Add velocity sensitivity preferences

A fairly simple feature - preferences for velocity sensitivity, but a
fair amount of UI infrastructure. This patch includes a new
KnobPreference, changes to KnobView to support a horizontal layout
(which works better in a layout with more compressed vertical space),
and of course the plumbing of the preference itself.

Also some rework of the touch handler in the KeyboardView. This patch
simplifies the logic a bit and fixes a long-standing bug in which the
pressure was always read from pointer index 0 rather than the pointer
index of the key being pressed.

android/res/layout/knobpreflayout_va.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.levien.synthesizer.android.widgets.knob.KnobView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res/com.levien.synthesizer"
+    android:id="@+id/knob"
+    app:value="0"
+    app:min="0"
+    app:max="127"
+    app:numberformat="%3.0f"
+    app:horizontal="true"
+    android:layout_width="200dp"
+    android:layout_height="match_parent"
+    app:label="" />

android/res/layout/knobpreflayout_vs.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.levien.synthesizer.android.widgets.knob.KnobView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res/com.levien.synthesizer"
+    android:id="@+id/knob"
+    app:value="0"
+    app:min="0"
+    app:max="2"
+    app:horizontal="true"
+    android:layout_width="200dp"
+    android:layout_height="match_parent"
+    app:label="" />

android/res/values/attrs.xml

@@ -8,6 +8,8 @@
     <attr name="min" format="float" />
     <attr name="max" format="float" />
     <attr name="label" format="string" />
+    <attr name="numberformat" format="string" />
+    <attr name="horizontal" format="boolean" />
   </declare-styleable>
   <declare-styleable name="PianoView">
     <attr name="octaves" format="integer" />

android/res/values/strings.xml

@@ -97,4 +97,12 @@
       </string-array>
   <string name="pref_keyboardType_default">2row</string>
 
+  <string name="pref_velAvg">Velocity average value</string>
+  <string name="pref_velAvg_summary">MIDI velocity at medium pressure</string>
+  <string name="pref_velAvg_default">64.0</string>
+
+  <string name="pref_velSens">Velocity sensitivity</string>
+  <string name="pref_velSens_summary">Sensitivity of MIDI velocity to pressure</string>
+  <string name="pref_velSens_default">0.5</string>
+
 </resources>

android/res/xml/preferences.xml

@@ -6,4 +6,16 @@
 		android:entries="@array/pref_keyboardType_entries"
 		android:entryValues="@array/pref_keyboardType_values"
 		android:defaultValue="@string/pref_keyboardType_default" />
+	<com.levien.synthesizer.android.widgets.knob.KnobPreference
+		android:key="vel_avg"
+		android:title="@string/pref_velAvg"
+		android:summary="@string/pref_velAvg_summary"
+		android:widgetLayout="@layout/knobpreflayout_va"
+		android:defaultValue="@string/pref_velAvg_default" />
+	<com.levien.synthesizer.android.widgets.knob.KnobPreference
+		android:key="vel_sens"
+		android:title="@string/pref_velSens"
+		android:summary="@string/pref_velSens_summary"
+		android:widgetLayout="@layout/knobpreflayout_vs"
+		android:defaultValue="@string/pref_velSens_default" />
 </PreferenceScreen>

android/src/com/levien/synthesizer/android/ui/PianoActivity2.java

@@ -108,6 +108,7 @@ public class PianoActivity2 extends SynthActivity implements OnSharedPreferenceC
     SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
     prefs.registerOnSharedPreferenceChangeListener(this);
     onSharedPreferenceChanged(prefs, "keyboard_type");
+    onSharedPreferenceChanged(prefs, "vel_sens");
   }
 
   @Override
@@ -122,6 +123,10 @@ public class PianoActivity2 extends SynthActivity implements OnSharedPreferenceC
     if (key.equals("keyboard_type")) {
       String keyboardType = prefs.getString(key, "2row");
       keyboard_.setKeyboardSpec(KeyboardSpec.make(keyboardType));
+    } else if (key.equals("vel_sens") || key.equals("vel_avg")) {
+      float velSens = prefs.getFloat("vel_sens", 0.5f);
+      float velAvg = prefs.getFloat("vel_avg", 64);
+      keyboard_.setVelocitySensitivity(velSens, velAvg);
     }
   }
 

android/src/com/levien/synthesizer/android/widgets/keyboard/KeyboardView.java

@@ -51,6 +51,8 @@ public class KeyboardView extends View {
     offset_ = 0.0f;
     zoom_ = 1.0f;
     setKeyboardSpec(KeyboardSpec.make2Row());
+    velSens_ = 0.5f;
+    velAvg_ = 64;
   }
 
   public void setKeyboardSpec(KeyboardSpec keyboardSpec) {
@@ -70,6 +72,11 @@ public class KeyboardView extends View {
     }
   }
 
+  public void setVelocitySensitivity(float velSens, float velAvg) {
+    velSens_ = velSens;
+    velAvg_ = velAvg;
+  }
+
   public void setScrollZoom(float offset, float zoom) {
     offset_ = offset;
     zoom_ = zoom;
@@ -138,51 +145,42 @@ public class KeyboardView extends View {
 
   @Override
   public boolean onTouchEvent(MotionEvent event) {
-    int action = event.getAction();
+    int actionCode = event.getActionMasked();
-    int actionCode = action & MotionEvent.ACTION_MASK;
     boolean redraw = false;
-    if (actionCode == MotionEvent.ACTION_DOWN) {
+    switch (actionCode) {
-      int pointerId = event.getPointerId(0);
+      case MotionEvent.ACTION_DOWN:
-      float x = event.getX();
+      case MotionEvent.ACTION_POINTER_DOWN:
-      float y = event.getY();
+        int index = actionCode == MotionEvent.ACTION_POINTER_DOWN ? event.getActionIndex() : 0;
-      float pressure = event.getPressure();
+        int pointerId = event.getPointerId(index);
-      redraw |= onTouchDown(pointerId, x, y, pressure);
+        if (pointerId < FINGERS && pointerId >= 0) {
-    } else if (actionCode == MotionEvent.ACTION_POINTER_DOWN) {
+          float x = event.getX(index);
-      int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
+          float y = event.getY(index);
-              >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
+          float pressure = event.getPressure(index);
-      int pointerId = event.getPointerId(pointerIndex);
+          redraw |= onTouchDown(pointerId, x, y, pressure);
-      if (pointerId < FINGERS && pointerId >= 0) {
-        float x = event.getX(pointerIndex);
-        float y = event.getY(pointerIndex);
-        float pressure = event.getPressure();
-        redraw |= onTouchDown(pointerId, x, y, pressure);
-      }
-    } else if (actionCode == MotionEvent.ACTION_UP) {
-      int pointerId = event.getPointerId(0);
-      float x = event.getX();
-      float y = event.getY();
-      float pressure = event.getPressure();
-      redraw |= onTouchUp(pointerId, x, y, pressure);
-    } else if (actionCode == MotionEvent.ACTION_POINTER_UP) {
-      int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
-              >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
-      int pointerId = event.getPointerId(pointerIndex);
-      if (pointerId < FINGERS && pointerId >= 0) {
-        float x = event.getX(pointerIndex);
-        float y = event.getY(pointerIndex);
-        float pressure = event.getPressure();
-        redraw |= onTouchUp(pointerId, x, y, pressure);
-      }
-    } else if (actionCode == MotionEvent.ACTION_MOVE) {
-      for (int pointerIndex = 0; pointerIndex < event.getPointerCount(); pointerIndex++) {
-        int pointerId = event.getPointerId(pointerIndex);
-        if (pointerId < FINGERS) {
-          float x = event.getX(pointerIndex);
-          float y = event.getY(pointerIndex);
-          float pressure = event.getPressure();
-          redraw |= onTouchMove(pointerId, x, y, pressure);
         }
-      }
+        break;
+      case MotionEvent.ACTION_UP:
+      case MotionEvent.ACTION_POINTER_UP:
+        index = actionCode == MotionEvent.ACTION_POINTER_UP ? event.getActionIndex() : 0;
+        pointerId = event.getPointerId(index);
+        if (pointerId < FINGERS && pointerId >= 0) {
+          float x = event.getX(index);
+          float y = event.getY(index);
+          float pressure = event.getPressure(index);
+          redraw |= onTouchUp(pointerId, x, y, pressure);
+        }
+        break;
+      case MotionEvent.ACTION_MOVE:
+        for (index = 0; index < event.getPointerCount(); index++) {
+          pointerId = event.getPointerId(index);
+          if (pointerId < FINGERS) {
+            float x = event.getX(index);
+            float y = event.getY(index);
+            float pressure = event.getPressure(index);
+            redraw |= onTouchMove(pointerId, x, y, pressure);
+          }
+        }
+        break;
     }
     if (redraw) {
       invalidate();
@@ -208,8 +206,7 @@ public class KeyboardView extends View {
   }
 
   private int computeVelocity(float pressure) {
-    float sensitivity = 0.5f;  // TODO: configure
+    int velocity = (int) (velSens_ * (pressure - 0.5f) * 127.0f + velAvg_ + 0.5f);
-    int velocity = (int) ((0.5f + sensitivity * (pressure - 0.5f)) * 127.0f + 0.5f);
     if (velocity < 1) {
       velocity = 1;
     } else if (velocity > 127) {
@@ -279,6 +276,9 @@ public class KeyboardView extends View {
     return NOTE_NAMES[note % 12] + Integer.toString(octave);
   }
 
+  private float velSens_;
+  private float velAvg_;
+
   private MidiListener midiListener_;
 
   private Rect drawingRect_;

android/src/com/levien/synthesizer/android/widgets/knob/KnobPreference.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2013 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.levien.synthesizer.android.widgets.knob;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.preference.Preference;
+import android.util.AttributeSet;
+import android.view.View;
+
+import com.levien.synthesizer.R;
+
+/**
+ * A wrapper so that a knob can be used in the preference dialog
+ */
+public class KnobPreference extends Preference {
+
+  public KnobPreference(Context context, AttributeSet attrs) {
+    super(context, attrs);
+    // TODO Auto-generated constructor stub
+  }
+
+  @Override
+  protected Object onGetDefaultValue(TypedArray a, int index) {
+    return a.getFloat(index, 0.0f);
+  }
+
+  @Override
+  protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
+    setValue(restoreValue ? getPersistedFloat(value_) : (Float)defaultValue);
+  }
+
+  private void setValue(float value) {
+    value_ = value;
+    persistFloat(value);
+  }
+
+  @Override
+  protected void onBindView(View view) {
+    super.onBindView(view);
+
+    KnobView knobView = (KnobView)view.findViewById(R.id.knob);
+    knobView.setValue(value_);
+    knobView.setKnobListenerUp(new KnobListener() {
+      public void onKnobChanged(double newValue) {
+        setValue((float)newValue);
+      }
+    });
+  }
+
+  private float value_;
+}

android/src/com/levien/synthesizer/android/widgets/knob/KnobView.java

@@ -16,6 +16,8 @@
 
 package com.levien.synthesizer.android.widgets.knob;
 
+import java.util.Locale;
+
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
@@ -50,6 +52,9 @@ public class KnobView extends View {
     min_ = a.getFloat(R.styleable.KnobView_min, 0.0f);
     max_ = a.getFloat(R.styleable.KnobView_max, 1.0f);
     label_ = a.getString(R.styleable.KnobView_label);
+    String numberFormat = a.getString(R.styleable.KnobView_numberformat);
+    numberFormat_ = numberFormat != null ? numberFormat : "%.2f";
+    horizontal_ = a.getBoolean(R.styleable.KnobView_horizontal, false);
     a.recycle();
 
     // Set up the drawing structures.
@@ -99,7 +104,11 @@ public class KnobView extends View {
         break;
       }
 
+      case MotionEvent.ACTION_CANCEL:
       case MotionEvent.ACTION_UP: {
+        if (listenerUp_ != null) {
+          listenerUp_.onKnobChanged(getValue());
+        }
         break;
       }
     }
@@ -113,6 +122,13 @@ public class KnobView extends View {
     listener_ = listener;
   }
 
+  /**
+   * Sets the listener to receive events when the knob's value finalizes (on touch up).
+   */
+  public void setKnobListenerUp(KnobListener listener) {
+    listenerUp_ = listener;
+  }
+
   /**
    * Sets the value for the knob when it is turned all the way counter-clockwise.
    */
@@ -178,7 +194,7 @@ public class KnobView extends View {
       rectF_.right = center + rectF_.height() / 2;
     }
 
-    float border = textHeight_ + rectF_.width() * 0.05f;
+    float border = (horizontal_ ? 0.5f * textHeight_ : textHeight_) + rectF_.width() * 0.05f;
 
     // Draw indicator.
 
@@ -214,17 +230,17 @@ public class KnobView extends View {
                       paint_);
 
     // Draw text.
-    String knobValueString = String.format("%.2f", getValue());
+    String knobValueString = String.format(Locale.getDefault(), numberFormat_, getValue());
     Typeface typeface = Typeface.DEFAULT_BOLD;
     paint_.setColor(Color.BLACK);
     paint_.setTypeface(typeface);
-    paint_.setTextAlign(Align.CENTER);
+    paint_.setTextAlign(horizontal_ ? Align.RIGHT : Align.CENTER);
+    float x = horizontal_ ? rectF_.left: rectF_.centerX();
+    float y = horizontal_ ? rectF_.centerY()  + 0.4f * textHeight_ :
+      rectF_.top + 0.8f * textHeight_;
     paint_.setSubpixelText(true);
     paint_.setStyle(Style.FILL);
-    canvas.drawText(knobValueString,
+    canvas.drawText(knobValueString, x, y, paint_);
-                    rect_.centerX(),
-                    rectF_.top + 0.8f * textHeight_,
-                    paint_);
 
     if (label_ != null) {
       paint_.setTypeface(Typeface.DEFAULT);
@@ -237,45 +253,12 @@ public class KnobView extends View {
    */
   @Override
   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
-    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
+    int width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
-    int widthSize = MeasureSpec.getSize(widthMeasureSpec);
+    int height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
-    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
+    if (!horizontal_) {
-    int heightSize = MeasureSpec.getSize(heightMeasureSpec);
+      // Make it square
-
+      width = height = Math.min(width, height);
-    // Specify that 100 is preferred for both dimensions.
-    int width = 0;
-    int height = 0;
-    switch (widthMode) {
-      case MeasureSpec.EXACTLY:
-        width = widthSize;
-        break;
-      case MeasureSpec.AT_MOST:
-        width = widthSize;
-        break;
-      case MeasureSpec.UNSPECIFIED:
-        width = 100;
-        break;
     }
-    switch (heightMode) {
-      case MeasureSpec.EXACTLY:
-        height = heightSize;
-        break;
-      case MeasureSpec.AT_MOST:
-        height = heightSize;
-        break;
-      case MeasureSpec.UNSPECIFIED:
-        height = 100;
-        break;
-    }
-
-    // Make it square.
-    if (width > height && widthMode != MeasureSpec.EXACTLY) {
-      width = height;
-    }
-    if (height > width && heightMode != MeasureSpec.EXACTLY) {
-      height = width;
-    }
-
     setMeasuredDimension(width, height);
   }
 
@@ -313,6 +296,8 @@ public class KnobView extends View {
   private double knobValue_;
   private double min_;
   private double max_;
+  private String numberFormat_;
+  private boolean horizontal_;
 
   // Structures used in drawing that we don't want to reallocate every time we draw.
   private Paint paint_;
@@ -334,4 +319,5 @@ public class KnobView extends View {
 
   // Object listening for events when the knob's value changes.
   private KnobListener listener_;
+  private KnobListener listenerUp_;
 }