feat: add PathKit.dash() (#238)

* feat: add PathKit.dash()

__test__/pathkit.spec.ts

@@ -215,6 +215,13 @@ test('trim', (t) => {
   t.snapshot(svg)
 })
 
+test('dash', (t) => {
+  const box = new Path2D()
+  box.rect(0, 0, 100, 100)
+  box.dash(20, 10, 3)
+  t.is(box.toSVGString(), 'M20 0L40 0M50 0L70 0M80 0L100 0M100 10L100 30M100 40L100 60M100 70L100 90M100 100L100 100L80 100M70 100L50 100M40 100L20 100M10 100L0 100L0 90M0 80L0 60M0 50L0 30M0 20L0 0L10 0')
+})
+
 function drawSimplePath() {
   const path = new Path2D()
   path.moveTo(0, 0)

index.d.ts

@@ -227,6 +227,7 @@ export class Path2D {
   getBounds(): [left: number, top: number, right: number, bottom: number]
   computeTightBounds(): [left: number, top: number, right: number, bottom: number]
   trim(start: number, end: number, isComplement?: boolean): Path2D
+  dash(on: number, off: number, phase: number): Path2D
   equals(path: Path2D): boolean
 }
 

skia-c/skia_c.cpp

@@ -542,6 +542,21 @@ extern "C"
     return false;
   }
 
+  bool skiac_path_dash(skiac_path *c_path, float on, float off, float phase)
+  {
+    float intervals[] = {on, off};
+    auto pe = SkDashPathEffect::Make(intervals, 2, phase);
+    if (!pe) {
+        return false;
+    }
+    SkStrokeRec rec(SkStrokeRec::InitStyle::kHairline_InitStyle);
+    if (pe->filterPath(PATH_CAST, *PATH_CAST, &rec, nullptr))
+    {
+      return true;
+    }
+    return false;
+  }
+
   bool skiac_path_equals(skiac_path *c_path, skiac_path *other_path)
   {
     return *PATH_CAST == *reinterpret_cast<SkPath *>(other_path);

skia-c/skia_c.hpp

@@ -176,6 +176,7 @@ extern "C"
   void skiac_path_get_bounds(skiac_path *c_path, skiac_rect *c_rect);
   void skiac_path_compute_tight_bounds(skiac_path *c_path, skiac_rect *c_rect);
   bool skiac_path_trim(skiac_path *c_path, float start_t, float stop_t, bool is_complement);
+  bool skiac_path_dash(skiac_path *c_path, float on, float off, float phase);
   bool skiac_path_equals(skiac_path *c_path, skiac_path *other_path);
   void skiac_path_destroy(skiac_path *c_path);
   void skiac_path_set_fill_type(skiac_path *c_path, int type);

src/path.rs

@@ -33,6 +33,7 @@ impl Path {
         Property::new(&env, "computeTightBounds")?.with_method(compute_tight_bounds),
         Property::new(&env, "transform")?.with_method(transform),
         Property::new(&env, "trim")?.with_method(trim),
+        Property::new(&env, "dash")?.with_method(dash),
         Property::new(&env, "equals")?.with_method(equals),
         Property::new(&env, "_stroke")?.with_method(stroke),
       ],
@@ -418,6 +419,18 @@ fn trim(ctx: CallContext) -> Result<JsObject> {
   Ok(this)
 }
 
+#[js_function(3)]
+fn dash(ctx: CallContext) -> Result<JsObject> {
+  let this: JsObject = ctx.this_unchecked();
+  let path_2d = ctx.env.unwrap::<Path>(&this)?;
+  let on = ctx.get::<JsNumber>(0)?.get_double()?;
+  let off = ctx.get::<JsNumber>(1)?.get_double()?;
+  let phase = ctx.get::<JsNumber>(1)?.get_double()?;
+
+  path_2d.dash(on as f32, off as f32, phase as f32,);
+  Ok(this)
+}
+
 #[js_function(1)]
 fn equals(ctx: CallContext) -> Result<JsBoolean> {
   let this: JsObject = ctx.this_unchecked();

src/sk.rs

@@ -367,6 +367,13 @@ mod ffi {
       is_complement: bool,
     ) -> bool;
 
+    pub fn skiac_path_dash(
+      path: *mut skiac_path,
+      on: f32,
+      off: f32,
+      phase: f32,
+    ) -> bool;
+
     pub fn skiac_path_equals(path: *mut skiac_path, other: *mut skiac_path) -> bool;
 
     pub fn skiac_path_destroy(path: *mut skiac_path);
@@ -1986,6 +1993,11 @@ impl Path {
   pub fn trim(&mut self, start: f32, end: f32, is_complement: bool) -> bool {
     unsafe { ffi::skiac_path_trim(self.0, start, end, is_complement) }
   }
+
+  #[inline]
+  pub fn dash(&mut self, on: f32, off: f32, phase: f32) -> bool {
+    unsafe { ffi::skiac_path_dash(self.0, on, off, phase) }
+  }
 }
 
 impl PartialEq for Path {