From 84b3e14da70db07ae589950e7203c362c1259be8 Mon Sep 17 00:00:00 2001
From: LongYinan <lynweklm@gmail.com>
Date: Mon, 18 Nov 2024 23:37:27 +0800
Subject: [PATCH] fix: panic when restore from scale(0,0) state

---
 __test__/regression.spec.ts | 10 ++++++++++
 src/ctx.rs                  | 12 ++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/__test__/regression.spec.ts b/__test__/regression.spec.ts
index f88077c6..16faf32e 100644
--- a/__test__/regression.spec.ts
+++ b/__test__/regression.spec.ts
@@ -210,3 +210,13 @@ test('isPointInPath with translate', (t) => {
   t.true(ctx.isPointInPath(100, 100))
   t.true(ctx.isPointInPath(110, 110))
 })
+
+test('restore from scale(0, 0)', (t) => {
+  const canvas = createCanvas(1200, 700)
+  const ctx = canvas.getContext('2d')
+  t.notThrows(() => {
+    ctx.scale(0, 0)
+    ctx.save()
+    ctx.restore()
+  })
+})
diff --git a/src/ctx.rs b/src/ctx.rs
index a8d7dcad..4e7d8344 100644
--- a/src/ctx.rs
+++ b/src/ctx.rs
@@ -213,7 +213,9 @@ impl Context {
     if let Some(s) = self.states.pop() {
       self.path.transform_self(&self.state.transform);
       self.surface.canvas.restore();
-      self.path.transform_self(&s.transform.invert().unwrap());
+      if let Some(inverse) = s.transform.invert() {
+        self.path.transform_self(&inverse);
+      }
       self.state = s;
     }
   }
@@ -275,9 +277,11 @@ impl Context {
 
   pub fn scale(&mut self, x: f32, y: f32) {
     let s = &mut self.state;
-    let mut inverse = Matrix::identity();
-    inverse.pre_scale(1f32 / x, 1f32 / y);
-    self.path.transform_self(&inverse);
+    if x != 0.0 && y != 0.0 {
+      let mut inverse = Matrix::identity();
+      inverse.pre_scale(1f32 / x, 1f32 / y);
+      self.path.transform_self(&inverse);
+    }
     s.transform.pre_scale(x, y);
     self.surface.canvas.set_transform(&s.transform);
   }