gecko-dev/layout/base/PositionedEventTargeting.cpp

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/* -*- 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/. */
#include "PositionedEventTargeting.h"
#include "mozilla/EventListenerManager.h"
#include "mozilla/EventStates.h"
#include "mozilla/MouseEvents.h"
#include "mozilla/Preferences.h"
#include "nsLayoutUtils.h"
#include "nsGkAtoms.h"
#include "nsFontMetrics.h"
#include "nsPrintfCString.h"
#include "mozilla/dom/Element.h"
#include "nsRegion.h"
#include "nsDeviceContext.h"
#include "nsIFrame.h"
#include <algorithm>
#include "LayersLogging.h"
// If debugging this code you may wish to enable this logging, and also
// uncomment the DumpFrameTree call near the bottom of the file.
#define PET_LOG(...)
// #define PET_LOG(...) printf_stderr("PET: " __VA_ARGS__);
namespace mozilla {
/*
* The basic goal of FindFrameTargetedByInputEvent() is to find a good
* target element that can respond to mouse events. Both mouse events and touch
* events are targeted at this element. Note that even for touch events, we
* check responsiveness to mouse events. We assume Web authors
* designing for touch events will take their own steps to account for
* inaccurate touch events.
*
* GetClickableAncestor() encapsulates the heuristic that determines whether an
* element is expected to respond to mouse events. An element is deemed
* "clickable" if it has registered listeners for "click", "mousedown" or
* "mouseup", or is on a whitelist of element tags (<a>, <button>, <input>,
* <select>, <textarea>, <label>), or has role="button", or is a link, or
* is a suitable XUL element.
* Any descendant (in the same document) of a clickable element is also
* deemed clickable since events will propagate to the clickable element from its
* descendant.
*
* If the element directly under the event position is clickable (or
* event radii are disabled), we always use that element. Otherwise we collect
* all frames intersecting a rectangle around the event position (taking CSS
* transforms into account) and choose the best candidate in GetClosest().
* Only GetClickableAncestor() candidates are considered; if none are found,
* then we revert to targeting the element under the event position.
* We ignore candidates outside the document subtree rooted by the
* document of the element directly under the event position. This ensures that
* event listeners in ancestor documents don't make it completely impossible
* to target a non-clickable element in a child document.
*
* When both a frame and its ancestor are in the candidate list, we ignore
* the ancestor. Otherwise a large ancestor element with a mouse event listener
* and some descendant elements that need to be individually targetable would
* disable intelligent targeting of those descendants within its bounds.
*
* GetClosest() computes the transformed axis-aligned bounds of each
* candidate frame, then computes the Manhattan distance from the event point
* to the bounds rect (which can be zero). The frame with the
* shortest distance is chosen. For visited links we multiply the distance
* by a specified constant weight; this can be used to make visited links
* more or less likely to be targeted than non-visited links.
*/
struct EventRadiusPrefs
{
uint32_t mVisitedWeight; // in percent, i.e. default is 100
uint32_t mSideRadii[4]; // TRBL order, in millimetres
bool mEnabled;
bool mRegistered;
bool mTouchOnly;
bool mRepositionEventCoords;
bool mTouchClusterDetectionEnabled;
bool mSimplifiedClusterDetection;
uint32_t mLimitReadableSize;
uint32_t mKeepLimitSizeForCluster;
};
static EventRadiusPrefs sMouseEventRadiusPrefs;
static EventRadiusPrefs sTouchEventRadiusPrefs;
static const EventRadiusPrefs*
GetPrefsFor(EventClassID aEventClassID)
{
EventRadiusPrefs* prefs = nullptr;
const char* prefBranch = nullptr;
if (aEventClassID == eTouchEventClass) {
prefBranch = "touch";
prefs = &sTouchEventRadiusPrefs;
} else if (aEventClassID == eMouseEventClass) {
// Mostly for testing purposes
prefBranch = "mouse";
prefs = &sMouseEventRadiusPrefs;
} else {
return nullptr;
}
if (!prefs->mRegistered) {
prefs->mRegistered = true;
nsPrintfCString enabledPref("ui.%s.radius.enabled", prefBranch);
Preferences::AddBoolVarCache(&prefs->mEnabled, enabledPref.get(), false);
nsPrintfCString visitedWeightPref("ui.%s.radius.visitedWeight", prefBranch);
Preferences::AddUintVarCache(&prefs->mVisitedWeight, visitedWeightPref.get(), 100);
static const char prefNames[4][9] =
{ "topmm", "rightmm", "bottommm", "leftmm" };
for (int32_t i = 0; i < 4; ++i) {
nsPrintfCString radiusPref("ui.%s.radius.%s", prefBranch, prefNames[i]);
Preferences::AddUintVarCache(&prefs->mSideRadii[i], radiusPref.get(), 0);
}
if (aEventClassID == eMouseEventClass) {
Preferences::AddBoolVarCache(&prefs->mTouchOnly,
"ui.mouse.radius.inputSource.touchOnly", true);
} else {
prefs->mTouchOnly = false;
}
nsPrintfCString repositionPref("ui.%s.radius.reposition", prefBranch);
Preferences::AddBoolVarCache(&prefs->mRepositionEventCoords, repositionPref.get(), false);
// These values were formerly set by ui.zoomedview preferences.
prefs->mTouchClusterDetectionEnabled = false;
prefs->mSimplifiedClusterDetection = false;
prefs->mLimitReadableSize = 8;
prefs->mKeepLimitSizeForCluster = 16;
}
return prefs;
}
static bool
HasMouseListener(nsIContent* aContent)
{
if (EventListenerManager* elm = aContent->GetExistingListenerManager()) {
return elm->HasListenersFor(nsGkAtoms::onclick) ||
elm->HasListenersFor(nsGkAtoms::onmousedown) ||
elm->HasListenersFor(nsGkAtoms::onmouseup);
}
return false;
}
static bool gTouchEventsRegistered = false;
static int32_t gTouchEventsEnabled = 0;
static bool
HasTouchListener(nsIContent* aContent)
{
EventListenerManager* elm = aContent->GetExistingListenerManager();
if (!elm) {
return false;
}
if (!gTouchEventsRegistered) {
Preferences::AddIntVarCache(&gTouchEventsEnabled,
"dom.w3c_touch_events.enabled", gTouchEventsEnabled);
gTouchEventsRegistered = true;
}
if (!gTouchEventsEnabled) {
return false;
}
return elm->HasListenersFor(nsGkAtoms::ontouchstart) ||
elm->HasListenersFor(nsGkAtoms::ontouchend);
}
static bool
IsDescendant(nsIFrame* aFrame, nsIContent* aAncestor, nsAutoString* aLabelTargetId)
{
for (nsIContent* content = aFrame->GetContent(); content;
content = content->GetFlattenedTreeParent()) {
if (aLabelTargetId && content->IsHTMLElement(nsGkAtoms::label)) {
content->GetAttr(kNameSpaceID_None, nsGkAtoms::_for, *aLabelTargetId);
}
if (content == aAncestor) {
return true;
}
}
return false;
}
static nsIContent*
GetClickableAncestor(nsIFrame* aFrame, nsAtom* stopAt = nullptr, nsAutoString* aLabelTargetId = nullptr)
{
// Input events propagate up the content tree so we'll follow the content
// ancestors to look for elements accepting the click.
for (nsIContent* content = aFrame->GetContent(); content;
content = content->GetFlattenedTreeParent()) {
if (stopAt && content->IsHTMLElement(stopAt)) {
break;
}
if (HasTouchListener(content) || HasMouseListener(content)) {
return content;
}
if (content->IsAnyOfHTMLElements(nsGkAtoms::button,
nsGkAtoms::input,
nsGkAtoms::select,
nsGkAtoms::textarea)) {
return content;
}
if (content->IsHTMLElement(nsGkAtoms::label)) {
if (aLabelTargetId) {
content->GetAttr(kNameSpaceID_None, nsGkAtoms::_for, *aLabelTargetId);
}
return content;
}
// Bug 921928: we don't have access to the content of remote iframe.
// So fluffing won't go there. We do an optimistic assumption here:
// that the content of the remote iframe needs to be a target.
if (content->IsHTMLElement(nsGkAtoms::iframe) &&
content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::mozbrowser,
nsGkAtoms::_true, eIgnoreCase) &&
content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::Remote,
nsGkAtoms::_true, eIgnoreCase)) {
return content;
}
// See nsCSSFrameConstructor::FindXULTagData. This code is not
// really intended to be used with XUL, though.
if (content->IsAnyOfXULElements(nsGkAtoms::button,
nsGkAtoms::checkbox,
nsGkAtoms::radio,
nsGkAtoms::autorepeatbutton,
nsGkAtoms::menu,
nsGkAtoms::menubutton,
nsGkAtoms::menuitem,
nsGkAtoms::menulist,
nsGkAtoms::scrollbarbutton,
nsGkAtoms::resizer)) {
return content;
}
static nsIContent::AttrValuesArray clickableRoles[] =
{ &nsGkAtoms::button, &nsGkAtoms::key, nullptr };
if (content->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::role,
clickableRoles, eIgnoreCase) >= 0) {
return content;
}
if (content->IsEditable()) {
return content;
}
nsCOMPtr<nsIURI> linkURI;
if (content->IsLink(getter_AddRefs(linkURI))) {
return content;
}
}
return nullptr;
}
static nscoord
AppUnitsFromMM(nsIFrame* aFrame, uint32_t aMM)
{
nsPresContext* pc = aFrame->PresContext();
nsIPresShell* presShell = pc->PresShell();
float result = float(aMM) *
(pc->DeviceContext()->AppUnitsPerPhysicalInch() / MM_PER_INCH_FLOAT);
if (presShell->ScaleToResolution()) {
result = result / presShell->GetResolution();
}
return NSToCoordRound(result);
}
/**
* Clip aRect with the bounds of aFrame in the coordinate system of
* aRootFrame. aRootFrame is an ancestor of aFrame.
*/
static nsRect
ClipToFrame(nsIFrame* aRootFrame, nsIFrame* aFrame, nsRect& aRect)
{
nsRect bound = nsLayoutUtils::TransformFrameRectToAncestor(
aFrame, nsRect(nsPoint(0, 0), aFrame->GetSize()), aRootFrame);
nsRect result = bound.Intersect(aRect);
return result;
}
static nsRect
GetTargetRect(nsIFrame* aRootFrame, const nsPoint& aPointRelativeToRootFrame,
nsIFrame* aRestrictToDescendants, const EventRadiusPrefs* aPrefs,
uint32_t aFlags)
{
nsMargin m(AppUnitsFromMM(aRootFrame, aPrefs->mSideRadii[0]),
AppUnitsFromMM(aRootFrame, aPrefs->mSideRadii[1]),
AppUnitsFromMM(aRootFrame, aPrefs->mSideRadii[2]),
AppUnitsFromMM(aRootFrame, aPrefs->mSideRadii[3]));
nsRect r(aPointRelativeToRootFrame, nsSize(0,0));
r.Inflate(m);
if (!(aFlags & INPUT_IGNORE_ROOT_SCROLL_FRAME)) {
// Don't clip this rect to the root scroll frame if the flag to ignore the
// root scroll frame is set. Note that the GetClosest code will still enforce
// that the target found is a descendant of aRestrictToDescendants.
r = ClipToFrame(aRootFrame, aRestrictToDescendants, r);
}
return r;
}
static float
ComputeDistanceFromRect(const nsPoint& aPoint, const nsRect& aRect)
{
nscoord dx = std::max(0, std::max(aRect.x - aPoint.x, aPoint.x - aRect.XMost()));
nscoord dy = std::max(0, std::max(aRect.y - aPoint.y, aPoint.y - aRect.YMost()));
return float(NS_hypot(dx, dy));
}
static float
ComputeDistanceFromRegion(const nsPoint& aPoint, const nsRegion& aRegion)
{
MOZ_ASSERT(!aRegion.IsEmpty(), "can't compute distance between point and empty region");
float minDist = -1;
for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
float dist = ComputeDistanceFromRect(aPoint, iter.Get());
if (dist < minDist || minDist < 0) {
minDist = dist;
}
}
return minDist;
}
// Subtract aRegion from aExposedRegion as long as that doesn't make the
// exposed region get too complex or removes a big chunk of the exposed region.
static void
SubtractFromExposedRegion(nsRegion* aExposedRegion, const nsRegion& aRegion)
{
if (aRegion.IsEmpty())
return;
nsRegion tmp;
tmp.Sub(*aExposedRegion, aRegion);
// Don't let *aExposedRegion get too complex, but don't let it fluff out to
// its bounds either. Do let aExposedRegion get more complex if by doing so
// we reduce its area by at least half.
if (tmp.GetNumRects() <= 15 || tmp.Area() <= aExposedRegion->Area()/2) {
*aExposedRegion = tmp;
}
}
// Search in the list of frames aCandidates if the element with the id "aLabelTargetId"
// is present.
static bool IsElementPresent(nsTArray<nsIFrame*>& aCandidates, const nsAutoString& aLabelTargetId)
{
for (uint32_t i = 0; i < aCandidates.Length(); ++i) {
nsIFrame* f = aCandidates[i];
nsIContent* aContent = f->GetContent();
if (aContent && aContent->IsElement()) {
if (aContent->GetID() && aLabelTargetId == nsAtomString(aContent->GetID())) {
return true;
}
}
}
return false;
}
static bool
IsLargeElement(nsIFrame* aFrame, const EventRadiusPrefs* aPrefs)
{
uint32_t keepLimitSizeForCluster = aPrefs->mKeepLimitSizeForCluster;
nsSize frameSize = aFrame->GetSize();
nsPresContext* pc = aFrame->PresContext();
nsIPresShell* presShell = pc->PresShell();
float cumulativeResolution = presShell->GetCumulativeResolution();
if ((pc->AppUnitsToGfxUnits(frameSize.height) * cumulativeResolution) > keepLimitSizeForCluster &&
(pc->AppUnitsToGfxUnits(frameSize.width) * cumulativeResolution) > keepLimitSizeForCluster) {
return true;
}
return false;
}
static nsIFrame*
GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
const nsRect& aTargetRect, const EventRadiusPrefs* aPrefs,
nsIFrame* aRestrictToDescendants, nsIContent* aClickableAncestor,
nsTArray<nsIFrame*>& aCandidates, int32_t* aElementsInCluster)
{
std::vector<nsIContent*> mContentsInCluster; // List of content elements in the cluster without duplicate
nsIFrame* bestTarget = nullptr;
// Lower is better; distance is in appunits
float bestDistance = 1e6f;
nsRegion exposedRegion(aTargetRect);
for (uint32_t i = 0; i < aCandidates.Length(); ++i) {
nsIFrame* f = aCandidates[i];
PET_LOG("Checking candidate %p\n", f);
bool preservesAxisAlignedRectangles = false;
nsRect borderBox = nsLayoutUtils::TransformFrameRectToAncestor(f,
nsRect(nsPoint(0, 0), f->GetSize()), aRoot, &preservesAxisAlignedRectangles);
nsRegion region;
region.And(exposedRegion, borderBox);
if (region.IsEmpty()) {
PET_LOG(" candidate %p had empty hit region\n", f);
continue;
}
if (preservesAxisAlignedRectangles) {
// Subtract from the exposed region if we have a transform that won't make
// the bounds include a bunch of area that we don't actually cover.
SubtractFromExposedRegion(&exposedRegion, region);
}
nsAutoString labelTargetId;
if (aClickableAncestor && !IsDescendant(f, aClickableAncestor, &labelTargetId)) {
PET_LOG(" candidate %p is not a descendant of required ancestor\n", f);
continue;
}
nsIContent* clickableContent = GetClickableAncestor(f, nsGkAtoms::body, &labelTargetId);
if (!aClickableAncestor && !clickableContent) {
PET_LOG(" candidate %p was not clickable\n", f);
continue;
}
// If our current closest frame is a descendant of 'f', skip 'f' (prefer
// the nested frame).
if (bestTarget && nsLayoutUtils::IsProperAncestorFrameCrossDoc(f, bestTarget, aRoot)) {
PET_LOG(" candidate %p was ancestor for bestTarget %p\n", f, bestTarget);
continue;
}
if (!aClickableAncestor && !nsLayoutUtils::IsAncestorFrameCrossDoc(aRestrictToDescendants, f, aRoot)) {
PET_LOG(" candidate %p was not descendant of restrictroot %p\n", f, aRestrictToDescendants);
continue;
}
// If the first clickable ancestor of f is a label element
// and "for" attribute is present in label element, search the frame list for the "for" element
// If this element is present in the current list, do not count the frame in
// the cluster elements counter
if ((labelTargetId.IsEmpty() || !IsElementPresent(aCandidates, labelTargetId)) &&
!IsLargeElement(f, aPrefs)) {
if (std::find(mContentsInCluster.begin(), mContentsInCluster.end(), clickableContent) == mContentsInCluster.end()) {
mContentsInCluster.push_back(clickableContent);
}
}
// distance is in appunits
float distance = ComputeDistanceFromRegion(aPointRelativeToRootFrame, region);
nsIContent* content = f->GetContent();
if (content && content->IsElement() &&
content->AsElement()->State().HasState(
EventStates(NS_EVENT_STATE_VISITED))) {
distance *= aPrefs->mVisitedWeight / 100.0f;
}
if (distance < bestDistance) {
PET_LOG(" candidate %p is the new best\n", f);
bestDistance = distance;
bestTarget = f;
}
}
*aElementsInCluster = mContentsInCluster.size();
return bestTarget;
}
/*
* Return always true when touch cluster detection is OFF.
* When cluster detection is ON, return true:
* if the text inside the frame is readable (by human eyes)
* or
* if the structure is too complex to determine the size.
* In both cases, the frame is considered as clickable.
*
* Frames with a too small size will return false.
* In this case, the frame is considered not clickable.
*/
static bool
IsElementClickableAndReadable(nsIFrame* aFrame, WidgetGUIEvent* aEvent, const EventRadiusPrefs* aPrefs)
{
if (!aPrefs->mTouchClusterDetectionEnabled) {
return true;
}
if (aPrefs->mSimplifiedClusterDetection) {
return true;
}
if (aEvent->mClass != eMouseEventClass) {
return true;
}
uint32_t limitReadableSize = aPrefs->mLimitReadableSize;
nsSize frameSize = aFrame->GetSize();
nsPresContext* pc = aFrame->PresContext();
nsIPresShell* presShell = pc->PresShell();
float cumulativeResolution = presShell->GetCumulativeResolution();
if ((pc->AppUnitsToGfxUnits(frameSize.height) * cumulativeResolution) < limitReadableSize ||
(pc->AppUnitsToGfxUnits(frameSize.width) * cumulativeResolution) < limitReadableSize) {
return false;
}
// We want to detect small clickable text elements using the font size.
// Two common cases are supported for now:
// 1. text node
// 2. any element with only one child of type text node
// All the other cases are currently ignored.
nsIContent *content = aFrame->GetContent();
bool testFontSize = false;
if (content) {
nsINodeList* childNodes = content->ChildNodes();
uint32_t childNodeCount = childNodes->Length();
if ((content->IsNodeOfType(nsINode::eTEXT)) ||
// click occurs on the text inside <a></a> or other clickable tags with text inside
(childNodeCount == 1 && childNodes->Item(0) &&
childNodes->Item(0)->IsNodeOfType(nsINode::eTEXT))) {
// The click occurs on an element with only one text node child. In this case, the font size
// can be tested.
// The number of child nodes is tested to avoid the following cases (See bug 1172488):
// Some jscript libraries transform text elements into Canvas elements but keep the text nodes
// with a very small size (1px) to handle the selection of text.
// With such libraries, the font size of the text elements is not relevant to detect small elements.
testFontSize = true;
}
}
if (testFontSize) {
RefPtr<nsFontMetrics> fm =
nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
if (fm && fm->EmHeight() > 0 && // See bug 1171731
(pc->AppUnitsToGfxUnits(fm->EmHeight()) * cumulativeResolution) < limitReadableSize) {
return false;
}
}
return true;
}
nsIFrame*
FindFrameTargetedByInputEvent(WidgetGUIEvent* aEvent,
nsIFrame* aRootFrame,
const nsPoint& aPointRelativeToRootFrame,
uint32_t aFlags)
{
uint32_t flags = (aFlags & INPUT_IGNORE_ROOT_SCROLL_FRAME) ?
nsLayoutUtils::IGNORE_ROOT_SCROLL_FRAME : 0;
nsIFrame* target =
nsLayoutUtils::GetFrameForPoint(aRootFrame, aPointRelativeToRootFrame, flags);
PET_LOG("Found initial target %p for event class %s point %s relative to root frame %p\n",
target, (aEvent->mClass == eMouseEventClass ? "mouse" :
(aEvent->mClass == eTouchEventClass ? "touch" : "other")),
mozilla::layers::Stringify(aPointRelativeToRootFrame).c_str(), aRootFrame);
const EventRadiusPrefs* prefs = GetPrefsFor(aEvent->mClass);
if (!prefs || !prefs->mEnabled) {
PET_LOG("Retargeting disabled\n");
return target;
}
nsIContent* clickableAncestor = nullptr;
if (target) {
clickableAncestor = GetClickableAncestor(target, nsGkAtoms::body);
if (clickableAncestor) {
if (!IsElementClickableAndReadable(target, aEvent, prefs)) {
aEvent->AsMouseEventBase()->hitCluster = true;
}
PET_LOG("Target %p is clickable\n", target);
// If the target that was directly hit has a clickable ancestor, that
// means it too is clickable. And since it is the same as or a descendant
// of clickableAncestor, it should become the root for the GetClosest
// search.
clickableAncestor = target->GetContent();
}
}
// Do not modify targeting for actual mouse hardware; only for mouse
// events generated by touch-screen hardware.
if (aEvent->mClass == eMouseEventClass &&
prefs->mTouchOnly &&
aEvent->AsMouseEvent()->inputSource !=
nsIDOMMouseEvent::MOZ_SOURCE_TOUCH) {
PET_LOG("Mouse input event is not from a touch source\n");
return target;
}
// If the exact target is non-null, only consider candidate targets in the same
// document as the exact target. Otherwise, if an ancestor document has
// a mouse event handler for example, targets that are !GetClickableAncestor can
// never be targeted --- something nsSubDocumentFrame in an ancestor document
// would be targeted instead.
nsIFrame* restrictToDescendants = target ?
target->PresShell()->GetRootFrame() : aRootFrame;
nsRect targetRect = GetTargetRect(aRootFrame, aPointRelativeToRootFrame,
restrictToDescendants, prefs, aFlags);
PET_LOG("Expanded point to target rect %s\n",
mozilla::layers::Stringify(targetRect).c_str());
AutoTArray<nsIFrame*,8> candidates;
nsresult rv = nsLayoutUtils::GetFramesForArea(aRootFrame, targetRect, candidates, flags);
if (NS_FAILED(rv)) {
return target;
}
int32_t elementsInCluster = 0;
nsIFrame* closestClickable =
GetClosest(aRootFrame, aPointRelativeToRootFrame, targetRect, prefs,
restrictToDescendants, clickableAncestor, candidates,
&elementsInCluster);
if (closestClickable) {
if ((prefs->mTouchClusterDetectionEnabled && elementsInCluster > 1) ||
(!IsElementClickableAndReadable(closestClickable, aEvent, prefs))) {
if (aEvent->mClass == eMouseEventClass) {
WidgetMouseEventBase* mouseEventBase = aEvent->AsMouseEventBase();
mouseEventBase->hitCluster = true;
}
}
target = closestClickable;
}
PET_LOG("Final target is %p\n", target);
// Uncomment this to dump the frame tree to help with debugging.
// Note that dumping the frame tree at the top of the function may flood
// logcat on Android devices and cause the PET_LOGs to get dropped.
// aRootFrame->DumpFrameTree();
if (!target || !prefs->mRepositionEventCoords) {
// No repositioning required for this event
return target;
}
// Take the point relative to the root frame, make it relative to the target,
// clamp it to the bounds, and then make it relative to the root frame again.
nsPoint point = aPointRelativeToRootFrame;
if (nsLayoutUtils::TRANSFORM_SUCCEEDED != nsLayoutUtils::TransformPoint(aRootFrame, target, point)) {
return target;
}
point = target->GetRectRelativeToSelf().ClampPoint(point);
if (nsLayoutUtils::TRANSFORM_SUCCEEDED != nsLayoutUtils::TransformPoint(target, aRootFrame, point)) {
return target;
}
// Now we basically undo the operations in GetEventCoordinatesRelativeTo, to
// get back the (now-clamped) coordinates in the event's widget's space.
nsView* view = aRootFrame->GetView();
if (!view) {
return target;
}
LayoutDeviceIntPoint widgetPoint = nsLayoutUtils::TranslateViewToWidget(
aRootFrame->PresContext(), view, point, aEvent->mWidget);
if (widgetPoint.x != NS_UNCONSTRAINEDSIZE) {
// If that succeeded, we update the point in the event
aEvent->mRefPoint = widgetPoint;
}
return target;
}
} // namespace mozilla