android/src/TextUtil.java

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 /* TextUtil.java - Android text handling to be used by C++ Code via jni.
  25  */
  26
  27 package org.xcsoar;
  28
  29 import android.graphics.Rect;
  30 import android.graphics.Paint;
  31 import android.graphics.Typeface;
  32 import android.graphics.Canvas;
  33 import android.graphics.Bitmap;
  34 import android.graphics.Color;
  35
  36 public class TextUtil {
  37   private Paint paint;
  38   private Paint.FontMetricsInt metrics;
  39   private int[] extent = new int[2];
  40   private int[] id = new int[3];
  41
  42   public TextUtil(String family_name, int style, int textSize) {
  43     Typeface tf = Typeface.create(family_name, style);
  44     paint = new Paint(Paint.ANTI_ALIAS_FLAG);
  45     paint.setTypeface(tf);
  46     paint.setTextSize(textSize);
  47     if ((style & Typeface.ITALIC) != 0 && !tf.isItalic())
  48       paint.setTextSkewX((float) -0.2);
  49
  50     metrics = paint.getFontMetricsInt();
  51   }
  52
  53   public void getFontMetrics(int[] metrics) {
  54     Rect bounds = new Rect();
  55     char[] m = new char[1];
  56     m[0] = 'M';
  57     paint.getTextBounds(m, 0, 1, bounds);
  58
  59     metrics[0] = Math.round(paint.descent() - paint.ascent());
  60     metrics[1] = paint.getTypeface().getStyle();
  61     metrics[2] = Math.round(-paint.ascent());
  62     metrics[3] = bounds.height();
  63     metrics[4] = Math.round(paint.getFontSpacing());
  64   }
  65
  66   public int[] getTextBounds(String text) {
  67     /* we cannot simply use getTextBounds() here, because xcsoar will not
  68      * know where the baseline of the text is inside the texture
  69      */
  70     extent[0] = Math.round(paint.measureText(text, 0, text.length()));
  71     extent[1] = metrics.descent - metrics.ascent;
  72     return extent;
  73   }
  74
  75   public int[] getTextTextureGL(String text) {
  76     getTextBounds(text);
  77
  78     // draw text into a bitmap
  79     Bitmap bmp = Bitmap.createBitmap(extent[0], extent[1],
  80                                      Bitmap.Config.ALPHA_8);
  81     bmp.eraseColor(Color.TRANSPARENT);
  82     paint.setColor(Color.WHITE);
  83     Canvas canvas = new Canvas(bmp);
  84     canvas.drawText(text, 0, -paint.getFontMetricsInt().ascent, paint);
  85
  86     // create OpenGL texture
  87     if (!BitmapUtil.bitmapToOpenGL(bmp, id))
  88       return null;
  89
  90     return id;
  91   }
  92 }