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history/005a_letter_test/src/main/java/com/gitee/drinkjava2/frog/util/StringPixelUtils.java

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+/* Copyright 2018-2020 the original author or authors.
+ *
+ * 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 com.gitee.drinkjava2.frog.util;
+
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * StringPixelUtils used to get pixel array from a given string
+ * 
+ * 根据给定的字体和字符串，返回它的像素点阵，lettersMap[0][0]是左下角素
+ * 
+ * @author Yong Zhu
+ * @since 2.0.2
+ */
+public class StringPixelUtils {
+	private static final Map<String, byte[][]> lettersMap = new HashMap<>();
+
+	public static byte[][] getSanserif10Pixels(String s) {
+		return getStringPixels(Font.SANS_SERIF, Font.PLAIN, 10, s);
+	}
+	
+	public static byte[][] getSanserif12Pixels(String s) {
+		return getStringPixels(Font.SANS_SERIF, Font.PLAIN, 12, s);
+	}
+	
+	public static byte[][] getSanserifItalic10Pixels(String s) {
+		return getStringPixels(Font.SANS_SERIF, Font.ITALIC, 10, s);
+	}
+
+	/* 在内存 BufferedImage里输出文本并获取它的像素点 */
+	public static byte[][] getStringPixels(String fontName, int fontStyle, int fontSize, String s) {
+		String key = new StringBuilder(fontName).append("_").append(fontStyle).append("_").append(fontSize).append("_")
+				.append(s).toString();
+		if (lettersMap.containsKey(key))
+			return lettersMap.get(key);
+		Font font = new Font(fontName, fontStyle, fontSize);
+
+		BufferedImage bi = new BufferedImage(fontSize * 10, fontSize * 50, BufferedImage.TYPE_INT_RGB);
+		Graphics g = bi.getGraphics();
+		Graphics2D g2d = (Graphics2D) g;
+		g2d.setFont(font);
+		FontMetrics fm = g2d.getFontMetrics();
+		int strHeight = fm.getAscent() + fm.getDescent() - 1;
+		int strWidth = fm.stringWidth(s);
+		g2d.drawString(s, 0, fm.getAscent() - fm.getLeading() -1);
+		
+        int ystart;//在命令行和eclipse下会有不同的空行，所以要用ystart和yend来获取有效象素行数
+        loop1: for (ystart = 0; ystart < strHeight; ystart++)
+            for (int x = 0; x < strWidth; x++) {
+                if (bi.getRGB(x, ystart) == -1)
+                    break loop1;
+            }
+        
+        int yend;
+        loop2: for (yend = strHeight; yend >= 0; yend--)
+            for (int x = 0; x < strWidth; x++) {
+                if (bi.getRGB(x, yend) == -1)
+                    break loop2;
+            }
+
+		byte[][] b = new byte[strWidth][yend-ystart+1];
+		for (int y = ystart; y <= yend; y++)
+			for (int x = 0; x < strWidth; x++)
+				if (bi.getRGB(x, y ) == -1)
+					b[x][yend-y] = 1;
+				else
+					b[x][yend-y] = 0;
+		lettersMap.put(key, b);
+		return b;
+	}
+
+	/*- 这个是测试输出，平时不需要用 
+	public static void main(String[] args) {
+		byte[][] c = getStringPixels(Font.SANS_SERIF, Font.PLAIN, 12, "Test点阵输出青青园中");
+		int w = c.length;
+		int h = c[0].length;
+	
+		for (int y = 0; y < h; y++) {
+			for (int x = 0; x < w; x++) {
+				if (c[x][h - y - 1] > 0)
+					System.out.print("*");
+				else
+					System.out.print(" ");
+			}
+			System.out.println("|");
+		}
+	}
+	*/
+}