Use an 8bpp virtual device (instead of a 1bpp one) in sw and sc for iOS

The reason why a 1bpp virtual device is used in these two places in sc
and sw is unclear to me. It causes complications on iOS as such a
bitmap gets passed to CGBitmapContextCreate() which does not accept
1bpp bitmaps. But let's keep the 1bpp for other platforms.

Change-Id: Ia34927cf728d4be05a31e88b7da78200d0b799ba

1 files changed, 23 insertions, 5 deletions

diff --git a/vcl/inc/vcl/virdev.hxx b/vcl/inc/vcl/virdev.hxx
index 9c8c4edc67d3..5d8a70e8f3dc 100644
--- a/vcl/inc/vcl/virdev.hxx
+++ b/vcl/inc/vcl/virdev.hxx
@@ -65,23 +65,41 @@ private:
     SAL_DLLPRIVATE bool ForceZeroExtleadBug() const
         { return ((meRefDevMode & REFDEV_FORCE_ZERO_EXTLEAD) != 0); }
 public:
+    /** Create a virtual device of size 1x1
+
+        @param nBitCount
+        Bit depth of the generated virtual device. Use 0 here, to
+        indicate: take default screen depth. Only 0, 1 and 8
+        are allowed here, with 1 denoting binary mask and 8 a graylevel mask.
+     */
                         VirtualDevice( sal_uInt16 nBitCount = 0 );
+
+    /** Create a virtual device of size 1x1
+
+        @param rCompDev
+        The generated vdev will be compatible to this device.
+
+        @param nBitCount
+        Bit depth of the generated virtual device. Use 0 here, to
+        indicate: take default screen depth. Only 0 and 1
+        are allowed here, with 1 denoting binary mask.
+     */
                         VirtualDevice( const OutputDevice& rCompDev,
                                        sal_uInt16 nBitCount = 0 );
-    /** Create a virtual device with alpha channel
+
+    /** Create a virtual device  of size 1x1 with alpha channel
 
         @param rCompDev
-        The generated vdev will be compatible to this device. By
-        default, Application::GetDefaultDevice() is used here.
+        The generated vdev will be compatible to this device.
 
         @param nBitCount
         Bit depth of the generated virtual device. Use 0 here, to
-        indicate: take default screen depth. Currently, only 0 and 1
+        indicate: take default screen depth. Only 0 and 1
         are allowed here, with 1 denoting binary mask.
 
         @param nAlphaBitCount
         Bit depth of the generated virtual device. Use 0 here, to
-        indicate: take default screen depth. Currently, only 0 and 1
+        indicate: take default screen depth. Only 0 and 1
         are allowed here, with 1 denoting binary mask.
      */
                         VirtualDevice( const OutputDevice& rCompDev,