// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/paint/render_surface_filters.h"

#include <stddef.h>

#include <algorithm>
#include <utility>

#include "base/compiler_specific.h"
#include "base/containers/span.h"
#include "base/numerics/angle_conversions.h"
#include "cc/paint/filter_operation.h"
#include "cc/paint/filter_operations.h"
#include "cc/paint/paint_filter.h"
#include "third_party/skia/include/core/SkColorFilter.h"
#include "third_party/skia/include/core/SkRegion.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/skia_conversions.h"

namespace cc {

namespace {

void GetBrightnessMatrix(float amount, base::span<float, 20> matrix) {
  // Spec implementation
  // (http://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#brightnessEquivalent)
  // <feFunc[R|G|B] type="linear" slope="[amount]">
  std::ranges::fill(matrix, 0.0f);
  matrix[0] = matrix[6] = matrix[12] = amount;
  matrix[18] = 1.f;
}

void GetSaturatingBrightnessMatrix(float amount, base::span<float, 20> matrix) {
  // Legacy implementation used by internal clients.
  // <feFunc[R|G|B] type="linear" intercept="[amount]"/>
  std::ranges::fill(matrix, 0.0f);
  matrix[0] = matrix[6] = matrix[12] = matrix[18] = 1.f;
  matrix[4] = matrix[9] = matrix[14] = amount;
}

void GetContrastMatrix(float amount, base::span<float, 20> matrix) {
  std::ranges::fill(matrix, 0.0f);
  matrix[0] = matrix[6] = matrix[12] = amount;
  matrix[4] = matrix[9] = matrix[14] = (-0.5f * amount + 0.5f);
  matrix[18] = 1.f;
}

void GetSaturateMatrix(float amount, base::span<float, 20> matrix) {
  // Note, these values are computed to ensure MatrixNeedsClamping is false
  // for amount in [0..1]
  matrix[0] = 0.213f + 0.787f * amount;
  matrix[1] = 0.715f - 0.715f * amount;
  matrix[2] = 1.f - (matrix[0] + matrix[1]);
  matrix[3] = matrix[4] = 0.f;
  matrix[5] = 0.213f - 0.213f * amount;
  matrix[6] = 0.715f + 0.285f * amount;
  matrix[7] = 1.f - (matrix[5] + matrix[6]);
  matrix[8] = matrix[9] = 0.f;
  matrix[10] = 0.213f - 0.213f * amount;
  matrix[11] = 0.715f - 0.715f * amount;
  matrix[12] = 1.f - (matrix[10] + matrix[11]);
  matrix[13] = matrix[14] = 0.f;
  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
  matrix[18] = 1.f;
}

void GetHueRotateMatrix(float hue, base::span<float, 20> matrix) {
  float cos_hue = cosf(base::DegToRad(hue));
  float sin_hue = sinf(base::DegToRad(hue));
  matrix[0] = 0.213f + cos_hue * 0.787f - sin_hue * 0.213f;
  matrix[1] = 0.715f - cos_hue * 0.715f - sin_hue * 0.715f;
  matrix[2] = 0.072f - cos_hue * 0.072f + sin_hue * 0.928f;
  matrix[3] = matrix[4] = 0.f;
  matrix[5] = 0.213f - cos_hue * 0.213f + sin_hue * 0.143f;
  matrix[6] = 0.715f + cos_hue * 0.285f + sin_hue * 0.140f;
  matrix[7] = 0.072f - cos_hue * 0.072f - sin_hue * 0.283f;
  matrix[8] = matrix[9] = 0.f;
  matrix[10] = 0.213f - cos_hue * 0.213f - sin_hue * 0.787f;
  matrix[11] = 0.715f - cos_hue * 0.715f + sin_hue * 0.715f;
  matrix[12] = 0.072f + cos_hue * 0.928f + sin_hue * 0.072f;
  matrix[13] = matrix[14] = 0.f;
  matrix[15] = matrix[16] = matrix[17] = 0.f;
  matrix[18] = 1.f;
  matrix[19] = 0.f;
}

void GetInvertMatrix(float amount, base::span<float, 20> matrix) {
  std::ranges::fill(matrix, 0.0f);
  matrix[0] = matrix[6] = matrix[12] = 1.f - 2.f * amount;
  matrix[4] = matrix[9] = matrix[14] = amount;
  matrix[18] = 1.f;
}

void GetOpacityMatrix(float amount, base::span<float, 20> matrix) {
  std::ranges::fill(matrix, 0.0f);
  matrix[0] = matrix[6] = matrix[12] = 1.f;
  matrix[18] = amount;
}

void GetGrayscaleMatrix(float amount, base::span<float, 20> matrix) {
  // Note, these values are computed to ensure MatrixNeedsClamping is false
  // for amount in [0..1]
  matrix[0] = 0.2126f + 0.7874f * amount;
  matrix[1] = 0.7152f - 0.7152f * amount;
  matrix[2] = 1.f - (matrix[0] + matrix[1]);
  matrix[3] = matrix[4] = 0.f;

  matrix[5] = 0.2126f - 0.2126f * amount;
  matrix[6] = 0.7152f + 0.2848f * amount;
  matrix[7] = 1.f - (matrix[5] + matrix[6]);
  matrix[8] = matrix[9] = 0.f;

  matrix[10] = 0.2126f - 0.2126f * amount;
  matrix[11] = 0.7152f - 0.7152f * amount;
  matrix[12] = 1.f - (matrix[10] + matrix[11]);
  matrix[13] = matrix[14] = 0.f;

  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
  matrix[18] = 1.f;
}

void GetSepiaMatrix(float amount, base::span<float, 20> matrix) {
  matrix[0] = 0.393f + 0.607f * amount;
  matrix[1] = 0.769f - 0.769f * amount;
  matrix[2] = 0.189f - 0.189f * amount;
  matrix[3] = matrix[4] = 0.f;

  matrix[5] = 0.349f - 0.349f * amount;
  matrix[6] = 0.686f + 0.314f * amount;
  matrix[7] = 0.168f - 0.168f * amount;
  matrix[8] = matrix[9] = 0.f;

  matrix[10] = 0.272f - 0.272f * amount;
  matrix[11] = 0.534f - 0.534f * amount;
  matrix[12] = 0.131f + 0.869f * amount;
  matrix[13] = matrix[14] = 0.f;

  matrix[15] = matrix[16] = matrix[17] = matrix[19] = 0.f;
  matrix[18] = 1.f;
}

sk_sp<PaintFilter> CreateMatrixImageFilter(const float matrix[20],
                                           sk_sp<PaintFilter> input) {
  return sk_make_sp<ColorFilterPaintFilter>(ColorFilter::MakeMatrix(matrix),
                                            std::move(input));
}

}  // namespace

sk_sp<PaintFilter> RenderSurfaceFilters::BuildImageFilter(
    const FilterOperations& filters,
    const gfx::Rect& layer_bounds) {
  sk_sp<PaintFilter> image_filter;
  float matrix[20];
  for (size_t i = 0; i < filters.size(); ++i) {
    const FilterOperation& op = filters.at(i);
    switch (op.type()) {
      case FilterOperation::GRAYSCALE:
        GetGrayscaleMatrix(1.f - op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::SEPIA:
        GetSepiaMatrix(1.f - op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::SATURATE:
        GetSaturateMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::HUE_ROTATE:
        GetHueRotateMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::INVERT:
        GetInvertMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::OPACITY:
        GetOpacityMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::BRIGHTNESS:
        GetBrightnessMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::CONTRAST:
        GetContrastMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::BLUR: {
        // SkImageFilters::Blur requires a crop rect for well-defined tiling
        // behavior when the blur_tile_mode() is not kDecal. When that is not
        // kDecal, setting the crop to the provided layer bounds means that
        // tile mode will be applied to the layer's pixels inside its bounds,
        // but pixels outside its bounds will not be read. Its output will still
        // be cropped to the layer bounds automatically.
        // TODO(b/1451898): The software_renderer does not calculate correct
        // layer bounds (it's always empty), so rely on the legacy clamp
        // handling in Skia for now. Once software_renderer does provide layer
        // bounds, FilterOperations::MapRect could be updated to reflect this
        // cropping, since a clamped blur doesn't actually move pixels.
        SkRect sk_layer_bounds = gfx::RectToSkRect(layer_bounds);
        const PaintFilter::CropRect* crop_rect = nullptr;
        if (!sk_layer_bounds.isEmpty() &&
            op.blur_tile_mode() != SkTileMode::kDecal) {
          crop_rect = &sk_layer_bounds;
        }
        image_filter = sk_make_sp<BlurPaintFilter>(
            op.amount(), op.amount(), op.blur_tile_mode(),
            std::move(image_filter), crop_rect);
        break;
      }
      case FilterOperation::DROP_SHADOW:
        image_filter = sk_make_sp<DropShadowPaintFilter>(
            SkIntToScalar(op.offset().x()), SkIntToScalar(op.offset().y()),
            SkIntToScalar(op.amount()), SkIntToScalar(op.amount()),
            op.drop_shadow_color(),
            DropShadowPaintFilter::ShadowMode::kDrawShadowAndForeground,
            std::move(image_filter));
        break;
      case FilterOperation::COLOR_MATRIX:
        image_filter = CreateMatrixImageFilter(op.matrix().data(),
                                               std::move(image_filter));
        break;
      case FilterOperation::ZOOM: {
        DCHECK_GE(op.amount(), 1.0);
        // ZOOM limits its output to the layer bounds automatically, so if it's
        // empty, then it produces nothing (regardless of prior filter ops).
        if (layer_bounds.IsEmpty()) {
          image_filter = nullptr;
        } else {
          image_filter = sk_make_sp<MagnifierPaintFilter>(
              gfx::RectToSkRect(layer_bounds), op.amount(), op.zoom_inset(),
              std::move(image_filter));
        }
        break;
      }
      case FilterOperation::SATURATING_BRIGHTNESS:
        GetSaturatingBrightnessMatrix(op.amount(), matrix);
        image_filter = CreateMatrixImageFilter(matrix, std::move(image_filter));
        break;
      case FilterOperation::REFERENCE: {
        if (!op.image_filter())
          break;

        sk_sp<ColorFilter> cf;
        bool has_input = false;
        if (op.image_filter()->type() == PaintFilter::Type::kColorFilter &&
            !op.image_filter()->GetCropRect()) {
          auto* color_paint_filter =
              static_cast<ColorFilterPaintFilter*>(op.image_filter().get());
          cf = color_paint_filter->color_filter();
          has_input = !!color_paint_filter->input();
        }

        if (cf && !has_input) {
          image_filter = sk_make_sp<ColorFilterPaintFilter>(
              std::move(cf), std::move(image_filter));
        } else if (image_filter) {
          image_filter = sk_make_sp<ComposePaintFilter>(
              op.image_filter(), std::move(image_filter));
        } else {
          image_filter = op.image_filter();
        }
        break;
      }
      case FilterOperation::ALPHA_THRESHOLD: {
        SkRegion region;
        for (const gfx::Rect& rect : op.shape())
          region.op(gfx::RectToSkIRect(rect), SkRegion::kUnion_Op);
        image_filter = sk_make_sp<AlphaThresholdPaintFilter>(
            region, std::move(image_filter));
        break;
      }
      case FilterOperation::OFFSET: {
        image_filter = sk_make_sp<OffsetPaintFilter>(
            SkIntToScalar(op.offset().x()), SkIntToScalar(op.offset().y()),
            std::move(image_filter));
        break;
      }
    }
  }
  return image_filter;
}

}  // namespace cc