Source/web/PageScaleConstraintsSet.h

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#ifndef PageScaleConstraintsSet_h
#define PageScaleConstraintsSet_h

#include "core/dom/ViewportDescription.h"
#include "core/page/PageScaleConstraints.h"
#include "platform/Length.h"
#include "platform/geometry/IntSize.h"

namespace blink {

// This class harmonizes the viewport (particularly page scale) constraints from
// the meta viewport tag and other sources.
class PageScaleConstraintsSet {
public:
    PageScaleConstraintsSet();

    blink::PageScaleConstraints defaultConstraints() const;

    // Settings defined in the website's viewport tag, if viewport tag support
    // is enabled.
    const blink::PageScaleConstraints& pageDefinedConstraints() const { return m_pageDefinedConstraints; }
    void updatePageDefinedConstraints(const blink::ViewportDescription&, blink::Length legacyFallbackWidth);
    void adjustForAndroidWebViewQuirks(const blink::ViewportDescription&, int layoutFallbackWidth, float deviceScaleFactor, bool supportTargetDensityDPI, bool wideViewportQuirkEnabled, bool useWideViewport, bool loadWithOverviewMode, bool nonUserScalableQuirkEnabled);

    // Constraints may also be set from Chromium -- this overrides any
    // page-defined values.
    const blink::PageScaleConstraints& userAgentConstraints() const { return m_userAgentConstraints; }
    void setUserAgentConstraints(const blink::PageScaleConstraints&);

    // Actual computed values, taking into account the above plus the current
    // viewport size and document width.
    const blink::PageScaleConstraints& finalConstraints() const { return m_finalConstraints; }
    void computeFinalConstraints();
    void adjustFinalConstraintsToContentsSize(blink::IntSize contentsSize, int nonOverlayScrollbarWidth);

    void didChangeContentsSize(blink::IntSize contentsSize, float pageScaleFactor);

    // This should be set to true on each page load to note that the page scale
    // factor needs to be reset to its initial value.
    void setNeedsReset(bool);
    bool needsReset() const { return m_needsReset; }

    // This is set when one of the inputs to finalConstraints changes.
    bool constraintsDirty() const { return m_constraintsDirty; }

    void didChangeViewSize(const blink::IntSize&);

    blink::IntSize mainFrameSize(const blink::IntSize& contentsSize) const;

private:
    blink::PageScaleConstraints computeConstraintsStack() const;

    blink::PageScaleConstraints m_pageDefinedConstraints;
    blink::PageScaleConstraints m_userAgentConstraints;
    blink::PageScaleConstraints m_finalConstraints;

    int m_lastContentsWidth;
    blink::IntSize m_viewSize;

    bool m_needsReset;
    bool m_constraintsDirty;
};

} // namespace blink

#endif // PageScaleConstraintsSet_h