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