diff --git a/packages/frontend/src/components/MkWatermarkEditorDialog.Layer.vue b/packages/frontend/src/components/MkWatermarkEditorDialog.Layer.vue
index 33ad6db78a..f58b08c393 100644
--- a/packages/frontend/src/components/MkWatermarkEditorDialog.Layer.vue
+++ b/packages/frontend/src/components/MkWatermarkEditorDialog.Layer.vue
@@ -108,9 +108,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 	</template>
 
 	<MkImageEffectorFxForm
-		v-else-if="fx != null"
+		v-else-if="layerParamDefs != null"
 		v-model="layer"
-		:paramDefs="fx.params"
+		:paramDefs="layerParamDefs"
 	/>
 </div>
 </template>
@@ -118,7 +118,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script setup lang="ts">
 import { ref, computed, onMounted } from 'vue';
 import * as Misskey from 'misskey-js';
-import { WATERMARK_FXS } from '@/utility/watermark.js';
+import { WatermarkRenderer } from '@/utility/watermark.js';
 import type { WatermarkPreset } from '@/utility/watermark.js';
 import type { ImageEffectorFx } from '@/utility/image-effector/ImageEffector.js';
 import { i18n } from '@/i18n.js';
@@ -134,7 +134,11 @@ import { selectFile } from '@/utility/drive.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
 
 const layer = defineModel<WatermarkPreset['layers'][number]>('layer', { required: true });
-const fx = computed(() => WATERMARK_FXS.find((fx) => fx.id !== 'watermarkPlacement' && fx.id === layer.value.type) as Exclude<typeof WATERMARK_FXS[number], ImageEffectorFx<"watermarkPlacement", any, any>> ?? null);
+const layerParamDefs = computed(() => {
+	const def = WatermarkRenderer.getLayerDef(layer.value.type);
+	if (def == null || def.id === 'watermarkPlacement') return null;
+	return def.params;
+});
 
 const driveFile = ref<Misskey.entities.DriveFile | null>(null);
 const driveFileError = ref(false);
diff --git a/packages/frontend/src/utility/watermark.ts b/packages/frontend/src/utility/watermark.ts
index 86e9a0ad8b..59f6732082 100644
--- a/packages/frontend/src/utility/watermark.ts
+++ b/packages/frontend/src/utility/watermark.ts
@@ -89,6 +89,29 @@ export class WatermarkRenderer {
 		});
 	}
 
+	public static getLayerDef(type: WatermarkPreset['layers'][number]['type']): ImageEffectorFx | null {
+		let fxId: typeof WATERMARK_FXS[number]['id'];
+		switch (type) {
+			case 'text':
+			case 'image':
+				fxId = 'watermarkPlacement';
+				break;
+			case 'stripe':
+				fxId = 'stripe';
+				break;
+			case 'polkadot':
+				fxId = 'polkadot';
+				break;
+			case 'checker':
+				fxId = 'checker';
+				break;
+			default:
+				throw new Error(`Unknown layer type: ${type}`);
+		}
+
+		return WATERMARK_FXS.find(fx => fx.id === fxId) ?? null;
+	}
+
 	private makeImageEffectorLayers(): ImageEffectorLayer[] {
 		return this.layers.map(layer => {
 			if (layer.type === 'text') {