[Libreoffice-commits] core.git: include/vcl

[Chris Sherlock]

 include/vcl/outdev.hxx |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

New commits:
commit 11ca83d180aa37f927f341cdc1726ff1491fcc49
Author: Chris Sherlock <chris.sherlock79 at gmail.com>
Date:   Fri Feb 14 01:36:30 2014 +1100

    Update the documentation for ImplInitGraphics()
    
    Better explain the whys and wherefores of the graphics LRU and
    how it is used.
    
    Change-Id: I345cd91044bc533c9650e2d17bf53d2879af3e39
    Reviewed-on: https://gerrit.libreoffice.org/8030
    Reviewed-by: Caolán McNamara <caolanm at redhat.com>
    Tested-by: Caolán McNamara <caolanm at redhat.com>

diff --git a/include/vcl/outdev.hxx b/include/vcl/outdev.hxx
index 9b012cc..8595400 100644
--- a/include/vcl/outdev.hxx
+++ b/include/vcl/outdev.hxx
@@ -368,6 +368,21 @@ public:
 
     /** Initialize the graphics device that the output device uses to draw on.
 
+     There is an LRU of OutputDevices that is used to get the graphics. The
+     actual creation of a SalGraphics instance is done via the SalFrame
+     implementation.
+
+     However, the SalFrame instance will only return a valid SalGraphics
+     instance if it is not in use or there wasn't one in the first place. When
+     this happens, ImplInitGraphics finds the least recently used OutputDevice
+     in a different frame and "steals" it (releases it then starts using it).
+
+     If there are no frames to steal an OutputDevice's SalGraphics instance from
+     then it blocks until the graphics is released.
+
+     Once it has acquired a graphics instance, then we add the OutputDevice to
+     the LRU.
+
      @returns true if was able to initialize the graphics device, false otherwise.
      */
     SAL_DLLPRIVATE bool         ImplInitGraphics() const;