基本上就是这样。我试图循环遍历文本中的每个字母(在本例中文本是“marius”)。现在的问题是第一个字母从未被绘制。如果文本是“marius”，则绘制“arius”。我已经尝试了我能想到的，但我找不到错误。有谁知道我做错了什么？不用担心其他任何事情。代码还没写完，但是这个问题真是费了我的脑筋。提前致谢。 :)
WebFont.load({
google: {
families: ['Audiowide']
},
active: function() {
// Just the requestAnimationFrame
// for different types of browsers
const requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
// Canvas
const c = document.getElementById('canvas');
const ctx = c.getContext('2d');
const cWidth = c.width = window.innerWidth;
const cHeight = c.height = window.innerHeight;
// Framerate settings
// Better not touch theese if you
// do not know what you are doing
let now, delta;
let fps = (/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)) ? 29 : 60;
let then = Date.now();
const interval = 1000 / fps;
/*-------------------------------------------------------
PREPARATION BELOW
-------------------------------------------------------*/
var text = 'marius';
var letters = [];
var lettersCount;
const config = {
'background': '#222',
'letterSize': '72px',
'letterFont': 'Audiowide',
'letterSpacing': 50,
'amp': 60,
'yOffset': cHeight / 2
};
for (let i = 0, lettersCount = text.length; i < lettersCount; i++) {
letters.push(new Letter(text[i]));
}
for (let i = 0, len = letters.length; i < len; i++) {
var addThisToo = (i == 0) ? 0 : letters[i - 1].letterOffset;
var letterWidth = getTextWidth(letters[i].letter, config.letterSize + ' ' + config.letterFont);
letters[i].letterOffset = letterWidth + addThisToo;
}
/*-------------------------------------------------------
END PREPARATION
-------------------------------------------------------*/
/**
* draw()
* The draw function, where everything is happening
* @return null
*/
function draw() {
looper();
if (delta > interval) {
// Calculate then
then = now - (delta % interval);
// All your own stuff here
drawBackground();
drawLetters();
}
}
/**
* drawLetters()
* Draw the letters from letters Array
* Sinusoidal wave!
*/
function drawLetters() {
for (let i = 0, len = letters.length; i < len; i++) {
// Prepare X and Y of the letter
let letterOffset = (i > 0) ? letters[i - 1].letterOffset : letters[i].letterOffset;
let x = letters[i].xPos + letterOffset;
let y = config.yOffset + (sin(letters[i].xPos / 45 + i) * config.amp);
// Create gradient color
var gradient = ctx.createLinearGradient(0, 0, cWidth, 0);
gradient.addColorStop('0', '#ff6666');
gradient.addColorStop('0.5', '#66ff66');
gradient.addColorStop('1', '#6666ff');
// Draw and fill the letter
ctx.font = config.letterSize + ' ' + config.letterFont;
ctx.fillText(letters[i].letter, x, y);
ctx.fillStyle = gradient;
// Update letter X and Y position
letters[i].yPos += 0.05 * i;
letters[i].xPos -= letters[i].xVel;
}
}
/**
* letter(letter)
* Letter object
* @return nul
*/
function Letter(letter) {
this.letter = letter;
this.xPos = cWidth;
this.yPos = 0;
this.xVel = 2;
this.yVel = 0;
this.letterOffset = 0;
}
/**
* Looper()
* Looper function, do not touch!
* @return null
*/
function looper() {
requestAnimationFrame(draw);
now = Date.now();
delta = now - then;
}
/**
* drawBackground()
* Draws the background
* @return null
*/
function drawBackground() {
ctx.fillStyle = config.background;
ctx.fillRect(0, 0, c.width, c.height);
}
/**
* randInt(min, max)
* Returns random integer between min - max
* @param integer min
* @param integer max
* @return integer
*/
function randInt(min, max) {
max = max === undefined ? min - (min = 0) : max;
return Math.floor(Math.random() * (max - min) + min);
}
/**
* sin(x)
* Sinus of X
* @return float
*/
function sin(x) {
return Math.sin(x);
}
/**
* getTextWidth(text, font)
* Return the width of the text
* @return integer
*/
function getTextWidth(text, font) {
ctx.font = font;
var metrics = ctx.measureText(text);
return Math.round(metrics.width);
}
/**
* EventListener - Click
*/
document.addEventListener('click', function(e) {
let x, y;
if (e.offsetX) {
x = e.offsetX;
y = e.offsetY;
} else if (e.layerX) {
x = e.layerX;
y = e.layerY;
}
});
requestAnimationFrame(draw);
}
});<script src="https://ajax.googleapis.com/ajax/libs/webfont/1.5.18/webfont.js"></script>
<canvas id="canvas"></canvas>最佳答案
您的实现中的问题是您在执行 fillText 调用后设置了 ctx.fillStyle。这意味着您只需设置第二个字母的 fillStyle，并且由于默认的 fillStyle 为黑色，因此第一个字母将不可见。如果你切换两条线，它就会起作用。
那么你还有第二个错误，那就是第一个和第二个字母位于相同的x位置。我改变了准备方法和绘制方法，使字母间距正常工作。
WebFont.load({
google: {
families: ['Audiowide']
},
active: function() {
// Just the requestAnimationFrame
// for different types of browsers
const requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
// Canvas
const c = document.getElementById('canvas');
const ctx = c.getContext('2d');
const cWidth = c.width = window.innerWidth;
const cHeight = c.height = window.innerHeight;
// Framerate settings
// Better not touch theese if you
// do not know what you are doing
let now, delta;
let fps = (/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)) ? 29 : 60;
let then = Date.now();
const interval = 1000 / fps;
/*-------------------------------------------------------
PREPARATION BELOW
-------------------------------------------------------*/
var text = 'marius';
var letters = [];
var lettersCount;
const config = {
'background': '#222',
'letterSize': '72px',
'letterFont': 'Audiowide',
'letterSpacing': 50,
'amp': 60,
'yOffset': cHeight / 2
};
for (let i = 0, lettersCount = text.length; i < lettersCount; i++) {
letters.push(new Letter(text[i]));
}
for (let i = 1, len = letters.length; i < len; i++) {
var addThisToo = letters[i - 1].letterOffset;
var letterWidth = getTextWidth(letters[i - 1].letter, config.letterSize + ' ' + config.letterFont);
letters[i].letterOffset = letterWidth + addThisToo + config['letterSpacing'];
}
/*-------------------------------------------------------
END PREPARATION
-------------------------------------------------------*/
/**
* draw()
* The draw function, where everything is happening
* @return null
*/
function draw() {
looper();
if (delta > interval) {
// Calculate then
then = now - (delta % interval);
// All your own stuff here
drawBackground();
drawLetters();
}
}
/**
* drawLetters()
* Draw the letters from letters Array
* Sinusoidal wave!
*/
function drawLetters() {
for (let i = 0, len = letters.length; i < len; i++) {
// Prepare X and Y of the letter
let letterOffset = letters[i].letterOffset;
let x = letters[i].xPos + letterOffset;
let y = config.yOffset + (sin(letters[i].xPos / 45 + i) * config.amp);
// Create gradient color
var gradient = ctx.createLinearGradient(0, 0, cWidth, 0);
gradient.addColorStop('0', '#ff6666');
gradient.addColorStop('0.5', '#66ff66');
gradient.addColorStop('1', '#6666ff');
// Draw and fill the letter
ctx.font = config.letterSize + ' ' + config.letterFont;
ctx.fillStyle = gradient;
ctx.fillText(letters[i].letter, x, y);
// Update letter X and Y position
letters[i].yPos += 0.05 * i;
letters[i].xPos -= letters[i].xVel;
}
}
/**
* letter(letter)
* Letter object
* @return nul
*/
function Letter(letter) {
this.letter = letter;
this.xPos = cWidth;
this.yPos = 0;
this.xVel = 2;
this.yVel = 0;
this.letterOffset = 0;
}
/**
* Looper()
* Looper function, do not touch!
* @return null
*/
function looper() {
requestAnimationFrame(draw);
now = Date.now();
delta = now - then;
}
/**
* drawBackground()
* Draws the background
* @return null
*/
function drawBackground() {
ctx.fillStyle = config.background;
ctx.fillRect(0, 0, c.width, c.height);
}
/**
* randInt(min, max)
* Returns random integer between min - max
* @param integer min
* @param integer max
* @return integer
*/
function randInt(min, max) {
max = max === undefined ? min - (min = 0) : max;
return Math.floor(Math.random() * (max - min) + min);
}
/**
* sin(x)
* Sinus of X
* @return float
*/
function sin(x) {
return Math.sin(x);
}
/**
* getTextWidth(text, font)
* Return the width of the text
* @return integer
*/
function getTextWidth(text, font) {
ctx.font = font;
var metrics = ctx.measureText(text);
return Math.round(metrics.width);
}
/**
* EventListener - Click
*/
document.addEventListener('click', function(e) {
let x, y;
if (e.offsetX) {
x = e.offsetX;
y = e.offsetY;
} else if (e.layerX) {
x = e.layerX;
y = e.layerY;
}
});
requestAnimationFrame(draw);
}
});<script src="https://ajax.googleapis.com/ajax/libs/webfont/1.5.18/webfont.js"></script>
<canvas id="canvas"></canvas>关于javascript - HTML5 canvas for 循环不会绘制数组中的第一个对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44477909/