如何在Android OpenCV 3中将风景图像旋转为人像

Question

This code rotate a image from Landscape to Portrait, but I can't do it in Android. What is the equivalent code?

import cv2
import numpy


img = cv2.imread('original.png')

h, w = img.shape[:2]

img2 = numpy.zeros((w, h, 3), numpy.uint8)
cv2.transpose(img, img2)
cv2.flip(img2, 1, img2)

cv2.imwrite('rotate.png', img2)

Answer 1

I assume you have your image as OpenCV Mat in Android (you can load an image by using the Imgcodecs.imread() method).

Then you can just do it like this:

Mat src = Imgcodecs.imread("path/to/file"); // initialize this with your image from file

Core.flip(src.t(), src, 1); // this will rotate the image 90° clockwise
Core.flip(src.t(), src, 0); // this will rotate the image 90° counter-clockwise

After that, use Imgcodecs.imwrite() to save the image. Make sure you add the permissions to your Manifest:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Answer 2

[SOLVED]...

Get a landscape, like (W)800 x (H) 600, and outpout a (H)800 x (W)600. :)

Core.transpose(mRgba, mRgbaT); Imgproc.resize(mRgbaT, mRgbaF, mRgbaT.size(), 0, 0, 0); Core.flip(mRgbaF, mRgbaF, 1);