Added some documentation :)

[wxWidgets.git] / src / generic / vscroll.cpp

diff --git a/src/generic/vscroll.cpp b/src/generic/vscroll.cpp
index 5d2ccf0cb63b1255110b49dc31896868b4020973..e592f8054169030b2e9e3e99e83a40a03f43880d 100644 (file)
--- a/src/generic/vscroll.cpp
+++ b/src/generic/vscroll.cpp
@@ -17,6 +17,17 @@
 // headers
 // ----------------------------------------------------------------------------
 
+#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
+#pragma implementation "vscroll.h"
+#endif
+
+// For compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
 #include "wx/vscroll.h"
 
 // ----------------------------------------------------------------------------
@@ -33,6 +44,8 @@ END_EVENT_TABLE()
 // implementation
 // ============================================================================
 
+IMPLEMENT_ABSTRACT_CLASS(wxVScrolledWindow, wxPanel)
+
 // ----------------------------------------------------------------------------
 // initialization
 // ----------------------------------------------------------------------------
@@ -53,6 +66,38 @@ void wxVScrolledWindow::Init()
 // various helpers
 // ----------------------------------------------------------------------------
 
+wxCoord wxVScrolledWindow::EstimateTotalHeight() const
+{
+    // estimate the total height: it is impossible to call
+    // OnGetLineHeight() for every line because there may be too many of
+    // them, so we just make a guess using some lines in the beginning,
+    // some in the end and some in the middle
+    static const size_t NUM_LINES_TO_SAMPLE = 10;
+
+    wxCoord heightTotal;
+    if ( m_lineMax < 3*NUM_LINES_TO_SAMPLE )
+    {
+        // in this case calculating exactly is faster and more correct than
+        // guessing
+        heightTotal = GetLinesHeight(0, m_lineMax);
+    }
+    else // too many lines to calculate exactly
+    {
+        // look at some lines in the beginning/middle/end
+        heightTotal =
+            GetLinesHeight(0, NUM_LINES_TO_SAMPLE) +
+                GetLinesHeight(m_lineMax - NUM_LINES_TO_SAMPLE, m_lineMax) +
+                    GetLinesHeight(m_lineMax/2 - NUM_LINES_TO_SAMPLE/2,
+                                   m_lineMax/2 + NUM_LINES_TO_SAMPLE/2);
+
+        // use the height of the lines we looked as the average
+        heightTotal = (wxCoord)
+                (((float)heightTotal / (3*NUM_LINES_TO_SAMPLE)) * m_lineMax);
+    }
+
+    return heightTotal;
+}
+
 wxCoord wxVScrolledWindow::GetLinesHeight(size_t lineMin, size_t lineMax) const
 {
     if ( lineMin == lineMax )
@@ -74,7 +119,7 @@ wxCoord wxVScrolledWindow::GetLinesHeight(size_t lineMin, size_t lineMax) const
     return height;
 }
 
-size_t wxVScrolledWindow::FindFirstFromBottom(size_t lineLast)
+size_t wxVScrolledWindow::FindFirstFromBottom(size_t lineLast, bool full)
 {
     const wxCoord hWindow = GetClientSize().y;
 
@@ -88,7 +133,13 @@ size_t wxVScrolledWindow::FindFirstFromBottom(size_t lineLast)
 
         if ( h > hWindow )
         {
-            lineFirst++;
+            // for this line to be fully visible we need to go one line
+            // down, but if it is enough for it to be only partly visible then
+            // this line will do as well
+            if ( full )
+            {
+                lineFirst++;
+            }
 
             break;
         }
@@ -141,33 +192,8 @@ void wxVScrolledWindow::SetLineCount(size_t count)
     // save the number of lines
     m_lineMax = count;
 
-
-    // estimate the total height: it is impossible to call
-    // OnGetLineHeight() for every line because there may be too many of
-    // them, so we just make a guess using some lines in the beginning,
-    // some in the end and some in the middle
-    static const size_t NUM_LINES_TO_SAMPLE = 10;
-
-    if ( count < 3*NUM_LINES_TO_SAMPLE )
-    {
-        // in this case calculating exactly is faster and more correct than
-        // guessing
-        m_heightTotal = GetLinesHeight(0, m_lineMax);
-    }
-    else // too many lines to calculate exactly
-    {
-        // look at some lines in the beginning/middle/end
-        m_heightTotal =
-            GetLinesHeight(0, NUM_LINES_TO_SAMPLE) +
-                GetLinesHeight(count - NUM_LINES_TO_SAMPLE, count) +
-                    GetLinesHeight(count/2 - NUM_LINES_TO_SAMPLE/2,
-                                   count/2 + NUM_LINES_TO_SAMPLE/2);
-
-        // use the height of the lines we looked as the average
-        m_heightTotal = (wxCoord)
-                (((float)m_heightTotal / (3*NUM_LINES_TO_SAMPLE)) * m_lineMax);
-    }
-
+    // and our estimate for their total height
+    m_heightTotal = EstimateTotalHeight();
 
     // recalculate the scrollbars parameters
     m_lineFirst = 1;    // make sure it is != 0
@@ -196,6 +222,35 @@ void wxVScrolledWindow::RefreshLine(size_t line)
     RefreshRect(rect);
 }
 
+void wxVScrolledWindow::RefreshLines(size_t from, size_t to)
+{
+    wxASSERT_MSG( from <= to, _T("RefreshLines(): empty range") );
+
+    // clump the range to just the visible lines -- it is useless to refresh
+    // the other ones
+    if ( from < GetFirstVisibleLine() )
+        from = GetFirstVisibleLine();
+
+    if ( to > GetLastVisibleLine() )
+        to = GetLastVisibleLine();
+
+    // calculate the rect occupied by these lines on screen
+    wxRect rect;
+    rect.width = GetClientSize().x;
+    for ( size_t nBefore = GetFirstVisibleLine(); nBefore < from; nBefore++ )
+    {
+        rect.y += OnGetLineHeight(nBefore);
+    }
+
+    for ( size_t nBetween = from; nBetween <= to; nBetween++ )
+    {
+        rect.height += OnGetLineHeight(nBetween);
+    }
+
+    // do refresh it
+    RefreshRect(rect);
+}
+
 void wxVScrolledWindow::RefreshAll()
 {
     UpdateScrollbar();
@@ -230,7 +285,7 @@ bool wxVScrolledWindow::ScrollToLine(size_t line)
 
     // determine the real first line to scroll to: we shouldn't scroll beyond
     // the end
-    size_t lineFirstLast = FindFirstFromBottom(m_lineMax - 1);
+    size_t lineFirstLast = FindFirstFromBottom(m_lineMax - 1, true);
     if ( line > lineFirstLast )
         line = lineFirstLast;