vnc: tight add PNG encoding

Introduce a new encoding: VNC_ENCODING_TIGHT_PNG [1] (-269) with a new
tight filter VNC_TIGHT_PNG (0x0A). When the client tells it supports the Tight PNG
encoding, the server will use tight, but will always send encoding pixels using
PNG instead of zlib. If the client also told it support JPEG, then the server can
send JPEG, because PNG will only be used in the cases zlib was used in normal tight.

This encoding was introduced to speed up HTML5 based VNC clients like noVNC [2], but
can also be used on devices like iPhone where PNG can be rendered in hardware.

[1] http://wiki.qemu.org/VNC_Tight_PNG
[2] http://github.com/kanaka/noVNC/

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/ui/vnc.c b/ui/vnc.c
index ccd7aad86b..1fc6d387d9 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -351,10 +351,6 @@ void do_info_vnc(Monitor *mon, QObject **ret_data)
     }
 }
 
-static inline uint32_t vnc_has_feature(VncState *vs, int feature) {
-    return (vs->features & (1 << feature));
-}
-
 /* TODO
    1) Get the queue working for IO.
    2) there is some weirdness when using the -S option (the screen is grey
@@ -661,6 +657,9 @@ static int send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
         case VNC_ENCODING_TIGHT:
             n = vnc_tight_send_framebuffer_update(vs, x, y, w, h);
             break;
+        case VNC_ENCODING_TIGHT_PNG:
+            n = vnc_tight_png_send_framebuffer_update(vs, x, y, w, h);
+            break;
         default:
             vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_RAW);
             n = vnc_raw_send_framebuffer_update(vs, x, y, w, h);
@@ -1669,6 +1668,10 @@ static void set_encodings(VncState *vs, int32_t *encodings, size_t n_encodings)
             vs->features |= VNC_FEATURE_TIGHT_MASK;
             vs->vnc_encoding = enc;
             break;
+        case VNC_ENCODING_TIGHT_PNG:
+            vs->features |= VNC_FEATURE_TIGHT_PNG_MASK;
+            vs->vnc_encoding = enc;
+            break;
         case VNC_ENCODING_ZLIB:
             vs->features |= VNC_FEATURE_ZLIB_MASK;
             vs->vnc_encoding = enc;