make it possible to write canvas unittests

One of the problems is that canvas apparently works only with windows,
but tests obviously need an offscreen surface. This patch moves
Window::GetCanvas() to OutputDevice, and makes vclcanvas capable
of working with OutputDevice classes that are not windows. Other
canvas implementations still don't work, but presumably at least
cairocanvas could be fixed too.

This commit adds a "simple" test that just draws a line and tries
to verify it's been drawn properly. Adding another test should
be a matter of basing it on this existing one, and then copy&pasting
the complicated UNO way of drawing using canvas from somewhere,
such as canvas/workben/canvasdemo.cxx.

Change-Id: I42db12b09433763cd31c3dd497c10157424b8598
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115117
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

4 files changed, 83 insertions, 42 deletions

diff --git a/vcl/inc/window.h b/vcl/inc/window.h
index 2411d2f7c663..b4a53a580a5c 100644
--- a/vcl/inc/window.h
+++ b/vcl/inc/window.h
@@ -29,7 +29,6 @@
 #include <vcl/window.hxx>
 #include <vcl/settings.hxx>
 #include <o3tl/typed_flags_set.hxx>
-#include <cppuhelper/weakref.hxx>
 
 #include <optional>
 #include <list>
@@ -61,10 +60,6 @@ namespace com::sun::star {
         class XAccessibleEditableText;
     }
 
-    namespace rendering {
-        class XCanvas;
-    }
-
     namespace awt {
         class XWindowPeer;
         class XWindow;
@@ -249,9 +244,6 @@ public:
     Link<vcl::Window&, bool> maMnemonicActivateHdl;
     Link<tools::JsonWriter&, void> maDumpAsPropertyTreeHdl;
 
-    // The canvas interface for this VCL window. Is persistent after the first GetCanvas() call
-    css::uno::WeakReference< css::rendering::XCanvas >    mxCanvas;
-
     vcl::Cursor*        mpCursor;
     PointerStyle        maPointer;
     Fraction            maZoom;
diff --git a/vcl/source/outdev/outdev.cxx b/vcl/source/outdev/outdev.cxx
index f2618c285b36..70ec9616ace7 100644
--- a/vcl/source/outdev/outdev.cxx
+++ b/vcl/source/outdev/outdev.cxx
@@ -29,12 +29,17 @@
 #include <vcl/toolkit/unowrap.hxx>
 #include <vcl/svapp.hxx>
 #include <vcl/sysdata.hxx>
+#include <vcl/lazydelete.hxx>
+#include <comphelper/processfactory.hxx>
 
 #include <salgdi.hxx>
 #include <window.h>
 #include <outdev.h>
 
 #include <com/sun/star/awt/DeviceCapability.hpp>
+#include <com/sun/star/awt/XWindow.hpp>
+#include <com/sun/star/rendering/CanvasFactory.hpp>
+#include <com/sun/star/rendering/XSpriteCanvas.hpp>
 
 #ifdef DISABLE_DYNLOADING
 // Linking all needed LO code into one .so/executable, these already
@@ -46,6 +51,8 @@ namespace {
 }
 #endif
 
+using namespace ::com::sun::star::uno;
+
 // Begin initializer and accessor public functions
 
 OutputDevice::OutputDevice(OutDevType eOutDevType) :
@@ -738,4 +745,77 @@ css::awt::DeviceInfo OutputDevice::GetDeviceInfo() const
     return aInfo;
 }
 
+Reference< css::rendering::XCanvas > OutputDevice::GetCanvas() const
+{
+    // try to retrieve hard reference from weak member
+    Reference< css::rendering::XCanvas > xCanvas( mxCanvas );
+    // canvas still valid? Then we're done.
+    if( xCanvas.is() )
+        return xCanvas;
+    xCanvas = ImplGetCanvas( false );
+    mxCanvas = xCanvas;
+    return xCanvas;
+}
+
+Reference< css::rendering::XSpriteCanvas > OutputDevice::GetSpriteCanvas() const
+{
+    Reference< css::rendering::XCanvas > xCanvas( mxCanvas );
+    Reference< css::rendering::XSpriteCanvas > xSpriteCanvas( xCanvas, UNO_QUERY );
+    if( xSpriteCanvas.is() )
+        return xSpriteCanvas;
+    xCanvas = ImplGetCanvas( true );
+    mxCanvas = xCanvas;
+    return Reference< css::rendering::XSpriteCanvas >( xCanvas, UNO_QUERY );
+}
+
+// Generic implementation, Window will override.
+com::sun::star::uno::Reference< css::rendering::XCanvas > OutputDevice::ImplGetCanvas( bool bSpriteCanvas ) const
+{
+    /* Arguments:
+       0: ptr to creating instance (Window or VirtualDevice)
+       1: current bounds of creating instance
+       2: bool, denoting always on top state for Window (always false for VirtualDevice)
+       3: XWindow for creating Window (or empty for VirtualDevice)
+       4: SystemGraphicsData as a streamed Any
+     */
+    Sequence< Any > aArg(5);
+    aArg[ 0 ] <<= reinterpret_cast<sal_Int64>(this);
+    aArg[ 1 ] <<= css::awt::Rectangle( mnOutOffX, mnOutOffY, mnOutWidth, mnOutHeight );
+    aArg[ 2 ] <<= false;
+    aArg[ 3 ] <<= Reference< css::awt::XWindow >();
+    aArg[ 4 ] = GetSystemGfxDataAny();
+
+    Reference< XComponentContext > xContext = comphelper::getProcessComponentContext();
+
+    static vcl::DeleteUnoReferenceOnDeinit<css::lang::XMultiComponentFactory> xStaticCanvasFactory(
+        css::rendering::CanvasFactory::create( xContext ) );
+    Reference<css::lang::XMultiComponentFactory> xCanvasFactory(xStaticCanvasFactory.get());
+    Reference< css::rendering::XCanvas > xCanvas;
+
+    if(xCanvasFactory.is())
+    {
+        xCanvas.set( xCanvasFactory->createInstanceWithArgumentsAndContext(
+                         bSpriteCanvas ?
+                         OUString( "com.sun.star.rendering.SpriteCanvas" ) :
+                         OUString( "com.sun.star.rendering.Canvas" ),
+                         aArg,
+                         xContext ),
+                     UNO_QUERY );
+    }
+
+    // no factory??? Empty reference, then.
+    return xCanvas;
+}
+
+void OutputDevice::ImplDisposeCanvas()
+{
+    css::uno::Reference< css::rendering::XCanvas > xCanvas( mxCanvas );
+    if( xCanvas.is() )
+    {
+        css::uno::Reference< css::lang::XComponent >  xCanvasComponent( xCanvas, css::uno::UNO_QUERY );
+        if( xCanvasComponent.is() )
+            xCanvasComponent->dispose();
+    }
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/source/window/window.cxx b/vcl/source/window/window.cxx
index 94c8cc2df391..44f5438e3864 100644
--- a/vcl/source/window/window.cxx
+++ b/vcl/source/window/window.cxx
@@ -154,13 +154,7 @@ void Window::dispose()
 
     // Dispose of the canvas implementation (which, currently, has an
     // own wrapper window as a child to this one.
-    Reference< css::rendering::XCanvas > xCanvas( mpWindowImpl->mxCanvas );
-    if( xCanvas.is() )
-    {
-        Reference < XComponent > xCanvasComponent( xCanvas, UNO_QUERY );
-        if( xCanvasComponent.is() )
-            xCanvasComponent->dispose();
-    }
+    ImplDisposeCanvas();
 
     mpWindowImpl->mbInDispose = true;
 
@@ -3680,13 +3674,6 @@ bool Window::IsNativeWidgetEnabled() const
 
 Reference< css::rendering::XCanvas > Window::ImplGetCanvas( bool bSpriteCanvas ) const
 {
-    // try to retrieve hard reference from weak member
-    Reference< css::rendering::XCanvas > xCanvas( mpWindowImpl->mxCanvas );
-
-    // canvas still valid? Then we're done.
-    if( xCanvas.is() )
-        return xCanvas;
-
     Sequence< Any > aArg(5);
 
     // Feed any with operating system's window handle
@@ -3707,6 +3694,7 @@ Reference< css::rendering::XCanvas > Window::ImplGetCanvas( bool bSpriteCanvas )
     static vcl::DeleteUnoReferenceOnDeinit<XMultiComponentFactory> xStaticCanvasFactory(
         css::rendering::CanvasFactory::create( xContext ) );
     Reference<XMultiComponentFactory> xCanvasFactory(xStaticCanvasFactory.get());
+    Reference< css::rendering::XCanvas > xCanvas;
 
     if(xCanvasFactory.is())
     {
@@ -3740,25 +3728,12 @@ Reference< css::rendering::XCanvas > Window::ImplGetCanvas( bool bSpriteCanvas )
                          UNO_QUERY );
 
         }
-        mpWindowImpl->mxCanvas = xCanvas;
     }
 
     // no factory??? Empty reference, then.
     return xCanvas;
 }
 
-Reference< css::rendering::XCanvas > Window::GetCanvas() const
-{
-    return ImplGetCanvas( false );
-}
-
-Reference< css::rendering::XSpriteCanvas > Window::GetSpriteCanvas() const
-{
-    Reference< css::rendering::XSpriteCanvas > xSpriteCanvas(
-        ImplGetCanvas( true ), UNO_QUERY );
-    return xSpriteCanvas;
-}
-
 OUString Window::GetSurroundingText() const
 {
   return OUString();
diff --git a/vcl/source/window/wrkwin.cxx b/vcl/source/window/wrkwin.cxx
index 9f90025a74aa..beaa1d48dbd8 100644
--- a/vcl/source/window/wrkwin.cxx
+++ b/vcl/source/window/wrkwin.cxx
@@ -145,13 +145,7 @@ void WorkWindow::ShowFullScreenMode( bool bFullScreenMode, sal_Int32 nDisplayScr
 
     // Dispose of the canvas implementation, which might rely on
     // screen-specific system data.
-    css::uno::Reference< css::rendering::XCanvas > xCanvas( mpWindowImpl->mxCanvas );
-    if( xCanvas.is() )
-    {
-        css::uno::Reference< css::lang::XComponent >  xCanvasComponent( xCanvas, css::uno::UNO_QUERY );
-        if( xCanvasComponent.is() )
-            xCanvasComponent->dispose();
-    }
+    ImplDisposeCanvas();
 
     mpWindowImpl->mpFrameWindow->mpWindowImpl->mbWaitSystemResize = true;
     ImplGetFrame()->ShowFullScreen( bFullScreenMode, nDisplayScreen );