Use a host java program to generate the background text

This program uses java.awt.Graphics2D to generate the background text
files used under recovery mode. And thus we don't need to do the manual
work by running emulators with different dpi.

The program takes the following parameters:
1. imageWidth: The number of pixels per line; and the text strings will be
   wrapped accordingly.
2. textName: The description of the text string, e.g. "recovery_erasing",
   "recovery_installing_security"
3. fontDirectory: The directory that contains all the support .ttf | .ttc
   files, e.g. $OUT/system/fonts/
4. resourceDirectory: The resource directory that contains all the translated
   strings in xml format, e.g. bootable/recovery/tools/recovery_l10n/res/
5. outputFilename: Path to the generated image.

Bug: 74397117
Test: checks the generated png files
Change-Id: Ia5506a0a4f5da1ebfd7090345eb246f44b265075

tools/image_generator/Android.bp

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+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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.
+
+java_library_host {
+    name: "RecoveryImageGenerator",
+
+    manifest: "ImageGenerator.mf",
+
+    srcs: [
+        "ImageGenerator.java",
+    ],
+}

tools/image_generator/ImageGenerator.java

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+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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.android.recovery.tools;
+
+import java.awt.Color;
+import java.awt.Font;
+import java.awt.FontFormatException;
+import java.awt.FontMetrics;
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.StringTokenizer;
+
+import javax.imageio.ImageIO;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * Command line tool to generate the localized image for recovery mode.
+ */
+public class ImageGenerator {
+  // Initial height of the image to draw.
+  private static final int INITIAL_HEIGHT = 20000;
+
+  private static final float DEFAULT_FONT_SIZE = 40;
+
+  // This is the canvas we used to draw texts.
+  private BufferedImage mBufferedImage;
+
+  // The width in pixels of our image. Once set, its value won't change.
+  private final int mImageWidth;
+
+  // The current height in pixels of our image. We will adjust the value when drawing more texts.
+  private int mImageHeight;
+
+  // The current vertical offset in pixels to draw the top edge of new text strings.
+  private int mVerticalOffset;
+
+  // The font size to draw the texts.
+  private final float mFontSize;
+
+  // The name description of the text to localize. It's used to find the translated strings in the
+  // resource file.
+  private final String mTextName;
+
+  // The directory that contains all the needed font files (e.g. ttf, otf, ttc files).
+  private final String mFontDirPath;
+
+  // An explicit map from language to the font name to use.
+  // The map is extracted from frameworks/base/data/fonts/fonts.xml.
+  // And the language-subtag-registry is found in:
+  // https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry
+  private static final String DEFAULT_FONT_NAME = "Roboto-Regular";
+  private static final Map<String, String> LANGUAGE_TO_FONT_MAP = new TreeMap<String, String>() {{
+    put("am", "NotoSansEthiopic-Regular");
+    put("ar", "NotoNaskhArabicUI-Regular");
+    put("as", "NotoSansBengaliUI-Regular");
+    put("bn", "NotoSansBengaliUI-Regular");
+    put("fa", "NotoNaskhArabicUI-Regular");
+    put("gu", "NotoSansGujaratiUI-Regular");
+    put("hi", "NotoSansDevanagariUI-Regular");
+    put("hy", "NotoSansArmenian-Regular");
+    put("iw", "NotoSansHebrew-Regular");
+    put("ja", "NotoSansCJK-Regular");
+    put("ka", "NotoSansGeorgian-Regular");
+    put("ko", "NotoSansCJK-Regular");
+    put("km", "NotoSansKhmerUI-Regular");
+    put("kn", "NotoSansKannadaUI-Regular");
+    put("lo", "NotoSansLaoUI-Regular");
+    put("ml", "NotoSansMalayalamUI-Regular");
+    put("mr", "NotoSansDevanagariUI-Regular");
+    put("my", "NotoSansMyanmarUI-Regular");
+    put("ne", "NotoSansDevanagariUI-Regular");
+    put("or", "NotoSansOriya-Regular");
+    put("pa", "NotoSansGurmukhiUI-Regular");
+    put("si", "NotoSansSinhala-Regular");
+    put("ta", "NotoSansTamilUI-Regular");
+    put("te", "NotoSansTeluguUI-Regular");
+    put("th", "NotoSansThaiUI-Regular");
+    put("ur", "NotoNaskhArabicUI-Regular");
+    put("zh", "NotoSansCJK-Regular");
+  }};
+
+  /**
+   * Exception to indicate the failure to find the translated text strings.
+   */
+  public static class LocalizedStringNotFoundException extends Exception {
+    public LocalizedStringNotFoundException(String message) {
+      super(message);
+    }
+
+    public LocalizedStringNotFoundException(String message, Throwable cause) {
+      super(message, cause);
+    }
+  }
+
+  /**
+   * Initailizes the fields of the image image.
+   */
+  public ImageGenerator(int imageWidth, String textName, float fontSize, String fontDirPath) {
+    mImageWidth = imageWidth;
+    mImageHeight = INITIAL_HEIGHT;
+    mVerticalOffset = 0;
+
+    // Initialize the canvas with the default height.
+    mBufferedImage = new BufferedImage(mImageWidth, mImageHeight, BufferedImage.TYPE_BYTE_GRAY);
+
+    mTextName = textName;
+    mFontSize = fontSize;
+    mFontDirPath = fontDirPath;
+  }
+
+  /**
+   * Finds the translated text string for the given textName by parsing the resourceFile.
+   * Example of the xml fields:
+   * <resources xmlns:android="http://schemas.android.com/apk/res/android">
+   *   <string name="recovery_installing_security" msgid="9184031299717114342">
+   * "Sicherheitsupdate wird installiert"</string>
+   * </resources>
+   *
+   * @param resourceFile the input resource file in xml format.
+   * @param textName the name description of the text.
+   *
+   * @return the string representation of the translated text.
+   */
+  private String getTextString(File resourceFile, String textName) throws IOException,
+      ParserConfigurationException, org.xml.sax.SAXException, LocalizedStringNotFoundException {
+    DocumentBuilderFactory builder = DocumentBuilderFactory.newInstance();
+    DocumentBuilder db = builder.newDocumentBuilder();
+
+    Document doc = db.parse(resourceFile);
+    doc.getDocumentElement().normalize();
+
+    NodeList nodeList = doc.getElementsByTagName("string");
+    for (int i = 0; i < nodeList.getLength(); i++) {
+      Node node = nodeList.item(i);
+      String name = node.getAttributes().getNamedItem("name").getNodeValue();
+      if (name.equals(textName)) {
+        return node.getTextContent();
+      }
+    }
+
+    throw new LocalizedStringNotFoundException(textName + " not found in "
+        + resourceFile.getName());
+  }
+
+  /**
+   * Constructs the locale from the name of the resource file.
+   */
+  private Locale getLocaleFromFilename(String filename) throws IOException {
+    // Gets the locale string by trimming the top "values-".
+    String localeString = filename.substring(7);
+    if (localeString.matches("[A-Za-z]+")) {
+      return Locale.forLanguageTag(localeString);
+    }
+    if (localeString.matches("[A-Za-z]+-r[A-Za-z]+")) {
+      // "${Language}-r${Region}". e.g. en-rGB
+      String[] tokens = localeString.split("-r");
+      return Locale.forLanguageTag(String.join("-", tokens));
+    }
+    if (localeString.startsWith("b+")) {
+      // The special case of b+sr+Latn, which has the form "b+${Language}+${ScriptName}"
+      String[] tokens = localeString.substring(2).split("\\+");
+      return Locale.forLanguageTag(String.join("-", tokens));
+    }
+
+    throw new IOException("Unrecognized locale string " + localeString);
+  }
+
+  /**
+   * Iterates over the xml files in the format of values-$LOCALE/strings.xml under the resource
+   * directory and collect the translated text.
+   *
+   * @param resourcePath the path to the resource directory
+   *
+   * @return a map with the locale as key, and translated text as value
+   *
+   * @throws LocalizedStringNotFoundException if we cannot find the translated text for the given
+   *    locale
+   **/
+  public Map<Locale, String> readLocalizedStringFromXmls(String resourcePath) throws
+      IOException, LocalizedStringNotFoundException {
+    File resourceDir = new File(resourcePath);
+    if (!resourceDir.isDirectory()) {
+      throw new LocalizedStringNotFoundException(resourcePath + " is not a directory.");
+    }
+
+    Map<Locale, String> result =
+        new TreeMap<Locale, String>(Comparator.comparing(Locale::toLanguageTag));
+
+    // Find all the localized resource subdirectories in the format of values-$LOCALE
+    String[] nameList = resourceDir.list(
+        (File file, String name) -> name.startsWith("values-"));
+    for (String name : nameList) {
+      File textFile = new File(resourcePath, name + "/strings.xml");
+      String localizedText;
+      try {
+        localizedText = getTextString(textFile, mTextName);
+      } catch (IOException | ParserConfigurationException | org.xml.sax.SAXException e) {
+        throw new LocalizedStringNotFoundException(
+            "Failed to read the translated text for locale " + name, e);
+      }
+
+      Locale locale = getLocaleFromFilename(name);
+      // Removes the double quotation mark from the text.
+      result.put(locale, localizedText.substring(1, localizedText.length() - 1));
+    }
+
+    return result;
+  }
+
+  /**
+   * Returns a font object associated given the given locale
+   *
+   * @throws IOException if the font file fails to open
+   * @throws FontFormatException if the font file doesn't have the expected format
+   */
+  private Font loadFontsByLocale(String language) throws IOException, FontFormatException {
+    String fontName = LANGUAGE_TO_FONT_MAP.getOrDefault(language, DEFAULT_FONT_NAME);
+    String[] suffixes = {".otf", ".ttf", ".ttc"};
+    for (String suffix : suffixes ) {
+      File fontFile = new File(mFontDirPath, fontName + suffix);
+      if (fontFile.isFile()) {
+        return Font.createFont(Font.TRUETYPE_FONT, fontFile).deriveFont(mFontSize);
+      }
+    }
+
+    throw new IOException("Can not find the font file " + fontName + " for language " + language);
+  }
+
+  /**
+   * Separates the text string by spaces and wraps it by words.
+  **/
+  private List<String> wrapTextByWords(String text, FontMetrics metrics) {
+    List<String> wrappedText = new ArrayList<>();
+    StringTokenizer st = new StringTokenizer(text, " \n");
+
+    StringBuilder line = new StringBuilder();
+    while (st.hasMoreTokens()) {
+      String token = st.nextToken();
+      if (metrics.stringWidth(line + token + " ") > mImageWidth) {
+        wrappedText.add(line.toString());
+        line = new StringBuilder();
+      }
+      line.append(token).append(" ");
+    }
+    wrappedText.add(line.toString());
+
+    return wrappedText;
+  }
+
+  /**
+   * Wraps the text with a maximum of mImageWidth pixels per line.
+   *
+   * @param text the string representation of text to wrap
+   * @param metrics the metrics of the Font used to draw the text; it gives the width in pixels of
+   *    the text given its string representation
+   *
+   * @return a list of strings with their width smaller than mImageWidth pixels
+   */
+  private List<String> wrapText(String text, FontMetrics metrics) {
+    // TODO(xunchang) handle other cases of text wrapping
+    // 1. RTL languages: "ar"(Arabic), "fa"(Persian), "he"(Hebrew), "iw"(Hebrew), "ur"(Urdu)
+    // 2. Language uses characters: CJK, "lo"(lao), "km"(khmer)
+
+    return wrapTextByWords(text, metrics);
+  }
+
+  /**
+   * Draws the text string on the canvas for given locale.
+   *
+   * @param text the string to draw on canvas
+   * @param locale the current locale tag of the string to draw
+   *
+   * @throws IOException if we cannot find the corresponding font file for the given locale.
+   * @throws FontFormatException if we failed to load the font file for the given locale.
+   */
+  private void drawText(String text, Locale locale) throws IOException, FontFormatException  {
+    Graphics2D graphics = mBufferedImage.createGraphics();
+    graphics.setColor(Color.WHITE);
+    graphics.setRenderingHint(
+        RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
+    graphics.setFont(loadFontsByLocale(locale.getLanguage()));
+
+    System.out.println("Drawing text for locale " + locale + " text " + text);
+
+    FontMetrics fontMetrics = graphics.getFontMetrics();
+    List<String> wrappedText = wrapTextByWords(text, fontMetrics);
+    for (String line : wrappedText) {
+      int lineHeight = fontMetrics.getHeight();
+      // Doubles the height of the image if we are short of space.
+      if (mVerticalOffset + lineHeight >= mImageHeight) {
+        resizeHeight(mImageHeight * 2);
+      }
+
+      // Draws the text at mVerticalOffset and increments the offset with line space.
+      int baseLine = mVerticalOffset + lineHeight - fontMetrics.getDescent();
+      graphics.drawString(line, 0, baseLine);
+      mVerticalOffset += lineHeight;
+    }
+  }
+
+  /**
+   * Redraws the image with the new height.
+   *
+   * @param height the new height of the image in pixels.
+   */
+  private void resizeHeight(int height) {
+    BufferedImage resizedImage =
+        new BufferedImage(mImageWidth, height, BufferedImage.TYPE_BYTE_GRAY);
+    Graphics2D graphic = resizedImage.createGraphics();
+    graphic.drawImage(mBufferedImage, 0, 0, null);
+    graphic.dispose();
+
+    mBufferedImage = resizedImage;
+    mImageHeight = height;
+  }
+
+  /**
+   *  This function draws the font characters and saves the result to outputPath.
+   *
+   * @param localizedTextMap a map from locale to its translated text string
+   * @param outputPath the path to write the generated image file.
+   *
+   * @throws FontFormatException if there's a format error in one of the font file
+   * @throws IOException if we cannot find the font file for one of the locale, or we failed to
+   *    write the image file.
+   */
+  public void generateImage(Map<Locale, String> localizedTextMap, String outputPath) throws
+      FontFormatException, IOException {
+    for (Locale locale : localizedTextMap.keySet()) {
+      // TODO(xunchang) reprocess the locales for the same language and make the last locale the
+      // catch-all type. e.g. "zh-CN, zh-HK, zh-TW" will become "zh-CN, zh-HK, zh"
+      // Or maybe we don't need to support these variants?
+      drawText(localizedTextMap.get(locale), locale);
+    }
+
+    // TODO(xunchang) adjust the width to save some space if all texts are smaller than imageWidth.
+    resizeHeight(mVerticalOffset);
+    ImageIO.write(mBufferedImage, "png", new File(outputPath));
+  }
+
+  public static void printUsage() {
+    System.out.println("Usage: java -jar path_to_jar imageWidth textName fontDirectory"
+        + " resourceDirectory outputFilename");
+  }
+
+  public static void main(String[] args) throws NumberFormatException, IOException,
+      FontFormatException, LocalizedStringNotFoundException {
+    if (args.length != 5) {
+      printUsage();
+      System.err.println("We expect 5 arguments, get " + args.length);
+      System.exit(1);
+    }
+
+    // TODO(xunchang) switch to commandline parser
+    int imageWidth = Integer.parseUnsignedInt(args[0]);
+
+    ImageGenerator imageGenerator =
+        new ImageGenerator(imageWidth, args[1], DEFAULT_FONT_SIZE, args[2]);
+
+    Map<Locale, String> localizedStringMap =
+        imageGenerator.readLocalizedStringFromXmls(args[3]);
+    imageGenerator.generateImage(localizedStringMap, args[4]);
+  }
+}
+

tools/image_generator/ImageGenerator.mf

@@ -0,0 +1 @@
+Main-Class: com.android.recovery.tools.ImageGenerator

tools/image_generator/README.md

@@ -0,0 +1,20 @@
+Recovery Image Generator
+-------------------------
+
+This program uses java.awt.Graphics2D to generate the background text files used
+under recovery mode. And thus we don't need to do the manual work by running
+emulators with different dpi.
+
+# Usage:
+  `java -jar path_to_jar imageWidth textName fontDirectory resourceDirectory outputFilename`
+
+# Description of the parameters:
+1. `imageWidth`: The number of pixels per line; and the text strings will be
+   wrapped accordingly.
+2. `textName`: The description of the text string, e.g. "recovery_erasing",
+   "recovery_installing_security"
+3. `fontDirectory`: The directory that contains all the support .ttf | .ttc
+   files, e.g. $OUT/system/fonts/
+4. `resourceDirectory`: The resource directory that contains all the translated
+   strings in xml format, e.g. bootable/recovery/tools/recovery_l10n/res/
+5. `outputFilename`: Path to the generated image.