Benchmark: Drawing pre-scaled image vs scaling (same size of result image)

HTML Preparation code:

 <canvas id="canvas1" width="50" height="50"></canvas>
 <br>
 <canvas id="canvas2" width="600" height="600"></canvas>
 <canvas id="canvas3" width="600" height="600"></canvas>

Script Preparation code:

var canvas1 = document.getElementById("canvas1")
var ctx1 = canvas1.getContext("2d");
var canvas2 = document.getElementById("canvas2")
var ctx2 = canvas2.getContext("2d");
var canvas3 = document.getElementById("canvas3")
var ctx3 = canvas3.getContext("2d");

ctx1.fillStyle = "rgb(10,80,80)";
ctx1.fillRect(0,0,50,50);
ctx1.fillStyle = "rgb(80,180,180)";
ctx1.fillRect(4,4,42,42);

Tests:

Scaling
ctx2.drawImage(canvas1, 0, 0, 50, 50, 0, 0, 500, 500); // Force to perform previous action ctx2.getImageData(0, 0, 1, 1);
Drawing pre-scaled image
ctx3.drawImage(canvas2, 0, 0, 500, 500); // Force to perform previous action ctx3.getImageData(0, 0, 1, 1);
No scaling, 1px with shift
ctx3.drawImage(canvas2, 0, 0, 1, 1, 1, 1, 1, 1); // Force to perform previous action ctx3.getImageData(1, 1, 1, 1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Scaling
Drawing pre-scaled image
No scaling, 1px with shift

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 what's being tested in this benchmark.

The test is comparing two approaches to drawing images on canvas: drawing the image at its original size and then scaling it, versus drawing the scaled image directly.

**Drawing Pre-Scaled Image vs Scaling**

In this approach:

1. The original image is drawn at a small size (50x50 pixels) on one canvas.
2. A second canvas is used to draw an image that scales from the original 50x50 pixels to a larger size (600x600 pixels).
3. The scaling process involves stretching or shrinking the image in both x and y directions.

In contrast:

1. In the alternative approach, the scaled image is drawn directly on a separate canvas without any intermediate scaling steps.
2. This means that the image is already at its final size of 600x600 pixels before it's even rendered to the screen.

**Pros and Cons:**

* **Drawing Pre-Scaled Image:**
	+ Pros:
		- May be faster since there's no need to scale the image, which can be a computationally expensive operation.
		- Can take advantage of hardware acceleration for scaling, if available.
	+ Cons:
		- Requires two extra canvas elements (for the original and scaled images).
		- May require more memory bandwidth since the larger image needs to be stored in RAM.
* **Scaling:**
	+ Pros:
		- Only requires one additional canvas element (for the scaled image).
		- Can potentially take advantage of hardware acceleration for scaling, if available.
	+ Cons:
		- Requires an extra scaling operation that can be slow or expensive, depending on the browser and system.

**Other Considerations:**

* **Browser-specific optimizations:** Modern browsers often have specific optimizations for drawing images on canvas, which might affect the performance differences between these two approaches. For example, some browsers may use hardware acceleration for scaling or may optimize certain rendering steps.
* **Image content:** The type of image being drawn (e.g., simple shapes vs. complex graphics) can impact the performance difference between these two approaches.

**Libraries and Special JS Features:**

In this benchmark, there is no specific library being used, as the code uses only built-in JavaScript APIs for canvas rendering.

However, some special features like `getImageData()` are used in both benchmark definitions to force certain browser behaviors. `getImageData()` can be used to intentionally trigger a re- layout or re-paint of the image, which might affect the performance measurements.

**Alternatives:**

If you're interested in exploring alternative approaches, here are some options:

* Use WebGL instead of canvas for rendering images.
* Implement your own scaling algorithm using JavaScript and CSS transformations (e.g., `transform` property).
* Compare different caching strategies for reducing memory bandwidth during repeated renderings.
* Investigate the impact of asynchronous rendering on performance.

Keep in mind that these alternatives might require significant changes to the benchmark code and testing setup.

Related benchmarks:

Drawing pre-scaled image vs scaling (same size of result image) (version: 8)

Comparing performance of: Scaling vs Drawing pre-scaled image vs No scaling, 1px with shift

Created: 3 years ago by: Registered User

Jump to the latest result

Scaling

Drawing pre-scaled image

No scaling, 1px with shift

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):