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

   1 const { execSync } = require('child_process');
   2 import { PDFDocument, RGB, ColorTypes } from "pdf-lib";
   3 import { readFileSync, writeFileSync } from "fs";
   4 import fontkit from '@pdf-lib/fontkit';
   5
   6
   7 export interface CloCommand {
   8     cmdName : string,
   9     args : TextStreamUnit[],
  10 }
  11
  12 export type TextStreamUnit = string | CloCommand;
  13
  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  * name : 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     name : 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 /**
  51  * guess the font path of a font style with fontconfig's commands
  52  * @param style the font style
  53  * @returns the font path in string, if found none or .ttc, return a empty string.
  54  */
  55 export function fontStyleTofontPath(style : FontStyle) : string{
  56     try {
  57         let fcMatchOut = execSync(
  58             `fc-match "${style.name}":${TextWeight[style.textWeight]}:`+
  59             `${TextStyle[style.textStyle]}`);
  60
  61         let fontFileName : string = fcMatchOut.toString().match(/^[^:]+/g)[0];
  62
  63         if (fontFileName.match(/[.]ttc$/g)){
  64             console.log("WARNING: the program doesn't support .ttc font format!\n"+
  65                 "Font file name: "+
  66                 fontFileName);
  67             return "";
  68         }
  69
  70         let fcListOut = execSync(
  71             `fc-list | grep ${fontFileName}`);
  72         let fontPath : string = fcListOut.toString().match(/^[^:]+/g)[0];
  73         return fontPath;
  74     } catch (error) {
  75         console.log("WARNING: You should install `fontconfig` to select the font.");
  76         return "";
  77     }
  78 };
  79
  80 export function hexToRGB(hex : string) : RGB{
  81     let matched = hex.match(/^#?([0-9a-fA-F]{2})([0-9a-fA-F]{2})([0-9a-fA-F]{2})$/);
  82
  83     var result : RGB ;
  84     if (!matched){
  85         console.log("WARNING: the hex color code is not valid. set to #000000")
  86         result = {
  87             type : ColorTypes.RGB,
  88             red: 0,
  89             green: 0,
  90             blue: 0,
  91         }
  92     }else{
  93         result = {
  94             type : ColorTypes.RGB,
  95             red: parseInt(matched[1], 16),
  96             green: parseInt(matched[2], 16),
  97             blue: parseInt(matched[3], 16)
  98       };
  99     }
 100
 101     return result;
 102 }
 103
 104 /**
 105  * put text in a clo canva.
 106  * @param clo : the clo object
 107  * @param str input string
 108  * @param sty input fontstyle
 109  * @param PageNo : the input page, 0-indexed.
 110  * @param x base x-point from left
 111  * @param y base y-point from top
 112  * @returns a new updated clo object
 113  */
 114 export async function putText(clo : Clo, str : string, sty : FontStyle,
 115     pageNo : number, x : number, y : number): Promise<Clo>{
 116
 117     clo.PDFCanvas.registerFontkit(fontkit);
 118     let canvaPage =  clo.PDFCanvas.getPage(pageNo);
 119
 120
 121     const fontBytes = readFileSync(fontStyleTofontPath(sty));
 122     const fontEmbed =  await clo.PDFCanvas.embedFont(fontBytes);
 123
 124     var textColor : RGB;
 125     if (sty.color === undefined){
 126         textColor =  hexToRGB("#000000");
 127     }else{
 128         textColor =  hexToRGB(sty.color);
 129     }
 130
 131     let drawTextOptions = {
 132         x : x,
 133         y : canvaPage.getHeight() - y,
 134         font : fontEmbed,
 135         size : sty.size,
 136         color : textColor};
 137
 138     canvaPage.drawText(str, drawTextOptions);
 139
 140     return clo;
 141 };