1 files changed, 90 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/voice/WaveformImage.java b/java/src/com/android/inputmethod/voice/WaveformImage.java
new file mode 100644
index 000000000..08d87c8f3
--- /dev/null
+++ b/java/src/com/android/inputmethod/voice/WaveformImage.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2008-2009 Google Inc.
+ * 
+ * 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.inputmethod.voice;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+
+import java.io.ByteArrayOutputStream;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.ShortBuffer;
+
+/**
+ * Utility class to draw a waveform into a bitmap, given a byte array
+ * that represents the waveform as a sequence of 16-bit integers.
+ * Adapted from RecognitionActivity.java.
+ */
+public class WaveformImage {
+    private static final int SAMPLING_RATE = 8000;
+
+    private WaveformImage() {}
+
+    public static Bitmap drawWaveform(
+        ByteArrayOutputStream waveBuffer, int w, int h, int start, int end) {
+        final Bitmap b = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
+        final Canvas c = new Canvas(b);
+        final Paint paint = new Paint();
+        paint.setColor(0xFFFFFFFF); // 0xRRGGBBAA
+        paint.setAntiAlias(true);
+        paint.setStrokeWidth(0);
+
+        final ShortBuffer buf = ByteBuffer
+            .wrap(waveBuffer.toByteArray())
+            .order(ByteOrder.nativeOrder())
+            .asShortBuffer();
+        buf.position(0);
+
+        final int numSamples = waveBuffer.size() / 2;
+        final int delay = (SAMPLING_RATE * 100 / 1000);
+        int endIndex = end / 2 + delay;
+        if (end == 0 || endIndex >= numSamples) {
+            endIndex = numSamples;
+        }
+        int index = start / 2 - delay;
+        if (index < 0) {
+            index = 0;
+        }
+        final int size = endIndex - index;
+        int numSamplePerPixel = 32;
+        int delta = size / (numSamplePerPixel * w);
+        if (delta == 0) {
+            numSamplePerPixel = size / w;
+            delta = 1;
+        }
+
+        final float scale = 3.5f / 65536.0f;
+        // do one less column to make sure we won't read past
+        // the buffer.
+        try {
+            for (int i = 0; i < w - 1 ; i++) {
+                final float x = i;
+                for (int j = 0; j < numSamplePerPixel; j++) {
+                    final short s = buf.get(index);
+                    final float y = (h / 2) - (s * h * scale);
+                    c.drawPoint(x, y, paint);
+                    index += delta;
+                }
+            }
+        } catch (IndexOutOfBoundsException e) {
+            // this can happen, but we don't care
+        }
+
+        return b;
+    }
+}