MobileViewportManager.cpp
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "MobileViewportManager.h"
#include "gfxPrefs.h"
#include "LayersLogging.h"
#include "nsIDOMEvent.h"
#include "nsIFrame.h"
#include "nsLayoutUtils.h"
#include "nsPresShell.h"
#include "nsViewManager.h"
#include "nsViewportInfo.h"
#include "UnitTransforms.h"
#include "nsIDocument.h"
#define MVM_LOG(...)
// #define MVM_LOG(...) printf_stderr("MVM: " __VA_ARGS__)
NS_IMPL_ISUPPORTS(MobileViewportManager, nsIDOMEventListener, nsIObserver)
static const nsLiteralString DOM_META_ADDED = NS_LITERAL_STRING("DOMMetaAdded");
static const nsLiteralString DOM_META_CHANGED = NS_LITERAL_STRING("DOMMetaChanged");
static const nsLiteralString FULL_ZOOM_CHANGE = NS_LITERAL_STRING("FullZoomChange");
static const nsLiteralString LOAD = NS_LITERAL_STRING("load");
static const nsLiteralCString BEFORE_FIRST_PAINT = NS_LITERAL_CSTRING("before-first-paint");
using namespace mozilla;
using namespace mozilla::layers;
MobileViewportManager::MobileViewportManager(nsIPresShell* aPresShell,
nsIDocument* aDocument)
: mDocument(aDocument)
, mPresShell(aPresShell)
, mIsFirstPaint(false)
, mPainted(false)
{
MOZ_ASSERT(mPresShell);
MOZ_ASSERT(mDocument);
MVM_LOG("%p: creating with presShell %p document %p\n", this, mPresShell, aDocument);
if (nsCOMPtr<nsPIDOMWindowOuter> window = mDocument->GetWindow()) {
mEventTarget = window->GetChromeEventHandler();
}
if (mEventTarget) {
mEventTarget->AddEventListener(DOM_META_ADDED, this, false);
mEventTarget->AddEventListener(DOM_META_CHANGED, this, false);
mEventTarget->AddEventListener(FULL_ZOOM_CHANGE, this, false);
mEventTarget->AddEventListener(LOAD, this, true);
}
nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
if (observerService) {
observerService->AddObserver(this, BEFORE_FIRST_PAINT.Data(), false);
}
}
MobileViewportManager::~MobileViewportManager()
{
}
void
MobileViewportManager::Destroy()
{
MVM_LOG("%p: destroying\n", this);
if (mEventTarget) {
mEventTarget->RemoveEventListener(DOM_META_ADDED, this, false);
mEventTarget->RemoveEventListener(DOM_META_CHANGED, this, false);
mEventTarget->RemoveEventListener(FULL_ZOOM_CHANGE, this, false);
mEventTarget->RemoveEventListener(LOAD, this, true);
mEventTarget = nullptr;
}
nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
if (observerService) {
observerService->RemoveObserver(this, BEFORE_FIRST_PAINT.Data());
}
mDocument = nullptr;
mPresShell = nullptr;
}
void
MobileViewportManager::SetRestoreResolution(float aResolution,
LayoutDeviceIntSize aDisplaySize)
{
mRestoreResolution = Some(aResolution);
ScreenIntSize restoreDisplaySize = ViewAs<ScreenPixel>(aDisplaySize,
PixelCastJustification::LayoutDeviceIsScreenForBounds);
mRestoreDisplaySize = Some(restoreDisplaySize);
}
void
MobileViewportManager::RequestReflow()
{
MVM_LOG("%p: got a reflow request\n", this);
RefreshViewportSize(false);
}
void
MobileViewportManager::ResolutionUpdated()
{
MVM_LOG("%p: resolution updated\n", this);
RefreshSPCSPS();
}
NS_IMETHODIMP
MobileViewportManager::HandleEvent(nsIDOMEvent* event)
{
nsAutoString type;
event->GetType(type);
if (type.Equals(DOM_META_ADDED)) {
MVM_LOG("%p: got a dom-meta-added event\n", this);
RefreshViewportSize(mPainted);
} else if (type.Equals(DOM_META_CHANGED)) {
MVM_LOG("%p: got a dom-meta-changed event\n", this);
RefreshViewportSize(mPainted);
} else if (type.Equals(FULL_ZOOM_CHANGE)) {
MVM_LOG("%p: got a full-zoom-change event\n", this);
RefreshViewportSize(false);
} else if (type.Equals(LOAD)) {
MVM_LOG("%p: got a load event\n", this);
if (!mPainted) {
// Load event got fired before the before-first-paint message
SetInitialViewport();
}
}
return NS_OK;
}
NS_IMETHODIMP
MobileViewportManager::Observe(nsISupports* aSubject, const char* aTopic, const char16_t* aData)
{
if (SameCOMIdentity(aSubject, mDocument) && BEFORE_FIRST_PAINT.EqualsASCII(aTopic)) {
MVM_LOG("%p: got a before-first-paint event\n", this);
if (!mPainted) {
// before-first-paint message arrived before load event
SetInitialViewport();
}
}
return NS_OK;
}
void
MobileViewportManager::SetInitialViewport()
{
MVM_LOG("%p: setting initial viewport\n", this);
mIsFirstPaint = true;
mPainted = true;
RefreshViewportSize(false);
}
CSSToScreenScale
MobileViewportManager::ClampZoom(const CSSToScreenScale& aZoom,
const nsViewportInfo& aViewportInfo)
{
CSSToScreenScale zoom = aZoom;
if (zoom < aViewportInfo.GetMinZoom()) {
zoom = aViewportInfo.GetMinZoom();
MVM_LOG("%p: Clamped to %f\n", this, zoom.scale);
}
if (zoom > aViewportInfo.GetMaxZoom()) {
zoom = aViewportInfo.GetMaxZoom();
MVM_LOG("%p: Clamped to %f\n", this, zoom.scale);
}
return zoom;
}
LayoutDeviceToLayerScale
MobileViewportManager::ScaleResolutionWithDisplayWidth(const LayoutDeviceToLayerScale& aRes,
const float& aDisplayWidthChangeRatio,
const CSSSize& aNewViewport,
const CSSSize& aOldViewport)
{
float cssViewportChangeRatio = (aOldViewport.width == 0)
? 1.0f : aNewViewport.width / aOldViewport.width;
LayoutDeviceToLayerScale newRes(aRes.scale * aDisplayWidthChangeRatio
/ cssViewportChangeRatio);
MVM_LOG("%p: Old resolution was %f, changed by %f/%f to %f\n", this, aRes.scale,
aDisplayWidthChangeRatio, cssViewportChangeRatio, newRes.scale);
return newRes;
}
CSSToScreenScale
MobileViewportManager::UpdateResolution(const nsViewportInfo& aViewportInfo,
const ScreenIntSize& aDisplaySize,
const CSSSize& aViewport,
const Maybe<float>& aDisplayWidthChangeRatio)
{
CSSToLayoutDeviceScale cssToDev =
mPresShell->GetPresContext()->CSSToDevPixelScale();
LayoutDeviceToLayerScale res(mPresShell->GetResolution());
if (mIsFirstPaint) {
CSSToScreenScale defaultZoom;
if (mRestoreResolution) {
LayoutDeviceToLayerScale restoreResolution(mRestoreResolution.value());
if (mRestoreDisplaySize) {
CSSSize prevViewport = mDocument->GetViewportInfo(mRestoreDisplaySize.value()).GetSize();
float restoreDisplayWidthChangeRatio = (mRestoreDisplaySize.value().width > 0)
? (float)aDisplaySize.width / (float)mRestoreDisplaySize.value().width : 1.0f;
restoreResolution =
ScaleResolutionWithDisplayWidth(restoreResolution,
restoreDisplayWidthChangeRatio,
aViewport,
prevViewport);
}
defaultZoom = CSSToScreenScale(restoreResolution.scale * cssToDev.scale);
MVM_LOG("%p: restored zoom is %f\n", this, defaultZoom.scale);
defaultZoom = ClampZoom(defaultZoom, aViewportInfo);
} else {
defaultZoom = aViewportInfo.GetDefaultZoom();
MVM_LOG("%p: default zoom from viewport is %f\n", this, defaultZoom.scale);
if (!aViewportInfo.IsDefaultZoomValid()) {
defaultZoom = MaxScaleRatio(ScreenSize(aDisplaySize), aViewport);
MVM_LOG("%p: Intrinsic computed zoom is %f\n", this, defaultZoom.scale);
defaultZoom = ClampZoom(defaultZoom, aViewportInfo);
}
}
MOZ_ASSERT(aViewportInfo.GetMinZoom() <= defaultZoom &&
defaultZoom <= aViewportInfo.GetMaxZoom());
CSSToParentLayerScale zoom = ViewTargetAs<ParentLayerPixel>(defaultZoom,
PixelCastJustification::ScreenIsParentLayerForRoot);
LayoutDeviceToLayerScale resolution = zoom / cssToDev * ParentLayerToLayerScale(1);
MVM_LOG("%p: setting resolution %f\n", this, resolution.scale);
mPresShell->SetResolutionAndScaleTo(resolution.scale);
return defaultZoom;
}
// If this is not a first paint, then in some cases we want to update the pre-
// existing resolution so as to maintain how much actual content is visible
// within the display width. Note that "actual content" may be different with
// respect to CSS pixels because of the CSS viewport size changing.
//
// aDisplayWidthChangeRatio is non-empty if:
// (a) The meta-viewport tag information changes, and so the CSS viewport
// might change as a result. If this happens after the content has been
// painted, we want to adjust the zoom to compensate. OR
// (b) The display size changed from a nonzero value to another nonzero value.
// This covers the case where e.g. the device was rotated, and again we
// want to adjust the zoom to compensate.
// Note in particular that aDisplayWidthChangeRatio will be None if all that
// happened was a change in the full-zoom. In this case, we still want to
// compute a new CSS viewport, but we don't want to update the resolution.
//
// Given the above, the algorithm below accounts for all types of changes I
// can conceive of:
// 1. screen size changes, CSS viewport does not (pages with no meta viewport
// or a fixed size viewport)
// 2. screen size changes, CSS viewport also does (pages with a device-width
// viewport)
// 3. screen size remains constant, but CSS viewport changes (meta viewport
// tag is added or removed)
// 4. neither screen size nor CSS viewport changes
if (aDisplayWidthChangeRatio) {
res = ScaleResolutionWithDisplayWidth(res, aDisplayWidthChangeRatio.value(),
aViewport, mMobileViewportSize);
mPresShell->SetResolutionAndScaleTo(res.scale);
}
return ViewTargetAs<ScreenPixel>(cssToDev * res / ParentLayerToLayerScale(1),
PixelCastJustification::ScreenIsParentLayerForRoot);
}
void
MobileViewportManager::UpdateSPCSPS(const ScreenIntSize& aDisplaySize,
const CSSToScreenScale& aZoom)
{
ScreenSize compositionSize(aDisplaySize);
ScreenMargin scrollbars =
LayoutDeviceMargin::FromAppUnits(
nsLayoutUtils::ScrollbarAreaToExcludeFromCompositionBoundsFor(
mPresShell->GetRootScrollFrame()),
mPresShell->GetPresContext()->AppUnitsPerDevPixel())
// Scrollbars are not subject to resolution scaling, so LD pixels =
// Screen pixels for them.
* LayoutDeviceToScreenScale(1.0f);
compositionSize.width -= scrollbars.LeftRight();
compositionSize.height -= scrollbars.TopBottom();
CSSSize compSize = compositionSize / aZoom;
MVM_LOG("%p: Setting SPCSPS %s\n", this, Stringify(compSize).c_str());
nsLayoutUtils::SetScrollPositionClampingScrollPortSize(mPresShell, compSize);
}
void
MobileViewportManager::UpdateDisplayPortMargins()
{
if (nsIFrame* root = mPresShell->GetRootScrollFrame()) {
bool hasDisplayPort = nsLayoutUtils::HasDisplayPort(root->GetContent());
bool hasResolution = mPresShell->ScaleToResolution() &&
mPresShell->GetResolution() != 1.0f;
if (!hasDisplayPort && !hasResolution) {
// We only want to update the displayport if there is one already, or
// add one if there's a resolution on the document (see bug 1225508
// comment 1).
return;
}
nsIScrollableFrame* scrollable = do_QueryFrame(root);
nsLayoutUtils::CalculateAndSetDisplayPortMargins(scrollable,
nsLayoutUtils::RepaintMode::DoNotRepaint);
}
}
void
MobileViewportManager::RefreshSPCSPS()
{
// This function is a subset of RefreshViewportSize, and only updates the
// SPCSPS.
if (!gfxPrefs::APZAllowZooming()) {
return;
}
ScreenIntSize displaySize = ViewAs<ScreenPixel>(
mDisplaySize, PixelCastJustification::LayoutDeviceIsScreenForBounds);
CSSToLayoutDeviceScale cssToDev =
mPresShell->GetPresContext()->CSSToDevPixelScale();
LayoutDeviceToLayerScale res(mPresShell->GetResolution());
CSSToScreenScale zoom = ViewTargetAs<ScreenPixel>(cssToDev * res / ParentLayerToLayerScale(1),
PixelCastJustification::ScreenIsParentLayerForRoot);
UpdateSPCSPS(displaySize, zoom);
}
void
MobileViewportManager::RefreshViewportSize(bool aForceAdjustResolution)
{
// This function gets called by the various triggers that may result in a
// change of the CSS viewport. In some of these cases (e.g. the meta-viewport
// tag changes) we want to update the resolution and in others (e.g. the full
// zoom changing) we don't want to update the resolution. See the comment in
// UpdateResolution for some more detail on this. An important assumption we
// make here is that this RefreshViewportSize function will be called
// separately for each trigger that changes. For instance it should never get
// called such that both the full zoom and the meta-viewport tag have changed;
// instead it would get called twice - once after each trigger changes. This
// assumption is what allows the aForceAdjustResolution parameter to work as
// intended; if this assumption is violated then we will need to add extra
// complicated logic in UpdateResolution to ensure we only do the resolution
// update in the right scenarios.
Maybe<float> displayWidthChangeRatio;
LayoutDeviceIntSize newDisplaySize;
if (nsLayoutUtils::GetContentViewerSize(mPresShell->GetPresContext(), newDisplaySize)) {
// See the comment in UpdateResolution for why we're doing this.
if (mDisplaySize.width > 0) {
if (aForceAdjustResolution || mDisplaySize.width != newDisplaySize.width) {
displayWidthChangeRatio = Some((float)newDisplaySize.width / (float)mDisplaySize.width);
}
} else if (aForceAdjustResolution) {
displayWidthChangeRatio = Some(1.0f);
}
MVM_LOG("%p: Display width change ratio is %f\n", this, displayWidthChangeRatio.valueOr(0.0f));
mDisplaySize = newDisplaySize;
}
MVM_LOG("%p: Computing CSS viewport using %d,%d\n", this,
mDisplaySize.width, mDisplaySize.height);
if (mDisplaySize.width == 0 || mDisplaySize.height == 0) {
// We can't do anything useful here, we should just bail out
return;
}
ScreenIntSize displaySize = ViewAs<ScreenPixel>(
mDisplaySize, PixelCastJustification::LayoutDeviceIsScreenForBounds);
nsViewportInfo viewportInfo = mDocument->GetViewportInfo(displaySize);
CSSSize viewport = viewportInfo.GetSize();
MVM_LOG("%p: Computed CSS viewport %s\n", this, Stringify(viewport).c_str());
if (!mIsFirstPaint && mMobileViewportSize == viewport) {
// Nothing changed, so no need to do a reflow
return;
}
// If it's the first-paint or the viewport changed, we need to update
// various APZ properties (the zoom and some things that might depend on it)
MVM_LOG("%p: Updating properties because %d || %d\n", this,
mIsFirstPaint, mMobileViewportSize != viewport);
if (gfxPrefs::APZAllowZooming()) {
CSSToScreenScale zoom = UpdateResolution(viewportInfo, displaySize, viewport,
displayWidthChangeRatio);
MVM_LOG("%p: New zoom is %f\n", this, zoom.scale);
UpdateSPCSPS(displaySize, zoom);
}
if (gfxPlatform::AsyncPanZoomEnabled()) {
UpdateDisplayPortMargins();
}
CSSSize oldSize = mMobileViewportSize;
// Update internal state.
mIsFirstPaint = false;
mMobileViewportSize = viewport;
// Kick off a reflow.
mPresShell->ResizeReflowIgnoreOverride(
nsPresContext::CSSPixelsToAppUnits(viewport.width),
nsPresContext::CSSPixelsToAppUnits(viewport.height),
nsPresContext::CSSPixelsToAppUnits(oldSize.width),
nsPresContext::CSSPixelsToAppUnits(oldSize.height));
}
