gecko-dev/layout/base/MobileViewportManager.h

125 строки
5.0 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MobileViewportManager_h_
#define MobileViewportManager_h_
#include "mozilla/Maybe.h"
#include "nsCOMPtr.h"
#include "nsIDOMEventListener.h"
#include "nsIObserver.h"
#include "Units.h"
class nsIDocument;
class nsIPresShell;
class nsViewportInfo;
namespace mozilla {
namespace dom {
class EventTarget;
} // namespace dom
} // namespace mozilla
class MobileViewportManager final : public nsIDOMEventListener
, public nsIObserver
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIDOMEVENTLISTENER
NS_DECL_NSIOBSERVER
MobileViewportManager(nsIPresShell* aPresShell,
nsIDocument* aDocument);
void Destroy();
/* Provide a resolution to use during the first paint instead of the default
* resolution computed from the viewport info metadata. This is in the same
* "units" as the argument to nsDOMWindowUtils::SetResolutionAndScaleTo.
* Also takes the previous display dimensions as they were at the time the
* resolution was stored in order to correctly adjust the resolution if the
* device was rotated in the meantime. */
void SetRestoreResolution(float aResolution,
mozilla::LayoutDeviceIntSize aDisplaySize);
/* Compute the "intrinsic resolution", which is the smallest resolution at
* which the layout viewport fills the visual viewport. (In typical
* scenarios, where the aspect ratios of the two viewports match, it's the
* resolution at which they are the same size.)
*
* The returned resolution is suitable for passing to
* nsIPresShell::SetResolutionAndScaleTo(). It's not in typed units for
* reasons explained at the declaration of FrameMetrics::mPresShellResolution.
*/
float ComputeIntrinsicResolution() const;
private:
void SetRestoreResolution(float aResolution);
public:
/* Notify the MobileViewportManager that a reflow was requested in the
* presShell.*/
void RequestReflow();
/* Notify the MobileViewportManager that the resolution on the presShell was
* updated, and the visual viewport size needs to be updated. */
void ResolutionUpdated();
/* Called to compute the initial viewport on page load or before-first-paint,
* whichever happens first. Also called directly if we are created after the
* presShell is initialized. */
void SetInitialViewport();
private:
~MobileViewportManager();
/* Main helper method to update the CSS viewport and any other properties that
* need updating. */
void RefreshViewportSize(bool aForceAdjustResolution);
/* Secondary main helper method to update just the visual viewport size. */
void RefreshVisualViewportSize();
/* Helper to clamp the given zoom by the min/max in the viewport info. */
mozilla::CSSToScreenScale ClampZoom(const mozilla::CSSToScreenScale& aZoom,
const nsViewportInfo& aViewportInfo) const;
/* Helper to update the given resolution according to changed display and viewport widths. */
mozilla::LayoutDeviceToLayerScale
ScaleResolutionWithDisplayWidth(const mozilla::LayoutDeviceToLayerScale& aRes,
const float& aDisplayWidthChangeRatio,
const mozilla::CSSSize& aNewViewport,
const mozilla::CSSSize& aOldViewport);
/* Updates the presShell resolution and returns the new zoom. */
mozilla::CSSToScreenScale UpdateResolution(const nsViewportInfo& aViewportInfo,
const mozilla::ScreenIntSize& aDisplaySize,
const mozilla::CSSSize& aViewport,
const mozilla::Maybe<float>& aDisplayWidthChangeRatio);
void UpdateVisualViewportSize(const mozilla::ScreenIntSize& aDisplaySize,
const mozilla::CSSToScreenScale& aZoom);
/* Updates the displayport margins for the presShell's root scrollable frame */
void UpdateDisplayPortMargins();
/* Helper function for ComputeIntrinsicResolution(). */
mozilla::CSSToScreenScale ComputeIntrinsicScale(const nsViewportInfo& aViewportInfo,
const mozilla::ScreenIntSize& aDisplaySize,
const mozilla::CSSSize& aViewportSize) const;
nsCOMPtr<nsIDocument> mDocument;
nsIPresShell* MOZ_NON_OWNING_REF mPresShell; // raw ref since the presShell owns this
nsCOMPtr<mozilla::dom::EventTarget> mEventTarget;
bool mIsFirstPaint;
bool mPainted;
mozilla::LayoutDeviceIntSize mDisplaySize;
mozilla::CSSSize mMobileViewportSize;
mozilla::Maybe<float> mRestoreResolution;
mozilla::Maybe<mozilla::ScreenIntSize> mRestoreDisplaySize;
};
#endif