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Bug 199607. Fix smoothscrolling bugs. r+sr=dbaron

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This commit is contained in:
roc+%cs.cmu.edu 2003-04-05 11:41:19 +00:00
parent d4f02b322e
commit 9ce6c8be14
3 changed files with 135 additions and 103 deletions
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83
layout/generic/nsGfxScrollFrame.cpp
View File

@ -151,6 +151,10 @@ public:
nsresult Layout(nsBoxLayoutState& aState);
nsresult LayoutBox(nsBoxLayoutState& aState, nsIBox* aBox, const nsRect& aRect);
// Like ScrollPositionDidChange, but initiated by this frame rather than from the
// scrolling view
void InternalScrollPositionDidChange(nscoord aX, nscoord aY);
PRBool AddRemoveScrollbar (PRBool& aHasScrollbar,
nscoord& aXY,
@ -199,7 +203,8 @@ public:
PRPackedBool mFirstPass;
PRPackedBool mIsRoot;
PRPackedBool mNeverReflowed;
PRPackedBool mScrollingInitiated;
PRPackedBool mViewInitiatedScroll;
PRPackedBool mFrameInitiatedScroll;
};
NS_IMPL_ISUPPORTS2(nsGfxScrollFrameInner, nsIDocumentObserver, nsIScrollPositionListener)
@ -227,7 +232,8 @@ nsGfxScrollFrame::nsGfxScrollFrame(nsIPresShell* aShell, nsIDocument* aDocument,
mPresContext = nsnull;
mInner->mIsRoot = PR_FALSE;
mInner->mNeverReflowed = PR_TRUE;
mInner->mScrollingInitiated = PR_FALSE;
mInner->mViewInitiatedScroll = PR_FALSE;
mInner->mFrameInitiatedScroll = PR_FALSE;
SetLayoutManager(nsnull);
}
@ -913,6 +919,19 @@ nsGfxScrollFrameInner::ScrollPositionWillChange(nsIScrollableView* aScrollable,
return NS_OK;
}
/**
* Called when someone (external or this frame) moves the scroll area.
*/
void
nsGfxScrollFrameInner::InternalScrollPositionDidChange(nscoord aX, nscoord aY)
{
if (mVScrollbarBox)
SetAttribute(mVScrollbarBox, nsXULAtoms::curpos, aY);
if (mHScrollbarBox)
SetAttribute(mHScrollbarBox, nsXULAtoms::curpos, aX);
}
/**
* Called if something externally moves the scroll area
* This can happen if the user pages up down or uses arrow keys
@ -921,13 +940,15 @@ nsGfxScrollFrameInner::ScrollPositionWillChange(nsIScrollableView* aScrollable,
NS_IMETHODIMP
nsGfxScrollFrameInner::ScrollPositionDidChange(nsIScrollableView* aScrollable, nscoord aX, nscoord aY)
{
if (mVScrollbarBox)
SetAttribute(mVScrollbarBox, nsXULAtoms::curpos, aY);
if (mHScrollbarBox)
SetAttribute(mHScrollbarBox, nsXULAtoms::curpos, aX);
return NS_OK;
NS_ASSERTION(!mViewInitiatedScroll, "Cannot reenter ScrollPositionDidChange");
mViewInitiatedScroll = PR_TRUE;
InternalScrollPositionDidChange(aX, aY);
mViewInitiatedScroll = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP
@ -938,11 +959,30 @@ nsGfxScrollFrameInner::AttributeChanged(nsIDocument *aDocument,
PRInt32 aModType,
nsChangeHint aHint)
{
// Don't reenter if we're getting this attribute change notification
// because we caused the view to scroll and the view is telling
// us about it.
if (mScrollingInitiated) return NS_OK;
// Attribute changes on the scrollbars happen in one of three ways:
// 1) The scrollbar changed the attribute in response to some user event
// 2) We changed the attribute in response to a ScrollPositionDidChange
// callback from the scrolling view
// 3) We changed the attribute to adjust the scrollbars for the start
// of a smooth scroll operation
//
// In case 2), we don't need to scroll the view because the scrolling
// has already happened. In case 3) we don't need to scroll because
// we're just adjusting the scrollbars back to the correct setting
// for the view.
//
// We used to detect this case implicitly because we'd compare the
// scrollbar attributes with the view's current scroll position and
// bail out if they were equal. But that approach is fragile; it can
// fail when, for example, the view scrolls horizontally and
// vertically simultaneously; we'll get here when only the vertical
// attribute has been set, so the attributes and the view scroll
// position don't yet agree, and we'd tell the view to scroll to the
// new vertical position and the old horizontal position! Even worse
// things could happen when smooth scrolling got involved ... crashes
// and other terrors.
if (mViewInitiatedScroll || mFrameInitiatedScroll) return NS_OK;
if (mHScrollbarBox && mVScrollbarBox)
{
nsIFrame* hframe = nsnull;
@ -1000,19 +1040,20 @@ nsGfxScrollFrameInner::AttributeChanged(nsIDocument *aDocument,
PRBool isSmooth = vcontent->HasAttr(kNameSpaceID_None, nsXULAtoms::smooth)
|| hcontent->HasAttr(kNameSpaceID_None, nsXULAtoms::smooth);
// Remember that we asked the view to scroll, so we don't need to
// take notice of any attribute change caused by the view's scrolling
// action.
mScrollingInitiated = PR_TRUE;
ScrollbarChanged(mOuter->mPresContext, x*mOnePixel, y*mOnePixel, isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : 0);
if (isSmooth) {
// Make sure an attribute-setting callback occurs even if the view didn't actually move yet
// We need to make sure other listeners see that the scroll position is not (yet)
// what they thought it was.
s->GetScrollPosition(curPosX, curPosY);
ScrollPositionDidChange(s, curPosX, curPosY);
NS_ASSERTION(!mFrameInitiatedScroll, "Unexpected reentry");
// Make sure we don't do anything in when the view calls us back for this
// scroll operation.
mFrameInitiatedScroll = PR_TRUE;
InternalScrollPositionDidChange(curPosX, curPosY);
mFrameInitiatedScroll = PR_FALSE;
}
mScrollingInitiated = PR_FALSE;
ScrollbarChanged(mOuter->mPresContext, x*mOnePixel, y*mOnePixel, isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : 0);
// Fire the onScroll event now that we have scrolled
nsCOMPtr<nsIPresShell> presShell;

83
layout/html/base/src/nsGfxScrollFrame.cpp
View File

@ -151,6 +151,10 @@ public:
nsresult Layout(nsBoxLayoutState& aState);
nsresult LayoutBox(nsBoxLayoutState& aState, nsIBox* aBox, const nsRect& aRect);
// Like ScrollPositionDidChange, but initiated by this frame rather than from the
// scrolling view
void InternalScrollPositionDidChange(nscoord aX, nscoord aY);
PRBool AddRemoveScrollbar (PRBool& aHasScrollbar,
nscoord& aXY,
@ -199,7 +203,8 @@ public:
PRPackedBool mFirstPass;
PRPackedBool mIsRoot;
PRPackedBool mNeverReflowed;
PRPackedBool mScrollingInitiated;
PRPackedBool mViewInitiatedScroll;
PRPackedBool mFrameInitiatedScroll;
};
NS_IMPL_ISUPPORTS2(nsGfxScrollFrameInner, nsIDocumentObserver, nsIScrollPositionListener)
@ -227,7 +232,8 @@ nsGfxScrollFrame::nsGfxScrollFrame(nsIPresShell* aShell, nsIDocument* aDocument,
mPresContext = nsnull;
mInner->mIsRoot = PR_FALSE;
mInner->mNeverReflowed = PR_TRUE;
mInner->mScrollingInitiated = PR_FALSE;
mInner->mViewInitiatedScroll = PR_FALSE;
mInner->mFrameInitiatedScroll = PR_FALSE;
SetLayoutManager(nsnull);
}
@ -913,6 +919,19 @@ nsGfxScrollFrameInner::ScrollPositionWillChange(nsIScrollableView* aScrollable,
return NS_OK;
}
/**
* Called when someone (external or this frame) moves the scroll area.
*/
void
nsGfxScrollFrameInner::InternalScrollPositionDidChange(nscoord aX, nscoord aY)
{
if (mVScrollbarBox)
SetAttribute(mVScrollbarBox, nsXULAtoms::curpos, aY);
if (mHScrollbarBox)
SetAttribute(mHScrollbarBox, nsXULAtoms::curpos, aX);
}
/**
* Called if something externally moves the scroll area
* This can happen if the user pages up down or uses arrow keys
@ -921,13 +940,15 @@ nsGfxScrollFrameInner::ScrollPositionWillChange(nsIScrollableView* aScrollable,
NS_IMETHODIMP
nsGfxScrollFrameInner::ScrollPositionDidChange(nsIScrollableView* aScrollable, nscoord aX, nscoord aY)
{
if (mVScrollbarBox)
SetAttribute(mVScrollbarBox, nsXULAtoms::curpos, aY);
if (mHScrollbarBox)
SetAttribute(mHScrollbarBox, nsXULAtoms::curpos, aX);
return NS_OK;
NS_ASSERTION(!mViewInitiatedScroll, "Cannot reenter ScrollPositionDidChange");
mViewInitiatedScroll = PR_TRUE;
InternalScrollPositionDidChange(aX, aY);
mViewInitiatedScroll = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP
@ -938,11 +959,30 @@ nsGfxScrollFrameInner::AttributeChanged(nsIDocument *aDocument,
PRInt32 aModType,
nsChangeHint aHint)
{
// Don't reenter if we're getting this attribute change notification
// because we caused the view to scroll and the view is telling
// us about it.
if (mScrollingInitiated) return NS_OK;
// Attribute changes on the scrollbars happen in one of three ways:
// 1) The scrollbar changed the attribute in response to some user event
// 2) We changed the attribute in response to a ScrollPositionDidChange
// callback from the scrolling view
// 3) We changed the attribute to adjust the scrollbars for the start
// of a smooth scroll operation
//
// In case 2), we don't need to scroll the view because the scrolling
// has already happened. In case 3) we don't need to scroll because
// we're just adjusting the scrollbars back to the correct setting
// for the view.
//
// We used to detect this case implicitly because we'd compare the
// scrollbar attributes with the view's current scroll position and
// bail out if they were equal. But that approach is fragile; it can
// fail when, for example, the view scrolls horizontally and
// vertically simultaneously; we'll get here when only the vertical
// attribute has been set, so the attributes and the view scroll
// position don't yet agree, and we'd tell the view to scroll to the
// new vertical position and the old horizontal position! Even worse
// things could happen when smooth scrolling got involved ... crashes
// and other terrors.
if (mViewInitiatedScroll || mFrameInitiatedScroll) return NS_OK;
if (mHScrollbarBox && mVScrollbarBox)
{
nsIFrame* hframe = nsnull;
@ -1000,19 +1040,20 @@ nsGfxScrollFrameInner::AttributeChanged(nsIDocument *aDocument,
PRBool isSmooth = vcontent->HasAttr(kNameSpaceID_None, nsXULAtoms::smooth)
|| hcontent->HasAttr(kNameSpaceID_None, nsXULAtoms::smooth);
// Remember that we asked the view to scroll, so we don't need to
// take notice of any attribute change caused by the view's scrolling
// action.
mScrollingInitiated = PR_TRUE;
ScrollbarChanged(mOuter->mPresContext, x*mOnePixel, y*mOnePixel, isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : 0);
if (isSmooth) {
// Make sure an attribute-setting callback occurs even if the view didn't actually move yet
// We need to make sure other listeners see that the scroll position is not (yet)
// what they thought it was.
s->GetScrollPosition(curPosX, curPosY);
ScrollPositionDidChange(s, curPosX, curPosY);
NS_ASSERTION(!mFrameInitiatedScroll, "Unexpected reentry");
// Make sure we don't do anything in when the view calls us back for this
// scroll operation.
mFrameInitiatedScroll = PR_TRUE;
InternalScrollPositionDidChange(curPosX, curPosY);
mFrameInitiatedScroll = PR_FALSE;
}
mScrollingInitiated = PR_FALSE;
ScrollbarChanged(mOuter->mPresContext, x*mOnePixel, y*mOnePixel, isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : 0);
// Fire the onScroll event now that we have scrolled
nsCOMPtr<nsIPresShell> presShell;

72
view/src/nsScrollPortView.cpp
View File

@ -222,69 +222,23 @@ NS_IMETHODIMP nsScrollPortView::GetScrollPreference(nsScrollPreference &aScrollP
static void ComputeVelocities(PRInt32 aCurVelocity, nscoord aCurPos, nscoord aDstPos,
PRInt32* aVelocities) {
PRInt32 absCurVelocity;
PRInt32 direction;
if (aCurPos < aDstPos) {
direction = 1;
if (aCurVelocity < 0) {
absCurVelocity = 0;
} else {
absCurVelocity = aCurVelocity;
}
} else {
direction = -1;
if (aCurVelocity > 0) {
absCurVelocity = 0;
} else {
absCurVelocity = -aCurVelocity;
}
}
PRInt32 absDistance = direction*(aDstPos - aCurPos);
// The target velocity is the velocity we want to reach at frame N/2. We choose the
// target velocity so that after coming to a stop at frame N, we will have reached
// the scroll destination (actually we'll overshoot because of rounding, but that's
// the idea).
// It's chosen to satisfy
// aDstPos - aCurPos = N/2 (aTargetVelocity/2) + N/2 ((aCurVelocity + aTargetVelocity)/2)
// distance travelled avg. velocity in 1st half avg. velocity in 2nd half
PRInt32 absTargetVelocity = (PRInt32)ceil(2.0*absDistance/SMOOTH_SCROLL_FRAMES - 0.5*absCurVelocity);
// if we're going too fast already, slow down to the target velocity
if (absCurVelocity > absTargetVelocity) {
absCurVelocity = absTargetVelocity;
}
PRInt32 i;
const int halfFrames = SMOOTH_SCROLL_FRAMES/2;
for (i = 0; i < halfFrames; i++) {
aVelocities[i*2] = PR_MAX(0, absCurVelocity + (absTargetVelocity*i + halfFrames - 1)/halfFrames);
}
for (i = halfFrames; i < halfFrames*2; i++) {
aVelocities[i*2] = PR_MAX(0, (absTargetVelocity*(halfFrames*2 - (i - 1)) + halfFrames - 1)/halfFrames);
}
PRInt32 direction = (aCurPos < aDstPos ? 1 : -1);
PRInt32 absDelta = (aDstPos - aCurPos)*direction;
PRInt32 baseVelocity = absDelta/SMOOTH_SCROLL_FRAMES;
PRInt32 total = 0;
for (i = 0; i < SMOOTH_SCROLL_FRAMES; i++) {
total += aVelocities[i*2];
aVelocities[i*2] = baseVelocity;
}
PRInt32 leftover = total - absDistance;
NS_ASSERTION(leftover >= 0, "Lost some distance due to rounding? We should have been rounding up only");
while (leftover > 0) {
for (i = SMOOTH_SCROLL_FRAMES - 1; i >= 0; i--) {
if (aVelocities[i*2] > 0) {
aVelocities[i*2]--;
leftover--;
if (leftover <= 0) {
break;
}
}
nscoord total = baseVelocity*SMOOTH_SCROLL_FRAMES;
for (i = 0; i < SMOOTH_SCROLL_FRAMES; i++) {
if (total < absDelta) {
aVelocities[i*2]++;
total++;
}
}
NS_ASSERTION(total == absDelta, "Invalid velocity sum");
for (i = 0; i < SMOOTH_SCROLL_FRAMES; i++) {
aVelocities[i*2] *= direction;
}
@ -392,10 +346,6 @@ NS_IMETHODIMP nsScrollPortView::ScrollTo(nscoord aDestinationX, nscoord aDestina
ComputeVelocities(currentVelocityY, mOffsetY,
mSmoothScroll->mDestinationY, mSmoothScroll->mVelocities + 1);
// call a scroll immediately, don't wait for the timer to callback.
// this improves responsiveness
IncrementalScroll();
return NS_OK;
}