Bug 263375

Summary:	display-p3 stroke color is invisible in canvas
Product:	WebKit	Reporter:	Starli0n <s_theroude>
Component:	Canvas	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Major	CC:	dino, heycam, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari 16
Hardware:	Mac (Apple Silicon)
OS:	macOS 12

Description Starli0n 2023-10-19 05:06:12 PDT

In a context of using a canvas, a display-p3 color stroke becomes invisible.

It happens after creating a line with a color.
Then, if the line width is changed but not the color,
a second stroke will be invisible.

The bug is not present for hexa colors.
If the color is changed between the two stoke, the bug is not present.

Here is a sample to easily reproduce the bug:
(The code needs to be copy/paste)


// https://www.w3schools.com/jsref/tryit.asp?filename=tryhtml5_canvas_stroke

<!DOCTYPE html>
<html>
<body>
<h1>HTML5 Canvas</h1>
<h2>The stroke() Method</h2>

<canvas id="myCanvas" width="300" height="150" style="border:1px solid grey"></canvas>

<script>
const c = document.getElementById("myCanvas");
const ctx = c.getContext("2d");

ctx.strokeStyle = "color(display-p3 1 0 0 / 1)";
ctx.lineWidth = 1;

ctx.beginPath();
ctx.moveTo(20, 20);
ctx.lineTo(20, 100);
ctx.stroke();

// ctx.strokeStyle = "color(display-p3 0 0 1 / 1)";
ctx.lineWidth = 2;

ctx.beginPath();
ctx.moveTo(40, 20);
ctx.lineTo(40, 100);
ctx.stroke();

</script>

</body>
</html>

Comment 1 Radar WebKit Bug Importer 2023-10-26 05:07:13 PDT

<rdar://problem/117528790>