This patch has 2 purposes,
1. revise the loaders infrastructure to support both static/external linking loaders.
2. add a template for static jpg/png loaders after external jpg/png.
Our default loaders prefer static linking, external loaders are only available
when dependent libraries on the build system are found.
You might wonder why we have the external loaders together,
they might be faster than static loaders since the popular libraries are likely to be well maintained,
fine-grained optimized.
Thus in this patch, meson tries to apply the external loaders first
then see if the dependencies were found or not,
if it's failed, it turns to the default static loaders.
Next this patch, we need the contribution for actual static jpg/png loaders implementation.
@Issue: https://github.com/Samsung/thorvg/issues/594
"runtime error: load of misaligned address 0x7fb67895c815 for type 'unsigned int', which requires 4 byte alignment"
This is actually not an issue but we can resolve it with an easy workaround,
since we don't need to see this report repeatedly.
Current paint::bounds() returns the coordinates under the raw status,
the values are not quite useful if the paint object has the transformed children.
Thus, we extends the feature and give an additional parameter "transformed"
to return the coordinates values after transformation by user demands.
This is also necessary for tvg format, since we need the exact view size of the scene information.
The previous api is deprecated and we introduce a new api to replace it.
@APIs:
+ Result Paint::bounds(float* x, float* y, float* w, float* h, bool transformed) const noexcept;
- Result Paint::bounds(float* x, float* y, float* w, float* h) const noexcept;
@Issues: https://github.com/Samsung/thorvg/issues/746
Since the arc flags can have values 0 or 1, we reported as
an error cases, when a float value was given.
Since the EBNF grammar can be used, we misread some paths.
Removing the condition that prevents giving a float as a flag solves
this problem and is in agreement with the w3 specs.
This reserved count was just missed,
Aside from it, tvg_loader logic is not well organized (hard to expect)
We can refine it by recovering the data tree structure in the reverse order.
@Issues: https://github.com/Samsung/thorvg/issues/768
By choosing compress option, tvg tries to compress the data to reduce the binary size.
Since the compression has the double-edges sword, we provides an option to users
to select it by their demand. Basically, compression is better than non-compression.
After profiling, we decided to use the encoder/decoder of Guilherme R. Lampert's.
Here is the profiling result:
test.tvg: 296037 -> 243411 (-17%)
tiger.tvg: 54568 -> 50622 (-7%)
image-embedded.tvg: 2282 -> 1231 (-46%)
@Issue: https://github.com/Samsung/thorvg/issues/639
About compression method:
Lempel–Ziv–Welch (LZW) encoder/decoder by Guilherme R. Lampert
This is the compression scheme used by the GIF image format and the Unix 'compress' tool.
Main differences from this implementation is that End Of Input (EOI) and Clear Codes (CC)
are not stored in the output and the max code length in bits is 12, vs 16 in compress.
EOI is simply detected by the end of the data stream, while CC happens if the
dictionary gets filled. Data is written/read from bit streams, which handle
byte-alignment for us in a transparent way.
The decoder relies on the hardcoded data layout produced by the encoder, since
no additional reconstruction data is added to the output, so they must match.
The nice thing about LZW is that we can reconstruct the dictionary directly from
the stream of codes generated by the encoder, so this avoids storing additional
headers in the bit stream.
The output code length is variable. It starts with the minimum number of bits
required to store the base byte-sized dictionary and automatically increases
as the dictionary gets larger (it starts at 9-bits and grows to 10-bits when
code 512 is added, then 11-bits when 1024 is added, and so on). If the dictionary
is filled (4096 items for a 12-bits dictionary), the whole thing is cleared and
the process starts over. This is the main reason why the encoder and the decoder
must match perfectly, since the lengths of the codes will not be specified with
the data itself.
This change protects against negative value in unsigned int of
RenderRegion.x/y. This fixes a problem of invisible paint if ClipPath
bounds was negative.
@issue: #704
Added error string printing on jpg image loading failure.
The error message help developer find the corrupted jpg file.
Error message is not printed for open from char* data as there the
loaders are tried on by one.
tvg binary format might break the compatibility if any major features have been changed.
It's allowed to do it when the major version is upgraded.
In that case, still we need to support the backward compatibility,
we can provide multiple binary interpreters and choose the proper one
based on the current loading tvg binary format version.
Thus, you can add further interpreters if it's necessary in the future.
Our policy is to derive the TvgBinInterpreterBase class to make it running on
the interface.
for example, if the major version is upgraded 1.x, you can implement TvgBinInterpreter1.
tvg file stores the version info of thorvg when it's generated,
in order to compare it with the runtime thorvg version when it's loaded.
For this, thorvg builds up the current version of symbol on the initilaization step,
that can be referred by the tvg loader.
This reduces tvg binary format size by converting PathCommand to more compact size.
This optimization increase +12% compress rate with our example:
195,668 => 174,071 (sum of all converted tvgs from svgs)
@Issues: https://github.com/Samsung/thorvg/issues/639
If svg contained multiple defs tags only the first one was handled correctly.
Every next 'defs' tag was skipped and its inner elements parsed as it was
outside the defs.
Bitmap based pictures doesn't need the viewbox,
LoaderModule should delegate the viewbox to the derived classes which
having vector-based image loaders such as svg, tvg.
In that case, paint resizing can be performed by the loaders by own
policy.
replace from Scene to Paint at the internal interface.
Picture doesn't need to know the returned Node type.
base class, Paint is enough to in the data passing.
