Source/core/rendering/FastTextAutosizer.h

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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#ifndef FastTextAutosizer_h
#define FastTextAutosizer_h

#include "wtf/HashMap.h"
#include "wtf/HashSet.h"
#include "wtf/Noncopyable.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/text/AtomicStringHash.h"

namespace WebCore {

class Document;
class RenderBlock;

// Single-pass text autosizer (work in progress). Works in two stages:
// (1) record information about page elements during style recalc
// (2) inflate sizes during layout
// See: http://tinyurl.com/chromium-fast-autosizer

class FastTextAutosizer FINAL {
    WTF_MAKE_NONCOPYABLE(FastTextAutosizer);

public:
    static PassOwnPtr<FastTextAutosizer> create(Document* document)
    {
        return adoptPtr(new FastTextAutosizer(document));
    }

    void record(const RenderBlock*);
    void destroy(const RenderBlock*);
    void inflate(RenderBlock*);

private:
    // TODO: make a proper API for this class?
    struct Cluster {
        explicit Cluster(AtomicString fingerprint)
            : m_fingerprint(fingerprint)
            , m_multiplier(0)
        {
        }

        AtomicString m_fingerprint;
        WTF::HashSet<const RenderBlock*> m_blocks;
        float m_multiplier;
    };

    explicit FastTextAutosizer(Document*);

    AtomicString fingerprint(const RenderBlock*);
    float computeMultiplier(const Cluster*);

    Document* m_document;

    WTF::HashMap<const RenderBlock*, Cluster*> m_clusterForBlock;
    WTF::HashMap<AtomicString, OwnPtr<Cluster> > m_clusterForFingerprint;
};

} // namespace WebCore

#endif // FastTextAutosizer_h