使用 Canvas，我可以将图像加载到 main.js 文件中来实现视差效果。视差效果很好 草稿代码在这里：https://github.com/bengabo/parallax-image 我的问题是我想延迟图像“layer_9_1.png”的显示，但是当我编写延迟时，它会应用于所有图像。我尝试了一个函数，一个条件......但没有任何作用。每次，它都适用于所有图像。
<html lang="en">
<head>
<meta charset="UTF-8" />
<link rel="stylesheet" type="text/css" href="/style.css" />
<meta name="author" content="Benjamin Gaboury" />
<meta
name="viewport"
content="width=device-width, initial-scale=1.0, user-scalable=no"
/>
<title>Interactive parallax illo</title>
</head>
<body>
<div class="image-container">
<canvas class="canvas" id="canvas" width="900" height="1200"></canvas>
<div class="loading-screen" id="loading">Loading...</div>
</div>
<script type="text/javascript" src="/main.js"></script>
</body>
</html>
body {
box-sizing: border-box;
margin: 0;
height: 100%;
background-color: #ffffff;
display: flex;
justify-content: center;
align-items: center;
font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
.image-container {
display: flex;
height: 100%;
width: 100%;
max-width: 100%;
position: relative;
}
.canvas {
width: auto;
max-width: 100%;
max-height: 100%;
display: block;
margin: auto;
background-color: rgb(255, 255, 255);
}
.loading-screen {
position: absolute;
width: 100%;
height: 100%;
background: white;
top: 0;
bottom: 0;
left: 0;
right: 0;
visibility: visible;
opacity: 1;
text-align: center;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
line-height: 40px;
transition: 0.25s ease all 0.75s;
color: #999;
transform: translateZ(50px);
}
.loading-screen.hidden {
visibility: hidden;
opacity: 0;
}
let ctx = canvas.getContext("2d");
// Loading screen
let loading_screen = document.getElementById("loading");
/**
* Images loader
*/
let loaded = false;
let load_counter = 0;
let background = new Image();
let stars_01 = new Image();
let stars_02 = new Image();
let stars_03 = new Image();
let shadows = new Image();
let mask = new Image();
let planets = new Image();
let stars_04 = new Image();
let title = new Image();
let layers_list = [
{
image: background,
src: "/layer_1_1.png",
z_index: -2,
position: { x: 0, y: 0 },
blend: null,
opacity: 1,
maxOffsetX: 100,
maxOffsetY: 100,
delay: 0,
},
{
image: stars_01,
src: "/layer_2_1.png",
z_index: -1.8,
position: { x: 0, y: 0 },
blend: null,
opacity: 1,
delay: 0,
},
{
image: stars_02,
src: "/layer_3_1.png",
z_index: -1.5,
position: { x: 0, y: 0 },
blend: "overlay",
opacity: 0.7,
delay: 0,
},
{
image: stars_03,
src: "/layer_4_1.png",
z_index: -1.25,
position: { x: 0, y: 0 },
blend: "overlay",
opacity: 0.8,
delay: 0,
},
{
image: shadows,
src: "/layer_5_1.png",
z_index: -0.75,
position: { x: 0, y: 0 },
blend: "multiply",
opacity: 1,
maxOffsetX: 100,
maxOffsetY: 100,
delay: 0,
},
{
image: mask,
src: "/layer_6_1.png",
z_index: 0,
position: { x: 0, y: 0 },
blend: null,
opacity: 1,
delay: 0,
},
{
image: planets,
src: "/layer_7_1.png",
z_index: 0.25,
position: { x: 0, y: 0 },
blend: null,
opacity: 1,
delay: 0,
},
{
image: stars_04,
src: "/layer_8_1.png",
z_index: 1.25,
position: { x: 0, y: 0 },
blend: null,
opacity: 0.8,
maxOffsetX: 100,
maxOffsetY: 100,
delay: 0,
},
{
image: title,
src: "/layer_9_1.png",
z_index: 1.5,
position: { x: canvas.width, y: 0 },
blend: null,
opacity: 1,
maxOffsetX: 120,
maxOffsetY: 100,
delay: 2000,
},
];
const hideLoading = () => {
loading_screen.classList.add("hidden");
};
layers_list.forEach((layer, index) => {
layer.image.onload = () => {
load_counter += 1;
if (load_counter >= layers_list.length) {
hideLoading();
requestAnimationFrame(drawCanvas);
}
};
layer.image.src = layer.src;
});
let getOffset = (layer) => {
let touch_multip = 0.1;
let touch_offset_x = pointer.x * layer.z_index * touch_multip;
let touch_offset_y = pointer.y * layer.z_index * touch_multip;
// Limit movement based on maxOffsetX and maxOffsetY
if (touch_offset_x > layer.maxOffsetX) {
touch_offset_x = layer.maxOffsetX;
}
if (touch_offset_x < -layer.maxOffsetX) {
touch_offset_x = -layer.maxOffsetX;
}
if (touch_offset_y > layer.maxOffsetY) {
touch_offset_y = layer.maxOffsetY;
}
if (touch_offset_y < -layer.maxOffsetY) {
touch_offset_y = -layer.maxOffsetY;
}
let offset = {
x: touch_offset_x,
y: touch_offset_y,
};
return offset;
};
const drawCanvas = () => {
ctx.clearRect(0, 0, canvas.width, canvas.height);
// const rotate_x = pointer.y * 0.15 + motion.y * 1.2;
// const rotate_y = pointer.x * 0.15 + motion.x * 1.2;
// const transform_string =
// "rotateX(" + rotate_x + "deg), rotateY(" + rotate_y + "deg)";
// canvas.style.transform = transform_string;
layers_list.forEach((layer, index) => {
layer.position = getOffset(layer);
// Blend modes
layer.blend
? (ctx.globalCompositeOperation = layer.blend)
: (ctx.globalCompositeOperation = "normal");
// Opacity
ctx.globalAlpha = layer.opacity;
ctx.drawImage(layer.image, layer.position.x, layer.position.y);
});
requestAnimationFrame(drawCanvas);
};
/**
* Mouse ctrl
*/
let moving = false;
let pointer_init = {
x: 0,
y: 0,
};
let pointer = {
x: 0,
y: 0,
};
const pointerStart = (event) => {
moving = true;
if (event.type === "touchstart") {
pointer_init.x = event.touches[0].clientX;
pointer_init.y = event.touches[0].clientY;
} else if (event.type === "mousedown") {
pointer_init.x = event.clientX;
pointer_init.y = event.clientY;
}
};
canvas.addEventListener("touchstart", pointerStart);
canvas.addEventListener("mousedown", pointerStart);
const pointerMmove = (event) => {
event.preventDefault();
if (moving === true) {
let current_x = 0;
let current_y = 0;
if (event.type === "touchemove") {
current_x = event.touches[0].clientX;
current_y = event.touches[0].clientY;
} else if (event.type === "mousemove") {
current_x = event.clientX;
current_y = event.clientY;
}
pointer.x = current_x - pointer_init.x;
pointer.y = current_y - pointer_init.y;
}
};
window.addEventListener("touchmove", pointerMmove);
window.addEventListener("mousemove", pointerMmove);
canvas.addEventListener("touchmove", (event) => {
event.preventDefault();
});
canvas.addEventListener("mousemove", (event) => {
event.preventDefault();
});
window.addEventListener("touchend", (event) => {
endGesture();
});
window.addEventListener("mouseup", (event) => {
endGesture();
});
const endGesture = () => {
moving = false;
pointer.x = 0;
pointer.y = 0;
};
setTimeoutlayer.delay我像这样编辑了你的部分代码：
layers_list.forEach((layer, index) => {
setTimeout(() => {
layer.image.onload = () => {
load_counter += 1;
if (load_counter >= layers_list.length) {
hideLoading();
requestAnimationFrame(drawCanvas);
}
};
layer.image.src = layer.src;
}, layer.delay);
});