X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/27c14b30bcc96bc408a146e91e4befb08f6dd0ea..a7b2c092b782f57a4aebd31802a9c81741f208b1:/src/html/htmlwin.cpp

diff --git a/src/html/htmlwin.cpp b/src/html/htmlwin.cpp
index 636a07610f..2b0e4b96cb 100644
--- a/src/html/htmlwin.cpp
+++ b/src/html/htmlwin.cpp
@@ -31,6 +31,7 @@
 #include "wx/html/htmlwin.h"
 #include "wx/html/htmlproc.h"
 #include "wx/clipbrd.h"
+#include "wx/recguard.h"
 
 #include "wx/arrimpl.cpp"
 #include "wx/listimpl.cpp"
@@ -689,38 +690,111 @@ void wxHtmlWindow::OnSetTitle(const wxString& title)
 }
 
 
-
+// return scroll steps such that a) scrollbars aren't shown needlessly
+// and b) entire content is viewable (i.e. round up)
+static int ScrollSteps(int size, int available)
+{
+    if ( size <= available )
+        return 0;
+    else
+        return (size + wxHTML_SCROLL_STEP - 1) / wxHTML_SCROLL_STEP;
+}
 
 
 void wxHtmlWindow::CreateLayout()
 {
-    int ClientWidth, ClientHeight;
+    // SetScrollbars() results in size change events -- and thus a nested
+    // CreateLayout() call -- on some platforms. Ignore nested calls, toplevel
+    // CreateLayout() will do the right thing eventually.
+    static wxRecursionGuardFlag s_flagReentrancy;
+    wxRecursionGuard guard(s_flagReentrancy);
+    if ( guard.IsInside() )
+        return;
 
-    if (!m_Cell) return;
+    if (!m_Cell)
+        return;
+
+    int clientWidth, clientHeight;
+    GetClientSize(&clientWidth, &clientHeight);
+
+    const int vscrollbar = wxSystemSettings::GetMetric(wxSYS_VSCROLL_X);
+    const int hscrollbar = wxSystemSettings::GetMetric(wxSYS_HSCROLL_Y);
+
+    if ( HasScrollbar(wxHORIZONTAL) )
+        clientHeight += hscrollbar;
+
+    if ( HasScrollbar(wxVERTICAL) )
+        clientWidth += vscrollbar;
 
     if ( HasFlag(wxHW_SCROLLBAR_NEVER) )
     {
         SetScrollbars(1, 1, 0, 0); // always off
-        GetClientSize(&ClientWidth, &ClientHeight);
-        m_Cell->Layout(ClientWidth);
+        m_Cell->Layout(clientWidth);
     }
     else // !wxHW_SCROLLBAR_NEVER
     {
-        GetClientSize(&ClientWidth, &ClientHeight);
-        m_Cell->Layout(ClientWidth);
-        if (ClientHeight < m_Cell->GetHeight() + GetCharHeight())
+        // Lay the content out with the assumption that it's too large to fit
+        // in the window (this is likely to be the case):
+        m_Cell->Layout(clientWidth - vscrollbar);
+
+        // If the layout is wider than the window, horizontal scrollbar will
+        // certainly be shown. Account for it here for subsequent computations.
+        if ( m_Cell->GetWidth() > clientWidth )
+            clientHeight -= hscrollbar;
+
+        if ( m_Cell->GetHeight() <= clientHeight )
         {
-            SetScrollbars(
-                  wxHTML_SCROLL_STEP, wxHTML_SCROLL_STEP,
-                  m_Cell->GetWidth() / wxHTML_SCROLL_STEP,
-                  (m_Cell->GetHeight() + GetCharHeight()) / wxHTML_SCROLL_STEP
-                  /*cheat: top-level frag is always container*/);
+            // we fit into the window, hide vertical scrollbar:
+            SetScrollbars
+            (
+                wxHTML_SCROLL_STEP, wxHTML_SCROLL_STEP,
+                ScrollSteps(m_Cell->GetWidth(), clientWidth - vscrollbar),
+                0
+            );
+            // ...and redo the layout to use the extra space
+            m_Cell->Layout(clientWidth);
         }
-        else /* we fit into window, no need for scrollbars */
+        else
         {
-            SetScrollbars(wxHTML_SCROLL_STEP, 1, m_Cell->GetWidth() / wxHTML_SCROLL_STEP, 0); // disable...
-            GetClientSize(&ClientWidth, &ClientHeight);
-            m_Cell->Layout(ClientWidth); // ...and relayout
+            // If the content doesn't fit into the window by only a small
+            // margin, chances are that it may fit fully with scrollbar turned
+            // off. It's something worth trying but on the other hand, we don't
+            // want to waste too much time redoing the layout (twice!) for
+            // long -- and thus expensive to layout -- pages. The cut-off value
+            // is an arbitrary heuristics.
+            static const int SMALL_OVERLAP = 60;
+            if ( m_Cell->GetHeight() <= clientHeight + SMALL_OVERLAP )
+            {
+                m_Cell->Layout(clientWidth);
+
+                if ( m_Cell->GetHeight() <= clientHeight )
+                {
+                    // Great, we fit in. Hide the scrollbar.
+                    SetScrollbars
+                    (
+                        wxHTML_SCROLL_STEP, wxHTML_SCROLL_STEP,
+                        ScrollSteps(m_Cell->GetWidth(), clientWidth),
+                        0
+                    );
+                    return;
+                }
+                else
+                {
+                    // That didn't work out, go back to previous layout. Note
+                    // that redoing the layout once again here isn't as bad as
+                    // it looks -- thanks to the small cut-off value, it's a
+                    // reasonably small page.
+                    m_Cell->Layout(clientWidth - vscrollbar);
+                }
+            }
+            // else: the page is very long, it will certainly need scrollbar
+
+            SetScrollbars
+            (
+                wxHTML_SCROLL_STEP, wxHTML_SCROLL_STEP,
+                ScrollSteps(m_Cell->GetWidth(), clientWidth - vscrollbar),
+                ScrollSteps(m_Cell->GetHeight(), clientHeight)
+            );
         }
     }
 }