feat(文字预览): 优化文字预览内存占用

assets/webui/ofdgo_edit.js

@@ -1379,6 +1379,8 @@ export class CanvasEditor {
 				bottom = Math.max(bottom, y + size - baseline);
 			}
 			for (const char of run.text) {
+				x = run.positions[index][0] * PX_PER_MM;
+				y = run.positions[index][1] * PX_PER_MM;
 				const span = document.createElement("span"), node = document.createTextNode(char);
 				span.append(node);
 				Object.assign(span.style, { display: "inline-block", opacity: String((item.alpha ?? 255) / 255), transformOrigin: "left top", transform: `translate(${x - naturalX}px,${y - baseline - lineIndex * size}px) scaleX(${source.scale})` });
@@ -1391,8 +1393,6 @@ export class CanvasEditor {
 				right = Math.max(right, x + advance * source.scale);
 				bottom = Math.max(bottom, y + size - baseline);
 				naturalX += advance;
-				x += run.dx?.length ? run.dx[Math.min(index, run.dx.length - 1)] * PX_PER_MM : 0;
-				y += run.dy?.length ? run.dy[Math.min(index, run.dy.length - 1)] * PX_PER_MM : 0;
 				index++;
 			}
 			if (!line.hasChildNodes()) {

internal/webui/wasm.go

@@ -2346,8 +2346,15 @@ func previewText(args []js.Value) (any, error) {
 			offset++
 		}
 		content := (ofdgo.TextObject{TextCode: []ofdgo.TextCode{code}}).Text()
-		runs = append(runs, map[string]any{"text": content, "x": x, "y": y, "dx": code.GetDeltaX(), "dy": code.GetDeltaY(), "line": line})
-		offset += len([]rune(content))
+		code.X, code.Y = fmt.Sprint(x), fmt.Sprint(y)
+		positioner := ofdgo.NewTextPositioner(code)
+		positions := make([][2]float64, len([]rune(content)))
+		for i := range positions {
+			point := positioner.Next()
+			positions[i] = [2]float64{point.X, point.Y}
+		}
+		runs = append(runs, map[string]any{"text": content, "x": x, "y": y, "positions": positions, "line": line})
+		offset += len(positions)
 	}
 	scale := text.HScale
 	if scale == 0 {