Merge pull request #31 from ninovanhooff/feature/vector-and-framerate…

…-independence

Feature/vector and framerate independence

README.md

@@ -36,15 +36,19 @@ In your Android layout file add:
     android:id="@+id/scrolling_background"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    scrolling_image_view:speed="1dp"
-    scrolling_image_view:src="@drawable/scrolling_background" />
+    scrolling_image_view:speed="60dp"
+    scrolling_image_view:contiguous="false"
+    scrolling_image_view:source="@drawable/scrolling_background" />
 ```
 
-There are two attributes for the `ScrollingImageView` namely `speed` and `src`.
-* `speed` is the number of `dp`'s to move the bitmap on each animation frame (may be a negative number)
-* `src` is the drawable to paint (**must be a bitmap!**)
+There are three attributes for the `ScrollingImageView`:
+* `speed` is the number of `dp`'s to move the drawable per second (may be a negative number)
+* `source` is the drawable to paint. May refer to an array of drawables
+* `contiguous` When source is an array of drawables, `contiguous` determines their ordering.
 
-Don't forget to add the namespace to your root XLM element
+  false (default) for random ordering, true for the same order as in the array
+
+Don't forget to add the namespace to your root XML element
 ```xml
 xmlns:scrolling_image_view="http://schemas.android.com/apk/res-auto"
 ```
@@ -67,14 +71,14 @@ In order to achieve a parallax effect, you can stack multiple `ScrollingImageVie
       android:id="@+id/scrolling_background"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
-      scrolling_image_view:speed="1dp"
-      scrolling_image_view:src="@drawable/scrolling_background" />
+      scrolling_image_view:speed="60dp"
+      scrolling_image_view:source="@drawable/scrolling_background" />
 
   <com.q42.android.scrollingimageview.ScrollingImageView
       android:id="@+id/scrolling_foreground"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
-      scrolling_image_view:speed="2.5dp"
-      scrolling_image_view:src="@drawable/scrolling_foreground" />
+      scrolling_image_view:speed="150dp"
+      scrolling_image_view:source="@drawable/scrolling_foreground" />
 </FrameLayout>
 ```

library/build.gradle

@@ -6,7 +6,7 @@ android {
     buildToolsVersion "27.0.3"
 
     defaultConfig {
-        minSdkVersion 16
+        minSdkVersion 21
         targetSdkVersion 27
         versionCode 1
         versionName "1.0"

library/src/main/java/com/q42/android/scrollingimageview/ScrollingImageView.java

@@ -3,9 +3,11 @@
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
-import android.graphics.BitmapFactory;
 import android.graphics.Canvas;
+import android.graphics.Paint;
 import android.graphics.Rect;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
 import android.util.TypedValue;
 import android.view.View;
@@ -21,42 +23,66 @@
 /**
  * Created by thijs on 08-06-15.
  */
+@SuppressWarnings("FieldCanBeLocal") // Declaring fields outside of onDraw improves performance
 public class ScrollingImageView extends View {
     public static ScrollingImageViewBitmapLoader BITMAP_LOADER = new ScrollingImageViewBitmapLoader() {
         @Override
-        public Bitmap loadBitmap(Context context, int resourceId) {
-            return BitmapFactory.decodeResource(context.getResources(), resourceId);
+        public Bitmap loadDrawable(Context context, int resourceId) {
+            Drawable drawable = context.getResources().getDrawable(resourceId, context.getTheme());
+            if (drawable instanceof BitmapDrawable) {
+                return ((BitmapDrawable) drawable).getBitmap();
+            }
+
+            // Render any other kind of drawable to a bitmap
+            Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
+                    drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
+            Canvas canvas = new Canvas(bitmap);
+            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
+            drawable.draw(canvas);
+
+            return bitmap;
         }
     };
 
+    public Paint paint = null;
+
     private List<Bitmap> bitmaps;
-    private float speed;
+    /** Pixels per second */
+    private final double speed;
     private int[] scene;
     private int arrayIndex = 0;
     private int maxBitmapHeight = 0;
 
-    private Rect clipBounds = new Rect();
+    private final Rect clipBounds = new Rect();
     private float offset = 0;
 
+    private static final double NANOS_PER_SECOND = 1e9;
+    /** Moment when the last call to onDraw() started */
+    private long lastFrameInstant = -1;
+    private long frameTimeNanos = -1;
+
     private boolean isStarted;
 
     public ScrollingImageView(Context context, AttributeSet attrs) {
         super(context, attrs);
-        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ParallaxView, 0, 0);
+        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ScrollingImageView, 0, 0);
         int initialState = 0;
         try {
-            initialState = ta.getInt(R.styleable.ParallaxView_initialState, 0);
-            speed = ta.getDimension(R.styleable.ParallaxView_speed, 10);
-            int sceneLength = ta.getInt(R.styleable.ParallaxView_sceneLength, 1000);
-            final int randomnessResourceId = ta.getResourceId(R.styleable.ParallaxView_randomness, 0);
+            initialState = ta.getInt(R.styleable.ScrollingImageView_initialState, 0);
+            speed = ta.getDimension(R.styleable.ScrollingImageView_speed, 60);
+            int sceneLength = ta.getInt(R.styleable.ScrollingImageView_sceneLength, 1000);
+            final int randomnessResourceId = ta.getResourceId(R.styleable.ScrollingImageView_randomness, 0);
+            // When true, randomness is ignored and bitmaps are loaded in the order as they appear in the src array */
+            final boolean contiguous = ta.getBoolean(R.styleable.ScrollingImageView_contiguous, false);
+
             int[] randomness = new int[0];
             if (randomnessResourceId > 0) {
                 randomness = getResources().getIntArray(randomnessResourceId);
             }
 
-            int type = isInEditMode() ? TypedValue.TYPE_STRING : ta.peekValue(R.styleable.ParallaxView_src).type;
+            int type = isInEditMode() ? TypedValue.TYPE_STRING : ta.peekValue(R.styleable.ScrollingImageView_source).type;
             if (type == TypedValue.TYPE_REFERENCE) {
-                int resourceId = ta.getResourceId(R.styleable.ParallaxView_src, 0);
+                int resourceId = ta.getResourceId(R.styleable.ScrollingImageView_source, 0);
                 TypedArray typedArray = getResources().obtainTypedArray(resourceId);
                 try {
                     int bitmapsSize = 0;
@@ -72,7 +98,7 @@ public ScrollingImageView(Context context, AttributeSet attrs) {
                             multiplier = Math.max(1, randomness[i]);
                         }
 
-                        Bitmap bitmap = BITMAP_LOADER.loadBitmap(getContext(), typedArray.getResourceId(i, 0));
+                        Bitmap bitmap = BITMAP_LOADER.loadDrawable(getContext(), typedArray.getResourceId(i, 0));
                         for (int m = 0; m < multiplier; m++) {
                             bitmaps.add(bitmap);
                         }
@@ -83,13 +109,17 @@ public ScrollingImageView(Context context, AttributeSet attrs) {
                     Random random = new Random();
                     this.scene = new int[sceneLength];
                     for (int i = 0; i < this.scene.length; i++) {
-                        this.scene[i] = random.nextInt(bitmaps.size());
+                        if (contiguous){
+                            this.scene[i] = i % bitmaps.size();
+                        } else {
+                            this.scene[i] = random.nextInt(bitmaps.size());
+                        }
                     }
                 } finally {
                     typedArray.recycle();
                 }
             } else if (type == TypedValue.TYPE_STRING) {
-                final Bitmap bitmap = BITMAP_LOADER.loadBitmap(getContext(), ta.getResourceId(R.styleable.ParallaxView_src, 0));
+                final Bitmap bitmap = BITMAP_LOADER.loadDrawable(getContext(), ta.getResourceId(R.styleable.ScrollingImageView_source, 0));
                 if (bitmap != null) {
                     bitmaps = singletonList(bitmap);
                     scene = new int[]{0};
@@ -116,6 +146,12 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     @Override
     public void onDraw(Canvas canvas) {
         if(!isInEditMode()) {
+            if (lastFrameInstant == -1){
+                lastFrameInstant = System.nanoTime();
+            }
+            frameTimeNanos = System.nanoTime() - lastFrameInstant;
+            lastFrameInstant = System.nanoTime();
+
             super.onDraw(canvas);
             if (canvas == null || bitmaps.isEmpty()) {
                 return;
@@ -132,12 +168,13 @@ public void onDraw(Canvas canvas) {
             for (int i = 0; left < clipBounds.width(); i++) {
                 Bitmap bitmap = getBitmap((arrayIndex + i) % scene.length);
                 int width = bitmap.getWidth();
-                canvas.drawBitmap(bitmap, getBitmapLeft(width, left), 0, null);
+                canvas.drawBitmap(bitmap, getBitmapLeft(width, left), 0, paint);
                 left += width;
             }
 
             if (isStarted && speed != 0) {
-                offset -= abs(speed);
+
+                offset -= (abs(speed) / NANOS_PER_SECOND) * frameTimeNanos;
                 postInvalidateOnAnimation();
             }
         }
@@ -161,24 +198,20 @@ private float getBitmapLeft(float layerWidth, float left) {
     public void start() {
         if (!isStarted) {
             isStarted = true;
+            lastFrameInstant = -1;
             postInvalidateOnAnimation();
         }
     }
 
     /**
      * Stop the animation
      */
+    @SuppressWarnings("unused")
     public void stop() {
         if (isStarted) {
             isStarted = false;
+            lastFrameInstant = -1;
             invalidate();
         }
     }
-
-    public void setSpeed(float speed) {
-        this.speed = speed;
-        if (isStarted) {
-            postInvalidateOnAnimation();
-        }
-    }
-}
+}

library/src/main/java/com/q42/android/scrollingimageview/ScrollingImageViewBitmapLoader.java

@@ -7,5 +7,5 @@
  * Created by thijs on 22-03-16.
  */
 public interface ScrollingImageViewBitmapLoader {
-    Bitmap loadBitmap(Context context, int resourceId);
+    Bitmap loadDrawable(Context context, int resourceId);
 }

library/src/main/res/values/attr.xml

@@ -1,10 +1,15 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <declare-styleable name="ParallaxView">
+    <declare-styleable name="ScrollingImageView">
+        <!-- dp per second -->
         <attr name="speed" format="dimension" />
-        <attr name="src" format="reference" />
+        <!-- Using src would clash with attribute android:src in multi-module apps -->
+        <attr name="source" format="reference" />
         <attr name="sceneLength" format="integer" />
         <attr name="randomness" format="reference" />
+        <!-- When true, slices are stitched in order. When false, slices are stitched in random order
+         default: false -->
+        <attr name="contiguous" format="boolean" />
         <attr name="initialState" format="enum">
             <enum name="started" value="0" />
             <enum name="stopped" value="1" />

sampleapp/build.gradle

@@ -6,7 +6,7 @@ android {
 
     defaultConfig {
         applicationId "scrollingimageview.android.q42.com.sampleapp"
-        minSdkVersion 16
+        minSdkVersion 21
         targetSdkVersion 27
         versionCode 1
         versionName "1.0"

sampleapp/src/main/res/layout/activity_main.xml

@@ -29,8 +29,8 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="3dp"
-                scrolling_image_view:src="@array/random_imgs"
+                scrolling_image_view:speed="180dp"
+                scrolling_image_view:source="@array/random_imgs"
                 scrolling_image_view:randomness="@array/randomness" />
 
             <ImageView
@@ -55,15 +55,16 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="1dp"
-                scrolling_image_view:src="@drawable/scrolling_background" />
+                scrolling_image_view:speed="60dp"
+                scrolling_image_view:source="@drawable/scrolling_background"
+                scrolling_image_view:initialState="started"/>
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="1.9dp"
-                scrolling_image_view:src="@drawable/scrolling_foreground" />
+                scrolling_image_view:speed="114dp"
+                scrolling_image_view:source="@drawable/scrolling_foreground" />
 
             <ImageView
                 android:layout_width="wrap_content"
@@ -76,7 +77,7 @@
             style="@style/Base.TextAppearance.AppCompat.Title"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
-            android:text="Left to right scrolling background"
+            android:text="Left to right, fixed tile order"
             android:layout_marginTop="30dp"/>
 
         <FrameLayout
@@ -88,15 +89,17 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="-1dp"
-                scrolling_image_view:src="@drawable/scrolling_background" />
+                scrolling_image_view:speed="-60dp"
+                scrolling_image_view:contiguous="true"
+                scrolling_image_view:source="@drawable/scrolling_background" />
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="-1.9dp"
-                scrolling_image_view:src="@drawable/scrolling_foreground" />
+                scrolling_image_view:speed="-114dp"
+                scrolling_image_view:contiguous="true"
+                scrolling_image_view:source="@drawable/scrolling_foreground" />
         </FrameLayout>
 
         <TextView
@@ -128,36 +131,36 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed=".3dp"
-                scrolling_image_view:src="@drawable/layer_3" />
+                scrolling_image_view:speed="18dp"
+                scrolling_image_view:source="@drawable/layer_3" />
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed=".6dp"
-                scrolling_image_view:src="@drawable/layer_4" />
+                scrolling_image_view:speed="36dp"
+                scrolling_image_view:source="@drawable/layer_4" />
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed=".9dp"
-                scrolling_image_view:src="@drawable/layer_5" />
+                scrolling_image_view:speed="54dp"
+                scrolling_image_view:source="@drawable/layer_5" />
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="1.5dp"
-                scrolling_image_view:src="@drawable/layer_6" />
+                scrolling_image_view:speed="90dp"
+                scrolling_image_view:source="@drawable/layer_6" />
 
             <com.q42.android.scrollingimageview.ScrollingImageView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="bottom"
-                scrolling_image_view:speed="1.7dp"
-                scrolling_image_view:src="@drawable/layer_7" />
+                scrolling_image_view:speed="102dp"
+                scrolling_image_view:source="@drawable/layer_7" />
         </FrameLayout>
     </LinearLayout>
 </ScrollView>