fix: Solved a bug that printing images is not correct

node-escpos · Oct 24, 2022 · bc7e2e5 · bc7e2e5
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diff --git a/.changeset/lovely-hairs-stare.md b/.changeset/lovely-hairs-stare.md
@@ -0,0 +1,7 @@
+---
+"@node-escpos/core": patch
+"@node-escpos/usb-adapter": patch
+---
+
+🐛 Solved a bug that printing images is not correct.  
+🧾 Update demo of README.
diff --git a/README.md b/README.md
@@ -7,7 +7,7 @@
 <br/>
 <br/>
 
-> It is a fork of [node-escpos](https://github.com/song940/node-escpos) with some improvements. Thanks to the original [author](https://github.com/song940). And I'll bring more improvements in the future.
+> It is a fork of [node-escpos](https://github.com/node-escpos/driver) with some improvements. Thanks to the original [author](https://github.com/song940). And I'll bring more improvements in the future.
 
 ### Improvements
 - 🛠 It is rewritten in TypeScript.
@@ -42,15 +42,26 @@ const device = new USB();
 const options = { encoding: "GB18030" /* default */ }
 const printer = new Printer(device, options);
 
-device.open(function(error){
+device.open(async function(err){
+  if(err){
+    // handle error
+    return
+  }
+
+  let printer = new Printer(device, {});
+
+  // Path to png image
+  const tux = join();
+  const image = await Image.load(tux);
+
   printer
     .font("a")
     .align("ct")
     .style("bu")
     .size(1, 1)
     .text("The quick brown fox jumps over the lazy dog")
     .text("敏捷的棕色狐狸跳过懒狗")
-    .barcode(1234567, "EAN13", { width: 50, height: 50 })
+    .barcode(112233445566, "EAN13", { width: 50, height: 50 })
     .table(["One", "Two", "Three"])
     .tableCustom(
       [
@@ -60,11 +71,15 @@ device.open(function(error){
       ],
       { encoding: "cp857", size: [1, 1] }, // Optional
     )
-    .qrimage("https://github.com/song940/node-escpos")
-    .then((printer) => {
-      printer.cut();
-      printer.close();
-    });
+
+  // inject qrimage to printer
+  printer = await printer.qrimage("https://github.com/node-escpos/driver")
+  // inject image to printer
+  printer = await printer.image(image, "s8")
+
+  printer
+    .cut()
+    .close()
 });
 ````
 - See `./examples/demo` for more examples.

diff --git a/examples/demo/test/barcode.test.ts b/examples/demo/test/barcode.test.ts
@@ -1,37 +1,51 @@
-import { Printer } from "@node-escpos/core";
+import { Image, Printer } from "@node-escpos/core";
 import USB from "@node-escpos/usb-adapter";
+import { join } from "path";
 import { describe, it } from "vitest";
 
 describe("should work as expected", () => {
   it("printing", async () => {
-    const device = new USB();
-    const printer = new Printer(device, {});
+    const device  = new USB();
+    await new Promise<void>((resolve,reject) => {
+      device.open(async function(err){
+        if(err){
+          reject(err);
+          return
+        }
 
-    await new Promise<void>((resolve) => {
-      printer
-        .font("a")
-        .align("ct")
-        .style("bu")
-        .size(1, 1)
-        .text("The quick brown fox jumps over the lazy dog")
-        .text("敏捷的棕色狐狸跳过懒狗")
-        .barcode(1234567, "EAN13", { width: 50, height: 50 })
-        .table(["One", "Two", "Three"])
-        .tableCustom(
-          [
-            { text: "Left", align: "LEFT", width: 0.33, style: "B" },
-            { text: "Center", align: "CENTER", width: 0.33 },
-            { text: "Right", align: "RIGHT", width: 0.33 },
-          ],
-          { encoding: "cp857", size: [1, 1] }, // Optional
-        )
-        .qrimage("https://github.com/song940/node-escpos")
-        .then((printer) => {
-          printer.cut();
-          printer.close();
-        }).finally(() => {
-          resolve();
-        });
+        let printer = new Printer(device, {});
+
+        const tux = join(__dirname, '../assets/tux.png');
+        const image = await Image.load(tux);
+
+        printer
+          .font("a")
+          .align("ct")
+          .style("bu")
+          .size(1, 1)
+          .text("The quick brown fox jumps over the lazy dog")
+          .text("敏捷的棕色狐狸跳过懒狗")
+          .barcode(112233445566, "EAN13", { width: 50, height: 50 })
+          .table(["One", "Two", "Three"])
+          .tableCustom(
+            [
+              { text: "Left", align: "LEFT", width: 0.33, style: "B" },
+              { text: "Center", align: "CENTER", width: 0.33 },
+              { text: "Right", align: "RIGHT", width: 0.33 },
+            ],
+            { encoding: "cp857", size: [1, 1] }, // Optional
+          )
+
+        // inject qrimage to printer
+        printer = await printer.qrimage("https://github.com/node-escpos/driver")
+        // inject image to printer
+        printer = await printer.image(image, "s8")
+
+        printer
+          .cut()
+          .close()
+          .finally(resolve)
+      });
     });
   });
 });
diff --git a/examples/demo/test/index.js b/examples/demo/test/index.js
@@ -17,7 +17,7 @@ device.open(function(err){
   .text('The quick brown fox jumps over the lazy dog')
   .text('敏捷的棕色狐狸跳过懒狗')
   .barcode('1234567', 'EAN8')
-  .qrimage('https://github.com/song940/node-escpos', function(err){
+  .qrimage('https://github.com/node-escpos/driver', function(err){
     this.cut();
     this.close();
   });

diff --git a/examples/demo/test/multiple.js b/examples/demo/test/multiple.js
@@ -24,7 +24,7 @@ device.open(function(){
   .text('The quick brown fox jumps over the lazy dog')
   .text('敏捷的棕色狐狸跳过懒狗')
   .barcode('12345678', 'EAN8')
-  .qrimage('https://github.com/song940/node-escpos', function(err){
+  .qrimage('https://github.com/node-escpos/driver', function(err){
     this.cut();
     this.close();
   });

diff --git a/examples/demo/test/qs_text.js b/examples/demo/test/qs_text.js
@@ -20,7 +20,7 @@ device.open(function(err){
   .close();
   // .text('敏捷的棕色狐狸跳过懒狗')
   // .barcode('1234567', 'EAN8')
-  // .qrimage('https://github.com/song940/node-escpos', function(err){
+  // .qrimage('https://github.com/node-escpos/driver', function(err){
   //   this.cut();
   //   this.close();
   // });

diff --git a/examples/demo/test/star_printer_index.js b/examples/demo/test/star_printer_index.js
@@ -20,7 +20,7 @@ device.open(function(err){
   .text('敏捷的棕色狐狸跳过懒狗')
   .align("STAR_RA")
   .barcode('1234567', 'EAN8')
-  .qrimage('https://github.com/song940/node-escpos', function(err){
+  .qrimage('https://github.com/node-escpos/driver', function(err){
     this.fullCut()
     this.close();
   });

diff --git a/package.json b/package.json
@@ -4,6 +4,7 @@
   "author": "Caspian <[email protected]> (https://github.com/dohooo)",
   "scripts": {
     "build": "pnpm -F '@node-escpos/*' build",
+    "build:watch": "pnpm -F '@node-escpos/*' build:watch",
     "publish": "pnpm run build && changeset publish",
     "version": "changeset version"
   },

diff --git a/packages/core/src/image.ts b/packages/core/src/image.ts
@@ -22,24 +22,25 @@ export default class Image {
       );
     }
 
-    this.data = rgbaData.map(
-      ([r, g, b, a]) => a !== 0 && r > 200 && g > 200 && b > 200,
-    );
+    // Convert RGB to grayscale:
+    this.data = rgbaData.map(([r, g, b, a]) => this.RGB2Gray(r, g, b, a));
   }
 
-  private get size() {
+  get size() {
     return {
       width: this.pixels.shape[0],
       height: this.pixels.shape[1],
       colors: this.pixels.shape[2],
     };
   }
 
-  /**
-   * [toBitmap description]
-   * @param  {[type]} density [description]
-   * @return {[type]}         [description]
-   */
+  private RGB2Gray(r: number, g: number, b: number, a: number) {
+    if (a === 0) {
+      return false;
+    }
+    return 0.29900 * r + 0.57800 * g + 0.11400 * b < 128;
+  }
+
   toBitmap(density = 24) {
     const result: number[][] = [];
     let x, y, b, l, i;
@@ -56,12 +57,13 @@ export default class Image {
         for (b = 0; b < density; b++) {
           i = x * c + (b >> 3);
 
-          if (ld[i] === undefined) ld[i] = 0;
+          if (ld[i] === undefined) { ld[i] = 0; }
 
           l = y * density + b;
           if (l < this.size.height) {
-            if (this.data[l * this.size.width + x])
+            if (this.data[l * this.size.width + x]) {
               ld[i] += (0x80 >> (b & 0x7));
+            }
           }
         }
       }
@@ -73,12 +75,8 @@ export default class Image {
     };
   }
 
-  /**
-   * [toRaster description]
-   * @return {[type]} [description]
-   */
   toRaster() {
-    const result = [];
+    const result: number[] = [];
     const { width, height } = this.size;
 
     // n blocks of lines
@@ -89,13 +87,15 @@ export default class Image {
         for (let b = 0; b < 8; b++) {
           const i = x * 8 + b;
 
-          if (result[y * n + x] === undefined)
+          if (result[y * n + x] === undefined) {
             result[y * n + x] = 0;
+          }
 
           const c = x * 8 + b;
           if (c < width) {
-            if (this.data[y * width + i])
+            if (this.data[y * width + i]) {
               result[y * n + x] += (0x80 >> (b & 0x7));
+            }
           }
         }
       }
@@ -113,11 +113,15 @@ export default class Image {
    * @param  {[type]}   type     [description]
    * @return {[Promise<Image>]}            [description]
    */
-  static load(url: string, type: ImageMimeType | null = null): Promise<Image> {
+  static load(url: string | Uint8Array, type: ImageMimeType | null = null): Promise<Image> {
     return new Promise((resolve, reject) => {
       getPixels(url, type ?? "", (error, pixels) => {
-        if (error) reject(error);
-        else resolve(new Image(pixels as NdArray<Uint8Array>));
+        if (error) {
+          reject(error);
+        }
+        else {
+          resolve(new Image(pixels as NdArray<Uint8Array>));
+        }
       });
     });
   }

diff --git a/packages/usb-adapter/src/index.ts b/packages/usb-adapter/src/index.ts
@@ -148,7 +148,7 @@ export default class USBAdapter extends Adapter<[]> {
   }
 
   close(callback?: ((error: Error | null) => void) | undefined): this {
-    if (!this.device) callback && callback(null);
+    if (!this.device) callback?.(new Error("Device not found"));
     try {
       this.device?.close();
       usb.removeAllListeners("detach");