LibGfx: Add a method to reset a Painter to its initial state

Author: https://github.com/tcl3
Commit: 017e8a5b8d
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6536
Reviewed-by: https://github.com/gmta ✅

Libraries/LibGfx/Painter.h

@@ -43,6 +43,8 @@ public:
     virtual void restore() = 0;
 
     virtual void clip(Gfx::Path const&, Gfx::WindingRule) = 0;
+
+    virtual void reset() = 0;
 };
 
 }

Libraries/LibGfx/PainterSkia.cpp

@@ -134,6 +134,9 @@ static SkPaint to_skia_paint(Gfx::PaintStyle const& style, Optional<Gfx::Filter
 PainterSkia::PainterSkia(NonnullRefPtr<Gfx::PaintingSurface> painting_surface)
     : m_impl(adopt_own(*new Impl { move(painting_surface) }))
 {
+    m_impl->with_canvas([this](auto& canvas) {
+        m_initial_save_count = canvas.save();
+    });
 }
 
 PainterSkia::~PainterSkia() = default;
@@ -335,4 +338,11 @@ void PainterSkia::clip(Gfx::Path const& path, Gfx::WindingRule winding_rule)
     });
 }
 
+void PainterSkia::reset()
+{
+    impl().with_canvas([&](auto& canvas) {
+        canvas.restoreToCount(m_initial_save_count);
+    });
+}
+
 }

Libraries/LibGfx/PainterSkia.h

@@ -32,11 +32,13 @@ public:
     virtual void save() override;
     virtual void restore() override;
     virtual void clip(Gfx::Path const&, Gfx::WindingRule) override;
+    virtual void reset() override;
 
 private:
     struct Impl;
     Impl& impl() { return *m_impl; }
     NonnullOwnPtr<Impl> m_impl;
+    u32 m_initial_save_count { 0 };
 };
 
 }