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       case FilterOperation::ALPHA_THRESHOLD:
 106         break;
 107     }
 108   }
 109   return false;
 110 }
 111
 112 bool FilterOperations::HasFilterThatAffectsOpacity() const {
 113   for (size_t i = 0; i < operations_.size(); ++i) {
 114     const FilterOperation& op = operations_[i];
 115     // TODO(ajuma): Make this smarter for reference filters. Once SkImageFilter
 116     // can report affectsOpacity(), call that.
 117     switch (op.type()) {
 118       case FilterOperation::OPACITY:
 119       case FilterOperation::BLUR:
 120       case FilterOperation::DROP_SHADOW:
 121       case FilterOperation::ZOOM:
 122       case FilterOperation::REFERENCE:
 123       case FilterOperation::ALPHA_THRESHOLD:
 124         return true;
 125       case FilterOperation::COLOR_MATRIX: {
 126         const SkScalar* matrix = op.matrix();
 127         if (matrix[15] ||
 128             matrix[16] ||
 129             matrix[17] ||
 130             matrix[18] != 1 ||
 131             matrix[19])
 132           return true;
 133         break;
 134       }
 135       case FilterOperation::GRAYSCALE:
 136       case FilterOperation::SEPIA:
 137       case FilterOperation::SATURATE:
 138       case FilterOperation::HUE_ROTATE:
 139       case FilterOperation::INVERT:
 140       case FilterOperation::BRIGHTNESS:
 141       case FilterOperation::CONTRAST:
 142       case FilterOperation::SATURATING_BRIGHTNESS:
 143         break;
 144     }
 145   }
 146   return false;
 147 }
 148
 149 bool FilterOperations::HasReferenceFilter() const {
 150   for (size_t i = 0; i < operations_.size(); ++i) {
 151     if (operations_[i].type() == FilterOperation::REFERENCE)
 152       return true;
 153   }
 154   return false;
 155 }
 156
 157 FilterOperations FilterOperations::Blend(const FilterOperations& from,
 158                                          double progress) const {
 159   if (HasReferenceFilter() || from.HasReferenceFilter())
 160     return *this;
 161
 162   bool from_is_longer = from.size() > size();
 163
 164   size_t shorter_size, longer_size;
 165   if (size() == from.size()) {
 166     shorter_size = longer_size = size();
 167   } else if  (from_is_longer) {
 168     longer_size = from.size();
 169     shorter_size = size();
 170   } else {
 171     longer_size = size();
 172     shorter_size = from.size();
 173   }
 174
 175   for (size_t i = 0; i < shorter_size; i++) {
 176     if (from.at(i).type() != at(i).type())
 177       return *this;
 178   }
 179
 180   FilterOperations blended_filters;
 181   for (size_t i = 0; i < shorter_size; i++) {
 182     blended_filters.Append(
 183         FilterOperation::Blend(&from.at(i), &at(i), progress));
 184   }
 185
 186   if (from_is_longer) {
 187     for (size_t i = shorter_size; i < longer_size; i++) {
 188       blended_filters.Append(
 189           FilterOperation::Blend(&from.at(i), NULL, progress));
 190     }
 191   } else {
 192     for (size_t i = shorter_size; i < longer_size; i++)
 193       blended_filters.Append(FilterOperation::Blend(NULL, &at(i), progress));
 194   }
 195
 196   return blended_filters;
 197 }
 198
 199 scoped_ptr<base::Value> FilterOperations::AsValue() const {
 200   scoped_ptr<base::ListValue> value(new base::ListValue);
 201   for (size_t i = 0; i < operations_.size(); ++i)
 202     value->Append(operations_[i].AsValue().release());
 203   return value.PassAs<base::Value>();
 204 }
 205
 206 }  // namespace cc