65 lines
1.8 KiB
TypeScript
65 lines
1.8 KiB
TypeScript
import { isNil, each, isString } from './util';
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import { getOffScreenContext } from './offscreen';
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import { ShapeAttrs } from '../types';
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/**
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* 获取文本的高度
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* @param text 文本
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* @param fontSize 字体大小
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* @param lineHeight 行高，可以为空
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*/
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export function getTextHeight(text: string, fontSize: number, lineHeight?: number): number {
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let lineCount = 1;
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if (isString(text)) {
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lineCount = text.split('\n').length;
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}
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if (lineCount > 1) {
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const spaceingY = getLineSpaceing(fontSize, lineHeight);
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return fontSize * lineCount + spaceingY * (lineCount - 1);
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}
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return fontSize;
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}
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/**
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* 获取行间距如果文本多行，需要获取文本间距
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* @param fontSize 字体大小
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* @param lineHeight 行高
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*/
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export function getLineSpaceing(fontSize: number, lineHeight?: number): number {
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return lineHeight ? lineHeight - fontSize : fontSize * 0.14;
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}
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/**
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* 字体宽度
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* @param text 文本
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* @param font 字体
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*/
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export function getTextWidth(text: string, font: string) {
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const context = getOffScreenContext(); // 获取离屏的 ctx 进行计算
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let width = 0;
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// null 或者 undefined 时，宽度为 0
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if (isNil(text) || text === '') {
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return width;
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}
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context.save();
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context.font = font;
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if (isString(text) && text.includes('\n')) {
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const textArr = text.split('\n');
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each(textArr, (subText) => {
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const measureWidth = context.measureText(subText).width;
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if (width < measureWidth) {
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width = measureWidth;
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}
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});
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} else {
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width = context.measureText(text).width;
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}
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context.restore();
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return width;
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}
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export function assembleFont(attrs: ShapeAttrs) {
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const { fontSize, fontFamily, fontWeight, fontStyle, fontVariant } = attrs;
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return [fontStyle, fontVariant, fontWeight, `${fontSize}px`, fontFamily].join(' ').trim();
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}
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