From 8404df55d818c9309ecc8f8f929158cd343156b3 Mon Sep 17 00:00:00 2001
From: Totto16 <tobiausgais@gmail.com>
Date: Wed, 18 Jun 2025 00:57:33 +0200
Subject: [PATCH] LibWeb: Add OffscreenCanvas tests

The tests cover working in Worker and some basic functionality
---
 .../HTML/Canvas/CanvasTextDrawingStyles.h     |  5 +--
 .../Worker/Worker-offscreencanvas.txt         |  3 ++
 .../2d-offscreencanvas-create-imagedata.txt   |  1 +
 .../canvas/export-offscreencanvas.txt         |  2 ++
 .../expected/canvas/offscreencanvas-basic.txt |  3 ++
 .../input/Worker/Worker-offscreencanvas.html  | 36 +++++++++++++++++++
 .../2d-offscreencanvas-create-imagedata.html  | 19 ++++++++++
 .../input/canvas/export-offscreencanvas.html  | 32 +++++++++++++++++
 .../input/canvas/offscreencanvas-basic.html   | 13 +++++++
 9 files changed, 110 insertions(+), 4 deletions(-)
 create mode 100644 Tests/LibWeb/Text/expected/Worker/Worker-offscreencanvas.txt
 create mode 100644 Tests/LibWeb/Text/expected/canvas/2d-offscreencanvas-create-imagedata.txt
 create mode 100644 Tests/LibWeb/Text/expected/canvas/export-offscreencanvas.txt
 create mode 100644 Tests/LibWeb/Text/expected/canvas/offscreencanvas-basic.txt
 create mode 100644 Tests/LibWeb/Text/input/Worker/Worker-offscreencanvas.html
 create mode 100644 Tests/LibWeb/Text/input/canvas/2d-offscreencanvas-create-imagedata.html
 create mode 100644 Tests/LibWeb/Text/input/canvas/export-offscreencanvas.html
 create mode 100644 Tests/LibWeb/Text/input/canvas/offscreencanvas-basic.html

diff --git a/Libraries/LibWeb/HTML/Canvas/CanvasTextDrawingStyles.h b/Libraries/LibWeb/HTML/Canvas/CanvasTextDrawingStyles.h
index 94556736e9c..6d1544b95a7 100644
--- a/Libraries/LibWeb/HTML/Canvas/CanvasTextDrawingStyles.h
+++ b/Libraries/LibWeb/HTML/Canvas/CanvasTextDrawingStyles.h
@@ -116,10 +116,7 @@ public:
         if (!font_list)
             return;
 
-        if (font_list->is_empty())
-            return;
-
-        my_drawing_state().current_font_cascade_list = font_list->first();
+        my_drawing_state().current_font_cascade_list = font_list;
     }
 
     Bindings::CanvasTextAlign text_align() const { return my_drawing_state().text_align; }
diff --git a/Tests/LibWeb/Text/expected/Worker/Worker-offscreencanvas.txt b/Tests/LibWeb/Text/expected/Worker/Worker-offscreencanvas.txt
new file mode 100644
index 00000000000..eb1f829eae7
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/Worker/Worker-offscreencanvas.txt
@@ -0,0 +1,3 @@
+Message received from worker: "{\"w\":10,\"h\":10}"
+Message received from worker: "normal normal 20px SerenitySans"
+Message received from worker: "normal normal 20px SerenitySans"
diff --git a/Tests/LibWeb/Text/expected/canvas/2d-offscreencanvas-create-imagedata.txt b/Tests/LibWeb/Text/expected/canvas/2d-offscreencanvas-create-imagedata.txt
new file mode 100644
index 00000000000..437b6add2c0
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/canvas/2d-offscreencanvas-create-imagedata.txt
@@ -0,0 +1 @@
+FAIL: NotSupportedError: (STUBBED) OffscreenCanvasRenderingContext2D::create_image_data(int, int)
diff --git a/Tests/LibWeb/Text/expected/canvas/export-offscreencanvas.txt b/Tests/LibWeb/Text/expected/canvas/export-offscreencanvas.txt
new file mode 100644
index 00000000000..42b776fbee9
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/canvas/export-offscreencanvas.txt
@@ -0,0 +1,2 @@
+1.Success: {"size":119,"type":"image/png"}
+2.Success: {"size":823,"type":"image/jpeg"}
diff --git a/Tests/LibWeb/Text/expected/canvas/offscreencanvas-basic.txt b/Tests/LibWeb/Text/expected/canvas/offscreencanvas-basic.txt
new file mode 100644
index 00000000000..4ae6a033d8a
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/canvas/offscreencanvas-basic.txt
@@ -0,0 +1,3 @@
+{"w":10,"h":10}
+normal normal 20px SerenitySans
+normal normal 20px SerenitySans
diff --git a/Tests/LibWeb/Text/input/Worker/Worker-offscreencanvas.html b/Tests/LibWeb/Text/input/Worker/Worker-offscreencanvas.html
new file mode 100644
index 00000000000..97ba3c728d0
--- /dev/null
+++ b/Tests/LibWeb/Text/input/Worker/Worker-offscreencanvas.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    asyncTest(done => {
+        const workerScript = `
+            self.onmessage = function(evt) {
+                try{
+                    let canvas = new OffscreenCanvas(10, 10);
+                    self.postMessage(JSON.stringify({ w: canvas.width, h: canvas.height }));
+                    let context = canvas.getContext("2d");
+                    context.font = "20px SerenitySans";
+                    self.postMessage(context.font);
+                    context.font = "!!!"; // Invalid value, should be ignored.
+                    self.postMessage(context.font);
+                    self.postMessage(null);
+                }catch(err){
+                    self.postMessage("Error: " + err);
+                    self.postMessage(null);
+                }
+            };
+        `;
+        const blob = new Blob([workerScript], { type: "application/javascript" });
+        const workerScriptURL = URL.createObjectURL(blob);
+        const worker = new Worker(workerScriptURL);
+
+        worker.onmessage = function (evt) {
+            if (evt.data === null) {
+                done();
+            }
+            println("Message received from worker: " + JSON.stringify(evt.data));
+        };
+
+        // Send a message to the worker
+        worker.postMessage("Hello from main script");
+    });
+</script>
diff --git a/Tests/LibWeb/Text/input/canvas/2d-offscreencanvas-create-imagedata.html b/Tests/LibWeb/Text/input/canvas/2d-offscreencanvas-create-imagedata.html
new file mode 100644
index 00000000000..9cd7f26c09b
--- /dev/null
+++ b/Tests/LibWeb/Text/input/canvas/2d-offscreencanvas-create-imagedata.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        try {
+            const canvas = new OffscreenCanvas(75, 75);
+            const context = canvas.getContext("2d");
+            const existing_image_data = context.createImageData(75, 75);
+            const image_data = context.createImageData(existing_image_data);
+            if (image_data.width === 75 && image_data.height === 75) {
+                println("PASS");
+            } else {
+                println("FAIL");
+            }
+        } catch (err) {
+            println(`FAIL: ${err}`);
+        }
+    });
+</script>
diff --git a/Tests/LibWeb/Text/input/canvas/export-offscreencanvas.html b/Tests/LibWeb/Text/input/canvas/export-offscreencanvas.html
new file mode 100644
index 00000000000..621842919af
--- /dev/null
+++ b/Tests/LibWeb/Text/input/canvas/export-offscreencanvas.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    asyncTest(async done => {
+        let testCounter = 1;
+        async function testPart(part) {
+            const currentTest = testCounter++;
+            try {
+                const result = await part();
+                println(`${currentTest}.Success: ${JSON.stringify(result)}`);
+            } catch (err) {
+                println(`${currentTest}.Error: ${err}`);
+            }
+        }
+
+        // 1. Export a OffscreenCanvas to a PNG blob
+        await testPart(async () => {
+            const offscreenCanvas = new OffscreenCanvas(100, 100);
+            const result = await offscreenCanvas.convertToBlob({ type: "image/png" });
+            return { size: result.size, type: result.type };
+        });
+
+        // 2. Export a OffscreenCanvas to a JPEG blob
+        await testPart(async () => {
+            const offscreenCanvas = new OffscreenCanvas(100, 100);
+            const result = await offscreenCanvas.convertToBlob({ type: "image/jpeg" });
+            return { size: result.size, type: result.type };
+        });
+
+        done();
+    });
+</script>
diff --git a/Tests/LibWeb/Text/input/canvas/offscreencanvas-basic.html b/Tests/LibWeb/Text/input/canvas/offscreencanvas-basic.html
new file mode 100644
index 00000000000..50c20d7b23c
--- /dev/null
+++ b/Tests/LibWeb/Text/input/canvas/offscreencanvas-basic.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        let canvas = new OffscreenCanvas(10, 10);
+        println(JSON.stringify({ w: canvas.width, h: canvas.height }));
+        let context = canvas.getContext("2d");
+        context.font = "20px SerenitySans";
+        println(context.font);
+        context.font = "!!!"; // Invalid value, should be ignored.
+        println(context.font);
+    });
+</script>