265 lines
9.0 KiB
C
265 lines
9.0 KiB
C
// Copyright 2014 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// WebPPicture tools: copy, crop, rescaling and view.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <assert.h>
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#include <stdlib.h>
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#include "./vp8i_enc.h"
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#include "../utils/rescaler_utils.h"
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#include "../utils/utils.h"
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#define HALVE(x) (((x) + 1) >> 1)
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// Grab the 'specs' (writer, *opaque, width, height...) from 'src' and copy them
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// into 'dst'. Mark 'dst' as not owning any memory.
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static void PictureGrabSpecs(const WebPPicture* const src,
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WebPPicture* const dst) {
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assert(src != NULL && dst != NULL);
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*dst = *src;
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WebPPictureResetBuffers(dst);
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}
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//------------------------------------------------------------------------------
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// Adjust top-left corner to chroma sample position.
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static void SnapTopLeftPosition(const WebPPicture* const pic,
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int* const left, int* const top) {
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if (!pic->use_argb) {
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*left &= ~1;
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*top &= ~1;
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}
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}
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// Adjust top-left corner and verify that the sub-rectangle is valid.
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static int AdjustAndCheckRectangle(const WebPPicture* const pic,
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int* const left, int* const top,
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int width, int height) {
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SnapTopLeftPosition(pic, left, top);
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if ((*left) < 0 || (*top) < 0) return 0;
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if (width <= 0 || height <= 0) return 0;
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if ((*left) + width > pic->width) return 0;
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if ((*top) + height > pic->height) return 0;
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return 1;
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}
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int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) {
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if (src == NULL || dst == NULL) return 0;
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if (src == dst) return 1;
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PictureGrabSpecs(src, dst);
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if (!WebPPictureAlloc(dst)) return 0;
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if (!src->use_argb) {
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WebPCopyPlane(src->y, src->y_stride,
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dst->y, dst->y_stride, dst->width, dst->height);
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WebPCopyPlane(src->u, src->uv_stride, dst->u, dst->uv_stride,
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HALVE(dst->width), HALVE(dst->height));
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WebPCopyPlane(src->v, src->uv_stride, dst->v, dst->uv_stride,
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HALVE(dst->width), HALVE(dst->height));
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if (dst->a != NULL) {
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WebPCopyPlane(src->a, src->a_stride,
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dst->a, dst->a_stride, dst->width, dst->height);
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}
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} else {
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WebPCopyPlane((const uint8_t*)src->argb, 4 * src->argb_stride,
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(uint8_t*)dst->argb, 4 * dst->argb_stride,
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4 * dst->width, dst->height);
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}
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return 1;
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}
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int WebPPictureIsView(const WebPPicture* picture) {
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if (picture == NULL) return 0;
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if (picture->use_argb) {
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return (picture->memory_argb_ == NULL);
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}
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return (picture->memory_ == NULL);
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}
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int WebPPictureView(const WebPPicture* src,
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int left, int top, int width, int height,
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WebPPicture* dst) {
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if (src == NULL || dst == NULL) return 0;
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// verify rectangle position.
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if (!AdjustAndCheckRectangle(src, &left, &top, width, height)) return 0;
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if (src != dst) { // beware of aliasing! We don't want to leak 'memory_'.
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PictureGrabSpecs(src, dst);
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}
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dst->width = width;
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dst->height = height;
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if (!src->use_argb) {
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dst->y = src->y + top * src->y_stride + left;
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dst->u = src->u + (top >> 1) * src->uv_stride + (left >> 1);
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dst->v = src->v + (top >> 1) * src->uv_stride + (left >> 1);
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dst->y_stride = src->y_stride;
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dst->uv_stride = src->uv_stride;
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if (src->a != NULL) {
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dst->a = src->a + top * src->a_stride + left;
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dst->a_stride = src->a_stride;
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}
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} else {
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dst->argb = src->argb + top * src->argb_stride + left;
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dst->argb_stride = src->argb_stride;
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}
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return 1;
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}
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//------------------------------------------------------------------------------
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// Picture cropping
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int WebPPictureCrop(WebPPicture* pic,
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int left, int top, int width, int height) {
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WebPPicture tmp;
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if (pic == NULL) return 0;
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if (!AdjustAndCheckRectangle(pic, &left, &top, width, height)) return 0;
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PictureGrabSpecs(pic, &tmp);
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tmp.width = width;
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tmp.height = height;
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if (!WebPPictureAlloc(&tmp)) return 0;
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if (!pic->use_argb) {
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const int y_offset = top * pic->y_stride + left;
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const int uv_offset = (top / 2) * pic->uv_stride + left / 2;
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WebPCopyPlane(pic->y + y_offset, pic->y_stride,
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tmp.y, tmp.y_stride, width, height);
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WebPCopyPlane(pic->u + uv_offset, pic->uv_stride,
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tmp.u, tmp.uv_stride, HALVE(width), HALVE(height));
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WebPCopyPlane(pic->v + uv_offset, pic->uv_stride,
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tmp.v, tmp.uv_stride, HALVE(width), HALVE(height));
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if (tmp.a != NULL) {
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const int a_offset = top * pic->a_stride + left;
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WebPCopyPlane(pic->a + a_offset, pic->a_stride,
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tmp.a, tmp.a_stride, width, height);
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}
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} else {
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const uint8_t* const src =
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(const uint8_t*)(pic->argb + top * pic->argb_stride + left);
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WebPCopyPlane(src, pic->argb_stride * 4, (uint8_t*)tmp.argb,
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tmp.argb_stride * 4, width * 4, height);
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}
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WebPPictureFree(pic);
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*pic = tmp;
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return 1;
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}
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//------------------------------------------------------------------------------
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// Simple picture rescaler
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static void RescalePlane(const uint8_t* src,
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int src_width, int src_height, int src_stride,
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uint8_t* dst,
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int dst_width, int dst_height, int dst_stride,
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rescaler_t* const work,
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int num_channels) {
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WebPRescaler rescaler;
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int y = 0;
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WebPRescalerInit(&rescaler, src_width, src_height,
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dst, dst_width, dst_height, dst_stride,
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num_channels, work);
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while (y < src_height) {
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y += WebPRescalerImport(&rescaler, src_height - y,
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src + y * src_stride, src_stride);
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WebPRescalerExport(&rescaler);
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}
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}
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static void AlphaMultiplyARGB(WebPPicture* const pic, int inverse) {
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assert(pic->argb != NULL);
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WebPMultARGBRows((uint8_t*)pic->argb, pic->argb_stride * sizeof(*pic->argb),
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pic->width, pic->height, inverse);
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}
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static void AlphaMultiplyY(WebPPicture* const pic, int inverse) {
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if (pic->a != NULL) {
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WebPMultRows(pic->y, pic->y_stride, pic->a, pic->a_stride,
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pic->width, pic->height, inverse);
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}
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}
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int WebPPictureRescale(WebPPicture* pic, int width, int height) {
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WebPPicture tmp;
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int prev_width, prev_height;
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rescaler_t* work;
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if (pic == NULL) return 0;
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prev_width = pic->width;
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prev_height = pic->height;
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if (!WebPRescalerGetScaledDimensions(
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prev_width, prev_height, &width, &height)) {
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return 0;
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}
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PictureGrabSpecs(pic, &tmp);
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tmp.width = width;
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tmp.height = height;
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if (!WebPPictureAlloc(&tmp)) return 0;
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if (!pic->use_argb) {
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work = (rescaler_t*)WebPSafeMalloc(2ULL * width, sizeof(*work));
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if (work == NULL) {
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WebPPictureFree(&tmp);
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return 0;
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}
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// If present, we need to rescale alpha first (for AlphaMultiplyY).
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if (pic->a != NULL) {
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WebPInitAlphaProcessing();
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RescalePlane(pic->a, prev_width, prev_height, pic->a_stride,
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tmp.a, width, height, tmp.a_stride, work, 1);
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}
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// We take transparency into account on the luma plane only. That's not
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// totally exact blending, but still is a good approximation.
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AlphaMultiplyY(pic, 0);
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RescalePlane(pic->y, prev_width, prev_height, pic->y_stride,
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tmp.y, width, height, tmp.y_stride, work, 1);
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AlphaMultiplyY(&tmp, 1);
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RescalePlane(pic->u,
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HALVE(prev_width), HALVE(prev_height), pic->uv_stride,
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tmp.u,
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HALVE(width), HALVE(height), tmp.uv_stride, work, 1);
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RescalePlane(pic->v,
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HALVE(prev_width), HALVE(prev_height), pic->uv_stride,
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tmp.v,
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HALVE(width), HALVE(height), tmp.uv_stride, work, 1);
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} else {
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work = (rescaler_t*)WebPSafeMalloc(2ULL * width * 4, sizeof(*work));
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if (work == NULL) {
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WebPPictureFree(&tmp);
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return 0;
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}
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// In order to correctly interpolate colors, we need to apply the alpha
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// weighting first (black-matting), scale the RGB values, and remove
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// the premultiplication afterward (while preserving the alpha channel).
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WebPInitAlphaProcessing();
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AlphaMultiplyARGB(pic, 0);
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RescalePlane((const uint8_t*)pic->argb, prev_width, prev_height,
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pic->argb_stride * 4,
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(uint8_t*)tmp.argb, width, height,
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tmp.argb_stride * 4,
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work, 4);
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AlphaMultiplyARGB(&tmp, 1);
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}
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WebPPictureFree(pic);
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WebPSafeFree(work);
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*pic = tmp;
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return 1;
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}
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//------------------------------------------------------------------------------
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