[Android] Util class to combine thumbnails in 1 image

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Fri May 26 17:14:11 2017 +0200| [f2a8d6931e42b1fe491ac0221d139236ca784f98] | committer: Geoffrey Métais

Util class to combine thumbnails in 1 image

> https://code.videolan.org/videolan/vlc-android/commit/f2a8d6931e42b1fe491ac0221d139236ca784f98
---

 .../src/org/videolan/vlc/util/ImageComposer.java   | 124 +++++++++++++++++++++
 1 file changed, 124 insertions(+)

diff --git a/vlc-android/src/org/videolan/vlc/util/ImageComposer.java b/vlc-android/src/org/videolan/vlc/util/ImageComposer.java
new file mode 100644
index 000000000..00eb80098
--- /dev/null
+++ b/vlc-android/src/org/videolan/vlc/util/ImageComposer.java
@@ -0,0 +1,124 @@
+/*****************************************************************************
+ * ImageComposer.java
+ *****************************************************************************
+ * Copyright © 2017 VLC authors, VideoLAN and VideoLabs
+ * Author: Geoffrey Métais
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+package org.videolan.vlc.util;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.net.Uri;
+
+import org.videolan.medialibrary.media.MediaWrapper;
+import org.videolan.vlc.R;
+import org.videolan.vlc.VLCApplication;
+import org.videolan.vlc.gui.helpers.AudioUtil;
+import org.videolan.vlc.media.MediaGroup;
+
+public class ImageComposer {
+
+    private static final String TAG = "VLC/ImageComposer";
+
+    private static final int sImageWidth = VLCApplication.getAppResources().getDimensionPixelSize(VLCApplication.showTvUi() ? R.dimen.tv_grid_card_thumb_width : R.dimen.grid_card_thumb_width);
+    private static final int MAX_IMAGES = 4;
+
+    /**
+     * Compose 1 image from combined media thumbnails
+     * @param group The MediaGroup instance
+     * @return a Bitmap object
+     */
+    public static Bitmap composeImage(MediaGroup group) {
+        Bitmap[] sourcesImages = new Bitmap[MAX_IMAGES];
+        int count = 0, minWidth = Integer.MAX_VALUE, minHeight = Integer.MAX_VALUE;
+        for (MediaWrapper media : group.getAll()) {
+            Bitmap bm = AudioUtil.readCoverBitmap(Uri.decode(media.getArtworkMrl()), sImageWidth);
+            if (bm != null) {
+                int width = bm.getWidth();
+                int height = bm.getHeight();
+                sourcesImages[count++] = bm;
+                minWidth = Math.min(minWidth, width);
+                minHeight = Math.min(minHeight, height);
+                if (count == MAX_IMAGES)
+                    break;
+            }
+        }
+        if (count == 0)
+            return null;
+        if (count == 1)
+            return sourcesImages[0];
+        return composeCanvas(sourcesImages, count, minWidth, minHeight);
+    }
+
+    private static Bitmap composeCanvas(Bitmap[] sourcesImages, int count, int minWidth, int minHeight) {
+        int overlayWidth, overlayHeight;
+        switch (count) {
+            case 4:
+                overlayWidth = 2*minWidth;
+                overlayHeight = 2*minHeight;
+                break;
+            default:
+                overlayWidth = minWidth;
+                overlayHeight = minHeight;
+                break;
+        }
+        Bitmap bmOverlay = Bitmap.createBitmap(overlayWidth, overlayHeight, sourcesImages[0].getConfig());
+
+        Canvas canvas = new Canvas(bmOverlay);
+        switch (count) {
+            case 2:
+                for (int i = 0; i < count; ++i)
+                    sourcesImages[i] = centerCrop(sourcesImages[i], minWidth/2, minHeight);
+                canvas.drawBitmap(sourcesImages[0], 0, 0, null);
+                canvas.drawBitmap(sourcesImages[1], minWidth / 2, 0, null);
+                break;
+            case 3:
+                sourcesImages[0] = centerCrop(sourcesImages[0], minWidth/2, minHeight/2);
+                sourcesImages[1] = centerCrop(sourcesImages[1], minWidth/2, minHeight/2);
+                sourcesImages[2] = centerCrop(sourcesImages[2], minWidth, minHeight/2);
+                canvas.drawBitmap(sourcesImages[0], 0, 0, null);
+                canvas.drawBitmap(sourcesImages[1], minWidth / 2, 0, null);
+                canvas.drawBitmap(sourcesImages[2], 0, minHeight/2, null);
+                break;
+            case 4:
+                for (int i = 0; i < count; ++i)
+                    sourcesImages[i] = centerCrop(sourcesImages[i], minWidth, minHeight);
+                canvas.drawBitmap(sourcesImages[0], 0, 0, null);
+                canvas.drawBitmap(sourcesImages[1], minWidth , 0, null);
+                canvas.drawBitmap(sourcesImages[2], 0, minHeight, null);
+                canvas.drawBitmap(sourcesImages[3], minWidth , minHeight, null);
+                break;
+        }
+        return bmOverlay;
+    }
+
+    private static Bitmap centerCrop(Bitmap srcBmp, int width, int height) {
+        Bitmap dstBmp;
+        int widthDiff = srcBmp.getWidth()-width;
+        int heightDiff = srcBmp.getHeight()-height;
+        if (widthDiff == 0 && heightDiff == 0)
+            return srcBmp;
+        dstBmp = Bitmap.createBitmap(
+                srcBmp,
+                widthDiff/2,
+                heightDiff/2,
+                width,
+                height
+        );
+        return dstBmp;
+    }
+}