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Commit 71a41d1f authored by wjf's avatar wjf
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toCanvas

parent dfa7baea
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dist/ToCanvas.js 0 → 100644
View file @ 71a41d1f
/**
* 节点类型
*/
var NodeType;
(function (NodeType) {
NodeType[NodeType["TEXT"] = 0] = "TEXT";
NodeType[NodeType["IMAGE"] = 1] = "IMAGE";
})(NodeType || (NodeType = {}));
/**
*
* @param data
* @param callback
*/
export async function toCanvas(data, callback) {
const { nodes, width, height } = data;
var canvas = document.createElement("canvas");
canvas.width = width;
canvas.height = height;
var ctx = canvas.getContext("2d");
//先加载完所有图片
var p = [];
nodes.forEach((n) => {
if (n.type !== NodeType.IMAGE)
return;
p.push(new Promise((r) => {
let img = new Image();
img.onload = () => {
n.img = img;
r();
};
img.src = n.src;
}));
});
if (p.length)
await Promise.all(p);
nodes.forEach((n) => {
switch (n.type) {
case NodeType.IMAGE:
drawImage(n, ctx);
break;
case NodeType.TEXT:
drawText(n, ctx);
break;
}
});
callback && callback(canvas);
return canvas;
}
/**
* 绘制图片
* @param data
* @param ctx
*/
function drawImage(data, ctx) {
const { x, y, img, width, height, borderRadius } = data;
if (borderRadius) { //有圆角,画遮罩,暂时只管一个
ctx.save();
let max = (width < height ? width : height) / 2;
let radius = Math.min(+borderRadius.replace("px", ""), max);
// ctx.beginPath();
// ctx.moveTo(x, y + radius);
// ctx.quadraticCurveTo(x, y, x + radius, y);
// ctx.lineTo(x + width - radius, y);
// ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
// ctx.lineTo(x + width, y + height - radius);
// ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
// ctx.lineTo(x + radius, y + height);
// ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
// ctx.lineTo(x, y + radius);
// ctx.clip();
ctx.beginPath();
ctx.moveTo(x + width - radius, y);
ctx.arcTo(x + width, y, x + width, y + radius, radius);
ctx.lineTo(x + width, y + height - radius);
ctx.arcTo(x + width, y + height, x + width - radius, y + height, radius);
ctx.lineTo(x + radius, y + height);
ctx.arcTo(x, y + height, x, y + height - radius, radius);
ctx.lineTo(x, y + radius);
ctx.arcTo(x, y, x + radius, y, radius);
ctx.closePath();
ctx.clip();
}
ctx.drawImage(img, x, y, width, height);
if (borderRadius)
ctx.restore();
}
/**
* 绘制文本,暂时没那么复杂,不用离屏玩
* @param data
* @param ctx
*/
function drawText(data, ctx) {
const { x, y, width, height, text, color, fontSize, fontWeight, wordWrap, textAlign } = data;
var font = fontSize;
font += " Arial"; //字体没有
//font-weight:bold;font-style:italic;
if (fontWeight)
font = fontWeight + " " + font;
ctx.font = font;
ctx.textBaseline = "top";
ctx.fillStyle = color;
var widthAll = ctx.measureText(text).width;
// console.log(ctx.measureText(text))
//超过宽度需要换行,且需要用到居中方式
if (wordWrap == "break-word" && widthAll > width) {
let realLines = [];
let w = ctx.measureText(text[0]).width;
let lineStr = text[0];
let wordW = 0;
let strLen = text.length;
for (let j = 1; j < strLen; j++) {
wordW = ctx.measureText(text[j]).width;
w += wordW;
if (w > width) {
realLines[realLines.length] = lineStr;
lineStr = text[j];
w = wordW;
}
else {
lineStr += text[j];
}
}
//最后一行
realLines[realLines.length] = lineStr;
ctx.textAlign = textAlign || "left";
let tx = 0;
if (ctx.textAlign == "center") {
tx = width * 0.5;
}
else if (ctx.textAlign == "right") {
tx = width;
}
//有待考虑.现在直接拿高度取平均算每行高度
var lineH = height / realLines.length;
realLines.forEach((r, i) => {
ctx.fillText(r, x + tx, y + i * lineH);
});
}
else {
ctx.textAlign = "left";
ctx.fillText(text, x, y);
}
}
dist/dom-parser.js 0 → 100644
View file @ 71a41d1f
/**
* Created by rockyl on 2021/1/11.
*/
const styleKeys = [
'fontSize',
'fontFamily',
'fontWeight',
'textAlign',
'color',
'wordWrap',
'borderRadius',
];
export function parseDom(el) {
const { left: pX, top: pY, width, height } = el.getBoundingClientRect();
let nodes = [];
walkNode(el, function (childNode) {
let vNode, bound, node;
if (childNode.nodeName === 'IMG') { //其他全部认为是文本
node = childNode;
vNode = {
type: 1,
src: childNode.src,
};
bound = childNode.getBoundingClientRect();
}
else {
if (childNode.data) {
node = childNode.parentElement;
let text = childNode.data.trim();
if (text) { //过滤空文本
let range = document.createRange();
range.selectNode(childNode);
bound = range.getBoundingClientRect();
range.detach();
vNode = {
type: 0,
text,
};
}
}
}
if (vNode) {
const { left, top, width, height } = bound;
vNode.x = left - pX;
vNode.y = top - pY;
vNode.width = width;
vNode.height = height;
let styles = getStylesWithoutDefaults(node);
for (let skey in styles) {
if (styleKeys.indexOf(skey) < 0) {
continue;
}
vNode[skey] = styles[skey];
}
nodes.push(vNode);
}
});
return {
width,
height,
nodes,
};
}
function walkNode(root, callback) {
callback(root);
for (let i = 0, li = root.childNodes.length; i < li; i++) {
const childNode = root.childNodes[i];
walkNode(childNode, callback);
}
}
function getStylesWithoutDefaults(element) {
let dummy = document.createElement('element-' + (new Date().getTime()));
document.body.appendChild(dummy);
let defaultStyles = getComputedStyle(dummy);
let elementStyles = getComputedStyle(element);
let diff = {};
for (let key in elementStyles) {
if (elementStyles.hasOwnProperty(key)
&& defaultStyles[key] !== elementStyles[key]) {
diff[key] = elementStyles[key];
}
}
dummy.remove();
return diff;
}
dist/index.js 0 → 100644
View file @ 71a41d1f
/**
* Created by rockyl on 2021/1/11.
*/
import { parseDom } from "./dom-parser.js";
import { toCanvas } from "./toCanvas.js";
let data = parseDom(document.getElementById('poster'));
console.log(data);
toCanvas(data, (c) => {
document.body.appendChild(c);
});
/**
*
* @param el html文本
* @param callback
*/
export function htmlToCanvas(el, callback) {
return toCanvas(parseDom(el), callback);
}
src/index.ts
View file @ 71a41d1f
...@@ -2,7 +2,21 @@ ...@@ -2,7 +2,21 @@
* Created by rockyl on 2021/1/11. * Created by rockyl on 2021/1/11.
*/ */
import {parseDom} from "./dom-parser.js"; import { parseDom } from "./dom-parser.js";
import { toCanvas } from "./toCanvas.js";
let data = parseDom(document.getElementById('poster')); let data = parseDom(document.getElementById('poster'));
console.log(data); console.log(data);
toCanvas(data,(c)=>{
document.body.appendChild(c)
})
/**
*
* @param el html文本
* @param callback
*/
export function htmlToCanvas(el: HTMLElement,callback?:(HTMLCanvasElement)=>void):Promise<HTMLCanvasElement> {
return toCanvas(parseDom(el),callback)
}
\ No newline at end of file
src/toCanvas.ts 0 → 100644
View file @ 71a41d1f
/**
* 转换接口数据
*/
interface ICData {
width: number,
height: number,
nodes: INodeData[]
}
/**
* 节点类型
*/
enum NodeType {
TEXT = 0,
IMAGE
}
/**
* 节点数据
*/
interface INodeData {
type: NodeType,
x: number,
y: number,
width: number,
height: number,
//图片需要
src?: string,
borderRadius?: string,
img?: HTMLImageElement,//加载后挂上的
//文本需要
text?: string
color?: string,
fontSize?: string,//文本字号
fontWeight?: string,//文本粗细
wordWrap?: "break-word" | null
textAlign?: "center" | "left" | "right"
}
/**
*
* @param data
* @param callback
*/
export async function toCanvas(data: ICData, callback?: (canvas: HTMLCanvasElement) => void): Promise<HTMLCanvasElement> {
const { nodes, width, height } = data;
var canvas = document.createElement("canvas");
canvas.width = width;
canvas.height = height;
var ctx = canvas.getContext("2d");
//先加载完所有图片
var p: Promise<void>[] = [];
nodes.forEach((n) => {
if (n.type !== NodeType.IMAGE) return;
p.push(
new Promise((r) => {
let img = new Image();
img.onload = () => {
n.img = img;
r()
}
img.src = n.src;
})
)
})
if (p.length) await Promise.all(p);
nodes.forEach((n) => {
switch (n.type) {
case NodeType.IMAGE:
drawImage(n, ctx)
break
case NodeType.TEXT:
drawText(n, ctx)
break
}
})
callback && callback(canvas)
return canvas
}
/**
* 绘制图片
* @param data
* @param ctx
*/
function drawImage(data: INodeData, ctx: CanvasRenderingContext2D) {
const { x, y, img, width, height, borderRadius } = data;
if (borderRadius) {//有圆角,画遮罩,暂时只管一个
ctx.save();
let max = (width < height ? width : height) / 2;
let radius = Math.min(+borderRadius.replace("px", ""), max);
// ctx.beginPath();
// ctx.moveTo(x, y + radius);
// ctx.quadraticCurveTo(x, y, x + radius, y);
// ctx.lineTo(x + width - radius, y);
// ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
// ctx.lineTo(x + width, y + height - radius);
// ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
// ctx.lineTo(x + radius, y + height);
// ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
// ctx.lineTo(x, y + radius);
// ctx.clip();
ctx.beginPath();
ctx.moveTo(x + width - radius, y);
ctx.arcTo(x + width, y, x + width, y + radius, radius)
ctx.lineTo(x + width, y + height - radius)
ctx.arcTo(x + width, y + height, x + width - radius, y + height, radius)
ctx.lineTo(x + radius, y + height)
ctx.arcTo(x, y + height, x, y + height - radius, radius)
ctx.lineTo(x, y + radius)
ctx.arcTo(x, y, x + radius, y, radius)
ctx.closePath();
ctx.clip();
}
ctx.drawImage(img, x, y, width, height)
if (borderRadius) ctx.restore();
}
/**
* 绘制文本,暂时没那么复杂,不用离屏玩
* @param data
* @param ctx
*/
function drawText(data: INodeData, ctx: CanvasRenderingContext2D) {
const { x, y, width, height,
text,
color,
fontSize,
fontWeight,
wordWrap,
textAlign } = data;
var font = fontSize;
font += " Arial";//字体没有
//font-weight:bold;font-style:italic;
if (fontWeight) font = fontWeight + " " + font;
ctx.font = font;
ctx.textBaseline = "top";
ctx.fillStyle = color;
var widthAll = ctx.measureText(text).width;
// console.log(ctx.measureText(text))
//超过宽度需要换行,且需要用到居中方式
if (wordWrap == "break-word" && widthAll > width) {
let realLines = [];
let w = ctx.measureText(text[0]).width;
let lineStr = text[0];
let wordW = 0;
let strLen = text.length;
for (let j = 1; j < strLen; j++) {
wordW = ctx.measureText(text[j]).width;
w += wordW;
if (w > width) {
realLines[realLines.length] = lineStr;
lineStr = text[j];
w = wordW;
} else {
lineStr += text[j];
}
}
//最后一行
realLines[realLines.length] = lineStr;
ctx.textAlign = textAlign || "left";
let tx = 0;
if (ctx.textAlign == "center") {
tx = width * 0.5;
} else if (ctx.textAlign == "right") {
tx = width;
}
//有待考虑.现在直接拿高度取平均算每行高度
var lineH = height / realLines.length;
realLines.forEach((r, i) => {
ctx.fillText(r, x + tx, y + i * lineH)
})
} else {
ctx.textAlign = "left"
ctx.fillText(text, x, y)
}
}
\ No newline at end of file
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