UpdateVersion to 0.3.0

	修改：     Cargo.toml
	修改：     UpdateLog.md
	修改：     src/lib.rs

Author: A4-Tacks

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "term_lattice"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2021"
 
 license = "MIT"

UpdateLog.md

@@ -7,3 +7,6 @@ Modified failed but reasonable assertions
 
 # v0.2.0
 Modified some display sections, added some practical methods, and adjusted the visibility of some fields.
+
+# v0.3.0
+Revised the visibility of some fields again and added some methods

src/lib.rs

@@ -5,7 +5,7 @@ use std::{
     },
     cell::{
         RefCell,
-        RefMut,
+        RefMut, Ref,
     },
 };
 use enum_variant_eq::{
@@ -470,12 +470,12 @@ mod color_test {
 /// ```
 #[derive(Clone, Debug)]
 pub struct ScreenBuffer {
-    pub colors: RefCell<Vec<Color>>,
+    colors: RefCell<Vec<Color>>,
     /// Colors present in the output area
-    pub background_colors: RefCell<Vec<Color>>,
+    background_colors: RefCell<Vec<Color>>,
     /// The value of this field should be the color of the last change.
     /// Subscript 0 is the background color, and subscript 1 is the foreground color
-    pub prev_color: RefCell<[Color; 2]>,
+    prev_color: RefCell<[Color; 2]>,
     size: Position,
     /// config
     pub cfg: Config,
@@ -592,6 +592,14 @@ impl ScreenBuffer {
     pub fn init_prev_color(&self) {
         *self.prev_color.borrow_mut() = [Color::None; 2];
     }
+    /// get prev_color ref
+    pub fn get_prev_color(&self) -> Ref<[Color; 2]> {
+        self.prev_color.borrow()
+    }
+    /// get prev_color mut ref
+    pub fn get_prev_color_mut(&self) -> RefMut<[Color; 2]> {
+        self.prev_color.borrow_mut()
+    }
     /// 两颜色在此缓冲区是否判定为相似
     fn color_similarity(&self, color1: &Color, color2: &Color) -> bool {
         color1.chromatic_aberration(color2) < self.cfg.chromatic_aberration