How to implement multiplication and blending modes of images through Vue?

How to implement multiplication and blending modes of images through Vue?

In front-end development, we often encounter situations that require special effects processing on images, such as multiplication and blending modes. This article will introduce how to achieve these two image effects through Vue and give code examples.

1. Multiply effect

Multiply is a common color mixing mode that multiplies the corresponding channel values ​​of two colors. Get the new color value. In image processing, we can achieve the multiplication effect by adjusting the transparency of the image.

First, we need to introduce a picture that needs to be processed into the Vue project. In the template, use the <img src="/static/imghwm/default1.png" data-src="@/assets/image.jpg" class="lazy" alt="How to implement multiplication and blending modes of images through Vue?" > tag to display the image:

<template>
  <img src="/static/imghwm/default1.png"  data-src="@/assets/image.jpg"  class="lazy" alt="image" ref="image" />
</template>

Next, in the computed attribute of Vue, use canvas to handle the transparency of the image:

<script>
export default {
  computed: {
    processImage() {
      const canvas = document.createElement("canvas");
      const ctx = canvas.getContext("2d");
      const image = this.$refs.image;
      canvas.width = image.width;
      canvas.height = image.height;

      ctx.drawImage(image, 0, 0);

      const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      const data = imageData.data;

      // 遍历每个像素点
      for (let i = 0; i < data.length; i += 4) {
        const red = data[i]; // 红色通道值
        const green = data[i + 1]; // 绿色通道值
        const blue = data[i + 2]; // 蓝色通道值

        // 计算新的颜色值
        data[i] = red * 0.5;
        data[i + 1] = green * 0.5;
        data[i + 2] = blue * 0.5;
      }

      ctx.clearRect(0, 0, canvas.width, canvas.height);
      ctx.putImageData(imageData, 0, 0);

      return canvas.toDataURL();
    },
  },
};
</script>

Finally, display the processed image through the <img src="/static/imghwm/default1.png" data-src="processImage" class="lazy" alt="How to implement multiplication and blending modes of images through Vue?" > tag in the template:

<template>
  <img src="/static/imghwm/default1.png"  data-src="processImage"  class="lazy"  : alt="processed image" />
</template>

In this way, the multiplied image can be displayed on the page.

2. Blend Mode Effect

Blend Mode (Blend Mode) can produce new color effects by changing the pixel color values ​​​​of two layers. Using mixed mode in Vue requires the help of the mix-blend-mode property of CSS.

First, add the image to be processed in the template:

<template>
  <div class="blend-mode-container">
    <img src="/static/imghwm/default1.png"  data-src="@/assets/image.jpg"  class="lazy" alt="image" />
    <img class="mask lazy"  src="/static/imghwm/default1.png"  data-src="@/assets/mask.png"  alt="mask" />
  </div>
</template>

Mix the two images by setting the mix-blend-mode attribute:

<style>
.blend-mode-container {
  position: relative;
}

.mask {
  position: absolute;
  top: 0;
  mix-blend-mode: multiply;
}
</style>

In this way, the mask image using the multiply blending mode is mixed with the original image with a multiplication effect.

To sum up, we can easily achieve the multiplication and blending mode effects of pictures through Vue. Whether you use canvas to process images or implement them through CSS blending modes, you can meet the needs of different scenes for special effects on images. Hope this article is helpful to you!

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