When discussing the implications of snapshot cow, one of the questions
that we raised was what happens on cairo_destroy()? The lifetime of the
context implicitly marks the extents of the drawing operations, typically
the expose event (or perhaps one phase of it). Therefore at the end of the
sequence we implicitly wish to flush the graphics events to the surface.
The previous LFSR generator used a large table to be speedy. The
replacement generator is the single stage generator (1) from section
5.4 of [HP2007], requires no tables or extra state. I've run the
generator through Rob Brown's extended Dieharder test suite and it
passes all but one self-proclaimed buggy test (-d2) and the 2D sphere
minimum distance test (-d12).
[HP2007] Hars L. and Petruska G., ``Pseudorandom Recursions: Small and Fast Pseurodandom Number Generators for Embedded Applications'',
Hindawi Publishing Corporation
EURASIP Journal on Embedded Systems
Volume 2007, Article ID 98417, 13 pages
doi:10.1155/2007/98417
http://www.hindawi.com/getarticle.aspx?doi=10.1155/2007/98417&e=cta
A new meta-surface backend for serialising drawing operations to a
CairoScript file. The principal use (as currently envisaged) is to provide
a round-trip testing mechanism for CairoScript - i.e. we can generate
script files for every test in the suite and check that we can replay them
with perfect fidelity. (Obviously this does not provide complete coverage
of CairoScript's syntax, but should give reasonable coverage over the
operators.)
Benjamin Otte noticed that the top-left vertex was now included within the
fill extents. Having updated the test case to check the insideness
conditions as defined by flash, fix the edge handling to match.
7944601864 broke the quartz backend.
Fix it by adding const to the appropriate parameters in the function
declarations and copying the pattern when needed.
Use the return value to return the result from _cairo_hash_table_lookup()
(as opposed to filling an output parameter on the stack) as this (a)
results in cleaner code (no strict-alias breaking pointer casts), (b)
produces a smaller binary and (c) is measurably faster.
As we obey the rule in Cairo that we only insert if we know that there is
no existing entry in the hash table, we can therefore perform a much quicker
search knowing that the key is unique.
A limitation of the current API was that the destroy notifier was called
on the mime-data block. This prevents the user from passing in a pointer
to a managed block, for example a mime-data block belonging to a
ref-counted object. We can overcome this by allowing the user to specify
the closure to be used with the destroy notifier.
Benjamin Otte reports that in one particular benchmark cairo_in_fill() is
a hotspot in the profile. Currently we tessellate the entire path and then
search for a containing trapezoid. This is very expensive compared to the
simple method of counting the number of edge crossing between the point of
interest and x=-∞. For example, this speeds tessellate-256 up by almost 3
orders of magnitude.
Write out the original PNG mime-data if attached to the surface during
cairo_surface_write_to_png(). Similar to how the compressed alternate
representations are handled by the other backends.
Note: by automatically attaching and using the mime-data in preference to
the image data, we break the read_from_png(); draw(); write_to_png()
cycle.
I moved the pixel centre to xc,yc but forgot to remove it during
compensation - as caught by the test suite.
Refresh a couple of reference images that depend upon exact pixel-centre
rounding conditions.
pixman limits the src] co-ordinates (and thus [xy]_offset] to 16bits,
so we need to be careful how much of the translation vector to push into
[xy]_offset. Since the range is the same for both, split the integer
component between the matrix and the offset.
test/scale-offset* now at least shows the source image, even if it is
misplaced.
Instead of doing a full-copy of the mime data (which can be 10K-100K,
or even larger) just copy a reference to the original mime to the
snapshot surface (as suggested by Behdad).
Use the surface user-data array allow to store an arbitrary set of
alternate image representations keyed by an interned string (which
ensures that it has a unique key in the user-visible namespace).
Update the API to mirror that of cairo_surface_set_user_data() [i.e.
return a status indicator] and switch internal users of the mime-data to
the public functions.
