1 files changed, 69 insertions, 0 deletions
diff --git a/android/source/src/java/org/mozilla/gecko/gfx/TextLayer.java b/android/source/src/java/org/mozilla/gecko/gfx/TextLayer.java
new file mode 100644
index 000000000..023433a88
--- /dev/null
+++ b/android/source/src/java/org/mozilla/gecko/gfx/TextLayer.java
@@ -0,0 +1,69 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.gfx;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.Typeface;
+
+import org.libreoffice.kit.DirectBufferAllocator;
+
+import java.nio.ByteBuffer;
+
+/**
+ * Draws text on a layer. This is used for the frame rate meter.
+ */
+public class TextLayer extends SingleTileLayer {
+    private final ByteBuffer mBuffer;   // this buffer is owned by the BufferedCairoImage
+    private final IntSize mSize;
+
+    /*
+     * This awkward pattern is necessary due to Java's restrictions on when one can call superclass
+     * constructors.
+     */
+    private TextLayer(ByteBuffer buffer, BufferedCairoImage image, IntSize size, String text) {
+        super(false, image);
+        mBuffer = buffer;
+        mSize = size;
+        renderText(text);
+    }
+
+    public static TextLayer create(IntSize size, String text) {
+        ByteBuffer buffer = DirectBufferAllocator.allocate(size.width * size.height * 4);
+        BufferedCairoImage image = new BufferedCairoImage(buffer, size.width, size.height,
+                                                          CairoImage.FORMAT_ARGB32);
+        return new TextLayer(buffer, image, size, text);
+    }
+
+    public void setText(String text) {
+        renderText(text);
+        invalidate();
+    }
+
+    private void renderText(String text) {
+        Bitmap bitmap = Bitmap.createBitmap(mSize.width, mSize.height, Bitmap.Config.ARGB_8888);
+        Canvas canvas = new Canvas(bitmap);
+
+        Paint textPaint = new Paint();
+        textPaint.setAntiAlias(true);
+        textPaint.setColor(Color.WHITE);
+        textPaint.setFakeBoldText(true);
+        textPaint.setTextSize(18.0f);
+        textPaint.setTypeface(Typeface.DEFAULT_BOLD);
+        float width = textPaint.measureText(text) + 18.0f;
+
+        Paint backgroundPaint = new Paint();
+        backgroundPaint.setColor(Color.argb(127, 0, 0, 0));
+        canvas.drawRect(0.0f, 0.0f, width, 18.0f + 6.0f, backgroundPaint);
+
+        canvas.drawText(text, 6.0f, 18.0f, textPaint);
+
+        bitmap.copyPixelsToBuffer(mBuffer.asIntBuffer());
+    }
+}
+