| // 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 <assert.h> |
| #include <stdlib.h> |
| |
| #include "./vp8enci.h" |
| #include "../utils/rescaler.h" |
| #include "../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 void 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; |
| WebPRescalerInit(&rescaler, src_width, src_height, |
| dst, dst_width, dst_height, dst_stride, |
| num_channels, work); |
| while (y < src_height) { |
| y += WebPRescalerImport(&rescaler, src_height - y, |
| src + y * src_stride, src_stride); |
| WebPRescalerExport(&rescaler); |
| } |
| } |
| |
| 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(); |
| RescalePlane(pic->a, prev_width, prev_height, pic->a_stride, |
| tmp.a, width, height, tmp.a_stride, work, 1); |
| } |
| |
| // 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); |
| RescalePlane(pic->y, prev_width, prev_height, pic->y_stride, |
| tmp.y, width, height, tmp.y_stride, work, 1); |
| AlphaMultiplyY(&tmp, 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); |
| } 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); |
| 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); |
| AlphaMultiplyARGB(&tmp, 1); |
| } |
| WebPPictureFree(pic); |
| WebPSafeFree(work); |
| *pic = tmp; |
| return 1; |
| } |
| |
| //------------------------------------------------------------------------------ |
