Decouple GAL printing interface and its Cairo-based implementation

common/gal/cairo/cairo_print.cpp

@@ -111,15 +111,17 @@ CAIRO_PRINT_CTX::~CAIRO_PRINT_CTX()
 
 
 CAIRO_PRINT_GAL::CAIRO_PRINT_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions,
-        cairo_t* aContext, cairo_surface_t* aSurface )
+        std::unique_ptr<CAIRO_PRINT_CTX> aContext )
     : CAIRO_GAL_BASE( aDisplayOptions )
 {
-    cairo_reference( aContext );
+    m_printCtx = std::move( aContext );
-    cairo_surface_reference( aSurface );
+    context = currentContext = m_printCtx->GetContext();
-    context = currentContext = aContext;
+    surface = m_printCtx->GetSurface();
-    surface = aSurface;
+    cairo_reference( context );
+    cairo_surface_reference( surface );
     m_clearColor = COLOR4D( 1.0, 1.0, 1.0, 1.0 );
     resetContext();
+    SetScreenDPI( m_printCtx->GetNativeDPI() );
 }
 
 
@@ -179,3 +181,10 @@ void CAIRO_PRINT_GAL::SetSheetSize( const VECTOR2D& aSize )
     SetScreenSize( VECTOR2I( std::ceil( aSize.x * screenDPI ) * 2,
                 std::ceil( aSize.y * screenDPI ) * 2 ) );
 }
+
+
+std::unique_ptr<GAL_PRINT> GAL_PRINT::Create( GAL_DISPLAY_OPTIONS& aOptions, wxDC* aDC )
+{
+    auto printCtx = std::make_unique<CAIRO_PRINT_CTX>( aDC );
+    return std::make_unique<CAIRO_PRINT_GAL>( aOptions, std::move( printCtx ) );
+}

include/gal/cairo/cairo_print.h

@@ -21,6 +21,7 @@
 #define _CAIRO_PRINT_H_
 
 #include <gal/cairo/cairo_gal.h>
+#include <gal/gal_print.h>
 
 class wxDC;
 class wxGCDC;
@@ -31,7 +32,7 @@ namespace KIGFX
  * CAIRO_PRINT_CTX provides a Cairo context created from wxPrintDC.
  * It allows one to prepare printouts using the Cairo library and let wxWidgets handle the rest.
  */
-class CAIRO_PRINT_CTX
+class CAIRO_PRINT_CTX : public PRINT_CONTEXT
 {
 public:
     CAIRO_PRINT_CTX( wxDC* aDC );
@@ -47,12 +48,12 @@ public:
         return m_surface;
     }
 
-    double GetNativeDPI() const
+    double GetNativeDPI() const override
     {
         return m_dpi;
     }
 
-    bool HasNativeLandscapeRotation() const
+    bool HasNativeLandscapeRotation() const override
     {
 #ifdef __WXGTK__
         return false;
@@ -75,25 +76,35 @@ private:
 };
 
 
-class CAIRO_PRINT_GAL : public CAIRO_GAL_BASE
+class CAIRO_PRINT_GAL : public CAIRO_GAL_BASE, public GAL_PRINT
 {
 public:
     CAIRO_PRINT_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions,
-            cairo_t* aContext, cairo_surface_t* aSurface );
+            std::unique_ptr<CAIRO_PRINT_CTX> aContext );
 
     void ComputeWorldScreenMatrix() override;
 
+    GAL* GetGAL() override
+    {
+        return this;
+    }
+
+    PRINT_CONTEXT* GetPrintCtx() const override
+    {
+        return m_printCtx.get();
+    }
+
     /**
      * @param aSize is the printing sheet size expressed in inches.
      * @param aRotateIfLandscape true if the platform requires 90 degrees
      * rotation in order to print in landscape format.
      */
-    void SetNativePaperSize( const VECTOR2D& aSize, bool aRotateIfLandscape );
+    void SetNativePaperSize( const VECTOR2D& aSize, bool aRotateIfLandscape ) override;
 
     /**
      * @param aSize is the schematics sheet size expressed in inches.
      */
-    void SetSheetSize( const VECTOR2D& aSize );
+    void SetSheetSize( const VECTOR2D& aSize ) override;
 
 private:
     ///> Returns true if page orientation is landscape
@@ -109,6 +120,7 @@ private:
     ///> GAL needs to handle it in the transformation matrix
     bool m_hasNativeLandscapeRotation;
 
+    std::unique_ptr<CAIRO_PRINT_CTX> m_printCtx;
 };
 } // namespace KIGFX
 

include/gal/gal_print.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2018 CERN
+ * Author: Maciej Suminski <maciej.suminski@cern.ch>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GAL_PRINT_H
+#define GAL_PRINT_H
+
+#ifdef WX_COMPATIBILITY
+class wxDC;
+#endif /* WX_COMPATIBILITY */
+
+namespace KIGFX {
+class GAL;
+class GAL_DISPLAY_OPTIONS;
+
+
+class PRINT_CONTEXT
+{
+public:
+    virtual ~PRINT_CONTEXT() {}
+    virtual double GetNativeDPI() const = 0;
+    virtual bool HasNativeLandscapeRotation() const = 0;
+};
+
+
+/**
+ * @brief Wrapper around GAL to provide information needed for printing.
+ */
+class GAL_PRINT
+{
+public:
+#ifdef WX_COMPATIBILITY
+    static std::unique_ptr<GAL_PRINT> Create( GAL_DISPLAY_OPTIONS& aOptions, wxDC* aDC );
+#endif /* WX_COMPATIBILITY */
+    virtual ~GAL_PRINT() {}
+
+    virtual GAL* GetGAL() = 0;
+
+    virtual PRINT_CONTEXT* GetPrintCtx() const = 0;
+
+    /**
+     * @param aSize is the printing sheet size expressed in inches.
+     * @param aRotateIfLandscape true if the platform requires 90 degrees
+     * rotation in order to print in landscape format.
+     */
+    virtual void SetNativePaperSize( const VECTOR2D& aSize, bool aRotateIfLandscape ) = 0;
+
+    /**
+     * @param aSize is the schematics sheet size expressed in inches.
+     */
+    virtual void SetSheetSize( const VECTOR2D& aSize ) = 0;
+};
+
+}; // end namespace KIGFX
+
+#endif /* GAL_PRINT_H */