Fix up a4d9315b: handle metrics of not visible paragraphs

The code is not ready for situations where some paragraphs that are
not visible have metrics available. This has been made visible by
a4d9315b, which removes a couple of full metrics updates: the screen
was not correctly scrolled after a scrollToCursor() call.

In PararagraphMetrics, some methods are added to be able to handle the
fact that paragraphs have or do not have a position.

In TextMetrics, a new method returns the first visible paragraph.

Finally, in BufferView::updateMetrics, the paragraphs' positions are
reset (in the case where everything is not cleared) and some care is
taken to skip the ones that are not relevant.

The assumption outside of this method is that all the paragraphs that
are in the TextMetrics are visible (we are talking about top-level
TextMetrics here). This could be changed (in order to avoid
recomputing paragraph metrics), but the cost is high in terms of
complexity and it is not clear that the gain in terms of performance
would be important.
This commit is contained in:
Jean-Marc Lasgouttes 2024-05-17 15:42:08 +02:00
parent 5a10c652a3
commit 145af7c2ac
5 changed files with 52 additions and 8 deletions

View File

@ -3211,6 +3211,7 @@ void BufferView::updateMetrics(bool force)
d->text_metrics_.clear();
}
// This should not be moved earlier
TextMetrics & tm = textMetrics(&buftext);
// make sure inline completion pointer is ok
@ -3226,14 +3227,16 @@ void BufferView::updateMetrics(bool force)
// Check that the end of the document is not too high
int const min_visible = lyxrc.scroll_below_document ? minVisiblePart() : height_;
if (tm.last().first == lastpit && tm.last().second->bottom() < min_visible) {
if (tm.last().first == lastpit && tm.last().second->hasPosition()
&& tm.last().second->bottom() < min_visible) {
d->anchor_ypos_ += min_visible - tm.last().second->bottom();
LYXERR(Debug::SCROLLING, "Too high, adjusting anchor ypos to " << d->anchor_ypos_);
tm.updateMetrics(d->anchor_pit_, d->anchor_ypos_, height_);
}
// Check that the start of the document is not too low
if (tm.first().first == 0 && tm.first().second->top() > 0) {
if (tm.first().first == 0 && tm.first().second->hasPosition()
&& tm.first().second->top() > 0) {
d->anchor_ypos_ -= tm.first().second->top();
LYXERR(Debug::SCROLLING, "Too low, adjusting anchor ypos to " << d->anchor_ypos_);
tm.updateMetrics(d->anchor_pit_, d->anchor_ypos_, height_);
@ -3246,11 +3249,11 @@ void BufferView::updateMetrics(bool force)
* extra paragraphs are removed
*/
// Remove paragraphs that are outside of screen
while(tm.first().second->bottom() <= 0) {
while(!tm.first().second->hasPosition() || tm.first().second->bottom() <= 0) {
//LYXERR0("Forget pit: " << tm.first().first);
tm.forget(tm.first().first);
}
while(tm.last().second->top() > height_) {
while(!tm.last().second->hasPosition() || tm.last().second->top() > height_) {
//LYXERR0("Forget pit: " << tm.first().first);
tm.forget(tm.last().first);
}

View File

@ -40,9 +40,10 @@ using namespace lyx::support;
namespace lyx {
const int pm_npos = -10000;
ParagraphMetrics::ParagraphMetrics(Paragraph const & par) :
position_(-1), id_(par.id()), par_(&par)
position_(pm_npos), id_(par.id()), par_(&par)
{}
@ -61,7 +62,14 @@ void ParagraphMetrics::reset(Paragraph const & par)
{
par_ = &par;
dim_ = Dimension();
//position_ = -1;
//position_ = pm_npos;
}
int ParagraphMetrics::position() const
{
LASSERT(hasPosition(), return pm_npos);
return position_;
}
@ -71,6 +79,18 @@ void ParagraphMetrics::setPosition(int position)
}
void ParagraphMetrics::resetPosition()
{
position_ = pm_npos;
}
bool ParagraphMetrics::hasPosition() const
{
return position_ != pm_npos;
}
Row const & ParagraphMetrics::getRow(pos_type pos, bool boundary) const
{
LBUFERR(!rows().empty());

View File

@ -70,8 +70,12 @@ public:
bool hfillExpansion(Row const & row, pos_type pos) const;
/// The vertical position of the baseline of the first line of the paragraph
int position() const { return position_; }
int position() const;
void setPosition(int position);
/// Set poistion to unknown
void resetPosition();
/// Return true when the position of the paragraph is known
bool hasPosition() const;
/// The vertical position of the top of the paragraph
int top() const { return position_ - dim_.ascent(); }
/// The vertical position of the bottom of the paragraph

View File

@ -131,6 +131,17 @@ pair<pit_type, ParagraphMetrics const *> TextMetrics::first() const
}
pair<pit_type, ParagraphMetrics const *> TextMetrics::firstVisible() const
{
// This only works in the main text, I think (bottom > 0)
LASSERT(text_->isMainText(), return first());
auto it = find_if(par_metrics_.begin(), par_metrics_.end(),
[] (ParMetricsCache::value_type const & p) {
return p.second.hasPosition() && p.second.bottom() > 0;
});
return make_pair(it->first, &it->second);
}
pair<pit_type, ParagraphMetrics const *> TextMetrics::last() const
{
LBUFERR(!par_metrics_.empty());
@ -220,7 +231,10 @@ void TextMetrics::updateMetrics(pit_type const anchor_pit, int const anchor_ypos
int const bv_height)
{
LASSERT(text_->isMainText(), return);
pit_type const npit = pit_type(text_->paragraphs().size());
// Forget existing positions
for (auto & pm_pair : par_metrics_)
pm_pair.second.resetPosition();
if (!contains(anchor_pit))
// Rebreak anchor paragraph.
@ -246,6 +260,7 @@ void TextMetrics::updateMetrics(pit_type const anchor_pit, int const anchor_ypos
int y2 = anchor_ypos + anchor_pm.descent();
// We are now just below the anchor paragraph.
pit_type pit2 = anchor_pit + 1;
pit_type const npit = pit_type(text_->paragraphs().size());
for (; pit2 < npit && y2 < bv_height; ++pit2) {
if (!contains(pit2))
redoParagraph(pit2);

View File

@ -50,6 +50,8 @@ public:
///
std::pair<pit_type, ParagraphMetrics const *> first() const;
///
std::pair<pit_type, ParagraphMetrics const *> firstVisible() const;
///
std::pair<pit_type, ParagraphMetrics const *> last() const;
/// is this row the last in the text?
bool isLastRow(Row const & row) const;