alcinnz

alcinnz, 6 days ago

@phryk Judging by prior art I'd theorize that the risc32imv alone at multi-megahertz might not be able to handle vector & 3D graphics in realtime, but if the code's optimized enough it could handle smaller scenes!

Might want to throw in the F or D extension...

alcinnz, 6 days ago

@phryk Certainly it'd be able to run Quake!

alcinnz, 6 days ago

@phryk As for audio: I specifically stated multi-megahertz (low ball figure) so it has time to filter the audio as it outputs it!

alcinnz, 6 days ago

@phryk The V extension gives a free alpha-channel alongside RGB...

alcinnz, 6 days ago

So far I heard a desire for 3D vector graphics (like in 80s/90s scifi; should be negligibly any harder 2D; from @phryk), audio filtering, making the abstractions optional, & an interpreted language like BASIC. (@millihertz)

I see mixed opinions (@vertigo) over whether CPU should generate the raw wire signal, or if that should be buffered in RAM. As a non-masochist not nostalgic for C64... I have an opinion...
Is it feasible to have a full MBs-large framebuffer with consistent timing?

1'/1.5'

alcinnz, 6 days ago (edited 6 days ago)

Now I'm wondering if I should explore implementing a risc32fimv to run a UXN/Varvara simulator & Love2D (extended SDL2 bindings for Lua) game engine? Once I've finished my hardware-browser hypothetical, which shouldn't be much longer...

I'll list it as an option when I poll "what next?"

1.5'/1.5'!

alcinnz, 6 days ago

Splash implements microoptimized math routines.

Regarding rasterizing glyphs from a font, FreeType is hooked up to Splash's path-building methods.

There's "Pattern" subclasses for computing the colour at a given pixel.

There's a linked stack of drawing state, closely resembling the one Poppler reimplemented for itself.

There's a scanline algorithm implemented for intersecting geometries, thus implementing clipping, as managed by a seperate class. Taking shortcuts for rectangles.

2/3?

alcinnz, 6 days ago

A "Screen" class constructs initial matrices.

Bitmaps (of which there's 2 classes) are 2D-sized byte arrays. Possibly with additional colour metadata. Most of the logic here is involved in outputting in various file formats, some of which utilize 3rd-party libs for compression.

There's a class interpolating curves to produce straight line segments.

Various trivial colour maths routines are provided.

But most of the rasterization logic is in a single class named for this library: Splash.
3/4!

alcinnz, 6 days ago

Splash's central class tracks various colour-blending options, a target bitmap, linked-stack state (to which it proxies accessors), an anti-aliasing bitmap, anti-aliasing Y coord, an alpha bitmap with coords, anti-aliasing coordinate array for anti-aliasing "gammas", min-line-width, a thin-line mode, whether all or some of the path was clipped away, & bitflags for: anti-aliasing, shading, & debugging.

Internally it is pipelines upon 2D slices of the image, with colourspace metadata.

4/5!!

alcinnz, 6 days ago

Results from those pipelines are written into the bitmap at given coords in appropriate encoding.

Antialiasing is done by rendering to a higher resolution & subsampling. With tweaked clipping.

Clearing the canvas is done via memset(), ensuring correct colour encoding.

Stroking a path involves matrix-transforming & interpolating curves on said path, splitting it according to the dash pattern (if any), & is either directly rasterized by split into "spans" or is converted into a fill 1st.

5/5.5

alcinnz, 6 days ago

Min/max coords can be taken to compute a bbox.

After applying hints & taking fast paths... Stroking a path involves lowering it to line segments & clipping it retrieving the bbox, then using that same scanline algorithm to split the path into scanlines our pipeline infrastructure can rasterize. With or without antialiasing.

There's a method for matrix-transformed clipping tests, & others for different fills. One matrix-transforms or scales masks.

Fastpath for transformed image blitting.

6/6!

alcinnz, 7 days ago

• Parsed sounds; used by links, annotations, & embedding frameworks.
• Stream base-class & various subclasses.
• Catalogs include a dynamically-typed tree structure.
• An OutputDev which extracts rearranged & decoded text from a PDF file, much harder than it needs to be!
• Key-value caches used in graphics & cross-reference.
• An OutputDev which strips away degenerate PDF data.
• An OutputDev outputting PostScript files utilizing an extra prolog.

2/3!

alcinnz, 7 days ago

• Parsed parameters for media playback, used by internal links.
• Parsed PageTransitions, called by embedders.
• Parsed Movies & their activation parameters, called by embedders.
• Lookup character names, called by Global Parameters.
• Stream subclasses to help decode JPEG images.
• Log info on link-triggered JS.
• An OutputDev extracting your annotations.
• Utils for embedding images, used by the PDFDoc class itself.
• Decode compact arithmetic instructions, used by JPG decoding.

3/4!!

alcinnz, 7 days ago

• Python script for generating Unicode dataheaders.
• General logic for parsing out files (fonts, images, video, audio) embedded in the PDF)
• Filepath parsing.
• ZLib compression, used by PostScript & the PDF doc itself. With a Stream subclass.
• Parsed FontInfo, used by Text Output & the global params.
• Loading PDFs via LibCURL
• Reading & writing dates.
• Discrete Cosine Transformation streams.
• Hashmaps & arrays.
• "Distinguished name" parsing, used by cryptography.

4/4.5!!

alcinnz, 7 days ago

• Error reporting.
• Gathering font metrics, used by Forms.
• Parsing char maps; used by graphics, global params, & text extraction.
• An Output Dev for computing the bbox.
• OutputDev hooking LibPoppler up to LibCairo Vector Graphics, with box rescaling util.

And I think that pretty much covers everything else in LibPoppler's core library!

4.5/4.5! Fin for today! Tomorrow: LibSplash! Amongst its vendored libs.