responsive_image_filter.h

Go to the documentation of this file.

/*
 * Copyright 2014 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef NET_INSTAWEB_REWRITER_PUBLIC_RESPONSIVE_IMAGE_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_RESPONSIVE_IMAGE_FILTER_H_

#include <map>
#include <vector>

#include "net/instaweb/rewriter/public/common_filter.h"
#include "net/instaweb/rewriter/public/rewrite_driver.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/html/html_element.h"
#include "pagespeed/kernel/html/html_filter.h"

namespace net_instaweb {

struct ResponsiveImageCandidate {
  ResponsiveImageCandidate(HtmlElement* element_arg, double resolution_arg)
      : element(element_arg), resolution(resolution_arg) {}
  ResponsiveImageCandidate() : element(NULL), resolution(0) {}

  HtmlElement* element;
  double resolution;
};
typedef std::vector<ResponsiveImageCandidate> ResponsiveImageCandidateVector;

struct ResponsiveVirtualImages {
  int width;
  int height;
  ResponsiveImageCandidateVector non_inlinable_candidates;
  ResponsiveImageCandidate inlinable_candidate;
  ResponsiveImageCandidate fullsized_candidate;
};
typedef std::map<HtmlElement*, ResponsiveVirtualImages>
        ResponsiveImageCandidateMap;

class ResponsiveImageFirstFilter : public CommonFilter {
 public:
  static const char kOriginalImage[];
  static const char kNonInlinableVirtualImage[];
  static const char kInlinableVirtualImage[];
  static const char kFullsizedVirtualImage[];

  explicit ResponsiveImageFirstFilter(RewriteDriver* driver);
  virtual ~ResponsiveImageFirstFilter();

  virtual void StartElementImpl(HtmlElement* element) {}
  virtual void StartDocumentImpl();
  virtual void EndElementImpl(HtmlElement* element);

  virtual const char* Name() const { return "ResponsiveImageFirst"; }

 private:
  void AddHiResImages(HtmlElement* element);
  ResponsiveImageCandidate AddHiResVersion(
      HtmlElement* img, const HtmlElement::Attribute& src_attr,
      int orig_width, int orig_height, StringPiece responsive_attribute_value,
      double resolution);

  friend class ResponsiveImageSecondFilter;

  std::vector<double> densities_;
  ResponsiveImageCandidateMap candidate_map_;

  
};

class ResponsiveImageSecondFilter : public CommonFilter {
 public:
  ResponsiveImageSecondFilter(
      RewriteDriver* driver, const ResponsiveImageFirstFilter* first_filter);
  virtual ~ResponsiveImageSecondFilter();

  virtual void StartElementImpl(HtmlElement* element) {}
  virtual void StartDocumentImpl();
  virtual void EndElementImpl(HtmlElement* element);
  virtual void EndDocument();

  virtual const char* Name() const { return "ResponsiveImageSecond"; }

  ScriptUsage GetScriptUsage() const override { return kMayInjectScripts; }

 private:
  void CombineHiResImages(HtmlElement* orig_element,
                          const ResponsiveVirtualImages& candidates);
  void Cleanup(HtmlElement* orig_element,
               const ResponsiveVirtualImages& candidates);
  void InsertPlaceholderDebugComment(
      const ResponsiveImageCandidate& candidate, const char* qualifier);

  const GoogleString responsive_js_url_;
  const ResponsiveImageFirstFilter* first_filter_;
  bool zoom_filter_enabled_;
  bool srcsets_added_;

  
};

}  

#endif