html2canvas/src/TextBounds.js

86 lines
2.8 KiB
JavaScript

/* @flow */
'use strict';
import type NodeContainer from './NodeContainer';
import {Bounds, parseBounds} from './Bounds';
import {TEXT_DECORATION} from './parsing/textDecoration';
import FEATURES from './Feature';
import {breakWords, toCodePoints, fromCodePoint} from './Unicode';
export class TextBounds {
text: string;
bounds: Bounds;
constructor(text: string, bounds: Bounds) {
this.text = text;
this.bounds = bounds;
}
}
export const parseTextBounds = (
value: string,
parent: NodeContainer,
node: Text
): Array<TextBounds> => {
const letterRendering = parent.style.letterSpacing !== 0;
const textList = letterRendering
? toCodePoints(value).map(i => fromCodePoint(i))
: breakWords(value, parent);
const length = textList.length;
const defaultView = node.parentNode ? node.parentNode.ownerDocument.defaultView : null;
const scrollX = defaultView ? defaultView.pageXOffset : 0;
const scrollY = defaultView ? defaultView.pageYOffset : 0;
const textBounds = [];
let offset = 0;
for (let i = 0; i < length; i++) {
let text = textList[i];
if (parent.style.textDecoration !== TEXT_DECORATION.NONE || text.trim().length > 0) {
if (FEATURES.SUPPORT_RANGE_BOUNDS) {
textBounds.push(
new TextBounds(
text,
getRangeBounds(node, offset, text.length, scrollX, scrollY)
)
);
} else {
const replacementNode = node.splitText(text.length);
textBounds.push(new TextBounds(text, getWrapperBounds(node, scrollX, scrollY)));
node = replacementNode;
}
} else if (!FEATURES.SUPPORT_RANGE_BOUNDS) {
node = node.splitText(text.length);
}
offset += text.length;
}
return textBounds;
};
const getWrapperBounds = (node: Text, scrollX: number, scrollY: number): Bounds => {
const wrapper = node.ownerDocument.createElement('html2canvaswrapper');
wrapper.appendChild(node.cloneNode(true));
const parentNode = node.parentNode;
if (parentNode) {
parentNode.replaceChild(wrapper, node);
const bounds = parseBounds(wrapper, scrollX, scrollY);
if (wrapper.firstChild) {
parentNode.replaceChild(wrapper.firstChild, wrapper);
}
return bounds;
}
return new Bounds(0, 0, 0, 0);
};
const getRangeBounds = (
node: Text,
offset: number,
length: number,
scrollX: number,
scrollY: number
): Bounds => {
const range = node.ownerDocument.createRange();
range.setStart(node, offset);
range.setEnd(node, offset + length);
return Bounds.fromClientRect(range.getBoundingClientRect(), scrollX, scrollY);
};