smallexecanvas/index/index.wxss

canvas{
  margin: 0 auto;
  width: 700rpx;
  height: 496rpx;
}
.tool {
  display: flex;
  justify-content: center;
  align-items: center;
}

.tool>image {
  width: 100rpx;
  height: 100rpx;
  margin: 0 10rpx;
}
.btns>view:first-child{
  display: flex;
  align-items: center;
  padding: 10rpx 0;
}