From 9d8565cf9a45c19d804d0da1a27462d625497249 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 26 Jun 2020 18:26:18 +0200
Subject: [PATCH] LibWeb: Add CanvasRenderingContext2D.rotate()

This is pretty limited since we don't have wholesale mapping through
the context transform, but we have to start somewhere. :^)
---
 Base/res/html/misc/canvas-rotate.html             | 12 ++++++++++++
 Base/res/html/misc/welcome.html                   |  1 +
 Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp |  6 ++++++
 Libraries/LibWeb/DOM/CanvasRenderingContext2D.h   |  1 +
 Libraries/LibWeb/DOM/CanvasRenderingContext2D.idl |  1 +
 5 files changed, 21 insertions(+)
 create mode 100644 Base/res/html/misc/canvas-rotate.html
diff --git a/Base/res/html/misc/canvas-rotate.html b/Base/res/html/misc/canvas-rotate.html
new file mode 100644
index 0000000000..9cdb9489ea
--- /dev/null
+++ b/Base/res/html/misc/canvas-rotate.html
@@ -0,0 +1,12 @@
+<html>
+    <canvas id=c width=200 height=200></canvas>
+    <script>
+        c = document.getElementById('c');
+        x = c.getContext('2d');
+        x.strokeStyle = 'black';
+        for (i = 0; i < 8; ++i) {
+            x.strokeRect(50, 50, 50, 50);
+            x.rotate(0.05);
+        }
+    </script>
+</html>
diff --git a/Base/res/html/misc/welcome.html b/Base/res/html/misc/welcome.html
index a4294f1605..d07b0ffd90 100644
--- a/Base/res/html/misc/welcome.html
+++ b/Base/res/html/misc/welcome.html
@@ -28,6 +28,7 @@ span#ua {
     <p>Your user agent is: <b><span id="ua"></span></b></p>
     <p>Some small test pages:</p>
     <ul>
+        <li><a href="canvas-rotate.html">canvas rotate()</a></li>
         <li><a href="margin-collapse-2.html">margin collapsing 2</a></li>
         <li><a href="margin-collapse-1.html">margin collapsing 1</a></li>
         <li><a href="position-absolute-from-edges.html">position: absolute, offset from edges</a></li>
diff --git a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp
index c210e36458..a56ac222e7 100644
--- a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp
+++ b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp
@@ -123,6 +123,12 @@ void CanvasRenderingContext2D::translate(float tx, float ty)
     m_transform.translate(tx, ty);
 }
 
+void CanvasRenderingContext2D::rotate(float radians)
+{
+    dbg() << "CanvasRenderingContext2D::rotate(): " << radians;
+    m_transform.rotate_radians(radians);
+}
+
 void CanvasRenderingContext2D::did_draw(const Gfx::FloatRect&)
 {
     // FIXME: Make use of the rect to reduce the invalidated area when possible.
diff --git a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h
index 1b68f13fc4..eee5804897 100644
--- a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h
+++ b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h
@@ -62,6 +62,7 @@ public:
 
     void scale(float sx, float sy);
     void translate(float x, float y);
+    void rotate(float degrees);
 
     void set_line_width(float line_width) { m_line_width = line_width; }
     float line_width() const { return m_line_width; }
diff --git a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.idl b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.idl
index 98861cc8ec..2aad0f8027 100644
--- a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.idl
+++ b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.idl
@@ -5,6 +5,7 @@ interface CanvasRenderingContext2D {
 
     void scale(double x, double y);
     void translate(double x, double y);
+    void rotate(double radians);
 
     void beginPath();
     void closePath();
