Benchmark: Setting multiple canvas pixels

HTML Preparation code:

<canvas id="c" width="800" height="1"></canvas>

Script Preparation code:

$N = 800;

$c = document.getElementById('c');
$ctx = c.getContext('2d');

$ctx.clearRect(0, 0, $N, 1);
$pxls = [];
for (let i = 0; i < $N; ++i) {
    $pxls.push({
        r: Math.random() * 255 << 0,
        g: Math.random() * 255 << 0,
        b: Math.random() * 255 << 0
    });
}

Tests:

FillRect
for (let i = 0; i < $N; i++) { let px = $pxls[i]; $ctx.fillStyle = 'rgb(' + px.r + ',' + px.g + ',' + px.b + ')'; $ctx.fillRect(i, 0, 1, 1); }
PutImageData
const imageData = $ctx.createImageData($N, 1); const data = imageData.data; for (let i = 0; i < $N; i++) { let px = $pxls[i]; data[i * 4 + 0] = px.r; data[i * 4 + 1] = px.g; data[i * 4 + 2] = px.b; data[i * 4 + 3] = 255; } $ctx.putImageData(imageData, 0, 0);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
FillRect
PutImageData

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36 Edg/119.0.0.0

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
FillRect	760.4 Ops/sec
PutImageData	4214.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Overview**

The benchmark, titled "Setting multiple canvas pixels," tests how efficiently different browsers can set multiple pixels on a canvas element. The test creates an array of random RGB values, representing individual pixels, and then uses these values to fill or update pixels on the canvas.

**Options Compared**

There are two main options being compared:

1. **FillRect**: This method involves using the `fillStyle` property to set the color of the pixel and then calling `fillRect()` to draw a rectangle at that position.
2. **PutImageData**: This method uses the `createImageData()` method to create an image data object, updates its data array with the RGB values, and finally calls `putImageData()` to update the canvas with the new data.

**Pros and Cons of Each Approach**

1. **FillRect**:
	* Pros: Simple and straightforward, requires less memory allocation compared to `PutImageData`.
	* Cons: May be slower due to repeated function calls, as it involves setting the fill style color multiple times.
2. **PutImageData**:
	* Pros: Can be faster for large datasets since it only needs to update the image data object once.
	* Cons: Requires more memory allocation and can lead to slower performance if not optimized correctly.

**Library Used**

The benchmark uses the `Canvas` API, which is a HTML5 standard for creating interactive graphics and animations. The Canvas API provides an efficient way to render 2D graphics and is widely supported by modern browsers.

**Special JavaScript Features/Syntax**

None are explicitly mentioned in this benchmark, but some related features like `let`, `const`, and template literals (`${}`) may be used implicitly due to the use of `$` variables.

**Other Considerations**

When dealing with large datasets or performance-critical code, consider the following:

* Minimize unnecessary function calls and memory allocations.
* Use optimization techniques like caching, batch processing, or spatial locality to reduce overhead.
* Profile your application to identify bottlenecks and optimize them accordingly.

**Alternative Approaches**

If you need to benchmark similar scenarios, consider these alternatives:

1. **Direct pixel access**: Instead of using `fillRect()` or `putImageData()`, try accessing the canvas's underlying pixel array directly (using `getContext('2d').getImageData()` and `fillRect()`). This can be a more direct way to set pixels.
2. **Canvas WebGL**: Consider using WebGL, which provides low-level access to graphics processing capabilities. However, this is typically suited for more complex graphics-intensive applications.

Remember that the choice of approach depends on your specific use case, performance requirements, and target audience. Always profile and test your code before making decisions about optimization techniques.

Related benchmarks:

Setting multiple canvas pixels (version: 0)

Comparing performance of: FillRect vs PutImageData

Created: 2 years ago by: Guest

Jump to the latest result

FillRect

PutImageData

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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