feat(文件拆分): 拆分字体图像基础能力

internal/base/font/usage.go

@@ -0,0 +1,28 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+// Usage 指定子集需要保留的字符、字形及引用是否存在不确定性
+type Usage struct {
+	Characters map[rune]bool
+	Glyphs     map[uint16]bool
+	Unsafe     bool
+}
+
+// newUsage 创建具有可写字符和字形集合的子集输入
+// 返回: *Usage 用字信息
+func newUsage() *Usage {
+	return &Usage{Characters: make(map[rune]bool), Glyphs: make(map[uint16]bool)}
+}