Implement wxDC mirroring for RTL layout with GTK3

Co-Authored-By: AliKet <aliket1435@gmail.com>

include/wx/gtk/dc.h

@@ -15,13 +15,16 @@
 
 class wxGTKCairoDCImpl: public wxGCDCImpl
 {
+    typedef wxGCDCImpl BaseType;
 public:
     wxGTKCairoDCImpl(wxDC* owner);
-    wxGTKCairoDCImpl(wxDC* owner, double scaleFactor);
+    wxGTKCairoDCImpl(wxDC* owner, wxWindow* window, wxLayoutDirection dir = wxLayout_Default, int width = 0);
-    wxGTKCairoDCImpl(wxDC* owner, wxWindow* window);
 
     virtual void DoDrawBitmap(const wxBitmap& bitmap, int x, int y, bool useMask) wxOVERRIDE;
+    virtual void DoDrawCheckMark(int x, int y, int width, int height) wxOVERRIDE;
     virtual void DoDrawIcon(const wxIcon& icon, int x, int y) wxOVERRIDE;
+    virtual void DoDrawText(const wxString& text, int x, int y) wxOVERRIDE;
+    virtual void DoDrawRotatedText(const wxString& text, int x, int y, double angle) wxOVERRIDE;
 #if wxUSE_IMAGE
     virtual bool DoFloodFill(int x, int y, const wxColour& col, wxFloodFillStyle style) wxOVERRIDE;
 #endif
@@ -32,12 +35,15 @@ public:
     virtual void* GetCairoContext() const wxOVERRIDE;
 
     virtual wxSize GetPPI() const wxOVERRIDE;
+    virtual void SetLayoutDirection(wxLayoutDirection dir) wxOVERRIDE;
+    virtual wxLayoutDirection GetLayoutDirection() const wxOVERRIDE;
 
 protected:
     // Set m_size from the given (valid) GdkWindow.
     void InitSize(GdkWindow* window);
 
     wxSize m_size;
+    wxLayoutDirection m_layoutDir;
 
     wxDECLARE_NO_COPY_CLASS(wxGTKCairoDCImpl);
 };
@@ -108,7 +114,7 @@ private:
 class WXDLLIMPEXP_CORE wxGTKCairoDC: public wxDC
 {
 public:
-    wxGTKCairoDC(cairo_t* cr, wxWindow* window);
+    wxGTKCairoDC(cairo_t* cr, wxWindow* window, wxLayoutDirection dir = wxLayout_LeftToRight, int width = 0);
 
     wxDECLARE_NO_COPY_CLASS(wxGTKCairoDC);
 };

src/gtk/dc.cpp

@@ -25,17 +25,14 @@
 wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner)
     : wxGCDCImpl(owner)
 {
+    m_layoutDir = wxLayout_Default;
 }
 
-wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, double scaleFactor)
+wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, wxWindow* window, wxLayoutDirection dir, int width)
-    : wxGCDCImpl(owner, 0)
-{
-    m_contentScaleFactor = scaleFactor;
-}
-
-wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, wxWindow* window)
     : wxGCDCImpl(owner, 0)
+    , m_size(width, 0)
 {
+    m_layoutDir = dir;
     if ( window )
     {
         m_window = window;
@@ -62,6 +59,12 @@ void wxGTKCairoDCImpl::DoDrawBitmap(const wxBitmap& bitmap, int x, int y, bool u
     if (cr)
     {
         cairo_save(cr);
+        if (m_layoutDir == wxLayout_RightToLeft)
+        {
+            // bitmap is not mirrored
+            cairo_scale(cr, -1, 1);
+            x = -x - bitmap.GetWidth();
+        }
         bitmap.Draw(cr, x, y, useMask, &m_textForegroundColour, &m_textBackgroundColour);
         cairo_restore(cr);
     }
@@ -81,6 +84,108 @@ bool wxGTKCairoDCImpl::DoFloodFill(int x, int y, const wxColour& col, wxFloodFil
 }
 #endif
 
+void wxGTKCairoDCImpl::DoDrawText(const wxString& text, int x, int y)
+{
+    wxCHECK_RET(IsOk(), "invalid DC");
+
+    if (text.empty())
+        return;
+
+    if (m_layoutDir == wxLayout_RightToLeft && text.find('\n') != wxString::npos)
+    {
+        // RTL needs each line separately to position text properly.
+        // DrawLabel() will split the text and call back for each line.
+        GetOwner()->DrawLabel(text, wxRect(x, y, 0, 0));
+        return;
+    }
+
+    int w, h;
+    DoGetTextExtent(text, &w, &h);
+
+    CalcBoundingBox(x, y);
+    CalcBoundingBox(x + w, y + h);
+
+    if (m_layoutDir == wxLayout_RightToLeft)
+    {
+        m_graphicContext->PushState();
+        // text is not mirrored
+        m_graphicContext->Scale(-1, 1);
+        x = -x - w;
+    }
+
+    wxCompositionMode curMode = m_graphicContext->GetCompositionMode();
+    m_graphicContext->SetCompositionMode(wxCOMPOSITION_OVER);
+
+    if (m_backgroundMode == wxBRUSHSTYLE_TRANSPARENT)
+        m_graphicContext->DrawText(text, x, y);
+    else
+        m_graphicContext->DrawText(text, x, y, m_graphicContext->CreateBrush(m_textBackgroundColour));
+
+    m_graphicContext->SetCompositionMode(curMode);
+
+    if (m_layoutDir == wxLayout_RightToLeft)
+        m_graphicContext->PopState();
+}
+
+void wxGTKCairoDCImpl::DoDrawRotatedText(const wxString& text, int x, int y, double angle)
+{
+    wxCHECK_RET(IsOk(), "invalid DC");
+
+    // save current bounding box
+    // rotation will cause DoDrawText() to update it incorrectly
+    const bool isBBoxValid = m_isBBoxValid;
+    const int minX = m_minX;
+    const int minY = m_minY;
+    const int maxX = m_maxX;
+    const int maxY = m_maxY;
+
+    const double rad = wxDegToRad(-angle);
+    m_graphicContext->PushState();
+    m_graphicContext->Translate(x, y);
+    m_graphicContext->Rotate(rad);
+    DoDrawText(text, 0, 0);
+    m_graphicContext->PopState();
+
+    // restore bounding box and update it correctly
+    m_isBBoxValid = isBBoxValid;
+    m_minX = minX;
+    m_minY = minY;
+    m_maxX = maxX;
+    m_maxY = maxY;
+
+    CalcBoundingBox(x, y);
+    int w, h;
+    DoGetTextExtent(text, &w, &h);
+    cairo_matrix_t m;
+    cairo_matrix_init_translate(&m, x, y);
+    cairo_matrix_rotate(&m, rad);
+    double xx = w, yy = 0;
+    cairo_matrix_transform_point(&m, &xx, &yy);
+    CalcBoundingBox(int(xx), int(yy));
+    xx = w; yy = h;
+    cairo_matrix_transform_point(&m, &xx, &yy);
+    CalcBoundingBox(int(xx), int(yy));
+    xx = 0; yy = h;
+    cairo_matrix_transform_point(&m, &xx, &yy);
+    CalcBoundingBox(int(xx), int(yy));
+}
+
+void wxGTKCairoDCImpl::DoDrawCheckMark(int x, int y, int width, int height)
+{
+    if (m_layoutDir == wxLayout_RightToLeft)
+    {
+        wxCHECK_RET(IsOk(), "invalid DC");
+
+        // checkmark is not mirrored
+        m_graphicContext->PushState();
+        m_graphicContext->Scale(-1, 1);
+        BaseType::DoDrawCheckMark(-x - width, y, width, height);
+        m_graphicContext->PopState();
+    }
+    else
+        BaseType::DoDrawCheckMark(x, y, width, height);
+}
+
 wxBitmap wxGTKCairoDCImpl::DoGetAsBitmap(const wxRect* /*subrect*/) const
 {
     wxFAIL_MSG("DoGetAsBitmap not implemented");
@@ -183,6 +288,12 @@ bool wxGTKCairoDCImpl::DoStretchBlit(int xdest, int ydest, int dstWidth, int dst
         }
     }
     cairo_save(cr);
+    if (m_layoutDir == wxLayout_RightToLeft)
+    {
+        // blit is not mirrored
+        cairo_scale(cr, -1, 1);
+        xdest = -xdest - dstWidth;
+    }
     cairo_translate(cr, xdest, ydest);
     cairo_rectangle(cr, 0, 0, dstWidth, dstHeight);
     double sx, sy;
@@ -250,6 +361,40 @@ wxSize wxGTKCairoDCImpl::GetPPI() const
     return wxGCDCImpl::GetPPI();
 }
 
+void wxGTKCairoDCImpl::SetLayoutDirection(wxLayoutDirection dir)
+{
+    if (dir == wxLayout_Default && m_window)
+        dir = m_window->GetLayoutDirection();
+
+    if (m_layoutDir != dir)
+    {
+        if (m_graphicContext)
+        {
+            if (dir == wxLayout_RightToLeft)
+            {
+                // wxDC is mirrored for RTL
+                m_graphicContext->Translate(m_size.x, 0);
+                m_graphicContext->Scale(-1, 1);
+            }
+            else if (m_layoutDir == wxLayout_RightToLeft)
+            {
+                m_graphicContext->Scale(-1, 1);
+                m_graphicContext->Translate(-m_size.x, 0);
+            }
+        }
+
+        m_layoutDir = dir;
+    }
+}
+
+wxLayoutDirection wxGTKCairoDCImpl::GetLayoutDirection() const
+{
+    // LTR unless explicitly RTL
+    return
+        m_layoutDir == wxLayout_RightToLeft
+            ? wxLayout_RightToLeft
+            : wxLayout_LeftToRight;
+}
 //-----------------------------------------------------------------------------
 
 wxWindowDCImpl::wxWindowDCImpl(wxWindowDC* owner, wxWindow* window)
@@ -292,6 +437,8 @@ wxWindowDCImpl::wxWindowDCImpl(wxWindowDC* owner, wxWindow* window)
         }
         if (x || y)
             SetDeviceLocalOrigin(x, y);
+
+        SetLayoutDirection(wxLayout_Default);
     }
     else
         SetGraphicsContext(wxGraphicsContext::Create());
@@ -326,6 +473,7 @@ wxClientDCImpl::wxClientDCImpl(wxClientDC* owner, wxWindow* window)
             cairo_clip(cr);
             SetDeviceLocalOrigin(a.x, a.y);
         }
+        SetLayoutDirection(wxLayout_Default);
     }
     else
         SetGraphicsContext(wxGraphicsContext::Create());
@@ -342,6 +490,8 @@ wxPaintDCImpl::wxPaintDCImpl(wxPaintDC* owner, wxWindow* window)
     wxGraphicsContext* gc = wxGraphicsContext::CreateFromNative(cr);
     gc->EnableOffset(m_contentScaleFactor <= 1);
     SetGraphicsContext(gc);
+    // context is already adjusted for RTL
+    m_layoutDir = window->GetLayoutDirection();
 }
 
 void wxPaintDCImpl::DestroyClippingRegion()
@@ -433,15 +583,23 @@ void wxMemoryDCImpl::Setup()
         gc->EnableOffset(m_contentScaleFactor <= 1);
     }
     SetGraphicsContext(gc);
+
+    // re-apply layout direction
+    const wxLayoutDirection dir = m_layoutDir;
+    m_layoutDir = wxLayout_Default;
+    SetLayoutDirection(dir);
 }
 //-----------------------------------------------------------------------------
 
-wxGTKCairoDC::wxGTKCairoDC(cairo_t* cr, wxWindow* window)
+wxGTKCairoDC::wxGTKCairoDC(cairo_t* cr, wxWindow* window, wxLayoutDirection dir, int width)
-    : wxDC(new wxGTKCairoDCImpl(this, window->GetContentScaleFactor()))
+    : wxDC(new wxGTKCairoDCImpl(this, window, dir, width))
 {
     wxGraphicsContext* gc = wxGraphicsContext::CreateFromNative(cr);
     gc->EnableOffset(window->GetContentScaleFactor() <= 1);
     SetGraphicsContext(gc);
+    if (dir == wxLayout_Default)
+        SetLayoutDirection(window->GetLayoutDirection());
+    // else context is already adjusted for RTL
 }
 
 #else

src/gtk/renderer.cpp

@@ -220,10 +220,6 @@ wxRendererGTK::DrawHeaderButton(wxWindow *win,
     if (flags & wxCONTROL_DIRTY)
         button = wxGTKPrivate::GetHeaderButtonWidgetLast();
 
-    int x_diff = 0;
-    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
-        x_diff = rect.width;
-
     GtkStateType state = GTK_STATE_NORMAL;
     if (flags & wxCONTROL_DISABLED)
         state = GTK_STATE_INSENSITIVE;
@@ -252,8 +248,8 @@ wxRendererGTK::DrawHeaderButton(wxWindow *win,
         sc.AddTreeviewHeaderButton(pos);
 
         gtk_style_context_set_state(sc, stateTypeToFlags[state]);
-        gtk_render_background(sc, cr, rect.x - x_diff, rect.y, rect.width, rect.height);
+        gtk_render_background(sc, cr, rect.x, rect.y, rect.width, rect.height);
-        gtk_render_frame(sc, cr, rect.x - x_diff, rect.y, rect.width, rect.height);
+        gtk_render_frame(sc, cr, rect.x, rect.y, rect.width, rect.height);
     }
     else
 #endif // GTK >= 3.20
@@ -261,11 +257,15 @@ wxRendererGTK::DrawHeaderButton(wxWindow *win,
         GtkStyleContext* sc = gtk_widget_get_style_context(button);
         gtk_style_context_save(sc);
         gtk_style_context_set_state(sc, stateTypeToFlags[state]);
-        gtk_render_background(sc, cr, rect.x - x_diff, rect.y, rect.width, rect.height);
+        gtk_render_background(sc, cr, rect.x, rect.y, rect.width, rect.height);
-        gtk_render_frame(sc, cr, rect.x - x_diff, rect.y, rect.width, rect.height);
+        gtk_render_frame(sc, cr, rect.x, rect.y, rect.width, rect.height);
         gtk_style_context_restore(sc);
     }
 #else
+    int x_diff = 0;
+    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
+        x_diff = rect.width;
+
     GdkWindow* gdk_window = wxGetGTKDrawable(dc);
     gtk_paint_box
     (
@@ -305,7 +305,7 @@ int wxRendererGTK::GetHeaderButtonMargin(wxWindow *WXUNUSED(win))
 
 // draw a ">" or "v" button
 void
-wxRendererGTK::DrawTreeItemButton(wxWindow* win,
+wxRendererGTK::DrawTreeItemButton(wxWindow* WXUNUSED_IN_GTK3(win),
                                   wxDC& dc, const wxRect& rect, int flags)
 {
     wxGTKDrawable* drawable = wxGetGTKDrawable(dc);
@@ -314,10 +314,6 @@ wxRendererGTK::DrawTreeItemButton(wxWindow* win,
 
     GtkWidget *tree = wxGTKPrivate::GetTreeWidget();
 
-    int x_diff = 0;
-    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
-        x_diff = rect.width;
-
 #ifdef __WXGTK3__
     int state = GTK_STATE_FLAG_NORMAL;
     if (flags & wxCONTROL_EXPANDED)
@@ -340,9 +336,13 @@ wxRendererGTK::DrawTreeItemButton(wxWindow* win,
     gtk_style_context_save(sc);
     gtk_style_context_set_state(sc, GtkStateFlags(state));
     gtk_style_context_add_class(sc, GTK_STYLE_CLASS_EXPANDER);
-    gtk_render_expander(sc, drawable, x - x_diff, y, expander_size, expander_size);
+    gtk_render_expander(sc, drawable, x, y, expander_size, expander_size);
     gtk_style_context_restore(sc);
 #else
+    int x_diff = 0;
+    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
+        x_diff = rect.width;
+
     GtkStateType state;
     if ( flags & wxCONTROL_CURRENT )
         state = GTK_STATE_PRELIGHT;
@@ -444,14 +444,10 @@ wxRendererGTK::DrawSplitterSash(wxWindow* win,
         rect.width = size.x;
     }
 
-    int x_diff = 0;
-    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
-        x_diff = rect.width;
-
 #ifdef __WXGTK3__
     wxGtkStyleContext sc(dc.GetContentScaleFactor());
     sc.AddWindow();
-    gtk_render_background(sc, drawable, rect.x - x_diff, rect.y, rect.width, rect.height);
+    gtk_render_background(sc, drawable, rect.x, rect.y, rect.width, rect.height);
 
     sc.Add(GTK_TYPE_PANED, "paned", "pane-separator", NULL);
     if (gtk_check_version(3,20,0) == NULL)
@@ -459,8 +455,12 @@ wxRendererGTK::DrawSplitterSash(wxWindow* win,
 
     gtk_style_context_set_state(sc,
         flags & wxCONTROL_CURRENT ? GTK_STATE_FLAG_PRELIGHT : GTK_STATE_FLAG_NORMAL);
-    gtk_render_handle(sc, drawable, rect.x - x_diff, rect.y, rect.width, rect.height);
+    gtk_render_handle(sc, drawable, rect.x, rect.y, rect.width, rect.height);
 #else
+    int x_diff = 0;
+    if (win->GetLayoutDirection() == wxLayout_RightToLeft)
+        x_diff = rect.width;
+
     GdkWindow* gdk_window = wxGetGTKDrawable(dc);
     if (gdk_window == NULL)
         return;
@@ -731,8 +731,17 @@ wxRendererGTK::DrawCheckBox(wxWindow*,
     const int w = info.indicator_width + info.margin_left + info.margin_right;
     const int h = info.indicator_height + info.margin_top + info.margin_bottom;
 
-    const int x = rect.x + (rect.width - w) / 2;
+    int x = rect.x + (rect.width  - w) / 2;
-    const int y = rect.y + (rect.height - h) / 2;
+    int y = rect.y + (rect.height - h) / 2;
+
+    const bool isRTL = dc.GetLayoutDirection() == wxLayout_RightToLeft;
+    if (isRTL)
+    {
+        // checkbox is not mirrored
+        cairo_save(cr);
+        cairo_scale(cr, -1, 1);
+        x = -x - w;
+    }
 
     if (gtk_check_version(3,20,0) == NULL)
     {
@@ -756,6 +765,9 @@ wxRendererGTK::DrawCheckBox(wxWindow*,
         gtk_render_check(sc, cr, x, y, w, h);
         gtk_style_context_restore(sc);
     }
+    if (isRTL)
+        cairo_restore(cr);
+
 #else // !__WXGTK3__
     GtkWidget* button = wxGTKPrivate::GetCheckButtonWidget();
 
@@ -867,10 +879,6 @@ wxRendererGTK::DrawItemSelectionRect(wxWindow* win,
 
     if (flags & wxCONTROL_SELECTED)
     {
-        int x_diff = 0;
-        if (win->GetLayoutDirection() == wxLayout_RightToLeft)
-            x_diff = rect.width;
-
         GtkWidget* treeWidget = wxGTKPrivate::GetTreeWidget();
 
 #ifdef __WXGTK3__
@@ -881,9 +889,13 @@ wxRendererGTK::DrawItemSelectionRect(wxWindow* win,
             state |= GTK_STATE_FLAG_FOCUSED;
         gtk_style_context_set_state(sc, GtkStateFlags(state));
         gtk_style_context_add_class(sc, GTK_STYLE_CLASS_CELL);
-        gtk_render_background(sc, drawable, rect.x - x_diff, rect.y, rect.width, rect.height);
+        gtk_render_background(sc, drawable, rect.x, rect.y, rect.width, rect.height);
         gtk_style_context_restore(sc);
 #else
+        int x_diff = 0;
+        if (win->GetLayoutDirection() == wxLayout_RightToLeft)
+            x_diff = rect.width;
+
         // the wxCONTROL_FOCUSED state is deduced
         // directly from the m_wxwindow by GTK+
         gtk_paint_flat_box(gtk_widget_get_style(treeWidget),

src/gtk/window.cpp

@@ -5065,9 +5065,11 @@ bool wxWindowGTK::DoIsExposed( int x, int y ) const
 
 bool wxWindowGTK::DoIsExposed( int x, int y, int w, int h ) const
 {
+#ifndef __WXGTK3__
     if (GetLayoutDirection() == wxLayout_RightToLeft)
         return m_updateRegion.Contains(x-w, y, w, h) != wxOutRegion;
-    else
+#endif
+
     return m_updateRegion.Contains(x, y, w, h) != wxOutRegion;
 }
 
@@ -5086,6 +5088,13 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
         cairo_rectangle(cr, rect.x, rect.y, rect.width, rect.height);
         cairo_clip(cr);
     }
+    if (GetLayoutDirection() == wxLayout_RightToLeft)
+    {
+        // wxDC is mirrored for RTL
+        const int w = gdk_window_get_width(gtk_widget_get_window(m_wxwindow));
+        cairo_translate(cr, w, 0);
+        cairo_scale(cr, -1, 1);
+    }
     double x1, y1, x2, y2;
     cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
 
@@ -5094,7 +5103,6 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
 
     m_paintContext = cr;
     m_updateRegion = wxRegion(int(x1), int(y1), int(x2 - x1), int(y2 - y1));
-    m_nativeUpdateRegion = m_updateRegion;
 #else // !__WXGTK3__
     m_updateRegion = wxRegion(region);
 #if wxGTK_HAS_COMPOSITING_SUPPORT
@@ -5106,6 +5114,7 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
 
     m_nativeUpdateRegion = m_updateRegion;
 
+#ifndef __WXGTK3__
     if (GetLayoutDirection() == wxLayout_RightToLeft)
     {
         // Transform m_updateRegion under RTL
@@ -5128,6 +5137,7 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
             ++upd;
         }
     }
+#endif
 
     switch ( GetBackgroundStyle() )
     {
@@ -5158,7 +5168,7 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
         case wxBG_STYLE_ERASE:
             {
 #ifdef __WXGTK3__
-                wxGTKCairoDC dc(cr, static_cast<wxWindow*>(this));
+                wxGTKCairoDC dc(cr, static_cast<wxWindow*>(this), GetLayoutDirection());
 #else
                 wxWindowDC dc( (wxWindow*)this );
                 dc.SetDeviceClippingRegion( m_updateRegion );