use a GtkAlignment to position m_mainWidget, avoiding need to re-size_allocate it

[wxWidgets.git] / src / gtk / scrolwin.cpp

diff --git a/src/gtk/scrolwin.cpp b/src/gtk/scrolwin.cpp
index 3d257acc26418fc66f55f741bb75a9c67a09dda1..2808986822679f3dbc5494dee5946738f7497e85 100644 (file)
--- a/src/gtk/scrolwin.cpp
+++ b/src/gtk/scrolwin.cpp
@@ -50,9 +50,9 @@ void wxScrollHelperNative::SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
     m_xScrollPixelsPerLine = pixelsPerUnitX;
     m_yScrollPixelsPerLine = pixelsPerUnitY;
 
-    m_win->m_scrollBar[0]->adjustment->value =
+    m_win->m_scrollBar[wxWindow::ScrollDir_Horz]->adjustment->value =
     m_xScrollPosition = xPos;
-    m_win->m_scrollBar[1]->adjustment->value =
+    m_win->m_scrollBar[wxWindow::ScrollDir_Vert]->adjustment->value =
     m_yScrollPosition = yPos;
 
     // Setting hints here should arguably be deprecated, but without it
@@ -85,43 +85,73 @@ void wxScrollHelperNative::DoAdjustScrollbar(GtkRange* range,
                                              int pixelsPerLine,
                                              int winSize,
                                              int virtSize,
+                                             int *pos,
                                              int *lines,
                                              int *linesPerPage)
 {
-    // GtkRange won't allow upper == lower, so for disabled state use [0,1]
-    //   with a page size of 1. This will also clamp position to 0.
-    int upper = 1;
-    int page_size = 1;
-    if (pixelsPerLine > 0 && winSize < virtSize)
+    int upper;
+    int page_size;
+    if (pixelsPerLine > 0 && winSize > 0 && winSize < virtSize)
     {
         upper = (virtSize + pixelsPerLine - 1) / pixelsPerLine;
         page_size = winSize / pixelsPerLine;
+        *lines = upper;
+        *linesPerPage = page_size;
+    }
+    else
+    {
+        // GtkRange won't allow upper == lower, so for disabled state use [0,1]
+        //   with a page size of 1. This will also clamp position to 0.
+        upper = 1;
+        page_size = 1;
+        *lines = 0;
+        *linesPerPage = 0;
     }
-
-    *lines = upper;
-    *linesPerPage = page_size;
 
     GtkAdjustment* adj = range->adjustment;
     adj->step_increment = 1;
     adj->page_increment =
     adj->page_size = page_size;
     gtk_range_set_range(range, 0, upper);
+
+    // ensure that the scroll position is always in valid range
+    if (*pos > *lines)
+        *pos = *lines;
 }
 
 void wxScrollHelperNative::AdjustScrollbars()
 {
-    int w, h;
+    // this flag indicates which window has the scrollbars
+    m_win->m_hasScrolling = m_xScrollPixelsPerLine != 0 ||
+                                m_yScrollPixelsPerLine != 0;
+
     int vw, vh;
+    m_targetWindow->GetVirtualSize( &vw, &vh );
 
-    m_targetWindow->m_hasScrolling = m_xScrollPixelsPerLine != 0 || m_yScrollPixelsPerLine != 0;
+    int w;
+    m_targetWindow->GetClientSize(&w, NULL);
+    DoAdjustHScrollbar(w, vw);
 
-    m_targetWindow->GetClientSize( &w, &h );
-    m_targetWindow->GetVirtualSize( &vw, &vh );
+    int h;
+    m_targetWindow->GetClientSize(NULL, &h);
+    DoAdjustVScrollbar(h, vh);
 
-    DoAdjustScrollbar(m_win->m_scrollBar[0], m_xScrollPixelsPerLine, w, vw,
-                      &m_xScrollLines, &m_xScrollLinesPerPage);
-    DoAdjustScrollbar(m_win->m_scrollBar[1], m_yScrollPixelsPerLine, h, vh,
-                      &m_yScrollLines, &m_yScrollLinesPerPage);
+    const int w_old = w;
+    m_targetWindow->GetClientSize(&w, NULL);
+    if ( w != w_old )
+    {
+        // It is necessary to repeat the calculations in this case to avoid an
+        // observed infinite series of size events, involving alternating
+        // changes in visibility of the scrollbars.
+        // At this point, GTK+ has already queued a resize, which will cause
+        // AdjustScrollbars() to be called again. If the scrollbar visibility
+        // is not correct before then, yet another resize will occur, possibly
+        // leading to an unending series if the sizes are just right.
+        DoAdjustHScrollbar(w, vw);
+
+        m_targetWindow->GetClientSize(NULL, &h);
+        DoAdjustVScrollbar(h, vh);
+    }
 }
 
 void wxScrollHelperNative::DoScroll(int orient,