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我已經構建了一個用戶可以拍照的自定義相機活動。圖片通過圖片回調保存在外部存儲目錄中。用戶然後被重定向到可以預覽圖片的另一個活動。在顯示預覽之前,圖片會在單獨的線程中縮小到某個最大尺寸。下面是縮放代碼:Android Desire HD位圖縮放
byte[] tempStorage = new byte[16 * 1024];
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(imagePath, options);
int oldWidth = options.outWidth;
int oldHeight = options.outHeight;
if (oldWidth > MAX_DIM || oldHeight > MAX_DIM) {
Logger.i(Constants.SCALE_TAG, "Must scale picture");
int scaleFactor = getScaleFactor(oldWidth, oldHeight);
options.inJustDecodeBounds = false;
options.inSampleSize = scaleFactor;
options.inTempStorage = tempStorage;
System.gc();
newB = BitmapFactory.decodeFile(imagePath, options);
} else {
Logger.i(Constants.SCALE_TAG, "No need for scaling");
// We do not need to scale the picture, it is small
// enough.
System.gc();
options.inJustDecodeBounds = false;
options.inTempStorage = tempStorage;
if (!stop) {
newB = BitmapFactory.decodeFile(imagePath, options);
} else {
return;
}
}
這裏是計算比例因子代碼:
private int getScaleFactor(int oldWidth, int oldHeight) {
// Holds the raw scale factor.
float rawScale;
// Get the scaling factor.
if (oldWidth >= oldHeight) {
rawScale = 1.0F/((MAX_DIM * 1.0F)/(oldWidth * 1.0F));
} else {
rawScale = 1.0F/((MAX_DIM * 1.0F)/(oldHeight * 1.0F));
}
Logger.i(Constants.SCALE_TAG, "Raw scale factor: " + rawScale);
return Math.round(rawScale);
}
此代碼工作正常上大多數設備,但不知何故的Desire HD將無法正確縮放圖片。它看起來像是拍攝了原始圖片並將其複製了30次左右,並將其縮放到位圖中,導致出現了奇怪的條紋狀圖片。有誰知道這個問題?