Merge #2206: effects: CC Radial Fast Blur grows its buffer so streaks pass the layer edge (#2095) (@mercuryVM)

crates/effects/src/blur2.rs

@@ -509,11 +509,24 @@ fn camera_lens_blur(ctx: &EffectCtx, mut b: Buf) -> Buf {
 // ---------------------------------------------------------------------------------------------
 // CC Radial Fast Blur
 
+/// Transparent pixels CC Radial Fast Blur adds on every side of a `w` × `h` buffer with Center
+/// at `c` (buffer pixels) and smear `s`: content `r` from Center streaks out to `r / (1 − s)`,
+/// so the farthest corner reaches `d · s / (1 − s)` past itself (at most 4096, as the other
+/// growing effects). Shared with the GPU path so both grow the same way.
+pub fn radial_fast_pad(c: (f64, f64), w: u32, h: u32, s: f64) -> u32 {
+    let (w, h) = (f64::from(w), f64::from(h));
+    let far = [(0.0, 0.0), (w, 0.0), (0.0, h), (w, h)].iter().map(|&(x, y)| (x - c.0).hypot(y - c.1)).fold(0.0, f64::max);
+    ((far * s / (1.0 - s)).ceil() + 1.0).min(4096.0) as u32
+}
+
 fn radial_fast_blur(ctx: &EffectCtx, mut b: Buf) -> Buf {
     let s = (ctx.params.f("amount") / 100.0).clamp(0.0, 1.0) * 0.5;
     if s <= 0.0 {
         return b;
     }
+    if !ctx.adjustment {
+        b.pad(radial_fast_pad(b.to_px(ctx.params.v2("center")), b.img.width, b.img.height, s));
+    }
     let c = b.to_px(ctx.params.v2("center"));
     let mode = ctx.params.e("zoom");
     let src = b.img.clone();
@@ -906,6 +919,23 @@ mod tests {
         assert_eq!(circle.len(), 21);
     }
 
+    #[test]
+    fn radial_fast_blur_streaks_past_the_layer_edge() {
+        // Center left of an opaque square: the streaks run right, beyond the layer rectangle (#2095).
+        let img = Image::filled(20, 20, [1.0, 1.0, 1.0, 1.0]);
+        let out = run("ec.blur.ccradialfast", &img, &[("center", Value::Vec2([-20.0, 10.0])), ("amount", num(80.0))]);
+        assert!(out.img.width > 20 && out.img.height > 20, "{}x{}", out.img.width, out.img.height);
+        let (o, d) = (out.offset[0] as i64, out.offset[1] as i64);
+        assert!(out.img.get(30 + o, 10 + d)[3] > 0.1, "{:?}", out.img.get(30 + o, 10 + d));
+        // Its streak samples only the square: still opaque, so the content keeps its place.
+        assert!((out.img.get(19 + o, 10 + d)[3] - 1.0).abs() < 1e-5, "{:?}", out.img.get(19 + o, 10 + d));
+        // An adjustment layer is comp-sized already; its buffer is not grown.
+        let s = find("ec.blur.ccradialfast").unwrap();
+        let params = Params { values: [("center".into(), Value::Vec2([-20.0, 10.0])), ("amount".into(), num(80.0))].into_iter().collect() };
+        let ctx = EffectCtx { params: &params, time: 0.0, layer_size: [20.0, 20.0], seed: 1, adjustment: true, env: Default::default() };
+        assert_eq!((s.render)(&ctx, Buf { img, offset: [0.0, 0.0], scale: 1.0 }).img.width, 20);
+    }
+
     #[test]
     fn reduce_flicker_blurs_vertically_only() {
         let mut img = Image::filled(8, 8, [0.0, 0.0, 0.0, 1.0]);

crates/effects/src/lib.rs

@@ -91,7 +91,7 @@ pub use sim::particle_state;
 pub use sim3::{PgBlit, PgPlan, playground_plan, playground_state};
 pub use stylize2::strobe_on;
 // CPU helpers the GPU kernels share (effectcraft-gpu).
-pub use blur2::{camera_lens_plain, camera_lens_spans};
+pub use blur2::{camera_lens_plain, camera_lens_spans, radial_fast_pad};
 pub use generate::{four_color_softening, gen_mode};
 pub use generate2::pattern_kind as cell_pattern_kind;
 pub use generate2::{BoltSeg, Contour, Ghost, RadioPlan, Wave, flare_ghosts, lightning_segments, radio_plan};

crates/gpu/src/fx_generate.rs

@@ -117,11 +117,14 @@ fn radial_blur(e: &mut Enc, ctx: &EffectCtx, b: GBuf) -> Option<GBuf> {
     run(e, "gen_radial_blur", &p, b, None, Some(&data))
 }
 
-fn radial_fast(e: &mut Enc, ctx: &EffectCtx, b: GBuf) -> Option<GBuf> {
+fn radial_fast(e: &mut Enc, ctx: &EffectCtx, mut b: GBuf) -> Option<GBuf> {
     let s = (ctx.params.f("amount") / 100.0).clamp(0.0, 1.0) * 0.5;
     if s <= 0.0 {
         return Some(b);
     }
+    if !ctx.adjustment {
+        b.pad(e, effectcraft_effects::radial_fast_pad(b.to_px(ctx.params.v2("center")), b.img.width, b.img.height, s))?;
+    }
     let c = b.to_px(ctx.params.v2("center"));
     let mut p = Params::default();
     p.u[0][0] = ctx.params.e("zoom");

crates/gpu/src/tests_fx_generate.rs

@@ -31,6 +31,8 @@ fn cc_radial_fast_blur() {
     effect_case("ec.blur.ccradialfast", &[("amount", n(40.0))]);
     effect_case("ec.blur.ccradialfast", &[("amount", n(70.0)), ("zoom", e(1)), ("center", pt(22.4, 16.1))]);
     effect_case("ec.blur.ccradialfast", &[("amount", n(25.0)), ("zoom", e(2))]);
+    // Center outside the layer: the buffer grows so the streaks pass its edge (#2095).
+    effect_case("ec.blur.ccradialfast", &[("amount", n(80.0)), ("center", pt(-30.0, 20.0))]);
 }
 
 #[test]