在Android的切断图像的边缘OpenCV的图像旋转 [英] image rotation with opencv in android cuts off the edges of an image

问题描述

可能重复：结果
  <一href=\"http://stackoverflow.com/questions/7813376/rotate-cvmat-using-cvwarpaffine-offsets-destination-image\">Rotate CV ::垫使用的CV :: warpAffine抵消目的地形象

code以下能成功地旋转图像，但它切断角落的图像，并将其旋转方向不对！

Code below can rotate an image successfully but it cuts off corners of the image and it rotates in wrong direction!!

Mat cvImage = Highgui.imread("mnt/sdcard/canvasgrid.png");
int degrees = 20;
Point center = new Point(cvImage.cols()/2, cvImage.rows()/2);
Mat rotImage = Imgproc.getRotationMatrix2D(center, degrees, 1.0);
Mat dummy = cvWaterImage;
Imgproc.warpAffine(cvImage, dummy, rotImage, cvImage.size());
rotatedImage = dummy;

Highgui.imwrite("mnt/sdcard/imageRotate.png",rotatedImage);

原始图像

旋转图片

PLUS旋转图像的背景是黑色的，但我希望它是透明的。

PLUS rotated image's background is black but I want it to be transparent.

难道我做错了什么？
谢谢

Am I doing anything wrong?? Thanks

修改解决

首先获得旋转图像的新宽度/高度

first of all get new width/height of rotated image

double radians = Math.toRadians(rotationAngle);
double sin = Math.abs(Math.sin(radians));
double cos = Math.abs(Math.cos(radians));

int newWidth = (int) (scaledImage.width() * cos + scaledImage.height() * sin);
int newHeight = (int) (scaledImage.width() * sin + scaledImage.height() * cos);

int[] newWidthHeight = {newWidth, newHeight};

//创建新的大小的盒子（newWidth / newHeight）

// create new sized box (newWidth/newHeight)

int pivotX = newWidthHeight[0]/2; 
int pivotY = newWidthHeight[1]/2;

//水旋图片

org.opencv.core.Point center = new org.opencv.core.Point(pivotX, pivotY);
Size targetSize = new Size(newWidthHeight[0], newWidthHeight[1]);

//现在创建另一个垫，所以我们可以用它来映射

// now create another mat, so we can use it for mapping

Mat targetMat = new Mat(targetSize, scaledImage.type());

int offsetX = (newWidthHeight[0] - scaledImage.width()) / 2;
int offsetY = (newWidthHeight[1] - scaledImage.height()) / 2;

//集中化水印

// Centralizing watermark

Mat waterSubmat = targetMat.submat(offsetY, offsetY + scaledImage.height(), offsetX,     offsetX + scaledImage.width());
scaledImage.copyTo(waterSubmat);

Mat rotImage = Imgproc.getRotationMatrix2D(center, waterMarkAngle, 1.0);
Mat resultMat = new Mat(); // CUBIC
Imgproc.warpAffine(targetMat, resultMat, rotImage, targetSize, Imgproc.INTER_LINEAR,    Imgproc.BORDER_CONSTANT, colorScalar);

//你用这个样子的不会被裁剪图片 resultMat
// BTW ..还有就是提供链接，该解决方案

// your resultMat with look like this NOT CROPPED Image // BTW.. there is a huge differce between provided link and this solution

推荐答案

我只是通过文档阅读：的 ImgProc.warpAffine

I just read through the documentation: ImgProc.warpAffine

的只是一个摘录：的

void warpAffine(InputArray src, OutputArray dst, InputArray M, Size dsize, [...]);
//Parameters: dsize – Size of the destination image.

请尝试以下操作：

Imgproc.warpAffine(cvImage, dummy, rotImage, dummy.size());

为了与透明度玩，小提琴，并在最后的参数：

In order to play with the transparency, fiddle with the parameter at the end:

Imgproc.warpAffine(cvImage, dummy, rotImage, dummy.size(), INTER_LINEAR, BORDER_TRANSPARENT);

这篇关于在Android的切断图像的边缘OpenCV的图像旋转的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！