优化

src/components/LabelDesigner.tsx

@@ -7,10 +7,10 @@ import {
   getTableColWidths,
   getTableRowHeights,
   iterTableCells,
-  getCellRectMm,
   toggleTableCellSelection,
   scaleTableTracks,
   getCellAnchor,
+  getCellRectPx,
   type TableCellCoord,
 } from '../tableUtils';
 import { useIsNarrowScreen } from '../hooks/useIsMobile';
@@ -1860,11 +1860,8 @@ export const LabelDesigner: React.FC<LabelDesignerProps> = ({
                     onSelectTableCells && (
                       <div className="absolute inset-0 z-10 pointer-events-none">
                         {iterTableCells(overlayElement).map(({ row, col }) => {
-                          const rect = getCellRectMm(overlayElement, row, col);
-                          const cellX = mmToPx(rect.x, displayZoom);
-                          const cellY = mmToPx(rect.y, displayZoom);
-                          const cellW = mmToPx(rect.width, displayZoom);
-                          const cellH = mmToPx(rect.height, displayZoom);
+                          const { x: cellX, y: cellY, width: cellW, height: cellH } =
+                            getCellRectPx(overlayElement, row, col, canvasRenderScale);
                           const isCellSelected = selectedTableCells.some((c) => {
                             const anchor = getCellAnchor(overlayElement, c.row, c.col);
                             return anchor.row === row && anchor.col === col;
@@ -1872,16 +1869,19 @@ export const LabelDesigner: React.FC<LabelDesignerProps> = ({
                           return (
                             <div
                               key={`cell-${row}-${col}`}
-                              className={`absolute pointer-events-auto cursor-grab active:cursor-grabbing border touch-none ${
+                              className={`absolute pointer-events-auto cursor-grab active:cursor-grabbing touch-none ${
                                 isCellSelected
-                                  ? 'bg-[#31a8ff]/25 border-[#31a8ff]'
-                                  : 'border-transparent hover:bg-[#31a8ff]/10 hover:border-[#31a8ff]/40'
+                                  ? 'bg-[#31a8ff]/25'
+                                  : 'hover:bg-[#31a8ff]/10'
                               }`}
                               style={{
                                 left: `${cellX}px`,
                                 top: `${cellY}px`,
                                 width: `${cellW}px`,
                                 height: `${cellH}px`,
+                                boxShadow: isCellSelected
+                                  ? 'inset 0 0 0 1px #31a8ff'
+                                  : undefined,
                               }}
                               onPointerDown={(e) =>
                                 handleTableCellPointerDown(e, overlayElement, row, col)

src/components/PropSidebar.tsx

@@ -482,7 +482,7 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
         <div className="space-y-3">
           <div className="text-[10px] font-bold text-[#31a8ff]">变量列表</div>
           <p className="text-[10px] text-[#666] leading-relaxed mb-3">
-            可编辑变量默认值，未被内容或显示条件引用的变量可删除。
+            可编辑变量预览值，未被内容或显示条件引用的变量可删除。
           </p>
           {templateVariables.map((v) => {
             const inUse = isTemplateVariableInUse(template, v);
@@ -501,7 +501,7 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
                   type="text"
                   value={template.variableDefaults?.[v] ?? ''}
                   onChange={(e) => setVariableDefault(v, e.target.value)}
-                  placeholder="预览默认值"
+                  placeholder="预览值"
                   className="ps-field font-mono text-[10px] w-full min-w-0"
                 />
                 <div className="flex items-center justify-center w-[44px] shrink-0">
@@ -661,6 +661,17 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
         )}
         {selectedElem.type !== 'table' && (
           <>
+            <div className="flex items-center justify-between gap-2">
+              <label className="ps-field-label">内容</label>
+              <button
+                type="button"
+                disabled={!selectedElem.content}
+                onClick={() => handleElemChange({ ...selectedElem, content: '' })}
+                className="text-[9px] text-[#31a8ff] hover:underline cursor-pointer disabled:opacity-40 disabled:cursor-not-allowed disabled:no-underline shrink-0"
+              >
+                清空内容
+              </button>
+            </div>
             <PropTextarea
               value={selectedElem.content}
               onCommit={(val) => handleElemChange({ ...selectedElem, content: val })}
@@ -691,6 +702,31 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
             )}
           </>
         )}
+        {(selectedElem.type === 'barcode' ||
+          selectedElem.type === 'qrcode' ||
+          selectedElem.type === 'image') && (
+          <label className="flex items-start gap-2 pt-1">
+            <input
+              type="checkbox"
+              checked={selectedElem.showWhenContentEmpty ?? false}
+              onChange={(e) =>
+                handleElemChange({
+                  ...selectedElem,
+                  showWhenContentEmpty: e.target.checked ? true : undefined,
+                })
+              }
+              className="ps-checkbox mt-0.5"
+            />
+            <span className="text-xs text-[#ccc] leading-normal">
+              输出模式下内容为空仍显示
+              {selectedElem.type === 'image' && (
+                <span className="block text-[9px] text-[#777] mt-0.5">
+                  开启后绑定数据为空时可显示默认图片
+                </span>
+              )}
+            </span>
+          </label>
+        )}
         {selectedElem.type === 'table' && (
           <p className="text-[10px] text-[#777] leading-normal">
             表格各单元格内容独立设置，默认为空。点击画布上的单元格后在属性面板编辑。
@@ -1407,6 +1443,45 @@ export const PropSidebar: React.FC<PropSidebarProps> = ({
                   <option value="fill">拉伸 (fill)</option>
                 </FieldSelect>
               </div>
+              <div>
+                <label className="ps-field-label">默认图片</label>
+                <p className="text-[9px] text-[#777] leading-normal mb-1.5">
+                  主图地址加载失败时使用；需同时开启「内容为空仍显示」才能在绑定数据为空时展示
+                </p>
+                <label className="ps-btn text-[10px] cursor-pointer mb-1.5 inline-flex">
+                  <Upload className="w-3.5 h-3.5" />
+                  选择默认图片
+                  <input
+                    type="file"
+                    accept="image/*"
+                    className="hidden"
+                    onChange={(e) => {
+                      const file = e.target.files?.[0];
+                      if (!file) return;
+                      const reader = new FileReader();
+                      reader.onload = () =>
+                        handleElemChange({
+                          ...selectedElem,
+                          defaultImage: reader.result as string,
+                        });
+                      reader.readAsDataURL(file);
+                      e.target.value = '';
+                    }}
+                  />
+                </label>
+                <PropTextarea
+                  value={selectedElem.defaultImage ?? ''}
+                  onCommit={(val) =>
+                    handleElemChange({
+                      ...selectedElem,
+                      defaultImage: val.trim() || undefined,
+                    })
+                  }
+                  rows={2}
+                  className="ps-field resize-none"
+                  placeholder="默认图片 URL 或 data URI"
+                />
+              </div>
             </div>
           )}
 

src/components/TableCellTextFields.tsx

@@ -58,7 +58,17 @@ export const TableCellTextFields: React.FC<TableCellTextFieldsProps> = ({
       )}
 
       <div>
+        <div className="flex items-center justify-between gap-2">
           <label className="ps-field-label">内容</label>
+          <button
+            type="button"
+            disabled={!textElem.content}
+            onClick={() => patchText({ ...textElem, content: '' })}
+            className="text-[9px] text-[#31a8ff] hover:underline cursor-pointer disabled:opacity-40 disabled:cursor-not-allowed disabled:no-underline shrink-0"
+          >
+            清空内容
+          </button>
+        </div>
         <textarea
           value={textElem.content}
           rows={2}

src/components/TablePropertyFields.tsx

@@ -242,7 +242,17 @@ export const TableCellContentFields: React.FC<TableCellContentFieldsProps> = ({
 
   return (
     <div className="space-y-2 pt-2 border-t border-[#3a3a3a]">
+      <div className="flex items-center justify-between gap-2">
         <label className="ps-field-label">批量设置内容（{selectedCells.length} 个单元格）</label>
+        <button
+          type="button"
+          disabled={!content}
+          onClick={() => onChange(updateTableCells(elem, selectedCells, { content: '' }))}
+          className="text-[9px] text-[#31a8ff] hover:underline cursor-pointer disabled:opacity-40 disabled:cursor-not-allowed disabled:no-underline shrink-0"
+        >
+          清空内容
+        </button>
+      </div>
       <textarea
         value={content}
         rows={2}

src/labelRenderer.ts

@@ -19,14 +19,13 @@ import {
 } from './elementBox';
 import {
   iterTableCells,
-  getCellRectMm,
   getCellAnchor,
   getCellData,
   getEffectiveCellStyle,
   getTableRows,
   getTableCols,
-  getTableRowHeights,
-  getTableColWidths,
+  buildTableGridBoundariesPx,
+  getCellRectPx,
 } from './tableUtils';
 
 const GENERATOR_TRANSPARENT_BG = '#00000000';
@@ -90,6 +89,34 @@ function loadImage(src: string): Promise<HTMLImageElement> {
   });
 }
 
+function loadImageOrNull(src: string): Promise<HTMLImageElement | null> {
+  const trimmed = src.trim();
+  if (!trimmed) return Promise.resolve(null);
+  return loadImage(trimmed).catch(() => null);
+}
+
+async function resolveElementImage(
+  elem: TemplateElement,
+  primarySrc: string,
+  mode: ContentResolveMode
+): Promise<{ img: HTMLImageElement | null; showPlaceholder: boolean }> {
+  const primary = primarySrc.trim();
+  const fallback = (elem.defaultImage ?? '').trim();
+
+  let img = await loadImageOrNull(primary);
+  if (!img && fallback) {
+    img = await loadImageOrNull(fallback);
+  }
+
+  if (img) return { img, showPlaceholder: false };
+
+  if (mode === 'design' && !primary && !fallback) {
+    return { img: null, showPlaceholder: true };
+  }
+
+  return { img: null, showPlaceholder: false };
+}
+
 function drawImageWithFit(
   ctx: CanvasRenderingContext2D,
   img: HTMLImageElement,
@@ -226,7 +253,7 @@ function layoutVerticalTextColumns(
   return columns;
 }
 
-function drawTextInRect(
+function drawTextContentInBox(
   ctx: CanvasRenderingContext2D,
   elem: TemplateElement,
   boxX: number,
@@ -236,9 +263,15 @@ function drawTextInRect(
   value: string,
   scale: number
 ) {
-  const pad = 2 * scale;
-  const writableW = Math.max(1, boxW - pad * 2);
-  const writableH = Math.max(1, boxH - pad * 2);
+  const pad = resolvePaddingMm(elem);
+  const padPx = {
+    top: Math.round(pad.top * scale),
+    right: Math.round(pad.right * scale),
+    bottom: Math.round(pad.bottom * scale),
+    left: Math.round(pad.left * scale),
+  };
+  const writableW = Math.max(1, boxW - padPx.left - padPx.right);
+  const writableH = Math.max(1, boxH - padPx.top - padPx.bottom);
 
   const fontStyle = elem.fontStyle === 'italic' ? 'italic ' : '';
   const fontWeight = elem.fontWeight === 'bold' ? 'bold ' : '';
@@ -267,8 +300,8 @@ function drawTextInRect(
 
   const textScaleX = Math.max(0.1, Math.min(5, elem.textScaleX ?? 1));
   const textScaleY = Math.max(0.1, Math.min(5, elem.textScaleY ?? 1));
-  const transformOriginX = boxX + boxW / 2;
-  const transformOriginY = boxY + boxH / 2;
+  const transformOriginX = boxX + padPx.left + writableW / 2;
+  const transformOriginY = boxY + padPx.top + writableH / 2;
 
   ctx.save();
   if (textScaleX !== 1 || textScaleY !== 1) {
@@ -285,11 +318,11 @@ function drawTextInRect(
 
     let startX: number;
     if (elem.textAlign === 'center') {
-      startX = boxX + pad + Math.max(0, (writableW - totalColumnsWidth) / 2) + columnWidth / 2;
+      startX = boxX + padPx.left + Math.max(0, (writableW - totalColumnsWidth) / 2) + columnWidth / 2;
     } else if (elem.textAlign === 'right') {
-      startX = boxX + pad + Math.max(0, writableW - totalColumnsWidth) + columnWidth / 2;
+      startX = boxX + padPx.left + Math.max(0, writableW - totalColumnsWidth) + columnWidth / 2;
     } else {
-      startX = boxX + pad + columnWidth / 2;
+      startX = boxX + padPx.left + columnWidth / 2;
     }
     ctx.textAlign = 'center';
 
@@ -298,17 +331,18 @@ function drawTextInRect(
       const colTextHeight = column.length * lineHeight;
       let colStartY: number;
       if (vAlign === 'top') {
-        colStartY = boxY + pad + lineHeight / 2;
+        colStartY = boxY + padPx.top + lineHeight / 2;
       } else if (vAlign === 'bottom') {
-        colStartY = boxY + boxH - pad - colTextHeight + lineHeight / 2;
+        colStartY = boxY + boxH - padPx.bottom - colTextHeight + lineHeight / 2;
       } else {
-        colStartY = boxY + pad + Math.max(0, (writableH - colTextHeight) / 2) + lineHeight / 2;
+        colStartY =
+          boxY + padPx.top + Math.max(0, (writableH - colTextHeight) / 2) + lineHeight / 2;
       }
 
       const colX = startX + col * columnWidth;
       for (let i = 0; i < column.length; i++) {
         const charY = colStartY + i * lineHeight;
-        if (charY - lineHeight / 2 <= boxY + boxH - pad) {
+        if (charY - lineHeight / 2 <= boxY + boxH - padPx.bottom) {
           ctx.fillText(column[i], colX, charY);
         }
       }
@@ -317,31 +351,31 @@ function drawTextInRect(
     const lines = layoutHorizontalTextLines(ctx, String(value), writableW, wordWrap);
     const totalTextHeight = lines.length * lineHeight;
 
-    let textX = boxX + pad;
+    let textX = boxX + padPx.left;
     let textAlign: CanvasTextAlign = 'left';
     if (elem.textAlign === 'center') {
-      textX = boxX + boxW / 2;
+      textX = boxX + padPx.left + writableW / 2;
       textAlign = 'center';
     } else if (elem.textAlign === 'right') {
-      textX = boxX + boxW - pad;
+      textX = boxX + padPx.left + (writableW - 2);
       textAlign = 'right';
     } else {
-      textX = boxX + pad + 2;
+      textX = boxX + padPx.left + 2;
     }
     ctx.textAlign = textAlign;
 
     let startY: number;
     if (vAlign === 'top') {
-      startY = boxY + pad + lineHeight / 2;
+      startY = boxY + padPx.top + lineHeight / 2;
     } else if (vAlign === 'bottom') {
-      startY = boxY + boxH - pad - totalTextHeight + lineHeight / 2;
+      startY = boxY + boxH - padPx.bottom - totalTextHeight + lineHeight / 2;
     } else {
-      startY = boxY + pad + Math.max(0, (writableH - totalTextHeight) / 2) + lineHeight / 2;
+      startY = boxY + padPx.top + Math.max(0, (writableH - totalTextHeight) / 2) + lineHeight / 2;
     }
 
     for (let i = 0; i < lines.length; i++) {
       const lineY = startY + i * lineHeight;
-      if (lineY - lineHeight / 2 <= boxY + boxH - pad) {
+      if (lineY - lineHeight / 2 <= boxY + boxH - padPx.bottom) {
         const line = lines[i];
         ctx.fillText(line, textX, lineY);
         drawTextLineDecorations(ctx, elem, textX, lineY, line, fontSizePx, textAlign);
@@ -376,19 +410,12 @@ function drawTableGridLines(
   const borderColor = elem.tableBorderColor ?? '#374151';
   const rows = getTableRows(elem);
   const cols = getTableCols(elem);
-  const rowHeights = getTableRowHeights(elem);
-  const colWidths = getTableColWidths(elem);
-  const pad = resolvePaddingMm(elem);
+  const { rowBounds, colBounds } = buildTableGridBoundariesPx(elem, scale, ex, ey);
 
-  const x0 = pad.left;
-  const y0 = pad.top;
-  const totalW = colWidths.reduce((a, b) => a + b, 0);
-  const totalH = rowHeights.reduce((a, b) => a + b, 0);
-
-  const left = ex + x0 * scale;
-  const top = ey + y0 * scale;
-  const width = totalW * scale;
-  const height = totalH * scale;
+  const left = colBounds[0];
+  const top = rowBounds[0];
+  const width = colBounds[colBounds.length - 1] - left;
+  const height = rowBounds[rowBounds.length - 1] - top;
 
   ctx.strokeStyle = borderColor;
   ctx.lineWidth = borderW;
@@ -402,45 +429,31 @@ function drawTableGridLines(
     Math.max(0, height - borderW)
   );
 
-  let yAcc = y0;
   for (let r = 1; r < rows; r++) {
-    yAcc += rowHeights[r - 1];
-    const y = alignStrokeCoord(ey + yAcc * scale);
-    let xAcc = x0;
+    const y = alignStrokeCoord(rowBounds[r]);
     for (let c = 0; c < cols; c++) {
-      const w = colWidths[c];
       const anchorAbove = getCellAnchor(elem, r - 1, c);
       const anchorBelow = getCellAnchor(elem, r, c);
       const sameMerge =
         anchorAbove.row === anchorBelow.row && anchorAbove.col === anchorBelow.col;
       if (!sameMerge) {
-        const x1 = alignStrokeCoord(ex + xAcc * scale);
-        const x2 = alignStrokeCoord(ex + (xAcc + w) * scale);
-        ctx.moveTo(x1, y);
-        ctx.lineTo(x2, y);
+        ctx.moveTo(alignStrokeCoord(colBounds[c]), y);
+        ctx.lineTo(alignStrokeCoord(colBounds[c + 1]), y);
       }
-      xAcc += w;
     }
   }
 
-  let xAcc = x0;
   for (let c = 1; c < cols; c++) {
-    xAcc += colWidths[c - 1];
-    const x = alignStrokeCoord(ex + xAcc * scale);
-    let yAcc2 = y0;
+    const x = alignStrokeCoord(colBounds[c]);
     for (let r = 0; r < rows; r++) {
-      const h = rowHeights[r];
       const anchorLeft = getCellAnchor(elem, r, c - 1);
       const anchorRight = getCellAnchor(elem, r, c);
       const sameMerge =
         anchorLeft.row === anchorRight.row && anchorLeft.col === anchorRight.col;
       if (!sameMerge) {
-        const y1 = alignStrokeCoord(ey + yAcc2 * scale);
-        const y2 = alignStrokeCoord(ey + (yAcc2 + h) * scale);
-        ctx.moveTo(x, y1);
-        ctx.lineTo(x, y2);
+        ctx.moveTo(x, alignStrokeCoord(rowBounds[r]));
+        ctx.lineTo(x, alignStrokeCoord(rowBounds[r + 1]));
       }
-      yAcc2 += h;
     }
   }
 
@@ -466,19 +479,26 @@ async function drawTableElement(
   drawElementFill(ctx, ex, ey, ew, eh, elem, radii);
   drawElementBorders(ctx, ex, ey, ew, eh, radii, sides, elem, scale);
 
-  const inner = getPaddedRectPx(ex, ey, ew, eh, elem, scale);
+  const { rowBounds, colBounds } = buildTableGridBoundariesPx(elem, scale, ex, ey);
+  const gridX = colBounds[0];
+  const gridY = rowBounds[0];
+  const gridW = colBounds[colBounds.length - 1] - gridX;
+  const gridH = rowBounds[rowBounds.length - 1] - gridY;
   ctx.save();
   ctx.beginPath();
-  ctx.rect(inner.x, inner.y, inner.w, inner.h);
+  ctx.rect(gridX, gridY, gridW, gridH);
   ctx.clip();
 
   const anchors = iterTableCells(elem);
   for (const { row, col } of anchors) {
-    const rect = getCellRectMm(elem, row, col);
-    const cellX = ex + Math.round(rect.x * scale);
-    const cellY = ey + Math.round(rect.y * scale);
-    const cellW = Math.round(rect.width * scale);
-    const cellH = Math.round(rect.height * scale);
+    const { x: cellX, y: cellY, width: cellW, height: cellH } = getCellRectPx(
+      elem,
+      row,
+      col,
+      scale,
+      ex,
+      ey
+    );
 
     const cellData = getCellData(elem, row, col);
     if (cellData?.backgroundColor && cellData.backgroundColor !== 'transparent') {
@@ -493,7 +513,23 @@ async function drawTableElement(
     const displayText = String(cellValue ?? '').trim();
     if (!displayText) continue;
 
-    drawTextInRect(ctx, textElem, cellX, cellY, cellW, cellH, displayText, scale);
+    drawTextContentInBox(
+      ctx,
+      {
+        ...textElem,
+        padding: 0,
+        paddingTop: 0,
+        paddingRight: 0,
+        paddingBottom: 0,
+        paddingLeft: 0,
+      },
+      cellX,
+      cellY,
+      cellW,
+      cellH,
+      displayText,
+      scale
+    );
   }
 
   drawTableGridLines(ctx, elem, ex, ey, scale);
@@ -561,8 +597,8 @@ export async function renderLabelToDataUrl(options: RenderLabelOptions): Promise
 
   const scale = scaleOption;
   const canvas = document.createElement('canvas');
-  canvas.width = Math.max(50, Math.round(widthMm * scale));
-  canvas.height = Math.max(50, Math.round(heightMm * scale));
+  canvas.width = Math.max(1, Math.round(widthMm * scale));
+  canvas.height = Math.max(1, Math.round(heightMm * scale));
 
   const ctx = canvas.getContext('2d');
   if (!ctx) return '';
@@ -618,133 +654,8 @@ export async function renderLabelToDataUrl(options: RenderLabelOptions): Promise
 
       drawElementFill(ctx, ex, ey, ew, eh, elem, radii);
 
-      const padPx = (() => {
-        const pad = resolvePaddingMm(elem);
-        return {
-          top: Math.round(pad.top * scale),
-          right: Math.round(pad.right * scale),
-          bottom: Math.round(pad.bottom * scale),
-          left: Math.round(pad.left * scale),
-        };
-      })();
-      const writableW = Math.max(1, ew - padPx.left - padPx.right);
-      const writableH = Math.max(1, eh - padPx.top - padPx.bottom);
+      drawTextContentInBox(ctx, elem, ex, ey, ew, eh, String(value), scale);
 
-      const fontStyle = elem.fontStyle === 'italic' ? 'italic ' : '';
-      const fontWeight = elem.fontWeight === 'bold' ? 'bold ' : '';
-      const fontSizePx = Math.max(6, Math.max(1, Math.round(elem.fontSize * 0.352777 * scale)));
-      const fontFamily =
-        elem.fontFamily === 'mono'
-          ? 'JetBrains Mono, SFMono-Regular, Consolas, Courier New, monospace'
-          : elem.fontFamily === 'serif'
-          ? 'Georgia, Times New Roman, serif'
-          : 'Inter, system-ui, -apple-system, Arial, sans-serif';
-
-      ctx.font = `${fontStyle}${fontWeight}${fontSizePx}px ${fontFamily}`.trim();
-      ctx.fillStyle = elem.textColor || '#111827';
-
-      const letterSpacingPx = Math.max(0, (elem.letterSpacing ?? 0) * scale);
-      if (letterSpacingPx > 0 && 'letterSpacing' in ctx) {
-        (ctx as CanvasRenderingContext2D & { letterSpacing: string }).letterSpacing =
-          `${letterSpacingPx}px`;
-      }
-
-      const wordWrap = elem.wordWrap !== false;
-      const lineHeight = fontSizePx * 1.25;
-      const columnWidth = lineHeight;
-      const isVertical = elem.textWritingMode === 'vertical';
-      ctx.textBaseline = 'middle';
-
-      const textScaleX = Math.max(0.1, Math.min(5, elem.textScaleX ?? 1));
-      const textScaleY = Math.max(0.1, Math.min(5, elem.textScaleY ?? 1));
-      const transformOriginX = ex + padPx.left + writableW / 2;
-      const transformOriginY = ey + padPx.top + writableH / 2;
-
-      ctx.save();
-      if (textScaleX !== 1 || textScaleY !== 1) {
-        ctx.translate(transformOriginX, transformOriginY);
-        ctx.scale(textScaleX, textScaleY);
-        ctx.translate(-transformOriginX, -transformOriginY);
-      }
-
-      const vAlign = elem.verticalAlign ?? 'middle';
-
-      if (isVertical) {
-        const columns = layoutVerticalTextColumns(String(value), writableH, lineHeight, wordWrap);
-        const totalColumnsWidth = columns.length * columnWidth;
-
-        let startX: number;
-        if (elem.textAlign === 'center') {
-          startX = ex + padPx.left + Math.max(0, (writableW - totalColumnsWidth) / 2) + columnWidth / 2;
-        } else if (elem.textAlign === 'right') {
-          startX = ex + padPx.left + Math.max(0, writableW - totalColumnsWidth) + columnWidth / 2;
-        } else {
-          startX = ex + padPx.left + columnWidth / 2;
-        }
-        ctx.textAlign = 'center';
-
-        for (let col = 0; col < columns.length; col++) {
-          const column = columns[col];
-          const colTextHeight = column.length * lineHeight;
-          let colStartY: number;
-          if (vAlign === 'top') {
-            colStartY = ey + padPx.top + lineHeight / 2;
-          } else if (vAlign === 'bottom') {
-            colStartY = ey + eh - padPx.bottom - colTextHeight + lineHeight / 2;
-          } else {
-            colStartY =
-              ey + padPx.top + Math.max(0, (writableH - colTextHeight) / 2) + lineHeight / 2;
-          }
-
-          const colX = startX + col * columnWidth;
-          for (let i = 0; i < column.length; i++) {
-            const charY = colStartY + i * lineHeight;
-            if (charY - lineHeight / 2 <= ey + eh - padPx.bottom) {
-              ctx.fillText(column[i], colX, charY);
-            }
-          }
-        }
-      } else {
-        const lines = layoutHorizontalTextLines(ctx, String(value), writableW, wordWrap);
-        const totalTextHeight = lines.length * lineHeight;
-
-        let textX = ex + padPx.left;
-        let textAlign: CanvasTextAlign = 'left';
-        if (elem.textAlign === 'center') {
-          textX = ex + padPx.left + writableW / 2;
-          textAlign = 'center';
-        } else if (elem.textAlign === 'right') {
-          textX = ex + padPx.left + (writableW - 2);
-          textAlign = 'right';
-        } else {
-          textX = ex + padPx.left + 2;
-        }
-        ctx.textAlign = textAlign;
-
-        let startY: number;
-        if (vAlign === 'top') {
-          startY = ey + padPx.top + lineHeight / 2;
-        } else if (vAlign === 'bottom') {
-          startY = ey + eh - padPx.bottom - totalTextHeight + lineHeight / 2;
-        } else {
-          startY =
-            ey + padPx.top + Math.max(0, (writableH - totalTextHeight) / 2) + lineHeight / 2;
-        }
-
-        for (let i = 0; i < lines.length; i++) {
-          const lineY = startY + i * lineHeight;
-          if (lineY - lineHeight / 2 <= ey + eh - padPx.bottom) {
-            const line = lines[i];
-            ctx.fillText(line, textX, lineY);
-            drawTextLineDecorations(ctx, elem, textX, lineY, line, fontSizePx, textAlign);
-          }
-        }
-      }
-
-      ctx.restore();
-      if (letterSpacingPx > 0 && 'letterSpacing' in ctx) {
-        (ctx as CanvasRenderingContext2D & { letterSpacing: string }).letterSpacing = '0px';
-      }
       ctx.restore();
       drawElementBorders(ctx, ex, ey, ew, eh, radii, sides, elem, scale);
     } else if (elem.type === 'barcode') {
@@ -813,22 +724,20 @@ export async function renderLabelToDataUrl(options: RenderLabelOptions): Promise
         }
       }
     } else if (elem.type === 'image') {
+      const primarySrc = value ? String(value).trim() : '';
+      const { img, showPlaceholder } = await resolveElementImage(elem, primarySrc, mode);
+
+      if (!img && !showPlaceholder) {
+        ctx.restore();
+        continue;
+      }
+
       drawElementChrome(ctx, ex, ey, ew, eh, elem, scale);
       const inner = getPaddedRectPx(ex, ey, ew, eh, elem, scale);
-      const src = value ? String(value).trim() : '';
-      if (!src) {
-        if (mode === 'design') {
-          drawImagePlaceholder(ctx, inner.x, inner.y, inner.w, inner.h, '图片');
-        }
-      } else {
-        try {
-          const img = await loadImage(src);
+      if (img) {
         drawImageWithFit(ctx, img, inner.x, inner.y, inner.w, inner.h, elem.imageFit ?? 'contain');
-        } catch {
-          if (mode === 'design') {
-            drawImagePlaceholder(ctx, inner.x, inner.y, inner.w, inner.h, '加载失败');
-          }
-        }
+      } else {
+        drawImagePlaceholder(ctx, inner.x, inner.y, inner.w, inner.h, '图片');
       }
     } else if (elem.type === 'table') {
       await drawTableElement(

src/tableUtils.ts

@@ -56,18 +56,49 @@ export function getTableColWidths(elem: TemplateElement): number[] {
   return Array.from({ length: cols }, () => even);
 }
 
-/** 内边距变化后保持行高/列宽不变，自动增大元素尺寸 */
+/** 将轨道尺寸总和调整为 targetTotal（保持相对比例，末项吸收取整误差） */
+function scaleTracksToTotal(tracks: number[], targetTotal: number, min = 0.5): number[] {
+  if (tracks.length === 0) return [];
+  const safeTotal = Math.max(tracks.length * min, targetTotal);
+  const current = tracks.reduce((a, b) => a + b, 0);
+  if (current <= 0) {
+    return distributeTracks(safeTotal, tracks.length, min);
+  }
+  const scaled = tracks.map((t) => round1(Math.max(min, (t / current) * safeTotal)));
+  const sum = scaled.reduce((a, b) => a + b, 0);
+  const diff = round1(safeTotal - sum);
+  if (scaled.length > 0 && diff !== 0) {
+    scaled[scaled.length - 1] = round1(Math.max(min, scaled[scaled.length - 1] + diff));
+  }
+  return scaled;
+}
+
+/** 将 inner 区域均分给 count 条轨道（末项吸收取整误差） */
+function distributeTracks(total: number, count: number, min = 0.5): number[] {
+  if (count <= 0) return [];
+  const safeTotal = Math.max(count * min, total);
+  const even = round1(safeTotal / count);
+  const tracks = Array.from({ length: count }, () => even);
+  const sum = tracks.reduce((a, b) => a + b, 0);
+  const diff = round1(safeTotal - sum);
+  if (tracks.length > 0 && diff !== 0) {
+    tracks[tracks.length - 1] = round1(Math.max(min, tracks[tracks.length - 1] + diff));
+  }
+  return tracks;
+}
+
+/** 内边距变化后保持元素外框尺寸不变，按比例重算行高/列宽以适配新的内容区 */
 export function expandTableForPadding(elem: TemplateElement): TemplateElement {
   if (elem.type !== 'table') return elem;
   const pad = resolvePaddingMm(elem);
-  const rowHeights = getTableRowHeights(elem);
-  const colWidths = getTableColWidths(elem);
+  const innerW = Math.max(1, elem.width - pad.left - pad.right);
+  const innerH = Math.max(1, elem.height - pad.top - pad.bottom);
   return {
     ...elem,
-    tableRowHeights: rowHeights,
-    tableColWidths: colWidths,
-    height: round1(rowHeights.reduce((a, b) => a + b, 0) + pad.top + pad.bottom),
-    width: round1(colWidths.reduce((a, b) => a + b, 0) + pad.left + pad.right),
+    tableRowHeights: scaleTracksToTotal(getTableRowHeights(elem), innerH),
+    tableColWidths: scaleTracksToTotal(getTableColWidths(elem), innerW),
+    width: elem.width,
+    height: elem.height,
   };
 }
 
@@ -183,6 +214,53 @@ export function getCellRectMm(
   return { x: round1(x), y: round1(y), width: round1(width), height: round1(height) };
 }
 
+/** 表格行列像素边界（累积取整，避免单元格背景/选区出现缝隙） */
+export function buildTableGridBoundariesPx(
+  elem: TemplateElement,
+  scale: number,
+  originX = 0,
+  originY = 0
+): { rowBounds: number[]; colBounds: number[] } {
+  const pad = resolvePaddingMm(elem);
+  const rowHeights = getTableRowHeights(elem);
+  const colWidths = getTableColWidths(elem);
+
+  const rowBounds: number[] = [originY + Math.round(pad.top * scale)];
+  for (const h of rowHeights) {
+    rowBounds.push(rowBounds[rowBounds.length - 1] + Math.round(h * scale));
+  }
+
+  const colBounds: number[] = [originX + Math.round(pad.left * scale)];
+  for (const w of colWidths) {
+    colBounds.push(colBounds[colBounds.length - 1] + Math.round(w * scale));
+  }
+
+  return { rowBounds, colBounds };
+}
+
+/** 单元格像素矩形，与 canvas 绘制及设计器选区 overlay 对齐 */
+export function getCellRectPx(
+  elem: TemplateElement,
+  row: number,
+  col: number,
+  scale: number,
+  originX = 0,
+  originY = 0
+): { x: number; y: number; width: number; height: number } {
+  const { rowBounds, colBounds } = buildTableGridBoundariesPx(elem, scale, originX, originY);
+  const anchor = getCellAnchor(elem, row, col);
+  const { rowSpan, colSpan } = getCellSpan(elem, anchor.row, anchor.col);
+
+  const x = colBounds[anchor.col];
+  const y = rowBounds[anchor.row];
+  return {
+    x,
+    y,
+    width: colBounds[anchor.col + colSpan] - x,
+    height: rowBounds[anchor.row + rowSpan] - y,
+  };
+}
+
 export function createDefaultTableElement(id: string, index: number): TemplateElement {
   const rows = 3;
   const cols = 3;
@@ -224,28 +302,6 @@ export function resizeTableGrid(
 ): TemplateElement {
   const rows = Math.max(1, Math.min(50, newRows));
   const cols = Math.max(1, Math.min(50, newCols));
-  const oldRows = getTableRows(elem);
-  const oldCols = getTableCols(elem);
-  const { width, height } = getTableInnerSizeMm(elem);
-
-  let rowHeights = getTableRowHeights(elem);
-  let colWidths = getTableColWidths(elem);
-
-  if (rows > oldRows) {
-    const added = rows - oldRows;
-    const avg = rowHeights.reduce((a, b) => a + b, 0) / oldRows;
-    rowHeights = [...rowHeights, ...Array.from({ length: added }, () => round1(avg))];
-  } else if (rows < oldRows) {
-    rowHeights = rowHeights.slice(0, rows);
-  }
-
-  if (cols > oldCols) {
-    const added = cols - oldCols;
-    const avg = colWidths.reduce((a, b) => a + b, 0) / oldCols;
-    colWidths = [...colWidths, ...Array.from({ length: added }, () => round1(avg))];
-  } else if (cols < oldCols) {
-    colWidths = colWidths.slice(0, cols);
-  }
 
   const newCells: Record<string, TableCellData> = {};
   if (elem.tableCells) {
@@ -259,15 +315,18 @@ export function resizeTableGrid(
   }
 
   const pad = resolvePaddingMm(elem);
+  const innerW = Math.max(1, elem.width - pad.left - pad.right);
+  const innerH = Math.max(1, elem.height - pad.top - pad.bottom);
+
   const next: TemplateElement = {
     ...elem,
     tableRows: rows,
     tableCols: cols,
-    tableRowHeights: rowHeights,
-    tableColWidths: colWidths,
+    tableRowHeights: distributeTracks(innerH, rows),
+    tableColWidths: distributeTracks(innerW, cols),
     tableCells: newCells,
-    width: round1(colWidths.reduce((a, b) => a + b, 0) + pad.left + pad.right),
-    height: round1(rowHeights.reduce((a, b) => a + b, 0) + pad.top + pad.bottom),
+    width: elem.width,
+    height: elem.height,
   };
   return sanitizeTableMerges(next);
 }

src/types.ts

@@ -133,6 +133,10 @@ export interface TemplateElement {
   locked?: boolean;
   /** 图片缩放方式，仅 type=image 时有效 */
   imageFit?: 'contain' | 'cover' | 'fill';
+  /** 默认图片 URL 或 data URI；主图加载失败时使用，仅 type=image 时有效 */
+  defaultImage?: string;
+  /** 输出模式下内容值为空时仍渲染；条码/二维码/图片有效，默认 false */
+  showWhenContentEmpty?: boolean;
   /** 文本显示格式，仅 type=text 时有效 */
   textFormat?: TextFormat;
   /** 数值/百分比/货币的小数位数，默认 2 */

src/utils.ts

@@ -524,7 +524,7 @@ export function extractTemplateVariables(template: {
       vars.add(v);
     }
     for (const rule of resolveVisibilityRules(elem)) {
-      const name = rule.variable.trim();
+      const name = (rule.variable ?? '').trim();
       if (name) vars.add(name);
     }
   }
@@ -539,7 +539,7 @@ export function getUsedTemplateVariables(template: { elements: TemplateElement[]
       vars.add(v);
     }
     for (const rule of resolveVisibilityRules(elem)) {
-      const name = rule.variable.trim();
+      const name = (rule.variable ?? '').trim();
       if (name) vars.add(name);
     }
   }
@@ -613,7 +613,7 @@ export function resolveVisibilityRules(elem: TemplateElement): VisibilityRule[]
     return elem.visibilityRules
       .map((r) => ({
         target: r.target ?? 'variable',
-        variable: r.variable.trim(),
+        variable: (r.variable ?? '').trim(),
         operator: r.operator,
         value: r.value,
       }))
@@ -1021,7 +1021,7 @@ export function resolveElementValue(
   return applyTextDisplayAffix(core, elem);
 }
 
-/** 输出模式下条码/二维码/图片内容为空时不渲染 */
+/** 输出模式下条码/二维码/图片内容为空时不渲染（除非 showWhenContentEmpty 为 true） */
 export function isGraphicContentEmpty(
   elem: TemplateElement,
   value: string,
@@ -1029,7 +1029,9 @@ export function isGraphicContentEmpty(
 ): boolean {
   if (mode === 'design') return false;
   if (elem.type !== 'barcode' && elem.type !== 'qrcode' && elem.type !== 'image') return false;
-  return !value || !String(value).trim();
+  const empty = !value || !String(value).trim();
+  if (!empty) return false;
+  return !elem.showWhenContentEmpty;
 }
 
 // Generate columns and rows based on paper dimensions, label dimensions, gaps, and margins