Benchmark: Setting Canvas Pixel

HTML Preparation code:

<canvas id="c" width="800" height="300"></canvas>

Script Preparation code:

$c = document.getElementById('c');
$ctx = $c.getContext('2d');
$ctx.clearRect(0, 0, 800, 300);
$px = $ctx.getImageData(0, 0, 800, 300);
$pxls = [];
for (var i=0; i<10000; ++i) $pxls.push({
   x: Math.random() * 800 << 0,
   y: Math.random() * 300 << 0,
   r: Math.random() * 255 << 0,
   g: Math.random() * 255 << 0,
   b: Math.random() * 255 << 0,
   a: Math.random() * 128 << 0 + 128
});
$i = 0;

Tests:

fillRect/concat
for (var i=500;i--;){ var px = $pxls[$i++ % 10000]; $ctx.fillStyle = 'rgba(' + px.r + ',' + px.g + ',' + px.b + ',' + (px.a / 255) + ')'; $ctx.fillRect(px.x, px.y, 1, 1); }
fillRect/join
for (var i=500;i--;){ var px = $pxls[$i++ % 10000]; $ctx.fillStyle = 'rgba(' + [px.r,px.g,px.b,px.a/255].join() + ')'; $ctx.fillRect(px.x, px.y, 1, 1); }
1×1 Image Data
for (var i=500;i--;){ var px=$pxls[$i++ % 10000], d=$px.data; d[0] = px.r; d[1] = px.g; d[2] = px.b; d[3] = px.a; $ctx.putImageData($px, px.x, px.y); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
fillRect/concat
fillRect/join
1×1 Image Data

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided benchmark measures the performance of three different approaches for drawing individual pixels on a canvas element using JavaScript.

**Approach 1: Concatenating RGB Values**

This approach concatenates the RGB values as strings to form the color string, which is then passed to the `fillStyle` property. The pixel data is accessed directly using the `[px.r, px.g, px.b]` syntax.

**Pros and Cons:**

* Pros:
	+ Simple and easy to implement
	+ Does not require accessing the pixel data array explicitly
* Cons:
	+ Concatenating strings can be slower than accessing elements of an array

**Approach 2: Joining RGB Values as an Array**

This approach uses the `join()` method to concatenate the RGB values into a string, which is then passed to the `fillStyle` property.

Pros and Cons:

* Pros:
	+ Faster than concatenating strings
	+ Does not require accessing the pixel data array explicitly
* Cons:
	+ Requires using an array and its methods (e.g., `join()`)
	+ May have a slightly larger memory footprint

**Approach 3: Accessing Pixel Data Array**

This approach accesses the pixel data array directly (`d`) and updates its elements with the RGB values. The updated pixel data is then passed to the `putImageData()` method.

Pros and Cons:

* Pros:
	+ Fast access to pixel data array
	+ Does not require concatenating strings or accessing the array elements explicitly
* Cons:
	+ Requires modifying the original pixel data array, which can be a performance bottleneck

**Library: Canvas API**

The benchmark uses the HTML5 Canvas API, which provides an interface for drawing and manipulating 2D graphics on the client-side. The `getContext()` method returns a 2D drawing context object (`$ctx`), which is used to perform various canvas operations.

In this benchmark, the `clearRect()`, `getImageData()`, `fillStyle`, `fillRect()`, and `putImageData()` methods are used to draw individual pixels on the canvas.

**Special JavaScript Feature or Syntax: None**

There are no special JavaScript features or syntaxes used in this benchmark. It only utilizes standard JavaScript features, such as arrays, loops, and method calls.

**Alternatives**

Other approaches for drawing individual pixels on a canvas element could include:

1. Using WebGL: If performance is critical, using WebGL (Web Graphics Library) might be a better option. However, it requires more complex setup and knowledge of the underlying API.
2. Using a library or framework: Some libraries or frameworks, such as Three.js or Pixi.js, provide optimized canvas rendering capabilities that can be used to improve performance.
3. Using a different drawing approach: Alternative drawing approaches, such as using a sprite sheet or vector graphics, might offer better performance for certain use cases.

However, the Canvas API remains a popular and widely supported choice for 2D graphics rendering in web applications.

Related benchmarks:

Setting Canvas Pixel (version: 0)

Comparing performance of: fillRect/concat vs fillRect/join vs 1×1 Image Data

Created: 8 years ago by: Guest

Jump to the latest result

fillRect/concat

fillRect/join

1×1 Image Data

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):