android - 如何在底部的图像位图上放置文本？

Question

我想要什么:我想在我从画廊或相机中选择的图像底部添加文本。

原始图片

我在底部的图像中添加了蓝色色带

在该 strip 中，我想恰好在中间添加一些文本。

问题是什么:

1. 我无法将文本准确定位在蓝色色带的中间。
2. 对于不同的图像，文字大小会发生变化。有时它很小，有时它很大。

我尝试了什么:我的代码如下所示。

MainActivity.java

    public class MainActivity extends AppCompatActivity {

    private ImageView mImageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mImageView = findViewById(R.id.imageView);
    }

    public void openGallery(View view) {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, "Select Picture"), 100);
    }

    public void openCamera(View view) {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(intent, 101);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (data != null && resultCode == Activity.RESULT_OK) {

            if (requestCode == 100) {

                Bitmap bitmap = null;
                try {
                    bitmap = MediaStore.Images.Media
                            .getBitmap(getApplicationContext().getContentResolver(), data.getData());
                } catch (IOException e) {
                    e.printStackTrace();
                }

                addStampToImage(bitmap);

            } else if (requestCode == 101) {

                Bitmap bitmap = (Bitmap) data.getExtras().get("data");
                ByteArrayOutputStream bytes = new ByteArrayOutputStream();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
                File destination = new File(Environment.getExternalStorageDirectory(),
                        System.currentTimeMillis() + ".jpg");
                FileOutputStream fo;
                try {
                    destination.createNewFile();
                    fo = new FileOutputStream(destination);
                    fo.write(bytes.toByteArray());
                    fo.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                addStampToImage(bitmap);
            }
        }
    }

    private void addStampToImage(Bitmap originalBitmap) {

        int extraHeight = (int) (originalBitmap.getHeight() * 0.15);

        Bitmap newBitmap = Bitmap.createBitmap(originalBitmap.getWidth(),
                originalBitmap.getHeight() + extraHeight, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(newBitmap);
        canvas.drawColor(Color.BLUE);
        canvas.drawBitmap(originalBitmap, 0, 0, null);

        Resources resources = getResources();
        float scale = resources.getDisplayMetrics().density;

        Paint pText = new Paint();
        pText.setColor(Color.WHITE);
        pText.setTextSize((int) (20 * scale));

        String text = "Maulik";

        /*Rect r = new Rect();
        canvas.getClipBounds(r);
        int cHeight = r.height();
        int cWidth = r.width();
        pText.setTextAlign(Paint.Align.LEFT);
        pText.getTextBounds(text, 0, text.length(), r);
        float x = -r.left;
        float y = cHeight / 2f + r.height() / 2f - r.bottom;

        int minusSpace = (int) (canvas.getClipBounds().bottom * 0.07);

        canvas.drawText(text, 0, canvas.getClipBounds().bottom - minusSpace, pText);*/

        Rect bounds = new Rect();
        pText.getTextBounds(text, 0, text.length(), bounds);
        int x = (newBitmap.getWidth() - bounds.width())/6;
        int y = (newBitmap.getHeight() + bounds.height())/5;

        canvas.drawText(text, x * scale, y * scale, pText);

        mImageView.setImageBitmap(newBitmap);
    }
}

任何帮助将不胜感激!

更新时间:2018 年 8 月 1 日

addStampToImage 方法的变化。

int extraHeight = (int) (originalBitmap.getHeight() * 0.15);

Rect textHeightWidth = new Rect();
pText.getTextBounds(fromWhichMode, 0, fromWhichMode.length(), textHeightWidth);

canvas.drawText(textToStamp, (canvas.getWidth() / 2) - (textHeightWidth.width() / 2),
                originalBitmap.getHeight() + (extraHeight / 2) + (textHeightWidth.height() / 2),
                pText);

以上更改在蓝色 strip 中间给我文本。但核心ISSUE 保持不变。即文本大小会根据不同的图像大小而变化。

Answer 1

检查下面的代码:-

private void addStampToImage(Bitmap originalBitmap) {

    int extraHeight = (int) (originalBitmap.getHeight() * 0.15);

    Bitmap newBitmap = Bitmap.createBitmap(originalBitmap.getWidth(),
            originalBitmap.getHeight() + extraHeight, Bitmap.Config.ARGB_8888);

    Canvas canvas = new Canvas(newBitmap);
    canvas.drawColor(Color.BLUE);
    canvas.drawBitmap(originalBitmap, 0, 0, null);

    Resources resources = getResources();
    float scale = resources.getDisplayMetrics().density;

    String text = "Maulik";
    Paint pText = new Paint();
    pText.setColor(Color.WHITE);

    setTextSizeForWidth(pText,(int) (originalBitmap.getHeight() * 0.10),text);




    Rect bounds = new Rect();
    pText.getTextBounds(text, 0, text.length(), bounds);

    int x=  ((newBitmap.getWidth()-(int)pText.measureText(text))/2);
    int h=(extraHeight+bounds.height())/2;
    int y=(originalBitmap.getHeight()+h);

    canvas.drawText(text, x, y, pText);

    imageView.setImageBitmap(newBitmap);
}


private void setTextSizeForWidth(Paint paint, float desiredHeight,
                                        String text) {

    // Pick a reasonably large value for the test. Larger values produce
    // more accurate results, but may cause problems with hardware
    // acceleration. But there are workarounds for that, too; refer to
    // http://stackoverflow.com/questions/6253528/font-size-too-large-to-fit-in-cache
    final float testTextSize = 48f;

    // Get the bounds of the text, using our testTextSize.
    paint.setTextSize(testTextSize);
    Rect bounds = new Rect();
    paint.getTextBounds(text, 0, text.length(), bounds);

    // Calculate the desired size as a proportion of our testTextSize.
    float desiredTextSize = testTextSize * desiredHeight / bounds.height();

    // Set the paint for that size.
    paint.setTextSize(desiredTextSize);
}

编辑:-除了上面的 addStampToImage 方法，您还可以使用更新后的 addStampToImage 方法，如下所示:-

private void addStampToImage(Bitmap originalBitmap) {

    int extraHeight = (int) (originalBitmap.getHeight() * 0.15);

    Bitmap newBitmap = Bitmap.createBitmap(originalBitmap.getWidth(),
            originalBitmap.getHeight() + extraHeight, Bitmap.Config.ARGB_8888);

    Canvas canvas = new Canvas(newBitmap);
    canvas.drawColor(Color.BLUE);
    canvas.drawBitmap(originalBitmap, 0, 0, null);

    Resources resources = getResources();
    float scale = resources.getDisplayMetrics().density;

    String text = "Maulik";
    Paint pText = new Paint();
    pText.setColor(Color.WHITE);

    setTextSizeForWidth(pText,(int) (originalBitmap.getHeight() * 0.10),text);


    Rect bounds = new Rect();
    pText.getTextBounds(text, 0, text.length(), bounds);

    Rect textHeightWidth = new Rect();
    pText.getTextBounds(text, 0, text.length(), textHeightWidth);

    canvas.drawText(text, (canvas.getWidth() / 2) - (textHeightWidth.width() / 2),
            originalBitmap.getHeight() + (extraHeight / 2) + (textHeightWidth.height() / 2),
            pText);

    imageView.setImageBitmap(newBitmap);
}