/**
* Decodes a bitmap from a file containing it minimizing the memory use, known that the bitmap
* will be drawn in a surface of reqWidth x reqHeight
*
* @param srcPath Absolute path to the file containing the image.
* @param reqWidth Width of the surface where the Bitmap will be drawn on, in pixels.
* @param reqHeight Height of the surface where the Bitmap will be drawn on, in pixels.
* @return
*/
public static Bitmap decodeSampledBitmapFromFile(String srcPath, int reqWidth, int reqHeight) {
// set desired options that will affect the size of the bitmap
final Options options = new Options();
options.inScaled = true;
options.inPurgeable = true;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1) {
options.inPreferQualityOverSpeed = false;
}
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
options.inMutable = false;
}
// make a false load of the bitmap to get its dimensions
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(srcPath, options);
// calculate factor to subsample the bitmap
options.inSampleSize = calculateSampleFactor(options, reqWidth, reqHeight);
// decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(srcPath, options);
}
/** 压缩图片 */
public static Bitmap compressImageFromFile(String srcPath) {
Options newOpts = new Options();
newOpts.inJustDecodeBounds = true; // 只读边,不读内容
Bitmap bitmap = BitmapFactory.decodeFile(srcPath, newOpts);
newOpts.inJustDecodeBounds = false;
int w = newOpts.outWidth;
int h = newOpts.outHeight;
float hh = 800f; //
float ww = 480f; //
int be = 1;
if (w > h && w > ww) {
be = (int) (newOpts.outWidth / ww);
} else if (w < h && h > hh) {
be = (int) (newOpts.outHeight / hh);
}
if (be <= 0) be = 1;
newOpts.inSampleSize = be; // 设置采样率
newOpts.inPreferredConfig = Config.ARGB_8888; // 该模式是默认的,可不设
newOpts.inPurgeable = true; // 同时设置才会有效
newOpts.inInputShareable = true; // 当系统内存不够时候图片自动被回收
bitmap = BitmapFactory.decodeFile(srcPath, newOpts);
// return compressBmpFromBmp(bitmap);//原来的方法调用了这个方法企图进行二次压缩
// 其实是无效的,大家尽管尝试
return bitmap;
}
/**
* @param data 数据或路径
* @param width 目标宽
* @param height 目标高
* @return 图片
*/
private Bitmap createBitmap(Object data, int width, int height) {
Options options = new Options();
int scale = 1;
if (width > 0 && height > 0) { // 创建目标大小的图片
options.inJustDecodeBounds = true;
if (data instanceof String) {
BitmapFactory.decodeFile((String) data, options);
} else {
BitmapFactory.decodeByteArray((byte[]) data, 0, ((byte[]) data).length, options);
}
int dw = options.outWidth / width;
int dh = options.outHeight / height;
scale = Math.max(dw, dh);
options = new Options();
}
options.inDensity = DeviceInfo.getInstance().getDencity();
options.inScaled = true;
options.inPurgeable = true;
options.inSampleSize = scale;
Bitmap bitmap = null;
if (data instanceof String) {
bitmap = BitmapFactory.decodeFile((String) data, options);
} else {
bitmap = BitmapFactory.decodeByteArray((byte[]) data, 0, ((byte[]) data).length, options);
}
return bitmap;
}
public PurgeableBitmapView(Context context, boolean isPurgeable) {
super(context);
setFocusable(true);
mOptions.inPurgeable = isPurgeable;
int[] colors = createColors();
Bitmap src = Bitmap.createBitmap(colors, 0, STRIDE, WIDTH, HEIGHT, Bitmap.Config.ARGB_8888);
bitstream = generateBitstream(src, Bitmap.CompressFormat.JPEG, 80);
mPaint.setTextSize(textSize);
mPaint.setColor(Color.GRAY);
}
private void copyOptions(Options srcOptions, Options destOptions) {
destOptions.inDensity = srcOptions.inDensity;
destOptions.inDither = srcOptions.inDither;
destOptions.inInputShareable = srcOptions.inInputShareable;
destOptions.inJustDecodeBounds = srcOptions.inJustDecodeBounds;
destOptions.inPreferredConfig = srcOptions.inPreferredConfig;
destOptions.inPurgeable = srcOptions.inPurgeable;
destOptions.inSampleSize = srcOptions.inSampleSize;
destOptions.inScaled = srcOptions.inScaled;
destOptions.inScreenDensity = srcOptions.inScreenDensity;
destOptions.inTargetDensity = srcOptions.inTargetDensity;
destOptions.inTempStorage = srcOptions.inTempStorage;
if (Build.VERSION.SDK_INT >= 10) copyOptions10(srcOptions, destOptions);
if (Build.VERSION.SDK_INT >= 11) copyOptions11(srcOptions, destOptions);
}
public Bitmap loadCachedResource(CachedResource resource) {
try {
Options options = new Options();
options.inPurgeable = true;
options.inInputShareable = true;
return BitmapFactory.decodeStream(
new FlushedInputStream(new FileInputStream(new File(resource.getPath()))));
} catch (Exception e) {
if (resource != null) {
Log.e("MyTag", "Error decoding image : " + resource.getPath(), e);
}
System.gc();
return null;
}
}
public Builder() {
decodingOptions.inPurgeable = true;
decodingOptions.inInputShareable = true;
}