decode_png_chunks() is not handling "critical" chunks, unlike
decode_png_size() for example. When we encounter a chunk decoding
failure, e.g. because not enough bytes were left to read, just continue
with decoding the bitmap - which will fail on its own, if we're missing
some required chunk(s).
Fixes#4984.
IPC::File should only be used when there's an actual file to pass.
Invalid ShareableBitmaps don't have a backing file, so fix this by
first encoding a "valid" flag.
Window icons in Taskbar were previously received in WM events with
shbuf ID's. Now that Gfx::ShareableBitmap is backed by anonymous files,
we can easily switch to using those.
Needed for the window server minimize animation.
draw_rect() can't just call draw_line() because that isn't
draw_op()-aware. The draw_op()-awareness in Painter looks a bit ad-hoc,
but that's for another day.
This adds a scale factor to Painter, which will be used for HighDPI
support. It's also a step towards general affine transforms on Painters.
All of Painter's public API takes logical coordinates, while some
internals deal with physical coordinates now. If scale == 1, logical
and physical coordinates are the same. For scale == 2, a 200x100 bitmap
would be covered by a logical {0, 0, 100, 50} rect, while its physical
size would be {0, 0, 200, 100}.
Most of Painter's functions just assert that scale() == 1 is for now,
but most functions called by WindowServer are updated to handle
arbitrary (integer) scale.
Also add a new Demo "LibGfxScaleDemo" that covers the converted
functions and that can be used to iteratively add scaling support
to more functions.
To make Painter's interface deal with logical coordinates only,
make translation() and clip_rect() non-public.
The underlying fill_rect() works correctly, but the special case for
thickness = 1 was not blending the new color with the target pixel's
color, causing RGBA colors to be painted as their RGB counterpart.
