// 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 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;

}

#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)