feat: Add QR code size setting for fixed-size QR codes

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/src/pages/printing/printing.tsx

@@ -24,6 +24,7 @@ export interface QRCodePrintSettings {
   textSize?: number;
   qrCodePadding?: number; // in mm, default 2
   qrCodeMaxWidth?: number; // percentage 0-100, 0 = no constraint (auto)
+  qrCodeSize?: number; // in mm, 0 = auto
   printSettings: PrintSettings;
 }
 

client/src/pages/printing/qrCodePrintingDialog.tsx

@@ -43,6 +43,7 @@ const QRCodePrintingDialog: React.FC<QRCodePrintingDialogProps> = ({
   const textSize = printSettings?.textSize || 3;
   const qrCodePadding = printSettings?.qrCodePadding ?? 2;
   const qrCodeMaxWidth = printSettings?.qrCodeMaxWidth ?? 0; // 0 = auto (no constraint)
+  const qrCodeSize = printSettings?.qrCodeSize ?? 0; // 0 = auto
 
   const elements = items.map((item) => {
     return (
@@ -224,6 +225,40 @@ const QRCodePrintingDialog: React.FC<QRCodePrintingDialogProps> = ({
               </Col>
             </Row>
           </Form.Item>
+          <Form.Item label={t("printing.qrcode.qrCodeSize")} tooltip={t("printing.qrcode.qrCodeSizeTooltip")}>
+            <Row>
+              <Col span={12}>
+                <Slider
+                  disabled={showQRCodeMode === "no"}
+                  tooltip={{ formatter: (value) => (value === 0 ? t("printing.qrcode.auto") : `${value} mm`) }}
+                  min={0}
+                  max={50}
+                  value={qrCodeSize}
+                  step={1}
+                  onChange={(value) => {
+                    printSettings.qrCodeSize = value;
+                    setPrintSettings(printSettings);
+                  }}
+                />
+              </Col>
+              <Col span={12}>
+                <InputNumber
+                  disabled={showQRCodeMode === "no"}
+                  min={0}
+                  max={100}
+                  step={1}
+                  style={{ margin: "0 16px" }}
+                  value={qrCodeSize}
+                  addonAfter="mm"
+                  placeholder={t("printing.qrcode.auto")}
+                  onChange={(value) => {
+                    printSettings.qrCodeSize = value ?? 0;
+                    setPrintSettings(printSettings);
+                  }}
+                />
+              </Col>
+            </Row>
+          </Form.Item>
 
           {extraSettings}
         </>
@@ -243,8 +278,8 @@ const QRCodePrintingDialog: React.FC<QRCodePrintingDialogProps> = ({
             }
 
             .print-page .print-qrcode {
-              width: auto !important;
-              height: auto !important;
+              width: ${qrCodeSize > 0 ? `${qrCodeSize}mm` : "auto"} !important;
+              height: ${qrCodeSize > 0 ? `${qrCodeSize}mm` : "auto"} !important;
               padding: ${qrCodePadding}mm;
             }