Android ApiDemos示例解析(62):Graphics->CreateBit地图

Android ApiDemos示例解析(62):Graphics->CreateBitmap

本例介绍了Bitmap中定义的创建Mutable Bitmap的几个静态函数

// these three are initialized with colors[]
mBitmaps[0] = Bitmap.createBitmap(colors, 0, STRIDE, WIDTH, HEIGHT,
 Bitmap.Config.ARGB_8888);
mBitmaps[1] = Bitmap.createBitmap(colors, 0, STRIDE, WIDTH, HEIGHT,
 Bitmap.Config.RGB_565);
mBitmaps[2] = Bitmap.createBitmap(colors, 0, STRIDE, WIDTH, HEIGHT,
 Bitmap.Config.ARGB_4444);
 
// these three will have their colors set later
mBitmaps[3] = Bitmap.createBitmap(WIDTH, HEIGHT,
 Bitmap.Config.ARGB_8888);
mBitmaps[4] = Bitmap.createBitmap(WIDTH, HEIGHT,
 Bitmap.Config.RGB_565);
mBitmaps[5] = Bitmap.createBitmap(WIDTH, HEIGHT,
 Bitmap.Config.ARGB_4444);

和使用compress来生成PNG或是JPEG格式的图像：

for (int i = 0; i < mBitmaps.length; i++) {
 mJPEG[i] = codec(mBitmaps[i], Bitmap.CompressFormat.JPEG, 80);
 mPNG[i] = codec(mBitmaps[i], Bitmap.CompressFormat.PNG, 0);
}
 ...
 
private static Bitmap codec(Bitmap src, Bitmap.CompressFormat format,
 int quality) {
 ByteArrayOutputStream os = new ByteArrayOutputStream();
 src.compress(format, quality, os);
 
 byte[] array = os.toByteArray();
 return BitmapFactory.decodeByteArray(array, 0, array.length);
}