Fix bug 1814 (scrolling)

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@10595 a592a061-630c-0410-9148-cb99ea01b6c8

diff --git a/src/BufferView_pimpl.C b/src/BufferView_pimpl.C
index 3902af1d596bb9fe4b6034a72157dc7fbb8e7251..419015a7967de124406fc388870c68481ec2c35a 100644 (file)
--- a/src/BufferView_pimpl.C
+++ b/src/BufferView_pimpl.C
@@ -141,8 +141,8 @@ T * getInsetByCode(LCursor & cur, InsetBase::Code code)
 
 BufferView::Pimpl::Pimpl(BufferView & bv, LyXView * owner,
                         int width, int height)
-       : bv_(&bv), owner_(owner), buffer_(0), cursor_timeout(400),
-         using_xterm_cursor(false), cursor_(bv) ,
+       : bv_(&bv), owner_(owner), buffer_(0), wh_(0), cursor_timeout(400),
+         using_xterm_cursor(false), cursor_(bv), 
          anchor_ref_(0), offset_ref_(0)
 {
        xsel_cache_.set = false;
@@ -439,8 +439,9 @@ void BufferView::Pimpl::updateScrollbar()
        }
 
        LyXText & t = *bv_->text();
-       if (anchor_ref_ >  int(t.paragraphs().size()) - 1) {
-               anchor_ref_ = int(t.paragraphs().size()) - 1;
+       int const parsize = int(t.paragraphs().size() - 1);
+       if (anchor_ref_ >  parsize)  {
+               anchor_ref_ = parsize;
                offset_ref_ = 0;
        }
 
@@ -454,21 +455,34 @@ void BufferView::Pimpl::updateScrollbar()
        // values in [0..1] and divide everything by wh
 
        // estimated average paragraph height:
-       int const wh = workarea().workHeight() / 4; 
+       if (wh_ == 0)
+               wh_ = workarea().workHeight() / 4; 
        int h = t.getPar(anchor_ref_).height();
+
        // Normalize anchor/offset (MV):
-       while (offset_ref_ > h) {
+       while (offset_ref_ > h && anchor_ref_ < parsize) {
                anchor_ref_++;
                offset_ref_ -= h;
                h = t.getPar(anchor_ref_).height();
        }
+       // Look at paragraph heights on-screen
+       int sumh = 0;
+       int nh = 0;
+       for (lyx::pit_type pit = anchor_ref_; pit <= parsize; ++pit) {
+               if (sumh > workarea().workHeight())
+                       break;
+               int const h2 = t.getPar(pit).height(); 
+               sumh += h2;
+               nh++;
+       }
+       int const hav = sumh / nh;
+       // More realistic average paragraph height
+       if (hav > wh_)
+               wh_ = hav;
        
-       // The "+ 2" makes inoculates doc bottom display against
-       // unrealistic wh values (docs with very large paragraphs) (MV)
-       workarea().setScrollbarParams((t.paragraphs().size() + 2) * wh, 
-               anchor_ref_ * wh + int(offset_ref_ * wh / float(h)), 
-               int(wh * defaultRowHeight() / float(h)));
-//     workarea().setScrollbarParams(t.paragraphs().size(), anchor_ref_, 1);
+       workarea().setScrollbarParams((parsize + 1) * wh_, 
+               anchor_ref_ * wh_ + int(offset_ref_ * wh_ / float(h)), 
+               int(wh_ * defaultRowHeight() / float(h)));
 }
 
 
@@ -482,13 +496,13 @@ void BufferView::Pimpl::scrollDocView(int value)
 
        screen().hideCursor();
 
-       int const wh = workarea().workHeight() / 4;
-
        LyXText & t = *bv_->text();
 
-       float const bar = value / float(wh * t.paragraphs().size());
+       float const bar = value / float(wh_ * t.paragraphs().size());
 
        anchor_ref_ = int(bar * t.paragraphs().size());
+       if (anchor_ref_ >  int(t.paragraphs().size()) - 1)
+               anchor_ref_ = int(t.paragraphs().size()) - 1;
        t.redoParagraph(anchor_ref_);
        int const h = t.getPar(anchor_ref_).height();
        offset_ref_ = int((bar * t.paragraphs().size() - anchor_ref_) * h);

diff --git a/src/BufferView_pimpl.h b/src/BufferView_pimpl.h
index 73d6d4262df881a15a0d399bb685fdf07e97dfce..b55cf924e27bcc0e73c52ba1ef0e44f893a0da0e 100644 (file)
--- a/src/BufferView_pimpl.h
+++ b/src/BufferView_pimpl.h
@@ -145,6 +145,8 @@ private:
        boost::scoped_ptr<LyXScreen> screen_;
        ///
        boost::scoped_ptr<WorkArea> workarea_;
+       /// Estimated average par height for scrollbar
+       int wh_;
        ///
        Timeout cursor_timeout;
        ///

diff --git a/src/ChangeLog b/src/ChangeLog
index c495f9774cf58243a1d53f75d4a26b4a7c1e45d1..00f542fc6cbff32b8228093592327d84cebdfa37 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,8 +1,13 @@
+2005-11-07  Martin Vermeer  <martin.vermeer@hut.fi>
+
+       * BufferView_pimpl.[Ch]: Fix bug 1814: better scroll behaviour for 
+       docs containing very large paragraphs.
+
 2005-11-07  Martin Vermeer  <martin.vermeer@hut.fi>
 
        * cursor.C (selectionBegin, selectionEnd):
        * text.C (drawSelection): Fix bug 2115: assertion when anchor and 
-       cursor at different depths
+       cursor at different depths.
 
 2005-11-03  Jürgen Spitzmüller  <j.spitzmueller@gmx.de>