v, tmp.uv_stride, HALVE(width), HALVE(height));
if (tmp.a != NULL) {
const int a_offset = top * pic->a_stride + left;
WebPCopyPlane(pic->a + a_offset, pic->a_stride,
tmp.a, tmp.a_stride, width, height);
}
} else {
const uint8_t* const src =
(const uint8_t*)(pic->argb + top * pic->argb_stride + left);
WebPCopyPlane(src, pic->argb_stride * 4, (uint8_t*)tmp.argb,
tmp.argb_stride * 4, width * 4, height);
}
WebPPictureFree(pic);
*pic = tmp;
return 1;
}
//------------------------------------------------------------------------------
// Simple picture rescaler
static int RescalePlane(const uint8_t* src,
int src_width, int src_height, int src_stride,
uint8_t* dst,
int dst_width, int dst_height, int dst_stride,
rescaler_t* const work,
int num_channels) {
WebPRescaler rescaler;
int y = 0;
if (!WebPRescalerInit(&rescaler, src_width, src_height,
dst, dst_width, dst_height, dst_stride,
num_channels, work)) {
return 0;
}
while (y < src_height) {
y += WebPRescalerImport(&rescaler, src_height - y,
src + y * src_stride, src_stride);
WebPRescalerExport(&rescaler);
}
return 1;
}
static void AlphaMultiplyARGB(WebPPicture* const pic, int inverse) {
assert(pic->argb != NULL);
WebPMultARGBRows((uint8_t*)pic->argb, pic->argb_stride * sizeof(*pic->argb),
pic->width, pic->height, inverse);
}
static void AlphaMultiplyY(WebPPicture* const pic, int inverse) {
if (pic->a != NULL) {
WebPMultRows(pic->y, pic->y_stride, pic->a, pic->a_stride,
pic->width, pic->height, inverse);
}
}
int WebPPictureRescale(WebPPicture* pic, int width, int height) {
WebPPicture tmp;
int prev_width, prev_height;
rescaler_t* work;
if (pic == NULL) return 0;
prev_width = pic->width;
prev_height = pic->height;
if (!WebPRescalerGetScaledDimensions(
prev_width, prev_height, &width, &height)) {
return 0;
}
PictureGrabSpecs(pic, &tmp);
tmp.width = width;
tmp.height = height;
if (!WebPPictureAlloc(&tmp)) return 0;
if (!pic->use_argb) {
work = (rescaler_t*)WebPSafeMalloc(2ULL * width, sizeof(*work));
if (work == NULL) {
WebPPictureFree(&tmp);
return 0;
}
// If present, we need to rescale alpha first (for AlphaMultiplyY).
if (pic->a != NULL) {
WebPInitAlphaProcessing();
if (!RescalePlane(pic->a, prev_width, prev_height, pic->a_stride,
tmp.a, width, height, tmp.a_stride, work, 1)) {
return 0;
}
}
// We take transparency into account on the luma plane only. That's not
// totally exact blending, but still is a good approximation.
AlphaMultiplyY(pic, 0);
if (!RescalePlane(pic->y, prev_width, prev_height, pic->y_stride,
tmp.y, width, height, tmp.y_stride, work, 1) ||
!RescalePlane(pic->u,
HALVE(prev_width), HALVE(prev_height), pic->uv_stride,
tmp.u,
HALVE(width), HALVE(height), tmp.uv_stride, work, 1) ||
!RescalePlane(pic->v,
HALVE(prev_width), HALVE(prev_height), pic->uv_stride,
tmp.v,
HALVE(width), HALVE(height), tmp.uv_stride, work, 1)) {
return 0;
}
AlphaMultiplyY(&tmp, 1);
} else {
work = (rescaler_t*)WebPSafeMalloc(2ULL * width * 4, sizeof(*work));
if (work == NULL) {
WebPPictureFree(&tmp);
return 0;
}
// In order to correctly interpolate colors, we need to apply the alpha
// weighting first (black-matting), scale the RGB values, and remove
// the premultiplication afterward (while preserving the alpha channel).
WebPInitAlphaProcessing();
AlphaMultiplyARGB(pic, 0);
if (!RescalePlane((const uint8_t*)pic->argb, prev_width, prev_height,
pic->argb_stride * 4,
(uint8_t*)tmp.argb, width, height,
tmp.argb_stride * 4, work, 4)) {
return 0;
}
AlphaMultiplyARGB(&tmp, 1);
}
WebPPictureFree(pic);
WebPSafeFree(work);
*pic = tmp;
return 1;
}
#else // defined(WEBP_REDUCE_SIZE)
int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) {
(void)src;
(void)dst;
return 0;
}
int WebPPictureIsView(const WebPPicture* picture) {
(void)picture;
return 0;
}
int WebPPictureView(const WebPPicture* src,
int left, int top, int width, int height,
WebPPicture* dst) {
(void)src;
(void)left;
(void)top;
(void)width;
(void)height;
(void)dst;
return 0;
}
int WebPPictureCrop(WebPPicture* pic,
int left, int top, int width, int height) {
(void)pic;
(void)left;
(void)top;
(void)width;
(void)height;
return 0;
}
int WebPPictureRescale(WebPPicture* pic, int width, int height) {
(void)pic;
(void)width;
(void)height;
return 0;
}
#endif // !defined(WEBP_REDUCE_SIZE)