Support 3D rotations when drawing text

If a perspective transform is set on the Canvas, drawText() should
not attempt to rasterize glyphs in screen space. This change uses
the old behavior instead (i.e. rasterize the glyphs at the native
font size and apply the transform on the resulting mesh.)

This change also adds an optimization: empty glyphs (spaces) do
not generate vertices anymore. This saves a lot of vertices in text
heavy applications such as Gmail.

Change-Id: Ib531384163f5165b5785501612a7b1474f3ff599

2 files changed, 74 insertions, 0 deletions

diff --git a/tests/HwAccelerationTest/AndroidManifest.xml b/tests/HwAccelerationTest/AndroidManifest.xml
index 0c59f30..46a539e 100644
--- a/tests/HwAccelerationTest/AndroidManifest.xml
+++ b/tests/HwAccelerationTest/AndroidManifest.xml
@@ -51,6 +51,16 @@
         </activity>
 
         <activity
+                android:name="Rotate3dTextActivity"
+                android:label="Text/3D Rotation"
+                android:theme="@android:style/Theme.Holo.Light">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="com.android.test.hwui.TEST" />
+            </intent-filter>
+        </activity>
+
+        <activity
                 android:name="NoAATextActivity"
                 android:label="Text/Aliased">
             <intent-filter>
diff --git a/tests/HwAccelerationTest/src/com/android/test/hwui/Rotate3dTextActivity.java b/tests/HwAccelerationTest/src/com/android/test/hwui/Rotate3dTextActivity.java
new file mode 100644
index 0000000..93b8705
--- /dev/null
+++ b/tests/HwAccelerationTest/src/com/android/test/hwui/Rotate3dTextActivity.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * 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.android.test.hwui;
+
+import android.app.Activity;
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.os.Bundle;
+import android.view.View;
+
+@SuppressWarnings({"UnusedDeclaration"})
+public class Rotate3dTextActivity extends Activity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        final Rotate3dTextView view = new Rotate3dTextView(this);
+        setContentView(view);
+    }
+
+    public static class Rotate3dTextView extends View {
+        private static final String TEXT = "Hello libhwui! ";
+
+        private final Paint mPaint;
+
+        public Rotate3dTextView(Context c) {
+            super(c);
+
+            mPaint = new Paint();
+            mPaint.setAntiAlias(true);
+            mPaint.setTextSize(50.0f);
+            mPaint.setTextAlign(Paint.Align.CENTER);
+
+            setRotationY(45.0f);
+            setScaleX(2.0f);
+            setScaleY(2.0f);
+        }
+
+        @Override
+        protected void onDraw(Canvas canvas) {
+            super.onDraw(canvas);
+
+            canvas.drawText(TEXT, getWidth() / 2.0f, getHeight() / 2.0f, mPaint);
+
+            invalidate();
+        }
+    }
+}