From ddc81d482ed85f856e6058cbdeb7d38334b59b68 Mon Sep 17 00:00:00 2001
From: Eduardo Dorado <dorado105@gmail.com>
Date: Fri, 22 May 2026 00:34:29 -0300
Subject: [PATCH] fix: render reversed fields and code128 barcodes

---
 server.js | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/server.js b/server.js
index 848ecbc..1ee9487 100644
--- a/server.js
+++ b/server.js
@@ -167,6 +167,7 @@ function createInitialState() {
     font: { name: "0", orientation: "N", height: 30, width: 30 },
     block: null,
     fieldHex: false,
+    fieldReverse: false,
     barcode: null,
     barcodeDefaults: { moduleWidth: 2, ratio: 3, height: 10 },
   };
@@ -194,6 +195,10 @@ function estimateGraphicHeight(operation) {
     return operation.size;
   }
 
+  if (operation.type === "code128") {
+    return operation.height;
+  }
+
   return estimateTextHeight(operation);
 }
 
@@ -211,10 +216,12 @@ function parseZpl(zpl, renderContext) {
       case "^XZ":
       case "^FS":
       case "^CI":
+      case "^FX":
       case "^MC":
         if (token.code === "^FS") {
           state.block = null;
           state.fieldHex = false;
+          state.fieldReverse = false;
           state.barcode = null;
         }
         break;
@@ -257,6 +264,9 @@ function parseZpl(zpl, renderContext) {
       case "^FH":
         state.fieldHex = true;
         break;
+      case "^FR":
+        state.fieldReverse = true;
+        break;
       case "^BY": {
         const [moduleWidth, ratio, height] = splitParams(params);
         state.barcodeDefaults = {
@@ -275,6 +285,18 @@ function parseZpl(zpl, renderContext) {
         };
         break;
       }
+      case "^BC": {
+        const [, height, printText, textAbove, checkDigit] = splitParams(params);
+        state.barcode = {
+          type: "code128",
+          height: parseInteger(height, 120),
+          printText: String(printText || "Y").toUpperCase() === "Y",
+          textAbove: String(textAbove || "N").toUpperCase() === "Y",
+          checkDigit: String(checkDigit || "N").toUpperCase() === "Y",
+          moduleWidth: state.barcodeDefaults.moduleWidth,
+        };
+        break;
+      }
       case "^FD": {
         const data = decodeFieldData(params, state.fieldHex);
 
@@ -289,6 +311,17 @@ function parseZpl(zpl, renderContext) {
             scale: state.barcode.magnification,
             size,
           });
+        } else if (state.barcode && state.barcode.type === "code128") {
+          addOperation(operations, {
+            type: "code128",
+            x: state.x,
+            y: state.y,
+            text: data.replace(/^>[:;>]?/, ""),
+            height: state.barcode.height,
+            printText: state.barcode.printText,
+            textAbove: state.barcode.textAbove,
+            moduleWidth: state.barcode.moduleWidth,
+          });
         } else {
           addOperation(operations, {
             type: "text",
@@ -297,10 +330,12 @@ function parseZpl(zpl, renderContext) {
             text: data,
             font: { ...state.font },
             block: state.block ? { ...state.block } : null,
+            reverse: state.fieldReverse,
           });
         }
 
         state.fieldHex = false;
+        state.fieldReverse = false;
         state.block = null;
         state.barcode = null;
         break;
@@ -483,9 +518,11 @@ function fillScaledText(ctx, text, x, y, font, renderContext) {
 
 function drawText(ctx, operation, renderContext) {
   configureTextContext(ctx, operation.font);
+  ctx.fillStyle = operation.reverse ? "#FFFFFF" : "#000000";
 
   if (!operation.block) {
     fillScaledText(ctx, operation.text, operation.x, operation.y, operation.font, renderContext);
+    ctx.fillStyle = "#000000";
     return;
   }
 
@@ -505,6 +542,8 @@ function drawText(ctx, operation, renderContext) {
 
     fillScaledText(ctx, line, x, operation.y + (index * lineHeight), operation.font, renderContext);
   });
+
+  ctx.fillStyle = "#000000";
 }
 
 function drawBox(ctx, operation) {
@@ -520,7 +559,7 @@ function drawBox(ctx, operation) {
     return;
   }
 
-  if (operation.width === operation.thickness && operation.height === operation.thickness) {
+  if (operation.thickness >= Math.min(operation.width, operation.height)) {
     ctx.fillRect(operation.x, operation.y, operation.width, operation.height);
     return;
   }
@@ -569,6 +608,27 @@ async function drawQr(ctx, operation) {
   ctx.drawImage(qrCanvas, operation.x, operation.y, operation.size, operation.size);
 }
 
+async function drawCode128(ctx, operation) {
+  const bwip = await loadBwip();
+  const targetWidth = Math.max(260, operation.text.length * operation.moduleWidth * 11);
+  const targetHeight = operation.height;
+  const barcodeCanvas = createCanvas(targetWidth, targetHeight);
+
+  bwip.render({
+    bcid: "code128",
+    text: operation.text,
+    scaleX: Math.max(1, operation.moduleWidth),
+    scaleY: 2,
+    height: Math.max(8, operation.height / 12),
+    includetext: operation.printText,
+    paddingwidth: 0,
+    paddingheight: 0,
+    textxalign: "center",
+  }, bwip.drawingCanvas(barcodeCanvas));
+
+  ctx.drawImage(barcodeCanvas, operation.x, operation.y, targetWidth, targetHeight);
+}
+
 async function renderZplToCanvas(zpl, options = {}) {
   const renderContext = createRenderContext(options);
   const { operations, warnings } = parseZpl(zpl, renderContext);
@@ -588,6 +648,8 @@ async function renderZplToCanvas(zpl, options = {}) {
       drawGraphic(ctx, operation);
     } else if (operation.type === "qr") {
       await drawQr(ctx, operation);
+    } else if (operation.type === "code128") {
+      await drawCode128(ctx, operation);
     }
   }