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我想在相機預覽上做一些圖像處理，但速度太慢，我在採樣時間圖像下，並在較小規模上進行處理。然後，我將處理後的（閾值）圖像疊加在預覽上。我的問題是，當我縮放較小的圖像以適應相機預覽時，像素保持相同的大小...我想看到一些大的像素由於縮放，但我不能。畫布縮放保留像素尺寸
這裏的XML：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:keepScreenOn="true"
android:orientation="vertical" >
<SurfaceView
android:id="@+id/svPreview"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<SurfaceView
android:id="@+id/svOverlay"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:adjustViewBounds="true" />
</RelativeLayout>
而且線程進入相機預覽圖像字節並執行閾值：
class PathThread extends Thread implements PreviewCallback
{
private final int width, height;
private final SurfaceHolder holder;
private Canvas overlayCanvas;
private int samples = 8;
final private float scale;
final private Paint red, blue, yellow;
public PathThread(int canvasWidth, int canvasHeight, SurfaceView canvasView)
{
// This is how much smaller image I want
width = canvasWidth/samples;
height = canvasHeight/samples;
holder = canvasView.getHolder();
// Scale to fit the camera preview SurfaceView
scale = (float) canvasView.getWidth()/height;
// No smoothing when scaling please
yellow = new Paint();
yellow.setColor(Color.parseColor("#ffbb33"));
yellow.setAntiAlias(false);
yellow.setDither(false);
yellow.setFilterBitmap(false);
}
public void onPreviewFrame(byte[] data, Camera camera)
{
overlayCanvas = holder.lockCanvas();
overlayCanvas.drawColor(0, Mode.CLEAR);
overlayCanvas.scale(scale, scale);
// Do the image processing and make a [samples] times smaller image
// Boring, pseudo-optimized, per-pixel thresholding process
holder.unlockCanvasAndPost(overlayCanvas);
}
}
這是結果：
我知道這有點偏移，但就是這樣我的問題最少。