support to compile ftgrays/ftraster/gpac-evg

preparing for new renderer implementation

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "C_Cpp.default.defines": [ "STANDALONE_",
+	"FALL_THROUGH=((void)0)", "FT_BEGIN_HEADER" ],
+    "C_Cpp.default.includePath": [ "src/evg", "src/raster" ]
+}

Cargo.toml

@@ -22,12 +22,30 @@ usvg  = "0.36"
 kurbo = "0.10"   # Bezier curves utils
 
 #build-time = { version = "0.1", git = "https://github.com/AlephAlpha/build-time" }
+png = { version = "0.17", optional = true }
+
+[lib]
+# Disable doctests as a workaround for https://github.com/rust-lang/rust-bindgen/issues/1313
+#doctest = false
+
+[features]
+#default = [ "cc" ]
+cc = [ "dep:cc", "dep:bindgen", "dep:glob", "dep:png" ]   # implied by optional dependency
 
 [dev-dependencies]
 #rexpect = "0.5"
 
 [build-dependencies]
+cc = { version = "1.0", optional = true }
+bindgen = { version = "0.68", optional = true }
+glob = { version = "0.3", optional = true }
 chrono = "0.4"
 
+[profile.release]
+codegen-units = 1
+strip = 'debuginfo'
+panic = 'abort'
+lto = 'fat' # true
+
 [workspace]
 

build.rs

@@ -1,16 +1,72 @@
 
-fn main() {     // https://doc.rust-lang.org/stable/cargo/reference/build-scripts.html
+//  https://doc.rust-lang.org/stable/cargo/reference/build-scripts.html
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    //println!("cargo:rerun-if-changed=build.rs");    // XXX: prevent re-run indead
     // By default, cargo always re-run the build script if any file within the package
     // is changed, and no any rerun-if instruction is emitted.
     println!("cargo:rerun-if-changed=src/");
 
     println!("cargo:rerun-if-changed=.git/index");
     let output = std::process::Command::new("git")
-        .args(["rev-parse", "--short", "HEAD"]).output().unwrap();
-    println!("cargo:rustc-env=BUILD_GIT_HASH={}", String::from_utf8(output.stdout).unwrap());
+        .args(["rev-parse", "--short", "HEAD"]).output()?;
+    println!("cargo:rustc-env=BUILD_GIT_HASH={}", String::from_utf8(output.stdout)?);
 
     println!("cargo:rustc-env=BUILD_TIMESTAMP={}",
         chrono::Local::now().format("%H:%M:%S%z %Y-%m-%d"));
 
-    //println!("cargo:rerun-if-changed=build.rs");    // XXX: prevent re-run indead
+  #[cfg(feature = "cc")] {  use std::path::PathBuf;
+    #[derive(Debug)] struct DoctestComment;
+    impl bindgen::callbacks::ParseCallbacks for DoctestComment {
+        fn process_comment(&self, comment: &str) -> Option<String> {
+            Some(format!("````c,ignore\n{comment}\n````"))  // FIXME:
+        }
+    }
+
+    let module = "ftgrays";
+    cc::Build::new().flag("-std=c99").flag("-pedantic")
+        .define("FALL_THROUGH", "((void)0)").file("src/raster/ftgrays.c")
+        .opt_level(3).define("NDEBUG", None).file("src/raster/ftraster.c")
+        .files(glob::glob("src/raster/stroke/*.c")?.filter_map(Result::ok))
+        //.flag("-Wno-unused-variable").flag("-Wno-unused-function")
+        .define("STANDALONE_", None).compile(module);
+
+    // The bindgen::Builder is the main entry point to bindgen,
+    // and lets you build up options for the resulting bindings.
+    bindgen::Builder::default().header("src/raster/ftmisc.h")
+        .clang_arg(r"-DFT_CONFIG_STANDARD_LIBRARY_H=<stdlib.h>")
+        .clang_arg("-DSTANDALONE_").header("src/raster/ftgrays.h")
+        .clang_arg("-DFT_BEGIN_HEADER=").clang_arg("-DFT_END_HEADER=")
+        .allowlist_item("FT_OUTLINE_.*|FT_RASTER_FLAG_.*|FT_CURVE_TAG.*")
+        .layout_tests(false).derive_copy(false).allowlist_var("ft_standard_raster")
+        .allowlist_var("ft_grays_raster").allowlist_type("FT_Outline|FT_Pixel_Mode")
+        .default_enum_style(bindgen::EnumVariation::Rust { non_exhaustive: true })
+        .default_macro_constant_type(bindgen::MacroTypeVariation::Signed)
+        .parse_callbacks(Box::new(DoctestComment)).generate_comments(false) // XXX:
+        // Tell cargo to invalidate the built crate whenever any of the
+        // included header files changed.
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks)).generate()?
+        .write_to_file(PathBuf::from(std::env::var("OUT_DIR")?).join(format!("{module}.rs")))?;
+
+    /* ln -s /path/to/freetype2/{include/freetype/ftimage.h,src/smooth/ftgrays.[ch],\
+             src/raster/{ftmisc.h,ftraster.c}} src/raster/  # ftstroke.c,fttrigon.c
+     * ln -s /path/to/gpac/src/evg/{ftgrays.c,rast_soft.h,stencil.c,surface.c,\
+             raster_{argb,rgb,565}.c} src/evg/
+     * ln -s /path/to/gpac/include/gpac/{evg,color,constants,maths,path2d,setup,\
+             tools,thread}.h src/evg/
+     * touch src/evg/gpac/{Remotery,config_file,configuration,main,module,version}.h
+     */
+    let module = "gpac_evg";
+    cc::Build::new().flag("-std=c17").flag("-Isrc/evg")
+        .flag("-Wno-unused-parameter").define("GPAC_DISABLE_THREADS", None)
+        .files(glob::glob("src/evg/*.c")?.filter_map(Result::ok))
+        .flag("-Wno-pointer-sign").opt_level(3).define("NDEBUG", None).compile(module);
+
+    bindgen::Builder::default().header("src/evg/gpac/evg.h").clang_arg("-Isrc/evg")
+        .layout_tests(false).derive_copy(false).allowlist_function("gf_evg_surface_.*")
+        .allowlist_function("gf_path_get_outline") // for stroke path
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks)).generate()?
+        .write_to_file(PathBuf::from(std::env::var("OUT_DIR")?).join(format!("{module}.rs")))?;
+  }
+
+    Ok(())
 }

src/lib.rs

@@ -1,4 +1,15 @@
 
+#![allow(non_snake_case)] #![allow(non_camel_case_types)] #![allow(non_upper_case_globals)]
+#![allow(clippy::approx_constant)] #![allow(clippy::useless_transmute)]
+#[cfg(feature = "cc")] pub mod ftgrays  {
+    include!(concat!(env!("OUT_DIR"), "/ftgrays.rs"));
+
+    impl From<(FT_Pos, FT_Pos)> for FT_Vector {
+        fn from(v: (FT_Pos, FT_Pos)) -> Self { Self { x: v.0, y: v.1 } }
+    }
+}
+#[cfg(feature = "cc")] pub mod gpac_evg { include!(concat!(env!("OUT_DIR"), "/gpac_evg.rs")); }
+
 pub mod tinyvg;
 pub mod render;
 pub mod convert;

src/render.rs

@@ -3,6 +3,13 @@ use crate::tinyvg::*;
 use tiny_skia as skia;
 use std::result::Result;
 
+/*  TODO: https://github.com/sammycage/plutovg
+    https://github.com/gpac/gpac/tree/master/src/evg/
+    https://github.com/kiba/SDL_svg/blob/master/ftgrays.c
+    https://github.com/Samsung/rlottie/tree/master/src/vector/freetype
+    https://gitlab.freedesktop.org/freetype/freetype/-/blob/master/src/smooth/ftgrays.c
+    https://gitlab.freedesktop.org/freetype/freetype/-/blob/master/src/raster/ftraster.c */
+
 pub trait Render { fn render(&self, scale: f32) -> Result<skia::Pixmap, &str>; }
 
 impl Render for TVGImage {  // TODO: to render with femtovg?

tests/raster.rs

@@ -0,0 +1,67 @@
+
+#[cfg(feature = "cc")]
+#[test] fn raster_ftgrays() -> Result<(), Box<dyn std::error::Error>> {
+    use core::{ptr::null_mut, ffi::c_void};     use intvg::ftgrays::*;
+
+    let mut points = vec![ // FTDemo_Icon @freetype2/demo/src/ftcommon.c
+        ( 4, 8).into(), ( 4,10).into(), ( 8,12).into(), ( 8,52).into(), ( 4,54).into(),
+        ( 4,56).into(), (60,56).into(), (60,44).into(), (58,44).into(), (56,52).into(),
+        (44,52).into(), (44,12).into(), (48,10).into(), (48, 8).into(), (32, 8).into(),
+        (32,10).into(), (36,12).into(), (36,52).into(), (16,52).into(), (16,36).into(),
+        (24,36).into(), (26,40).into(), (28,40).into(), (28,28).into(), (26,28).into(),
+        (24,32).into(), (16,32).into(), (16,12).into(), (20,10).into(), (20, 8).into(), ];
+    let mut tags = vec![FT_CURVE_TAG_ON as i8; points.len()];
+    let mut contours = vec![29];
+
+    let mut bitmap = FT_Bitmap {
+        rows: 0, width: 0, pitch: 0, buffer: null_mut(), // FIXME:
+
+        pixel_mode: FT_Pixel_Mode::FT_PIXEL_MODE_LCD as u8, // FT_PIXEL_MODE_BGRA
+        // https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#enums
+        // Not used currently, or only used with FT_PIXEL_MODE_GRAY
+        palette_mode: 0, palette: null_mut(), num_grays: 0,
+    };
+
+    #[allow(unused)]
+    unsafe extern "C" fn span_func(y: i32, count: i32, // TODO: solid/linear/radial/stroke
+        spans: *const FT_Span, user: *mut c_void) { // The gray span drawing callback.
+        let bitmap = user as *mut FT_Bitmap;    assert!(0 < count);
+
+        for span in core::slice::from_raw_parts(spans, count as usize) {
+            for x in span.x..span.len as i16 {
+                // TODO: handle pixel at (x, y) with span.coverage (alpha)
+            }
+        }
+    }
+
+    let outline = FT_Outline {
+        n_points: points.len() as i16, points: points.as_mut_ptr(), tags: tags.as_mut_ptr(),
+        n_contours: contours.len() as i16, contours: contours.as_mut_ptr(),
+        flags: FT_OUTLINE_NONE, // XXX: FT_OUTLINE_IGNORE_DROPOUTS
+    };  assert!(tags.len() == points.len());
+
+    let mut params = FT_Raster_Params {
+        source: &outline  as *const _ as *const c_void,
+        user: &mut bitmap as *mut   _ as *mut   c_void, gray_spans: Some(span_func),
+
+        // ftgrays.c: `ft_grays_raster` are typoed as `ft_gray_raster` in some comments.
+        // ftimage.h: FT_Pos can be typed as `signed int` rather than `long`? // XXX:
+        clip_box: FT_BBox { xMin: 0, yMin: 0, xMax: 0, yMax: 0 }, // FT_RASTER_FLAG_CLIP
+        flags: FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT,
+        black_spans: None, bit_test: None, bit_set: None, // Unused
+        target: null_mut(), // &bitmap, unused in direct mode
+    };  let mut raster = null_mut();
+
+    unsafe {    // use of extern static (ft_grays_raster/ft_standard_raster) is unsafe
+        let _ = ft_grays_raster.raster_new.unwrap()(null_mut(), &mut raster);
+        //if  res != 0 { panic!("raster_new failed: {}", res); }
+        //ft_grays_raster.raster_reset.unwrap()(raster, null_mut(), 0);
+        //ft_grays_raster.raster_set_mode.unwrap()(raster, 0, null_mut());
+
+        let res = ft_grays_raster.raster_render.unwrap()(raster, &mut params);
+        if  res != 0 { panic!("raster_render failed: {res}"); }
+        //ft_grays_raster.raster_done.unwrap()(raster);
+    }
+
+    Ok(())
+}