git.kianting.info Git - clo/blob - src/canva.ts

   1 const { execSync } = require('child_process');
   2 import { readFileSync, writeFileSync } from "fs";
   3 import "pdfkit";
   4
   5
   6 export interface CloCommand {
   7     cmdName : string,
   8     args : TextStreamUnit[],
   9 }
  10
  11
  12 export type TextStreamUnit = string | CloCommand;
  13 export type PDFDocument = PDFKit.PDFDocument;
  14 /**
  15  * a clo document
  16  */
  17 export interface Clo{
  18     mainText : TextStreamUnit[],
  19     mainFontStyle? : FontStyle,
  20     PDFCanvas : PDFDocument;
  21
  22 }
  23
  24 /**
  25  * Font Style Interface
  26  * family : eg. "FreeSans"
  27  * size : in px, not in pt.
  28  * textWeight : TextWeight.REGULAR ,etc
  29  * textWeight : TextStyle.ITALIC ,etc
  30  */
  31 export interface FontStyle{
  32     family : string,
  33     size : number,
  34     textWeight : TextWeight,
  35     textStyle : TextStyle,
  36     color? : string,
  37 };
  38
  39 export enum TextWeight {
  40     REGULAR,
  41     BOLD,
  42   };
  43
  44 export enum TextStyle{
  45     NORMAL,
  46     ITALIC,
  47     OBLIQUE,
  48 };
  49
  50 export interface fontPathPSNamePair{
  51     path : string,
  52     psName : string,
  53 }
  54
  55 /**
  56  * guess the font path and postscript name of a font style with fontconfig's commands
  57  * @param style the font style
  58  * @returns pair of the font path and postscript name.
  59  */
  60 export function fontStyleTofont(style : FontStyle) : fontPathPSNamePair{
  61     try {
  62         let fcMatchCommand = `fc-match "${style.family}":${TextWeight[style.textWeight]}:`+
  63         `${TextStyle[style.textStyle]}` +` postscriptname file`;
  64
  65         let fcMatchOut = execSync(fcMatchCommand);
  66         let matched = fcMatchOut
  67                             .toString()
  68                             .match(/\:file=(.+):postscriptname=(.+)\n/);
  69
  70         let fontPath : string = matched[1];
  71         let psName : string = matched[2];
  72
  73         return {path: fontPath, psName : psName};
  74
  75
  76     } catch (error) {
  77         console.log(`WARNING: You should install "fontconfig" to select the font.
  78          Detail of the error:` + error);
  79
  80         return {path: "", psName : ""};
  81     }
  82 };
  83
  84
  85
  86 /**
  87  * put text in a clo canva.
  88  * @param clo : the clo object
  89  * @param str input string
  90  * @param sty input fontstyle
  91  * @param PageNo : the input page, 0-indexed.
  92  * @param x base x-point from left
  93  * @param y base y-point from top
  94  * @returns a new updated clo object
  95  */
  96 export async function putText(clo : Clo, str : string, sty : FontStyle,
  97     pageNo : number, x : number, y : number): Promise<Clo>{
  98
  99     let fontInfo = fontStyleTofont(sty);
 100
 101     if (fontInfo.path.match(/\.ttc$/g)){
 102         var middle = clo.PDFCanvas
 103         .font(fontInfo.path, fontInfo.psName)
 104         .fontSize(sty.size);}
 105     else{
 106         var middle = clo.PDFCanvas
 107         .font(fontInfo.path)
 108         .fontSize(sty.size);
 109     }
 110
 111     if (sty.color !== undefined){
 112         middle.fill(sty.color);
 113     }
 114
 115     middle.text(str,  x, y);
 116
 117     clo.PDFCanvas = middle;
 118
 119     return clo;
 120 };