Fix bug #4464: Missing autoscroll when selecting by mouse drag.

It's not very fast, but I guess that's a general problem with our scrolling. At least it works now, but it's not perfect.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@34659 a592a061-630c-0410-9148-cb99ea01b6c8

diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index d67ee9ad0c912bbc56d3118dfd14189a1efea16c..bef40d88cbc16e82170ff4fa12d06b5c457d7718 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -37,6 +37,7 @@
 #include "LyXVC.h"
 #include "qt_helpers.h"
 #include "Text.h"
+#include "TextMetrics.h"
 #include "version.h"
 
 #include "graphics/GraphicsImage.h"
@@ -224,8 +225,7 @@ private:
 // This is a 'heartbeat' generating synthetic mouse move events when the
 // cursor is at the top or bottom edge of the viewport. One scroll per 0.2 s
 SyntheticMouseEvent::SyntheticMouseEvent()
-       : timeout(200), restart_timeout(true),
-         x_old(-1), y_old(-1), min_scrollbar_old(-1), max_scrollbar_old(-1)
+       : timeout(200), restart_timeout(true)
 {}
 
 
@@ -770,18 +770,19 @@ void GuiWorkArea::mouseMoveEvent(QMouseEvent * e)
        e->accept();
 
        // If we're above or below the work area...
-       if (e->y() <= 20 || e->y() >= viewport()->height() - 20) {
+       if ((e->y() <= 20 || e->y() >= viewport()->height() - 20)
+                       && e->buttons() == mouse_button::button1) {
                // Make sure only a synthetic event can cause a page scroll,
                // so they come at a steady rate:
                if (e->y() <= 20)
                        // _Force_ a scroll up:
-                       cmd.set_y(-40);
+                       cmd.set_y(e->y() - 21);
                else
-                       cmd.set_y(viewport()->height());
+                       cmd.set_y(e->y() + 21);
                // Store the event, to be handled when the timeout expires.
                synthetic_mouse_event_.cmd = cmd;
 
-               if (synthetic_mouse_event_.timeout.running())
+               if (synthetic_mouse_event_.timeout.running()) {
                        // Discard the event. Note that it _may_ be handled
                        // when the timeout expires if
                        // synthetic_mouse_event_.cmd has not been overwritten.
@@ -790,7 +791,8 @@ void GuiWorkArea::mouseMoveEvent(QMouseEvent * e)
                        // occurred after the one used to start the timeout
                        // in the first place.
                        return;
-
+               }
+               
                synthetic_mouse_event_.restart_timeout = true;
                synthetic_mouse_event_.timeout.start();
                // Fall through to handle this event...
@@ -806,24 +808,6 @@ void GuiWorkArea::mouseMoveEvent(QMouseEvent * e)
                synthetic_mouse_event_.restart_timeout = false;
                return;
        }
-
-       // Has anything changed on-screen since the last QMouseEvent
-       // was received?
-       if (e->x() == synthetic_mouse_event_.x_old
-               && e->y() == synthetic_mouse_event_.y_old
-               && synthetic_mouse_event_.min_scrollbar_old == verticalScrollBar()->minimum()
-               && synthetic_mouse_event_.max_scrollbar_old == verticalScrollBar()->maximum()) {
-               // Nothing changed on-screen since the last QMouseEvent.
-               return;
-       }
-
-       // Yes something has changed. Store the params used to check this.
-       synthetic_mouse_event_.x_old = e->x();
-       synthetic_mouse_event_.y_old = e->y();
-       synthetic_mouse_event_.min_scrollbar_old = verticalScrollBar()->minimum();
-       synthetic_mouse_event_.max_scrollbar_old = verticalScrollBar()->maximum();
-
-       // ... and dispatch the event to the LyX core.
        dispatch(cmd);
 }
 
@@ -863,23 +847,81 @@ void GuiWorkArea::wheelEvent(QWheelEvent * ev)
 
 void GuiWorkArea::generateSyntheticMouseEvent()
 {
+       int const e_y = synthetic_mouse_event_.cmd.y();
+       int const wh = buffer_view_->workHeight();
+       bool const up = e_y < 0;
+       bool const down = e_y > wh;
+
        // Set things off to generate the _next_ 'pseudo' event.
-       if (synthetic_mouse_event_.restart_timeout)
+       int step = 50;
+       if (synthetic_mouse_event_.restart_timeout) {
+               // This is some magic formulae to determine the speed
+               // of scrolling related to the position of the mouse.
+               int time = 200;
+               if (up || down) {
+                       int dist = up ? -e_y : e_y - wh;
+                       time = max(min(200, 250000 / (dist * dist)), 1) ;
+                       
+                       if (time < 40) {
+                               step = 80000 / (time * time);
+                               time = 40;
+                       }
+               }
+               synthetic_mouse_event_.timeout.setTimeout(time);
                synthetic_mouse_event_.timeout.start();
+       }
+
+       // Can we scroll further ?
+       int const value = verticalScrollBar()->value();
+       if (value == verticalScrollBar()->maximum()
+                 || value == verticalScrollBar()->minimum()) {
+               synthetic_mouse_event_.timeout.stop();
+               return;
+       }
+
+       // Scroll
+       if (step <= 2 * wh) {
+               buffer_view_->scroll(up ? -step : step);
+               buffer_view_->updateMetrics();
+       } else {
+               buffer_view_->scrollDocView(value + up ? -step : step, false);
+       }
+
+       // In which paragraph do we have to set the cursor ?
+       Cursor & cur = buffer_view_->cursor();
+       TextMetrics const & tm = buffer_view_->textMetrics(cur.text());
 
-       // Has anything changed on-screen since the last timeout signal
-       // was received?
-       int const min_scrollbar = verticalScrollBar()->minimum();
-       int const max_scrollbar = verticalScrollBar()->maximum();
-       if (min_scrollbar == synthetic_mouse_event_.min_scrollbar_old
-               && max_scrollbar == synthetic_mouse_event_.max_scrollbar_old) {
+       pair<pit_type, const ParagraphMetrics *> p = up ? tm.first() : tm.last();
+       ParagraphMetrics const & pm = *p.second;
+       pit_type const pit = p.first;
+
+       if (pm.rows().empty())
                return;
+
+       // Find the row at which we set the cursor.
+       RowList::const_iterator rit = pm.rows().begin();
+       RowList::const_iterator rlast = pm.rows().end();
+       int yy = pm.position() - pm.ascent();
+       for (--rlast; rit != rlast; ++rit) {
+               int h = rit->height();
+               if ((up && yy + h > 0)
+                         || (!up && yy + h > wh - defaultRowHeight()))
+                       break;
+               yy += h;
        }
-       // Yes it has. Store the params used to check this.
-       synthetic_mouse_event_.min_scrollbar_old = min_scrollbar;
-       synthetic_mouse_event_.max_scrollbar_old = max_scrollbar;
-       // ... and dispatch the event to the LyX core.
-       dispatch(synthetic_mouse_event_.cmd);
+       
+       // Find the position of the cursor
+       bool bound;
+       int x = synthetic_mouse_event_.cmd.x();
+       pos_type const pos = rit->pos() + tm.getColumnNearX(pit, *rit, x, bound);
+
+       // Set the cursor
+       cur.pit() = pit;
+       cur.pos() = pos;
+       cur.boundary(bound);
+
+       buffer_view_->buffer().changed(false);
+       return;
 }
 
 

diff --git a/src/frontends/qt4/GuiWorkArea.h b/src/frontends/qt4/GuiWorkArea.h
index 9a0e2a2d22e72f44a8a51eb9fd67a60695df3c04..0858521a9a5bf0f98d36553dc9e39b51fa76a156 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea.h
+++ b/src/frontends/qt4/GuiWorkArea.h
@@ -85,10 +85,6 @@ public:
        FuncRequest cmd;
        Timeout timeout;
        bool restart_timeout;
-       int x_old;
-       int y_old;
-       int min_scrollbar_old;
-       int max_scrollbar_old;
 };