custom_font.java

本光盘是《J2ME无线移动游戏开发》一书的配套光盘

package ch10;

import javax.microedition.lcdui.*;

//该类实现了一个具有Font类同样功能的自定义字体类
public class Custom_Font {

  //声明一个代表字体风格的int型变量
  private int style;

  //声明一个代表字体大小的int型变量
  private int size;

  //声明一个代表字体基线的int型变量
  private int baseline;

  //声明一个代表字体高度的int型变量
  private int height;

  //声明一个代表字体宽度的int型变量
  private int width;

  //声明一个代表字库的Image型变量
  private Image image;

  /*
   5.构造器
   */
  private Custom_Font(
      Image inImage, int inStyle, int inSize) {
    image = inImage;
    style = inStyle;
    size = inSize;
    try {
      height = image.getHeight();
      width = image.getWidth() / 128;
      baseline = calculateBaseline();
    }
    catch (Exception e) {
      System.out.println(e.getMessage());
    }
  }

  /*
   6.获取字体
   */
  public static Custom_Font getFont(
      String inName, int inStyle, int inSize) {
    Image i;
    String filename = inName;
    try {
      i = Image.createImage(filename);
    }
    catch (Throwable t) {
      t.printStackTrace();
      throw new IllegalArgumentException(
          "Could not locate font: " + filename + " : " + t);
    }
    return new Custom_Font(i, inSize, inStyle);
  }

  /*
   7.计算基线
   */
  private int calculateBaseline() {

    int result = height;
    int imageWidth = image.getWidth();
    int max = 0;
    int total;
    int[] row = new int[imageWidth];
    int background;

    image.getRGB(row, 0, 1, 0, 0, 1, 1);
    background = row[0];

    for (int y = height / 2; y < height; y++) {
      total = 0;
      image.getRGB(row, 0, imageWidth, 0, y, imageWidth, 1);
      for (int x = 0; x < imageWidth; x++) {
        if (row[x] != background) {
          total++;
        }
      }
      if (total > max) {
        max = total;
        result = y;
      }
    }
    return result;
  }

  //获取多个字符宽度
  public int charsWidth(char[] ch, int offset, int length) {
    // monospaced font makes this an easy calculation
    return length * width;
  }

  //获取单个字符宽度
  public int charWidth(char ch) {
    return width;
  }

  //获取基线
  public int getBaselinePosition() {
    return baseline;
  }

  //获取高度
  public int getHeight() {
    return height;
  }

  //获取字符串宽度
  public int stringWidth(String str) {
    return charsWidth(str.toCharArray(), 0, str.length());
  }

  //获取子字符串宽度
  public int substringWidth(String str, int offset, int len) {
    return charsWidth(str.toCharArray(), offset, len);
  }

  //获取字体大小
  public int getSize() {
    return size;
  }

  //获取字体风格
  public int getStyle() {
    return style;
  }

  //测试字体是否为黑体
  public boolean isBold() {
    return ( (style & Font.STYLE_BOLD) != 0);
  }

  //测试字体是否为斜体
  public boolean isItalic() {
    return ( (style & Font.STYLE_ITALIC) != 0);
  }

  //测试字体是否为平体
  public boolean isPlain() {
    return (style == 0);
  }

  //测试字体是否为强调体
  public boolean isUnderlined() {
    return ( (style & Font.STYLE_UNDERLINED) != 0);
  }

  //绘制单个字符
  public void drawChar(
      Graphics g, char character, int x, int y, int anchor) {
    int clipX = g.getClipX();
    int clipY = g.getClipY();
    int clipW = g.getClipWidth();
    int clipH = g.getClipHeight();

    drawCharInternal(g, character, x, y, anchor);

    g.setClip(clipX, clipY, clipW, clipH);
  }

  /*
   8.绘制多个字符
   */
  public void drawChars(
      Graphics g, char[] data,
      int offset, int length, int x, int y, int anchor) {
    if ( (anchor & g.RIGHT) != 0) {
      x -= charsWidth(data, offset, length);
    }
    else
    if ( (anchor & g.HCENTER) != 0) {
      x -= (charsWidth(data, offset, length) / 2);
    }

    if ( (anchor & g.BOTTOM) != 0) {
      y -= height;
    }
    else
    if ( (anchor & g.VCENTER) != 0) {
      y -= height / 2;
    }

    int clipX = g.getClipX();
    int clipY = g.getClipY();
    int clipW = g.getClipWidth();
    int clipH = g.getClipHeight();

    char c;
    for (int i = 0; i < length; i++) {
      c = data[offset + i];
      drawCharInternal(g, c, x, y, g.TOP | g.LEFT);
      x += width;
    }

    g.setClip(clipX, clipY, clipW, clipH);
  }

  /*
    9.绘制图形字符
   */
  private void drawCharInternal(
      Graphics g, char character, int x, int y, int anchor) {
    if ( (style & Font.STYLE_ITALIC) != 0) {
      g.setClip(x + 1, y, width, height / 2);
      g.drawImage(
          image, x - width * character + 1, y, anchor);
      g.setClip(x, y + height / 2, width, height / 2);
      g.drawImage(
          image, x - width * character, y, anchor);

      if ( (style & Font.STYLE_BOLD) != 0) {
        g.setClip(x, y, width, height / 2);
        g.drawImage(
            image, x - width * character + 2, y, anchor);
        g.setClip(x, y + height / 2, width, height / 2);
        g.drawImage(
            image, x - width * character + 1, y, anchor);
      }
    }
    else {
      g.setClip(x, y, width, height);
      g.drawImage(
          image, x - width * character, y, anchor);

      if ( (style & Font.STYLE_BOLD) != 0) {
        g.drawImage(
            image, x - width * character + 1, y, anchor);
      }
    }

    if ( (style & Font.STYLE_UNDERLINED) != 0) {
      g.drawLine(
          x, y + baseline + 2, x + width, y + baseline + 2);
    }
  }

  //绘制字符串
  public void drawString(Graphics g, String str, int x, int y, int anchor) {
    drawChars(g, str.toCharArray(), 0, str.length(), x, y, anchor);
  }

  //绘制子字符串
  public void drawSubstring(
      Graphics g, String str,
      int offset, int len, int x, int y, int anchor) {
    drawChars(g, str.toCharArray(), offset, len, x, y, anchor);
  }

}