The caret movement code already handles unselectable text frames if we
happen to land in the middle of one in nsTextFrame::PeekOffsetCharacter/Word.
However, when performing frame traversal to find the next frame to jump
to, we don't remember if we skipped over an unselectable frame, which causes
us to jump one offset too much when the caret is on the boundary of
selectable and unselectable content. The test cases demonstrate the
scenario. Note that an <img alt=foo> is implemented by adding a
generated content to the inline frame representing it, so as far as
the caret movement code is concerned, both test cases are treated similarly.
Note that we need to do this only when moving the selection, and not
when extending it. We are adding an aExtend argument to
nsPeekOffsetStruct's constructor in order to be able to special case
that.
The caret movement code already handles unselectable text frames if we
happen to land in the middle of one in nsTextFrame::PeekOffsetCharacter/Word.
However, when performing frame traversal to find the next frame to jump
to, we don't remember if we skipped over an unselectable frame, which causes
us to jump one offset too much when the caret is on the boundary of
selectable and unselectable content. The test cases demonstrate the
scenario. Note that an <img alt=foo> is implemented by adding a
generated content to the inline frame representing it, so as far as
the caret movement code is concerned, both test cases are treated similarly.
Note that we need to do this only when moving the selection, and not
when extending it. We are adding an aExtend argument to
nsPeekOffsetStruct's constructor in order to be able to special case
that.
There's no need for this method to turn off blinking anymore. Its only
caller already calls SetCaretReadOnly to achieve the same effect. That
means we don't actually need the mIsBlinking flag after all.
A few things got mashed together here:
-- Inline KillTimer/PrimeTimer into their callers.
-- Instead of having to call StopBlinking and StartBlinking together,
change StartBlinking to ResetBlinking and have it set up
the correct blink state and reset the blink cycle.
-- nsCaret::NotifySelectionChange needs a SchedulePaint
-- nsCaret::DrawAtPosition needs a ResetBlinking
This is the core of the whole patch set.
Now GetPaintGeometry/PaintCaret figure out on their own almost all the state
they need every time we paint. So when caret flags change, all we need
to do is SchedulePaint. We don't need to fiddle with mDrawn and most of the
logic in DrawCaret is obsolete. (In fact, it was duplicated by GetGeometry
and friends, and we're removing that duplication.) EraseCaret, CheckCaretState
and UpdateCaretPosition are also obsolete.
We need to have GetPaintGeometry/PaintCaret choose the correct content node
and offset, either getting them from the Selection or using specific data set by
DrawAtPosition. This logic, plus a bit of other code shared between them, is
put into the helper GetFrameAndOffset.
Instead of checking the mysterious mDrawn state (which is evil and will be
removed), let nsCaret::GetPaintGeometry take sole responsibilty for deciding
whether to draw. It takes the nsStyleUserInterface checks. It also needs to
check blink state, which is made possible by separating blink state into
the mIsBlinkOn flag.
This also fixes what appears to be a bug. MustDrawCaret returned true
when mShowDuringSelection is set even if the caret would otherwise be
hidden due a popup showing. That doesn't make sense.
This code is somewhat tricky. nsCaret::ComputeCaretRects was checking to see
if we have a bidi keyboard, and if so, what direction it's set to.
If the direction changed from the last direction seen for *this caret*,
we fired a SelectionLanguageChange notification on the caret's current
Selection. This looked bogus because the caret can be switched between
selections so it would seem some selections won't get a notification when
they should, but that's how it was. Also, when the SelectionLanguageChange
notification fired we then didn't draw the caret in that iteration, which
seems even more bogus.
This patch fixes all that by moving the logic to fire SelectionLanguageChange
out to GetPaintGeometry and firing the notification every single time without
trying to detect whether the state has changed or not. I carefully examined
the implementation of SelectionLanguageChange and I'm pretty sure it's
idempotent so this should be correct. That doesn't look like an
expensive function, and runs at most once per window paint, so I'm not
worried about perf. Because we now fire SelectionLanguageChange before
reading selection or frame state, it should be fine to carry on after
calling SelectionLanguageChange and drawing the caret based on whatever
changes SelectionLanguageChange has performed.
This also lets us remove mKeyboardRTL, which as noted above seems inherently
bogus.
Also, moves the "If the offset falls outside of the frame" check from
PaintCaret to GetPaintGeometry so we do less work in that case.
UpdateCaretRects is no longer needed.
This is the start of the changes to caret-drawing proper.
The idea is to combine GetCaretFrame and GetCaretRect into a method
GetPaintGeometry which looks like GetGeometry but returns values
needed for painting (i.e. including bidi decorations, and returning
a null frame if we're not supposed to paint due to specific caret
state, e.g. in the "off" phase of the blink cycle).
Mostly a straightforward refactoring but there are a few interesting changes:
-- nsDisplayCaret stores its bounds instead of getting them from nsCaret on
demand. Eventually those bounds will not be stored in nsCaret at all.
-- nsDisplayCaret::GetBounds returns true for aSnap. nsCaret draws snapped
rects, so why not.
-- I removed "if (caretRect.Intersects(aDirtyRect))" in EnterPresShell.
As far as I can tell, this check is incorrect because it doesn't take
transforms into account. Since there's at most one drawn caret per window,
hence we do this at most once per paint, I don't think there's any real
performance advantage to having this check.
This patch started an attempt to remove nsFrameSelection.h from nsCaret.h
and metastasized into a rather large refactoring patch that removed it
from some other header files as well, and changed nsFrameSelection::HINT
into a global-scope enum with better names. I also converted bools
into CaretAssociationHint in a few places where that was appropriate,
but there are still some more places (GetChildFrameContainingOffset)
where bools need to be converted. I figured this patch was big enough already.
GetGeometry is used in two different ways. Sometimes it's used to get
information about a particular caret. Sometimes it's used to get
information about a particular selection that's not associated with
a caret. Splitting GetGeometry into a non-static version for the former
and a static version for the latter makes this more clear. Also it saves
code since for the latter version we don't have to get an nsCaret first.
We don't need to store the blink rate. Instead we can just fetch it whenever
we need it. However we do need a flag to handle the case where
nsCaret::DrawAtPosition disables blinking.
