Android Picasso会自动旋转图像?

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我正在使用毕加索在我的应用程序中从网络加载图像。我注意到一些图像显示旋转90度,虽然当我在浏览器中打开图像时,我发现它正确定位。我假设这些图像具有EXIF数据。有没有办法指示毕加索忽略EXIF?

提问于
用户回答回答于

你可以发布你正在使用的图像吗?因为正如此线程所说,从Web上加载的图像的Exif方向将被忽略。

我也尝试在picasso 2.5.2中显示此图像,图像的真实方向正面临版权(图像底部的代码正面朝右)。exif方向,顺时针旋转90度。尝试在chrome中打开它(chrome正在兑现exif旋转),图像将朝下(图像底部的代码朝下)。

用户回答回答于

我们知道,毕加索支持本地存储EXIF,这是通过Android内部Utils完成的。由于能够使用自定义的Http加载库,因此提供相同的功能并不容易。我的解决方案很简单:我们必须重写缓存并在缓存项目之前应用Exif旋转:

    OkHttpClient client = new OkHttpClient.Builder()
        .addNetworkInterceptor(chain -> {
            Response originalResponse = chain.proceed(chain.request());
            byte[] body = originalResponse.body().bytes();
            ResponseBody newBody = ResponseBody
                .create(originalResponse.body().contentType(), ImageUtils.processImage(body));
            return originalResponse.newBuilder().body(newBody).build();
        })
        .cache(cache)
        .build();

这里我们添加NetworkInterceptor,它可以在请求和响应被缓存之前转换它:

public class ImageUtils {

    public static byte[] processImage(byte[] originalImg) {
        int orientation = Exif.getOrientation(originalImg);
        if (orientation != 0) {
            Bitmap bmp = BitmapFactory.decodeByteArray(originalImg, 0, originalImg.length);
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            rotateImage(orientation, bmp).compress(Bitmap.CompressFormat.PNG, 100, stream);

            return stream.toByteArray();
        }
        return originalImg;
    }

    private static Bitmap rotateImage(int angle, Bitmap bitmapSrc) {
        Matrix matrix = new Matrix();
        matrix.postRotate(angle);
        return Bitmap.createBitmap(bitmapSrc, 0, 0,
                bitmapSrc.getWidth(), bitmapSrc.getHeight(), matrix, true);
    }
}

Exif转换:

public class Exif {
    private static final String TAG = "Exif";

    // Returns the degrees in clockwise. Values are 0, 90, 180, or 270.
    public static int getOrientation(byte[] jpeg) {
        if (jpeg == null) {
            return 0;
        }

        int offset = 0;
        int length = 0;

        // ISO/IEC 10918-1:1993(E)
        while (offset + 3 < jpeg.length && (jpeg[offset++] & 0xFF) == 0xFF) {
            int marker = jpeg[offset] & 0xFF;

            // Check if the marker is a padding.
            if (marker == 0xFF) {
                continue;
            }
            offset++;

            // Check if the marker is SOI or TEM.
            if (marker == 0xD8 || marker == 0x01) {
                continue;
            }
            // Check if the marker is EOI or SOS.
            if (marker == 0xD9 || marker == 0xDA) {
                break;
            }

            // Get the length and check if it is reasonable.
            length = pack(jpeg, offset, 2, false);
            if (length < 2 || offset + length > jpeg.length) {
                Log.e(TAG, "Invalid length");
                return 0;
            }

            // Break if the marker is EXIF in APP1.
            if (marker == 0xE1 && length >= 8 &&
                    pack(jpeg, offset + 2, 4, false) == 0x45786966 &&
                    pack(jpeg, offset + 6, 2, false) == 0) {
                offset += 8;
                length -= 8;
                break;
            }

            // Skip other markers.
            offset += length;
            length = 0;
        }

        // JEITA CP-3451 Exif Version 2.2
        if (length > 8) {
            // Identify the byte order.
            int tag = pack(jpeg, offset, 4, false);
            if (tag != 0x49492A00 && tag != 0x4D4D002A) {
                Log.e(TAG, "Invalid byte order");
                return 0;
            }
            boolean littleEndian = (tag == 0x49492A00);

            // Get the offset and check if it is reasonable.
            int count = pack(jpeg, offset + 4, 4, littleEndian) + 2;
            if (count < 10 || count > length) {
                Log.e(TAG, "Invalid offset");
                return 0;
            }
            offset += count;
            length -= count;

            // Get the count and go through all the elements.
            count = pack(jpeg, offset - 2, 2, littleEndian);
            while (count-- > 0 && length >= 12) {
                // Get the tag and check if it is orientation.
                tag = pack(jpeg, offset, 2, littleEndian);
                if (tag == 0x0112) {
                    // We do not really care about type and count, do we?
                    int orientation = pack(jpeg, offset + 8, 2, littleEndian);
                    switch (orientation) {
                        case 1:
                            return 0;
                        case 3:
                            return 180;
                        case 6:
                            return 90;
                        case 8:
                            return 270;
                    }
                    Log.i(TAG, "Unsupported orientation");
                    return 0;
                }
                offset += 12;
                length -= 12;
            }
        }

        Log.i(TAG, "Orientation not found");
        return 0;
    }

    private static int pack(byte[] bytes, int offset, int length,
                            boolean littleEndian) {
        int step = 1;
        if (littleEndian) {
            offset += length - 1;
            step = -1;
        }

        int value = 0;
        while (length-- > 0) {
            value = (value << 8) | (bytes[offset] & 0xFF);
            offset += step;
        }
        return value;
    }
}

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