Are Android View transformations applied after rasterization?

问题

The lines (A) and the lines (B) in the code below should produce the same image.

Yet lines (A) produce instead the image:

What is happening? Are View/Canvas transformations applied after rasterization?

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.view.View;
import android.graphics.Matrix;

public class MyView extends View {
    Paint paint = new Paint();

    public MyView(Context c) {
        super(c);
        // this.setLayerType(View.LAYER_TYPE_SOFTWARE, null); // (C)
    }

    Rect canvasRect   = new Rect();
    RectF canvasRectf = new RectF();
    RectF scene = new RectF();
    Matrix M = new Matrix();

    @Override
    protected void onDraw(Canvas canvas) {
        getDrawingRect(canvasRect);
        canvasRectf.set(canvasRect);

        scene.set(0,0, 100,100); // (A)
        // scene.set(0,0, 500,500); // (B)

        M.setRectToRect(scene, canvasRectf, Matrix.ScaleToFit.CENTER);
        canvas.setMatrix(M);

        canvas.drawCircle( 50, 50, 1, paint); // (A)
        // canvas.drawCircle(250,250, 5, paint); // (B)
    }
}

Update: If line (C) is uncommented, the problem does not arise (Thanks, Henry). Is it possible to get the first image while using hardware acceleration?

回答1:

I could reproduce the problem only with Android 4.1.2 when hardware acceleration is enabled. Could it be a bug?

来源：https://stackoverflow.com/questions/13996058/are-android-view-transformations-applied-after-rasterization