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Diffstat (limited to '')
-rw-r--r-- | src/main/jni/libwebp/enc/picture_rescale.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/src/main/jni/libwebp/enc/picture_rescale.c b/src/main/jni/libwebp/enc/picture_rescale.c new file mode 100644 index 000000000..de52848ce --- /dev/null +++ b/src/main/jni/libwebp/enc/picture_rescale.c @@ -0,0 +1,285 @@ +// 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); +} + +//------------------------------------------------------------------------------ +// Picture copying + +static void CopyPlane(const uint8_t* src, int src_stride, + uint8_t* dst, int dst_stride, int width, int height) { + while (height-- > 0) { + memcpy(dst, src, width); + src += src_stride; + dst += dst_stride; + } +} + +// 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) { + CopyPlane(src->y, src->y_stride, + dst->y, dst->y_stride, dst->width, dst->height); + CopyPlane(src->u, src->uv_stride, + dst->u, dst->uv_stride, HALVE(dst->width), HALVE(dst->height)); + CopyPlane(src->v, src->uv_stride, + dst->v, dst->uv_stride, HALVE(dst->width), HALVE(dst->height)); + if (dst->a != NULL) { + CopyPlane(src->a, src->a_stride, + dst->a, dst->a_stride, dst->width, dst->height); + } + } else { + CopyPlane((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; + CopyPlane(pic->y + y_offset, pic->y_stride, + tmp.y, tmp.y_stride, width, height); + CopyPlane(pic->u + uv_offset, pic->uv_stride, + tmp.u, tmp.uv_stride, HALVE(width), HALVE(height)); + CopyPlane(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; + CopyPlane(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); + CopyPlane(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, + int32_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, + src_width, dst_width, + src_height, dst_height, + work); + memset(work, 0, 2 * dst_width * num_channels * sizeof(*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; + int32_t* work; + + if (pic == NULL) return 0; + prev_width = pic->width; + prev_height = pic->height; + // if width is unspecified, scale original proportionally to height ratio. + if (width == 0) { + width = (prev_width * height + prev_height / 2) / prev_height; + } + // if height is unspecified, scale original proportionally to width ratio. + if (height == 0) { + height = (prev_height * width + prev_width / 2) / prev_width; + } + // Check if the overall dimensions still make sense. + if (width <= 0 || height <= 0) return 0; + + PictureGrabSpecs(pic, &tmp); + tmp.width = width; + tmp.height = height; + if (!WebPPictureAlloc(&tmp)) return 0; + + if (!pic->use_argb) { + work = (int32_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 = (int32_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; +} + +//------------------------------------------------------------------------------ |