feat(design1): 光盘导出环形裁剪与画布/缩略图样式统一

导出与预览 PNG 按光盘外圆与中心孔透明裁剪；画布蒙版改为与背景同色 #31373D；缩略图改 PNG 环形铺底；Web/Electron 同步。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-electron/js/design1/output.js

@@ -51,6 +51,91 @@ async function saveImageAsPNG(buffer) {
     }
 }
 
+function soonDesign1GetHoleDiameterMm(canvas) {
+    var hole = 24;
+    if (canvas === window.canvas1 && typeof window.bg_version !== 'undefined' && window.bg_version === 2) {
+        hole = 42;
+    }
+    return hole;
+}
+
+function soonDesign1ApplyDiscAlpha(tctx, w, h, holeDiameterMm) {
+    var cx = w / 2;
+    var cy = h / 2;
+    var rOuter = w / 2;
+    var rInner = rOuter * (holeDiameterMm / 120);
+    tctx.save();
+    tctx.globalCompositeOperation = 'destination-in';
+    tctx.fillStyle = '#fff';
+    tctx.beginPath();
+    tctx.arc(cx, cy, rOuter, 0, Math.PI * 2);
+    tctx.moveTo(cx + rInner, cy);
+    tctx.arc(cx, cy, rInner, 0, Math.PI * 2, true);
+    tctx.fill('evenodd');
+    tctx.restore();
+}
+
+function soonDesign1ApplyDiscMatte(tctx, w, h, holeDiameterMm, color) {
+    var snap = document.createElement('canvas');
+    snap.width = w;
+    snap.height = h;
+    snap.getContext('2d').drawImage(tctx.canvas, 0, 0);
+    tctx.fillStyle = color;
+    tctx.fillRect(0, 0, w, h);
+    tctx.save();
+    var cx = w / 2;
+    var cy = h / 2;
+    var rOuter = w / 2;
+    var rInner = rOuter * (holeDiameterMm / 120);
+    tctx.beginPath();
+    tctx.arc(cx, cy, rOuter, 0, Math.PI * 2);
+    tctx.moveTo(cx + rInner, cy);
+    tctx.arc(cx, cy, rInner, 0, Math.PI * 2, true);
+    tctx.clip('evenodd');
+    tctx.drawImage(snap, 0, 0);
+    tctx.restore();
+}
+
+function soonDesign1CaptureCanvasRect(canvas, outW, outH, format, quality, clipDisc, discMatte) {
+    var bg = window.background_image1 || window.background_image;
+    if (!canvas || !bg) return '';
+    var srcEl = canvas.lowerCanvasEl;
+    if (!srcEl || !srcEl.getContext) return '';
+    var sx = bg.scaleX == null ? 1 : bg.scaleX;
+    var sy = bg.scaleY == null ? 1 : bg.scaleY;
+    var sw = bg.width * sx;
+    var sh = bg.height * sy;
+    var retina = (typeof canvas.getRetinaScaling === 'function') ? canvas.getRetinaScaling() : 1;
+    outW = outW || Math.round(sw);
+    outH = outH || Math.round(sh);
+    var tmp = document.createElement('canvas');
+    tmp.width = outW;
+    tmp.height = outH;
+    var tctx = tmp.getContext('2d');
+    tctx.drawImage(
+        srcEl,
+        bg.left * retina, bg.top * retina, sw * retina, sh * retina,
+        0, 0, outW, outH
+    );
+    if (discMatte) {
+        soonDesign1ApplyDiscMatte(tctx, outW, outH, soonDesign1GetHoleDiameterMm(canvas), discMatte);
+    } else if (clipDisc && format !== 'jpeg') {
+        soonDesign1ApplyDiscAlpha(tctx, outW, outH, soonDesign1GetHoleDiameterMm(canvas));
+    }
+    if (format === 'jpeg') return tmp.toDataURL('image/jpeg', quality == null ? 0.75 : quality);
+    return tmp.toDataURL('image/png');
+}
+
+function soonDesign1CaptureDiscPng(canvas, outW, outH) {
+    window._soonSkipDesign1CdMask = true;
+    if (canvas.discardActiveObject) canvas.discardActiveObject();
+    canvas.renderAll();
+    var url = soonDesign1CaptureCanvasRect(canvas, outW, outH, 'png', null, true);
+    window._soonSkipDesign1CdMask = false;
+    canvas.renderAll();
+    return url;
+}
+
 // 将 display_func 附加到 window 对象，确保全局可访问
 window.display_func = function display_func(img1, img2, img3) {
     $("#base_control").hide();
@@ -217,13 +302,16 @@ window.display_func = function display_func(img1, img2, img3) {
         left: all_left
     });
 
-    g3.push(img1);
-    let url3 = new fabric.Group(g3).toDataURL({
-        height: 2787,
-        width: 2787,
-        top: all_top,
-        left: all_left
+    var hiddenForPreview = [];
+    canvas1.getObjects().forEach(function (o) {
+        if (o.isGuideLine) {
+            hiddenForPreview.push(o);
+            o.visible = false;
+        }
     });
+    let url3 = soonDesign1CaptureDiscPng(canvas1, 2787, 2787);
+    hiddenForPreview.forEach(function (o) { o.visible = true; });
+    canvas1.renderAll();
     let url5 = new fabric.Group(g5).toDataURL({
         height: 2787,
         width: 2787,
@@ -596,12 +684,16 @@ window.output = function output(callback = null, _save = save) {
                 left: all_left
             });
             g3.push(img1);
-            let url3 = new fabric.Group(g3).toDataURL({
-                height: 2787,
-                width: 2787,
-                top: all_top,
-                left: all_left
+            var hiddenForSave = [];
+            canvas1.getObjects().forEach(function (o) {
+                if (o.isGuideLine) {
+                    hiddenForSave.push(o);
+                    o.visible = false;
+                }
             });
+            let url3 = soonDesign1CaptureDiscPng(canvas1, 2787, 2787);
+            hiddenForSave.forEach(function (o) { o.visible = true; });
+            canvas1.renderAll();
             let url5 = new fabric.Group(g5).toDataURL({
                 height: 2787,
                 width: 2787,