Tips for rotating an image taken with the getscreenshot function in react-webcam?

Question

Tips for rotating an image taken with the getscreenshot function in react-webcam?

When using the react-webcam package, I am encountering an issue where the captured images are in a horizontal orientation. To solve this problem, I need the image to be displayed vertically by rotating it 90 degrees.

The method currently used to capture the image is this.webcam.getScreenshot(). I have been attempting to adjust the properties of this method to ensure that the resulting image is rotated at 90 degrees for vertical display.

Despite trying to rotate the preview before capturing the image, the output still remains horizontal. My goal is to rotate the image automatically upon capture.

I attempted the code snippet

// imageSrc.css('transform','rotate(90deg)');

, but unfortunately, it did not work as expected. It's worth noting that the captured image is in base64 format.

In my setup, the webcam serves as the preview for capturing images, and the capture button is activated by a separate button click event.

capture = () => {
    const imageSrc =  this.webcam.getScreenshot();
    this.setState({
        picsArray: [...this.state.picsArray, imageSrc],
    })
};

Expected Outcome: The captured picture should automatically rotate 90 degrees when using the provided method.

Actual Outcome: Despite efforts, the image does not rotate as desired during capture, leaving me unsure how to resolve this issue.

Thank you for your attention to this matter.

javascript html css reactjs

Answer 1

Answer №1

import React, { Component } from 'react';
import { render } from 'react-dom';
import Webcam from "react-webcam";

class PhotoApp extends Component {
  state = {
    url: '',
  };

  dimension = {
    height: 300,
    width: 200,
  };

  setRef = webcam => {
    this.webcam = webcam;
  };

  takePhoto = () => {
    const imageSrc = this.webcam.getScreenshot();
    this.rotateImage(imageSrc, (url) => {
    this.setState({ url});
    console.log(url, imageSrc);
    });
  };

  rotateImage = (imageBase64, cb) => {
            var img = new Image();
            img.src = imageBase64;
            img.onload = () => {
              var canvas = document.createElement("canvas");
              const maxDim = Math.max(img.height, img.width);
              canvas.width = img.height;
              canvas.height = img.width;
              var ctx = canvas.getContext("2d");
              ctx.setTransform(1, 0, 0, 1, maxDim / 2, maxDim / 2);
              ctx.rotate(90 * (Math.PI / 180));
              ctx.drawImage(img, -maxDim / 2, -maxDim / 2);
              cb(canvas.toDataURL("image/jpeg"))
            };
};

  render() {
    const videoSettings = {
      width: this.dimension.width,
      height: this.dimension.height,
      facingMode: "user"
    };

    return (
      <div>
        <Webcam
          audio={false}
          height={this.dimension.height}
          ref={this.setRef}
          screenshotFormat="image/jpeg"
          width={this.dimension.width}
          videoConstraints={videoSettings}
        />
        <button onClick={this.takePhoto}>Take a Picture</button>
        <img src={this.state.url} width={this.dimension.height} height={this.dimension.width} />
        <canvas id="canvas" style={{display: 'none'}}></canvas>
      </div>
    );
  }
}

render(<PhotoApp />, document.getElementById('root'));

Update: The code above is flexible for any dimensions; you only need to adjust the values in this.dimension according to your requirements.

Answer 2

import React, { Component } from 'react';
import { render } from 'react-dom';
import Webcam from "react-webcam";

class PhotoApp extends Component {
  state = {
    url: '',
  };

  dimension = {
    height: 300,
    width: 200,
  };

  setRef = webcam => {
    this.webcam = webcam;
  };

  takePhoto = () => {
    const imageSrc = this.webcam.getScreenshot();
    this.rotateImage(imageSrc, (url) => {
    this.setState({ url});
    console.log(url, imageSrc);
    });
  };

  rotateImage = (imageBase64, cb) => {
            var img = new Image();
            img.src = imageBase64;
            img.onload = () => {
              var canvas = document.createElement("canvas");
              const maxDim = Math.max(img.height, img.width);
              canvas.width = img.height;
              canvas.height = img.width;
              var ctx = canvas.getContext("2d");
              ctx.setTransform(1, 0, 0, 1, maxDim / 2, maxDim / 2);
              ctx.rotate(90 * (Math.PI / 180));
              ctx.drawImage(img, -maxDim / 2, -maxDim / 2);
              cb(canvas.toDataURL("image/jpeg"))
            };
};

  render() {
    const videoSettings = {
      width: this.dimension.width,
      height: this.dimension.height,
      facingMode: "user"
    };

    return (
      <div>
        <Webcam
          audio={false}
          height={this.dimension.height}
          ref={this.setRef}
          screenshotFormat="image/jpeg"
          width={this.dimension.width}
          videoConstraints={videoSettings}
        />
        <button onClick={this.takePhoto}>Take a Picture</button>
        <img src={this.state.url} width={this.dimension.height} height={this.dimension.width} />
        <canvas id="canvas" style={{display: 'none'}}></canvas>
      </div>
    );
  }
}

render(<PhotoApp />, document.getElementById('root'));

Update: The code above is flexible for any dimensions; you only need to adjust the values in this.dimension according to your requirements.

Answer 3

Answer №2

To quickly rotate the image in the preview, you can utilize the style property:

Rotate 90 degrees:
<Webcam style={{ transformOrigin: '0 0', transform: `translateX(${(480 + 640) / 2}px) rotate(90deg)` }} /> // height + width
Rotate 180 degrees:
<Webcam style={{transform: 'rotate(180deg)'}} />,
Rotate 270 degrees:
<Webcam style={{ transformOrigin: '0 0', transform: `translate(${(480 - 640) / 2}px, ${480}px) rotate(-90deg)` }} />

Answer 4

To quickly rotate the image in the preview, you can utilize the style property:

Rotate 90 degrees:
<Webcam style={{ transformOrigin: '0 0', transform: `translateX(${(480 + 640) / 2}px) rotate(90deg)` }} /> // height + width
Rotate 180 degrees:
<Webcam style={{transform: 'rotate(180deg)'}} />,
Rotate 270 degrees:
<Webcam style={{ transformOrigin: '0 0', transform: `translate(${(480 - 640) / 2}px, ${480}px) rotate(-90deg)` }} />

Answer 5

Answer №3

To display your base64 image, insert it into the img tag like this:

<img src="data:image/png;base64, YOUR_BASE_64" />

After that, you can apply the CSS transform to the img element as you mentioned.

Answer 6

To display your base64 image, insert it into the img tag like this:

<img src="data:image/png;base64, YOUR_BASE_64" />

After that, you can apply the CSS transform to the img element as you mentioned.

Tips for rotating an image taken with the getscreenshot function in react-webcam?

Answer №1

Answer №2

Answer №3

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