This partially reverts 2edbda252619b.
Using cairo-groups increases performance on MacOS, and retains retina-resolution. However it adds a performance regression for MS Windows graphics rendering. cairo-groups use a "similar" surface, not an image surface. Empirically this adds significant overhead compared to rendering using the CPU and using bitblt.
0b266a54f0 Return of image-surface backed canvas (windows graphics performance)
libs/canvas/canvas.cc | 47 ++++++++++++++++++++++++++++++++++++++-------
libs/canvas/canvas/canvas.h | 2 ++
2 files changed, 42 insertions(+), 7 deletions(-)