如何在DOM的同级元素的画布屏幕快照中获取？

Question

是否可以在画布标签中获取DOM的所有同级元素（图像，按钮，链接等）以适合浏览器的个人大小？我将展示一个简单的例子。

.bl_game__bigScreen {
  position: relative;
  display: block;
  width: 100%;
  min-height: 480px;
  background-color: #000;
  vertical-align: top;
}

.bl_game__wrapper {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  color: #fff;
  z-index: 2;
}

.bl_game__img {
  margin-right: 4vw;
}

.bl_game__nav {
  width: 100%;
  max-width: 600px;
}

.gamePage_title {
  position: relative;
  display: initial;
  max-width: 550px;
  line-height: normal;
  font-size: 48px;
  text-transform: uppercase;
  color: #FFF;
  text-shadow: 0 8px 12px rgba(0, 0, 0, 0.36);
}

.bl_game__desc {
  position: relative;
  display: block;
  margin-top: 24px;
  max-height: 140px;
  overflow-y: auto;
  line-height: 23px;
  font-size: 16px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: #FFF;
}

.bl_game__buttons {
  margin-top: 24px;
}

.btn_playGame {
  width: 184px;
  height: 56px;
  background-color: #000;
  border-radius: 44px;
  margin-right: 24px;
  line-height: 23px;
  font-size: 16px;
  text-align: center;
  font-weight: 600;
  cursor: pointer;
  color: #fff;
  outline: none;
  transition: .15s all;
}

.btn_watchVideo {
  width: 184px;
  height: 56px;
  background: #FFF;
  border-radius: 44px;
  cursor: pointer;
  line-height: 23px;
  font-size: 16px;
  text-align: center;
  font-weight: 600;
  color: #000;
  outline: none;
  transition: .2s all;
}

<div class="bl_game">

  <img class="bl_game__bigScreen" src="https://baconmockup.com/1600/512" alt="mainImage-slot">

  <div class="bl_game__wrapper">
    <img class="bl_game__img" src="https://placekitten.com/302/250
" alt="gameLogo">

    <div class="bl_game__nav">
      <h1 class="gamePage_title">Game Title</h1>

      <div class="bl_game__desc">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum eveniet nesciunt consequuntur distinctio neque esse, ut dolor illum cupiditate. Veniam.</div>
      <div class="bl_game__buttons">
        <button class="btn_playGame" data-href="" type="button">Run Demo</button>
        <button class="btn_watchVideo" data-href="" type="button">Play Video</button>
      </div>
    </div>
  </div>


  <canvas id="canvas"></canvas>

</div>

如何单击btn_watchVideo按钮以获取您在浏览器中看到的图像，并在canvas标签中使用它？实际上，对于浏览器的每种分辨率，我都希望在canvas标签中接收图像，以便以后以某种方式使用它。通常是真实的吗？