cc/output/filter_operations.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/output/filter_operations.h"
   6
   7 #include <cmath>
   8
   9 #include "base/debug/trace_event_argument.h"
  10 #include "base/values.h"
  11 #include "cc/output/filter_operation.h"
  12
  13 namespace cc {
  14
  15 FilterOperations::FilterOperations() {}
  16
  17 FilterOperations::FilterOperations(const FilterOperations& other)
  18     : operations_(other.operations_) {}
  19
  20 FilterOperations::~FilterOperations() {}
  21
  22 FilterOperations& FilterOperations::operator=(const FilterOperations& other) {
  23   operations_ = other.operations_;
  24   return *this;
  25 }
  26
  27 bool FilterOperations::operator==(const FilterOperations& other) const {
  28   if (other.size() != size())
  29     return false;
  30   for (size_t i = 0; i < size(); ++i) {
  31     if (other.at(i) != at(i))
  32       return false;
  33   }
  34   return true;
  35 }
  36
  37 void FilterOperations::Append(const FilterOperation& filter) {
  38   operations_.push_back(filter);
  39 }
  40
  41 void FilterOperations::Clear() {
  42   operations_.clear();
  43 }
  44
  45 bool FilterOperations::IsEmpty() const {
  46   return operations_.empty();
  47 }
  48
  49 static int SpreadForStdDeviation(float std_deviation) {
  50   // https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#feGaussianBlurElement
  51   // provides this approximation for evaluating a gaussian blur by a triple box
  52   // filter.
  53   float d = floorf(std_deviation * 3.f * sqrt(8.f * atan(1.f)) / 4.f + 0.5f);
  54   return static_cast<int>(ceilf(d * 3.f / 2.f));
  55 }
  56
  57 void FilterOperations::GetOutsets(int* top,
  58                                   int* right,
  59                                   int* bottom,
  60                                   int* left) const {
  61   *top = *right = *bottom = *left = 0;
  62   for (size_t i = 0; i < operations_.size(); ++i) {
  63     const FilterOperation& op = operations_[i];
  64     // TODO(ajuma): Add support for reference filters once SkImageFilter
  65     // reports its outsets.
  66     DCHECK(op.type() != FilterOperation::REFERENCE);
  67     if (op.type() == FilterOperation::BLUR ||
  68         op.type() == FilterOperation::DROP_SHADOW) {
  69       int spread = SpreadForStdDeviation(op.amount());
  70       if (op.type() == FilterOperation::BLUR) {
  71         *top += spread;
  72         *right += spread;
  73         *bottom += spread;
  74         *left += spread;
  75       } else {
  76         *top += spread - op.drop_shadow_offset().y();
  77         *right += spread + op.drop_shadow_offset().x();
  78         *bottom += spread + op.drop_shadow_offset().y();
  79         *left += spread - op.drop_shadow_offset().x();
  80       }
  81     }
  82   }
  83 }
  84
  85 bool FilterOperations::HasFilterThatMovesPixels() const {
  86   for (size_t i = 0; i < operations_.size(); ++i) {
  87     const FilterOperation& op = operations_[i];
  88     // TODO(ajuma): Once SkImageFilter reports its outsets, use those here to
  89     // determine whether a reference filter really moves pixels.
  90     switch (op.type()) {
  91       case FilterOperation::BLUR:
  92       case FilterOperation::DROP_SHADOW:
  93       case FilterOperation::ZOOM:
  94       case FilterOperation::REFERENCE:
  95         return true;
  96       case FilterOperation::OPACITY:
  97       case FilterOperation::COLOR_MATRIX:
  98       case FilterOperation::GRAYSCALE:
  99       case FilterOperation::SEPIA:
 100       case FilterOperation::SATURATE:
 101       case FilterOperation::HUE_ROTATE:
 102       case FilterOperation::INVERT:
 103       case FilterOperation::BRIGHTNESS:
 104       case FilterOperation::CONTRAST:
 105       case FilterOperation::SATURATING_BRIGHTNESS:
 106       case FilterOperation::ALPHA_THRESHOLD:
 107         break;
 108     }
 109   }
 110   return false;
 111 }
 112
 113 bool FilterOperations::HasFilterThatAffectsOpacity() const {
 114   for (size_t i = 0; i < operations_.size(); ++i) {
 115     const FilterOperation& op = operations_[i];
 116     // TODO(ajuma): Make this smarter for reference filters. Once SkImageFilter
 117     // can report affectsOpacity(), call that.
 118     switch (op.type()) {
 119       case FilterOperation::OPACITY:
 120       case FilterOperation::BLUR:
 121       case FilterOperation::DROP_SHADOW:
 122       case FilterOperation::ZOOM:
 123       case FilterOperation::REFERENCE:
 124       case FilterOperation::ALPHA_THRESHOLD:
 125         return true;
 126       case FilterOperation::COLOR_MATRIX: {
 127         const SkScalar* matrix = op.matrix();
 128         if (matrix[15] ||
 129             matrix[16] ||
 130             matrix[17] ||
 131             matrix[18] != 1 ||
 132             matrix[19])
 133           return true;
 134         break;
 135       }
 136       case FilterOperation::GRAYSCALE:
 137       case FilterOperation::SEPIA:
 138       case FilterOperation::SATURATE:
 139       case FilterOperation::HUE_ROTATE:
 140       case FilterOperation::INVERT:
 141       case FilterOperation::BRIGHTNESS:
 142       case FilterOperation::CONTRAST:
 143       case FilterOperation::SATURATING_BRIGHTNESS:
 144         break;
 145     }
 146   }
 147   return false;
 148 }
 149
 150 bool FilterOperations::HasReferenceFilter() const {
 151   for (size_t i = 0; i < operations_.size(); ++i) {
 152     if (operations_[i].type() == FilterOperation::REFERENCE)
 153       return true;
 154   }
 155   return false;
 156 }
 157
 158 FilterOperations FilterOperations::Blend(const FilterOperations& from,
 159                                          double progress) const {
 160   if (HasReferenceFilter() || from.HasReferenceFilter())
 161     return *this;
 162
 163   bool from_is_longer = from.size() > size();
 164
 165   size_t shorter_size, longer_size;
 166   if (size() == from.size()) {
 167     shorter_size = longer_size = size();
 168   } else if  (from_is_longer) {
 169     longer_size = from.size();
 170     shorter_size = size();
 171   } else {
 172     longer_size = size();
 173     shorter_size = from.size();
 174   }
 175
 176   for (size_t i = 0; i < shorter_size; i++) {
 177     if (from.at(i).type() != at(i).type())
 178       return *this;
 179   }
 180
 181   FilterOperations blended_filters;
 182   for (size_t i = 0; i < shorter_size; i++) {
 183     blended_filters.Append(
 184         FilterOperation::Blend(&from.at(i), &at(i), progress));
 185   }
 186
 187   if (from_is_longer) {
 188     for (size_t i = shorter_size; i < longer_size; i++) {
 189       blended_filters.Append(
 190           FilterOperation::Blend(&from.at(i), NULL, progress));
 191     }
 192   } else {
 193     for (size_t i = shorter_size; i < longer_size; i++)
 194       blended_filters.Append(FilterOperation::Blend(NULL, &at(i), progress));
 195   }
 196
 197   return blended_filters;
 198 }
 199
 200 void FilterOperations::AsValueInto(base::debug::TracedValue* value) const {
 201   for (size_t i = 0; i < operations_.size(); ++i) {
 202     value->BeginDictionary();
 203     operations_[i].AsValueInto(value);
 204     value->EndDictionary();
 205   }
 206 }
 207
 208 }  // namespace cc