Benchmark: Setting Canvas Pixe3

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.createImageData(1, 1);
$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/optimized further
var i=500, px=null, alphmult = 1 / 255 for (;i--;){ px = $pxls[$i++ % 10000]; $ctx.fillStyle = `rgba(${px.r},${px.g},${px.b},${px.a * alphmult})`; $ctx.fillRect(px.x, px.y, 1, 1); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
fillRect/concat
fillRect/optimized further

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.

Let's break down the provided benchmark and explain what is tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark defines a script preparation code that sets up a 2D canvas context (`$ctx`) on an HTML element with an ID of "c". The canvas has a width of 800 pixels and a height of 300 pixels. A random image data is created using `createImageData(1, 1)` and stored in `$pxls`. This image data consists of 10,000 pixel values with random red, green, blue, and alpha channels.

**Script Preparation Code**

The script preparation code is:
```javascript
$c = document.getElementById('c');
$ctx = $c.getContext('2d');
$ctx.clearRect(0, 0, 800, 300);
$px = $ctx.createImageData(1, 1);
$pxls = [];
for (var i=0; i<10000; ++i) {
  $pxls.push({
    x: Math.random() * 800 << 0,
    y: Math.random() * 300 << 0,
    r: Math.random() * 255 << 0,
    g: Math.random() * 255 << 0,
    b: Math.random() * 255 << 0,
    a: Math.random() * 128 << 0 + 128
  });
}
i = 0;
```
This code sets up the canvas context, clears it, creates an image data object, and populates `$pxls` with random pixel values.

**Html Preparation Code**

The HTML preparation code is:
```html
<canvas id="c" width="800" height="300"></canvas>
```
This code creates a canvas element with an ID of "c", setting its width to 800 pixels and its height to 300 pixels.

**Individual Test Cases**

There are two individual test cases:

1. `fillRect/concat`:
```javascript
for (var i=500;i--;){\r\nvar px = $pxls[$i++ % 10000];\r\n$ctx.fillStyle = 'rgba(' + px.r + ',' + px.g + ',' + px.b + ',' + (px.a / 255) + ')';\r\n$ctx.fillRect(px.x, px.y, 1, 1);\r\n}
```
This test case uses the `fillStyle` property to set the color of the fill, concatenating the red, green, blue, and alpha values. It then fills a rectangle with the specified color at the corresponding pixel coordinates.

2. `fillRect/optimized further`:
```javascript
var i=500, px=null, alphmult = 1 / 255\r\nfor (;i--;){\r\npx = $pxls[$i++ % 10000];\r\n$ctx.fillStyle = `rgba(${px.r},${px.g},${px.b},${px.a * alphmult})`;\r\n$ctx.fillRect(px.x, px.y, 1, 1);\r\n}
```
This test case is similar to the previous one, but it uses template literals to construct the color string and multiplies the alpha value by a constant factor (`alphmult`) to optimize performance.

**Options Compared**

The two test cases compare different approaches to filling rectangles with the same pixel values:

* `fillRect/concat`: uses concatenation to construct the color string
* `fillRect/optimized further`: uses template literals and multiplies the alpha value by a constant factor

**Pros and Cons**

* `fillRect/concat`:
	+ Pros: simple, easy to understand
	+ Cons: may be slower due to concatenation overhead
* `fillRect/optimized further`:
	+ Pros: optimized for performance (alpha multiplication)
	+ Cons: uses template literals, which may be less intuitive

**Other Considerations**

* Both test cases assume that the canvas context is already set up and cleared.
* The `$pxls` array is populated with random pixel values, which are used to determine the color of each rectangle.

**Alternatives**

If you want to compare other approaches to filling rectangles, you could consider adding additional test cases:

* Using a fixed color instead of concatenating or multiplying alpha values
* Using a different data structure (e.g., an array of objects with `x`, `y`, `r`, `g`, `b`, and `a` properties)
* Using a different library or framework for rendering the rectangles

Related benchmarks:

Setting Canvas Pixe3 (version: 0)

Comparing performance of: fillRect/concat vs fillRect/optimized further

Created: 6 years ago by: Guest

Jump to the latest result

fillRect/concat

fillRect/optimized further

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):