1 files changed, 168 insertions, 0 deletions
diff --git a/samples/ApiDemos/src/com/example/android/apis/graphics/BitmapPixels.java b/samples/ApiDemos/src/com/example/android/apis/graphics/BitmapPixels.java
new file mode 100644
index 000000000..88717bcc9
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+++ b/samples/ApiDemos/src/com/example/android/apis/graphics/BitmapPixels.java
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2007 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.example.android.apis.graphics;
+
+import com.example.android.apis.R;
+
+import android.app.Activity;
+import android.content.Context;
+import android.graphics.*;
+import android.graphics.drawable.*;
+import android.os.Bundle;
+import android.view.KeyEvent;
+import android.view.*;
+
+import java.nio.IntBuffer;
+import java.nio.ShortBuffer;
+
+public class BitmapPixels extends GraphicsActivity {
+    
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(new SampleView(this));
+    }
+    
+    private static class SampleView extends View {
+        private Bitmap mBitmap1;
+        private Bitmap mBitmap2;
+        private Bitmap mBitmap3;
+        private Bitmap mBitmap4;
+
+        // access the red component from a premultiplied color
+        private static int getR32(int c) { return (c >>  0) & 0xFF; }
+        // access the red component from a premultiplied color
+        private static int getG32(int c) { return (c >>  8) & 0xFF; }
+        // access the red component from a premultiplied color
+        private static int getB32(int c) { return (c >> 16) & 0xFF; }
+        // access the red component from a premultiplied color
+        private static int getA32(int c) { return (c >> 24) & 0xFF; }
+
+        /**
+         * This takes components that are already in premultiplied form, and
+         * packs them into an int in the correct device order.
+         */
+        private static int pack8888(int r, int g, int b, int a) {
+            return (r << 0) | ( g << 8) | (b << 16) | (a << 24);
+        }
+
+        private static short pack565(int r, int g, int b) {
+            return (short)((r << 11) | ( g << 5) | (b << 0));
+        }
+
+        private static short pack4444(int r, int g, int b, int a) {
+            return (short)((a << 0) | ( b << 4) | (g << 8) | (r << 12));
+        }
+        
+        private static int mul255(int c, int a) {
+            int prod = c * a + 128;
+            return (prod + (prod >> 8)) >> 8;
+        }
+
+        /**
+         * Turn a color int into a premultiplied device color
+         */
+        private static int premultiplyColor(int c) {
+            int r = Color.red(c);
+            int g = Color.green(c);
+            int b = Color.blue(c);
+            int a = Color.alpha(c);
+            // now apply the alpha to r, g, b
+            r = mul255(r, a);
+            g = mul255(g, a);
+            b = mul255(b, a);
+            // now pack it in the correct order
+            return pack8888(r, g, b, a);
+        }
+        
+        private static void makeRamp(int from, int to, int n,
+                                     int[] ramp8888, short[] ramp565,
+                                     short[] ramp4444) {
+            int r = getR32(from) << 23;
+            int g = getG32(from) << 23;
+            int b = getB32(from) << 23;
+            int a = getA32(from) << 23;
+            // now compute our step amounts per componenet (biased by 23 bits)
+            int dr = ((getR32(to) << 23) - r) / (n - 1);
+            int dg = ((getG32(to) << 23) - g) / (n - 1);
+            int db = ((getB32(to) << 23) - b) / (n - 1);
+            int da = ((getA32(to) << 23) - a) / (n - 1);
+
+            for (int i = 0; i < n; i++) {
+                ramp8888[i] = pack8888(r >> 23, g >> 23, b >> 23, a >> 23);
+                ramp565[i] = pack565(r >> (23+3), g >> (23+2), b >> (23+3));
+                ramp4444[i] = pack4444(r >> (23+4), g >> (23+4), b >> (23+4),
+                                       a >> (23+4));
+                r += dr;
+                g += dg;
+                b += db;
+                a += da;
+            }
+        }
+        
+        private static IntBuffer makeBuffer(int[] src, int n) {
+            IntBuffer dst = IntBuffer.allocate(n*n);
+            for (int i = 0; i < n; i++) {
+                dst.put(src);
+            }
+            dst.rewind();
+            return dst;
+        }
+        
+        private static ShortBuffer makeBuffer(short[] src, int n) {
+            ShortBuffer dst = ShortBuffer.allocate(n*n);
+            for (int i = 0; i < n; i++) {
+                dst.put(src);
+            }
+            dst.rewind();
+            return dst;
+        }
+        
+        public SampleView(Context context) {
+            super(context);
+            setFocusable(true);
+            
+            final int N = 100;
+            int[] data8888 = new int[N];
+            short[] data565 = new short[N];
+            short[] data4444 = new short[N];
+            
+            makeRamp(premultiplyColor(Color.RED), premultiplyColor(Color.GREEN),
+                     N, data8888, data565, data4444);
+            
+            mBitmap1 = Bitmap.createBitmap(N, N, Bitmap.Config.ARGB_8888);
+            mBitmap2 = Bitmap.createBitmap(N, N, Bitmap.Config.RGB_565);
+            mBitmap3 = Bitmap.createBitmap(N, N, Bitmap.Config.ARGB_4444);
+            
+            mBitmap1.copyPixelsFromBuffer(makeBuffer(data8888, N));
+            mBitmap2.copyPixelsFromBuffer(makeBuffer(data565, N));
+            mBitmap3.copyPixelsFromBuffer(makeBuffer(data4444, N));
+        }
+        
+        @Override protected void onDraw(Canvas canvas) {
+            canvas.drawColor(0xFFCCCCCC);            
+            
+            int y = 10;
+            canvas.drawBitmap(mBitmap1, 10, y, null);
+            y += mBitmap1.getHeight() + 10;
+            canvas.drawBitmap(mBitmap2, 10, y, null);
+            y += mBitmap2.getHeight() + 10;
+            canvas.drawBitmap(mBitmap3, 10, y, null);
+        }
+    }
+}
+