android/apps: Add CanvasProof App;

platform_tools/android/apps/canvasproof/src/main/java/org/skia/canvasproof/CanvasProofActivity.java

Index: platform_tools/android/apps/canvasproof/src/main/java/org/skia/canvasproof/CanvasProofActivity.java
diff --git a/platform_tools/android/apps/canvasproof/src/main/java/org/skia/canvasproof/CanvasProofActivity.java b/platform_tools/android/apps/canvasproof/src/main/java/org/skia/canvasproof/CanvasProofActivity.java
new file mode 100644
index 0000000000000000000000000000000000000000..522414ec3e7db4867377448ae3e54cd86f870421
--- /dev/null
+++ b/platform_tools/android/apps/canvasproof/src/main/java/org/skia/canvasproof/CanvasProofActivity.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+package org.skia.canvasproof;
+
+import android.app.Activity;
+import android.content.res.AssetManager;
+import android.content.res.Resources;
+import android.graphics.Picture;
+import android.opengl.GLSurfaceView;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.Gravity;
+import android.view.MotionEvent;
+import android.view.View;
+import android.widget.LinearLayout.LayoutParams;
+import android.widget.LinearLayout;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
+public class CanvasProofActivity extends Activity {
+    private class PictureAsset {
+        public String path;
+        public long ptr;
+        public Picture picture;
+    };
+    private static final String TAG = "CanvasProofActivity";
+    private PictureAsset[] assets;
+
+    @SuppressWarnings("deprecation")  // purposely using this

[tomhudson, 2015/08/22 19:15:52]

Nit: given that we're using a deprecated feature, I'd appreciate the comment
saying *why*; this comment doesn't tell me much.

+    private static Picture ReadPicture(InputStream inputStream)
+        throws IOException {
+        Picture p = null;
+        try {
+            p = Picture.createFromStream(inputStream);
+        } catch (java.lang.Exception e) {
+            Log.e(TAG, "Exception in Picture.createFromStream", e);
+        }
+        inputStream.close();
+        return p;
+    }
+
+
+    private void getAssetPaths() {
+        String directory = "skps";
+        AssetManager mgr = this.getAssets();
+        assert (mgr != null);
+        String[] resources;
+        try {
+            resources = mgr.list(directory);
+        } catch (IOException e) {
+            Log.e(TAG, "IOException in getAssetPaths", e);

[tomhudson, 2015/08/22 19:15:52]

Can you more explicitly list what failed here? Not knowing where to install
assets is a common failure mode, and good error messages are a backstop to good
documentation.

[hal.canary, 2015/08/31 21:16:55]

Done.

+            return;
+        }
+        if (resources == null) {
+            Log.e(TAG, "this.getAssets().getAssetPaths returned null");

[tomhudson, 2015/08/22 19:15:52]

How about "found no resources in path <directory>"?
Isn't a non-null but 0-length resources also something we should be erroring on?

[hal.canary, 2015/08/31 21:16:55]

Done.

+            return;
+        }
+        if (resources != null && resources.length > 0) {
+            CreateSkiaPicture.init();
+            this.assets = new PictureAsset[resources.length];
+            for (int i = 0; i < resources.length; ++i) {
+                String path = directory + File.separator + resources[i];
+                Log.v(TAG, "loading " + path);

[tomhudson, 2015/08/22 19:15:52]

If we don't need these logs any more, please strip them out before committing -
Android logspam is nasty tragedy of the commons.

[hal.canary, 2015/08/31 21:16:55]

Done.  I've removed all Log.v();

+                this.assets[i] = new PictureAsset();
+                this.assets[i].path = path;
+                try {
+                    Log.v(TAG, "calling CreateSkiaPicture.create...");
+                    this.assets[i].ptr = CreateSkiaPicture.create(mgr.open(path));
+                    if (0 == this.assets[i].ptr) {
+                        Log.e(TAG, "CreateSkiaPicture.create returned 0 " + path);
+                    }
+                    Log.v(TAG, "calling CanvasProofActivity.ReadPicture...");
+                    Picture p = CanvasProofActivity.ReadPicture(mgr.open(path));
+                    if (null == p) {
+                        Log.e(TAG, "CanvasProofActivity.ReadPicture.create " +
+                              "returned null " + path);
+                    } else if (0 == p.getHeight() || 0 == p.getWidth()) {
+                        Log.e(TAG, "CanvasProofActivity.ReadPicture.create " +
+                              "empty picture" + path);
+                        p = null;
+                    }
+                    this.assets[i].picture = p;
+                } catch (IOException e) {
+                    Log.e(TAG, "IOException in getAssetPaths " + path + e);
+                    return;
+                }
+            }
+        }
+    }
+
+    private void nextPicture(int d) {
+        if (this.assets == null) {
+            Log.w(TAG, "this.assets == null");
+            return;
+        }
+        assert (this.assets.length > 0);
+        resourcesIndex = (resourcesIndex + d) % this.assets.length;
+        while (resourcesIndex < 0) {
+            resourcesIndex += this.assets.length;
+        }
+        while (resourcesIndex >= this.assets.length) {
+            resourcesIndex -= this.assets.length;
+        }
+        //String path = assets[resourcesIndex].path;
+        this.ganeshPictureRenderer.setPicture(assets[resourcesIndex].ptr);
+        this.hwuiPictureView.setPicture(assets[resourcesIndex].picture);
+        this.hwuiPictureView.invalidate();
+
+        this.ganeshPictureView.requestRender();
+        this.ganeshPictureView.invalidate();
+    }
+
+    @Override
+    protected void onStop() {
+        this.ganeshPictureRenderer.releaseResources();
+        super.onStop();
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        this.getAssetPaths();
+
+        this.ganeshPictureRenderer = new GaneshPictureRenderer();
+        this.hwuiPictureView = new HwuiPictureView(this);
+        this.ganeshPictureView = ganeshPictureRenderer.makeView(this);
+
+        this.ganeshPictureRenderer.setScale(2.0f);
+        this.hwuiPictureView.setScale(2.0f);
+
+        this.nextPicture(0);
+        LinearLayout layout = new LinearLayout(this);
+        layout.setOrientation(LinearLayout.VERTICAL);
+        layout.setGravity(Gravity.FILL);
+        LayoutParams layoutParams =
+            new LayoutParams(
+                    LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT, 0.5f);
+        for (View v : new View[]{
+                this.ganeshPictureView,
+                this.hwuiPictureView

[tomhudson, 2015/08/22 19:15:52]

If HwuiPictureView extends View, why have another anonymous view here wrapping
it instead of just setting its layout params and adding it directly?

[hal.canary, 2015/08/31 21:16:55]

Done.

+            }) {
+            v.setLayoutParams(layoutParams);
+            layout.addView(v);
+        }
+        this.setContentView(layout);
+    }
+    @Override
+    public boolean dispatchTouchEvent (MotionEvent event) {
+        switch(event.getAction()) {
+            case MotionEvent.ACTION_DOWN:
+                x = event.getX();
+                y = event.getY();
+                break;
+            case MotionEvent.ACTION_UP:
+                float dx = event.getX() - x;
+                float dy = event.getY() - y;
+                float dx2 = dx * dx;
+                float dy2 = dy * dy;
+                if (dx2 + dy2 > 22500.0) {
+                    if (dy2 < dx2) {
+                        if (dx > 0) {
+                            this.nextPicture(1);
+                        } else {
+                            this.nextPicture(-1);
+                        }
+                    }
+                }
+                break;
+        }
+        return super.onTouchEvent(event);
+    }
+
+    private GaneshPictureRenderer ganeshPictureRenderer;

[djsollen, 2015/08/24 12:42:56]

java style is to put the member variables at the top of the file.

[hal.canary, 2015/08/31 21:16:55]

Done.

+    private GLSurfaceView ganeshPictureView;
+    private HwuiPictureView hwuiPictureView;
+    private float x, y;
+    private int resourcesIndex;
+}