gtk3: move createCairoContext down to svpgdi

Change-Id: Ib3c6d6689c4b79a636a3f2f0f985f3573aa46f3d

vcl/headless/svpgdi.cxx

@@ -33,6 +33,10 @@
 #include <basegfx/polygon/b2dpolygontools.hxx>
 #include <basebmp/scanlineformats.hxx>
 
+#if ENABLE_CAIRO_CANVAS
+#include <cairo.h>
+#endif
+
 #if OSL_DEBUG_LEVEL > 2
 #include <basebmp/debug.hxx>
 #include <fstream>
@@ -738,6 +742,27 @@ bool SvpSalGraphics::supportsOperation( OutDevSupportType ) const
 
 #if ENABLE_CAIRO_CANVAS
 
+cairo_t* SvpSalGraphics::createCairoContext(const basebmp::BitmapDeviceSharedPtr &rBuffer)
+{
+    if (rBuffer->getScanlineFormat() != basebmp::Format::ThirtyTwoBitTcMaskBGRX)
+        return NULL;
+
+    basegfx::B2IVector size = rBuffer->getSize();
+    sal_Int32 nStride = rBuffer->getScanlineStride();
+    if (cairo_format_stride_for_width(CAIRO_FORMAT_RGB24, size.getX()) != nStride)
+        return NULL;
+
+    basebmp::RawMemorySharedArray data = rBuffer->getBuffer();
+    cairo_surface_t *target =
+        cairo_image_surface_create_for_data(data.get(),
+                                        CAIRO_FORMAT_RGB24,
+                                        size.getX(), size.getY(),
+                                        nStride);
+    cairo_t* cr = cairo_create(target);
+    cairo_surface_destroy(target);
+    return cr;
+}
+
 bool SvpSalGraphics::SupportsCairo() const
 {
     return false;

vcl/inc/headless/svpgdi.hxx

@@ -36,6 +36,7 @@
 
 class GlyphCache;
 class ServerFont;
+typedef struct _cairo cairo_t;
 
 class VCL_DLLPUBLIC SvpSalGraphics : public SalGraphics
 {
@@ -210,6 +211,8 @@ public:
 
     virtual SystemFontData  GetSysFontData( int nFallbacklevel ) const SAL_OVERRIDE;
 
+    static cairo_t*         createCairoContext(const basebmp::BitmapDeviceSharedPtr& rBuffer);
+
 #endif // ENABLE_CAIRO_CANVAS
 
     virtual void            BeginPaint() SAL_OVERRIDE { };

vcl/unx/gtk/window/gtksalframe.cxx

@@ -3465,17 +3465,8 @@ gboolean GtkSalFrame::signalCrossing( GtkWidget*, GdkEventCrossing* pEvent, gpoi
 
 cairo_t* GtkSalFrame::getCairoContext() const
 {
-    basebmp::RawMemorySharedArray data = m_aFrame->getBuffer();
-    basegfx::B2IVector size = m_aFrame->getSize();
-    sal_Int32 nStride = m_aFrame->getScanlineStride();
-    assert(cairo_format_stride_for_width(CAIRO_FORMAT_RGB24, size.getX()) == nStride);
-    cairo_surface_t *target =
-        cairo_image_surface_create_for_data(data.get(),
-                                        CAIRO_FORMAT_RGB24,
-                                        size.getX(), size.getY(),
-                                        nStride);
-    cairo_t* cr = cairo_create(target);
-    cairo_surface_destroy(target);
+    cairo_t* cr = SvpSalGraphics::createCairoContext(m_aFrame);
+    assert(cr);
     return cr;
 }