如何在整个屏幕上的画布上绘制位图？

Question

在我的应用程序中，我需要在整个屏幕上绘制位图。出于某种原因，当我绘制位图时，只有部分位图加载到屏幕的一部分上。换句话说，不是整个画面都显示在屏幕上。这是我绘制位图的一段代码：

byte[]byteArray=getIntent().getByteArrayExtra("image");
Bitmap tmp=BitmapFactory.decodeByteArray(byteArray,0,byteArray.length);

operation = Bitmap.createBitmap(tmp.getWidth(), tmp.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(operation);
Paint paint = new Paint();
tmp.setDensity(c.getDensity());

c.drawBitmap(tmp, 0f, 0f, paint);
tmp.recycle();

还有：

private void drawOverlays() {
    Canvas c = null;
    try {
        c = holder.lockCanvas(null);
        synchronized (holder) {
            if (c != null)
                c.drawBitmap(operation, 0, 0, null); 
        }
    } catch (Exception e) {
        Log.e("SurfaceView", "Error drawing frame", e);
    } finally {
        // do this in a finally so that if an exception is thrown
        // during the above, we don't leave the Surface in an
        // inconsistent state
        if (c != null) {
            holder.unlockCanvasAndPost(c);
        }
    }
}

Answer 1

为此，您需要获取设备的宽度和高度，然后将图像缩放到该尺寸并将其显示在画布上。

这是你的代码的修改。

//add this code before your code
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;

//your code with modification
byte[]byteArray=getIntent().getByteArrayExtra("image");
Bitmap tmp=BitmapFactory.decodeByteArray(byteArray,0,byteArray.length);
operation = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(operation);
Paint paint = new Paint();
tmp.setDensity(c.getDensity());
c.drawBitmap(tmp, 0f, 0f, paint);
tmp.recycle();

现在它将填满您的整个屏幕，请确保您将画布应用到整个屏幕。