Add wxRendererNative::DrawCollapseButton() for use in collapsible pane like controls.

Add a new method that should be used for controls like wxCollapsiblePane.

It is implemented natively for wxMSW (Windows Vista+) and provides a generic fallback for other ports and WinXP.

include/wx/renderer.h

@@ -260,6 +260,17 @@ public:
                                 const wxRect& rect,
                                 int flags = 0) = 0;
 
+    // draw collapse button
+    //
+    // flags may use wxCONTROL_CHECKED, wxCONTROL_UNDETERMINED and wxCONTROL_CURRENT
+    virtual void DrawCollapseButton(wxWindow *win,
+                                    wxDC& dc,
+                                    const wxRect& rect,
+                                    int flags = 0) = 0;
+
+    // Returns the default size of a collapse button
+    virtual wxSize GetCollapseButtonSize(wxWindow *win, wxDC& dc) = 0;
+
     // draw rectangle indicating that an item in e.g. a list control
     // has been selected or focused
     //
@@ -470,6 +481,15 @@ public:
                                 int flags = 0)
         { m_rendererNative.DrawPushButton( win, dc, rect, flags ); }
 
+    virtual void DrawCollapseButton(wxWindow *win,
+                                    wxDC& dc,
+                                    const wxRect& rect,
+                                    int flags = 0)
+        { m_rendererNative.DrawCollapseButton(win, dc, rect, flags); }
+
+    virtual wxSize GetCollapseButtonSize(wxWindow *win, wxDC& dc)
+        { return m_rendererNative.GetCollapseButtonSize(win, dc); }
+
     virtual void DrawItemSelectionRect(wxWindow *win,
                                        wxDC& dc,
                                        const wxRect& rect,

interface/wx/renderer.h

@@ -37,7 +37,7 @@ enum
     /** Only for the menu items. */
     wxCONTROL_ISSUBMENU  = wxCONTROL_SPECIAL,
 
-    /** Only for the tree items. */
+    /** Only for the tree items and collapse buttons. */
     wxCONTROL_EXPANDED   = wxCONTROL_SPECIAL,
 
     /** Only for the status bar panes. */
@@ -441,6 +441,24 @@ public:
     virtual void DrawPushButton(wxWindow* win, wxDC& dc, const wxRect& rect,
                                 int flags = 0) = 0;
 
+    /**
+        Draw a collapse button.
+
+        @a flags may have the @c wxCONTROL_EXPANDED or @c wxCONTROL_CURRENT
+        bit set, see @ref wxCONTROL_FLAGS.
+
+        @since 3.1.0
+    */
+    virtual void DrawCollapseButton(wxWindow *win, wxDC& dc,
+                                    const wxRect& rect, int flags = 0) = 0;
+
+    /**
+        Returns the size of a collapse button.
+
+        @since 3.1.0
+    */
+    virtual wxSize GetCollapseButtonSize(wxWindow *win, wxDC& dc) = 0;
+
     /**
         Draw the border for sash window: this border must be such that the sash
         drawn by DrawSplitterSash() blends into it well.

samples/render/render.cpp

@@ -246,6 +246,12 @@ private:
                                  wxRect(wxPoint(x2, y), sizeCheck), m_flags);
         y += lineHeight + sizeCheck.y;
 
+        dc.DrawText("DrawCollapseButton()", x1, y);
+        const wxSize sizeCollapse = renderer.GetCollapseButtonSize(this, dc);
+        renderer.DrawCollapseButton(this, dc,
+                                    wxRect(wxPoint(x2, y), sizeCollapse), m_flags);
+        y += lineHeight + sizeCollapse.y;
+
         dc.DrawText("DrawTreeItemButton()", x1, y);
         renderer.DrawTreeItemButton(this, dc,
                                     wxRect(x2, y, 20, 20), m_flags);

src/generic/renderg.cpp

@@ -113,6 +113,13 @@ public:
                                 const wxRect& rect,
                                 int flags = 0) wxOVERRIDE;
 
+    virtual void DrawCollapseButton(wxWindow *win,
+        wxDC& dc,
+        const wxRect& rect,
+        int flags = 0);
+
+    virtual wxSize GetCollapseButtonSize(wxWindow *win, wxDC& dc);
+
     virtual void DrawItemSelectionRect(wxWindow *win,
                                        wxDC& dc,
                                        const wxRect& rect,
@@ -686,6 +693,42 @@ wxRendererGeneric::DrawPushButton(wxWindow *win,
     dc.DrawRectangle(rect);
 }
 
+void
+wxRendererGeneric::DrawCollapseButton(wxWindow *win,
+                                wxDC& dc,
+                                const wxRect& rect,
+                                int flags)
+{
+    int arrowHalf = rect.width / 5;
+    int rectMid = rect.width / 2;
+    int arrowTopY = (rect.height / 2) - (arrowHalf / 2);
+
+    wxPoint pt[3];
+    if (flags & wxCONTROL_EXPANDED)
+    {
+        // This should always result in arrow with odd width.
+        pt[0] = wxPoint(rectMid - arrowHalf, arrowTopY);
+        pt[1] = wxPoint(rectMid + arrowHalf, arrowTopY);
+        pt[2] = wxPoint(rectMid, arrowTopY + arrowHalf);
+    }
+    else
+    {
+        // This should always result in arrow with odd height.
+        pt[0] = wxPoint(arrowTopY, rectMid - arrowHalf);
+        pt[1] = wxPoint(arrowTopY + arrowHalf, rectMid);
+        pt[2] = wxPoint(arrowTopY, rectMid + arrowHalf);
+    }
+
+    dc.SetBrush(wxBrush(win->GetForegroundColour()));
+    dc.SetPen(wxPen(win->GetForegroundColour()));
+    dc.DrawPolygon(WXSIZEOF(pt), pt, rect.x, rect.y);
+}
+
+wxSize wxRendererGeneric::GetCollapseButtonSize(wxWindow *WXUNUSED(win), wxDC& WXUNUSED(dc))
+{
+    return wxSize(18, 18);
+}
+
 void
 wxRendererGeneric::DrawItemSelectionRect(wxWindow * win,
                                          wxDC& dc,

src/msw/renderer.cpp

@@ -114,6 +114,15 @@
 
     #define DTT_TEXTCOLOR       (1UL << 0)      // crText has been specified
     #define DTT_STATEID         (1UL << 8)      // IStateId has been specified
+
+    #define TDLG_EXPANDOBUTTON 13
+
+    #define TDLGEBS_NORMAL 1
+    #define TDLGEBS_HOVER 2
+    #define TDLGEBS_PRESSED 3
+    #define TDLGEBS_EXPANDEDNORMAL 4
+    #define TDLGEBS_EXPANDEDHOVER 5
+    #define TDLGEBS_EXPANDEDPRESSED 6
 #endif
 
 #if defined(__WXWINCE__)
@@ -294,6 +303,13 @@ public:
             m_rendererNative.DrawPushButton(win, dc, rect, flags);
     }
 
+    virtual void DrawCollapseButton(wxWindow *win,
+                                    wxDC& dc,
+                                    const wxRect& rect,
+                                    int flags = 0);
+
+    virtual wxSize GetCollapseButtonSize(wxWindow *win, wxDC& dc);
+
     virtual void DrawItemSelectionRect(wxWindow *win,
                                        wxDC& dc,
                                        const wxRect& rect,
@@ -858,6 +874,74 @@ wxRendererXP::DrawTitleBarBitmap(wxWindow *win,
     DoDrawButtonLike(hTheme, part, dc, rect, flags);
 }
 
+void
+wxRendererXP::DrawCollapseButton(wxWindow *win,
+                                 wxDC& dc,
+                                 const wxRect& rect,
+                                 int flags)
+{
+    wxUxThemeHandle hTheme(win, L"TASKDIALOG");
+    wxUxThemeEngine* const te = wxUxThemeEngine::Get();
+
+    int state;
+    if (flags & wxCONTROL_PRESSED)
+        state = TDLGEBS_PRESSED;
+    else if (flags & wxCONTROL_CURRENT)
+        state = TDLGEBS_HOVER;
+    else
+        state = TDLGEBS_NORMAL;
+
+    if ( flags & wxCONTROL_EXPANDED )
+        state += 3;
+
+    if ( te->IsThemePartDefined(hTheme, TDLG_EXPANDOBUTTON, state) )
+    {
+        if (flags & wxCONTROL_EXPANDED)
+            flags |= wxCONTROL_CHECKED;
+
+        wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
+
+        RECT r;
+        wxCopyRectToRECT(adjustedRect, r);
+
+        te->DrawThemeBackground
+            (
+            hTheme,
+            GetHdcOf(dc.GetTempHDC()),
+            TDLG_EXPANDOBUTTON,
+            state,
+            &r,
+            NULL
+            );
+    }
+    else
+        m_rendererNative.DrawCollapseButton(win, dc, rect, flags);
+}
+
+wxSize wxRendererXP::GetCollapseButtonSize(wxWindow *win, wxDC& dc)
+{
+    wxUxThemeHandle hTheme(win, L"TASKDIALOG");
+    wxUxThemeEngine* const te = wxUxThemeEngine::Get();
+
+    // EXPANDOBUTTON scales ugly if not using the correct size, get size from theme
+
+    if ( te->IsThemePartDefined(hTheme, TDLG_EXPANDOBUTTON, TDLGEBS_NORMAL) )
+    {
+        SIZE s;
+        te->GetThemePartSize(hTheme,
+            GetHdcOf(dc.GetTempHDC()),
+            TDLG_EXPANDOBUTTON,
+            TDLGEBS_NORMAL,
+            NULL,
+            TS_TRUE,
+            &s);
+
+        return wxSize(s.cx, s.cy);
+    }
+    else
+        return m_rendererNative.GetCollapseButtonSize(win, dc);
+}
+
 void
 wxRendererXP::DrawItemSelectionRect(wxWindow *win,
                                     wxDC& dc,