android将3个位图保存为1

Question

我有一个可以拍照的应用。它创建 2 个子集位图，用失真处理这些位图，然后将子集作为叠加层放置在原始位图上。有没有办法将所有三个位图保存为一个（如手机屏幕上显示的那样）？我想将用户在屏幕上看到的内容保存为 sdcard 上的第四个位图？我觉得我做错了。

谢谢

[更新1]

@Override
    public void onDraw(Canvas canvas){
        super.onDraw(canvas);

        Log.e(TAG, "******about to draw bgr ");
        canvas.drawBitmap(bgr, 0, 0, null);

        if (isLocked == true && bothCirclesInPlace == true){
            if(overLay != null)
             canvas.drawBitmap(overLay, centreX-radius, centreY-radius, null);
            if(overLay2 != null)
             canvas.drawBitmap(overLay2, centreA-radius, centreB-radius, null);
        }

Answer 1

是的，可以叠加多个位图并保存为单个图像文件（PNG / JPEG / ..）。

一种方法是使用 Canvas 类。 Canvas 与 Paint 类一起定义了位图的叠加方式。

以下代码将演示多个位图叠加到单个图像文件中。

try {
        // String mFilePath  : Absolute Path of the file to be saved 

        // Bitmap mBitmap1   : First bitmap. This goes as background.
        // Bitmap mCBitmap   : Bitmap associated with the Canvas. All draws on the canvas are drawn into this bitmap.
        // Bitmap mBitmap2   : Second bitmap. This goes on top of first (in this example serves as foreground.

        // Paint mPaint1     : Paint to draw first bitmap
        // Paint mPaint2     : Paint to draw second bitmap on top of first bitmap

        Bitmap mCBitmap = Bitmap.createBitmap(mBitmap1.getWidth(), mBitmap1.getHeight(), mBitmap1.getConfig());

        Canvas tCanvas = new Canvas(mCBitmap);

        tCanvas.drawBitmap(mBitmap1, 0, 0, mPaint1);

        mPaint2.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DARKEN));
        // XFer modes define the overlay characteristic

        tCanvas.drawBitmap(mBitmap2, 0, 0, mPaint2);

        FileOutputStream stream = new FileOutputStream(mFilePath);
        mCBitmap.compress(CompressFormat.JPEG, 100, stream);

        stream.flush();
        stream.close();
    } catch(Exception e) {
        Log.e("Could not save", e.toString());
}

沙士

Answer 2

您可以尝试以下方法。 如果可以，将图像绘制到画布上：

Bitmap bitmap = new Bitmap(// Set the params you like //);
Canvas canvas = new Canvas(bitmap);

canvas.drawBitmap(// The first picture //);
canvas.drawBitmap(// First overlay //);
canvas.drawBitmap(// Second overlay //);
// You can draw whatever you like
// For example:
canvas.drawRectangle(...);

// Now the bitmap can will hold everything you draw on the canvas.
// You can save the bitmap to the SD
bitmap.compress(...);

Answer 3

您可以使用Bitma.compress(..) 和FileOutputStream 作为最后一个参数。

阅读external storage 以获取有关如何写入 sd 卡的说明。