这是我用来旋转图像的代码。我需要通过网络发送它。图像正在正确旋转，但我得到的图像没有正确的颜色。我在 cpp 中将此代码编写为 native 代码。 DecodeNV21() 有 3 个参数宽度、高度、旋转。我得到的宽度和高度是 640,480。如果旋转是纵向变量旋转为 1，高度和宽度将为 640,480。旋转为 0，即横向，则宽度和高度 640 和 480。请知道的人帮我解决这个问题。纵向模式旋转是正确的。但横向模式有问题。
void DecodeNV21(int SrcHeight,int SrcWidth,int rotation)
/* decodes NV21-encoded image data, which is the default camera preview image format. */
{
//int SrcWidth = encoderContext.m_width;
//int SrcHeight = encoderContext.m_height;
int Rotate = rotation;
int Alpha = 0xFF;
int AlphaMask = Alpha << 24;
/* Rotation involves accessing either the source or destination pixels in a
non-sequential fashion. Since the source is smaller, I figure it's less
cache-unfriendly to go jumping around that. */
int DstWidth = (Rotate & 1) != 0 ? SrcHeight : SrcWidth;
int DstHeight = (Rotate & 1) != 0 ? SrcWidth : SrcHeight;
bool DecrementRow = Rotate > 1;
bool DecrementCol = Rotate == 1 || Rotate == 2;
int LumaRowStride = (Rotate & 1) != 0 ? 1 : SrcWidth;
int LumaColStride = (Rotate & 1) != 0 ? SrcWidth : 1;
int ChromaRowStride = (Rotate & 1) != 0 ? 2 : SrcWidth;
int ChromaColStride = (Rotate & 1) != 0 ? SrcWidth : 2;
// LOGME("DecodeNV21 decoding w:%d,h:%d,DecrementRow:%d,ChromaRowStride:%d, DecrementCol:%d,ChromaColStride:%d,LumaRowStride%d,LumaColStride:%d",DstWidth,DstHeight,DecrementRow,ChromaRowStride, DecrementCol,ChromaColStride,LumaRowStride,LumaColStride);
int dst = 0;
int i=0;
for (int row = DecrementRow ? DstHeight : 0;;)
{
if (row == (DecrementRow ? 0 : DstHeight))
break;
if (DecrementRow)
{
--row;
} /*if*/
for (int col = DecrementCol ? DstWidth : 0;;)
{
if (col == (DecrementCol ? 0 : DstWidth))
break;
if (DecrementCol)
{
--col;
} /*if*/
int Y = 0xff & (int)byte_array[row * LumaRowStride + col * LumaColStride]; /* [0 .. 255] */
/* U/V data follows entire luminance block, downsampled to half luminance
resolution both horizontally and vertically */
/* decoding follows algorithm shown at
<http://www.mail-archive.com/android-developers@googlegroups.com/msg14558.html>,
except it gets red and blue the wrong way round */
int Cr =
(0xff & (int)byte_array[SrcHeight * SrcWidth + row / 2 * ChromaRowStride + col / 2 * ChromaColStride]) - 128;
/* [-128 .. +127] */
int Cb =
(0xff & (int)byte_array[SrcHeight * SrcWidth + row / 2 * ChromaRowStride + col / 2 * ChromaColStride + 1]) - 128;
/* [-128 .. +127] */
int r,g,b;
int color =
AlphaMask
|
(r=max(
min(
(int)(
Y
+
Cr
+
(Cr >> 1)
+
(Cr >> 2)
+
(Cr >> 6)
),
255
),
0
))
<<
16 /* red */
|
(g=max(
min(
(int)(
Y
-
(Cr >> 2)
+
(Cr >> 4)
+
(Cr >> 5)
-
(Cb >> 1)
+
(Cb >> 3)
+
(Cb >> 4)
+
(Cb >> 5)
),
255
),
0
))
<<
8 /* green */
| (b=max(
min(
(int)(
Y
+
Cb
+
(Cb >> 2)
+
(Cb >> 3)
+
(Cb >> 5)
),
255
),
0
)); /* blue */
//color = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
TypeConvert::udwordToBytes(color, encoderContext.m_in_Array_Encode,i * 4);
i++;
if (!DecrementCol)
{
++col;
} /*if*/
} /*for*/
if (!DecrementRow)
{
++row;
} /*if*/
} /*for*/
} /*DecodeNV21*/
最佳答案
我真的不想整理你的旧代码，只是让我粘贴我采用的解决方案(从我忘记的地方得到它......)将图像旋转 90、180、270 度并返回一个字节数组.因此，例如，您处于纵向模式，您可以将后置摄像头旋转 90 度，将前置摄像头旋转 270 度。其他轮换方式可以按照类似的方式实现。我认为这应该足以让您继续这条路。
private byte[] rotateYUV420Degree90(byte[] data, int imageWidth, int imageHeight)
{
byte [] yuv = new byte[imageWidth*imageHeight*3/2];
// Rotate the Y luma
int i = 0;
for(int x = 0;x < imageWidth;x++)
{
for(int y = imageHeight-1;y >= 0;y--)
{
yuv[i] = data[y*imageWidth+x];
i++;
}
}
// Rotate the U and V color components
i = imageWidth*imageHeight*3/2-1;
for(int x = imageWidth-1;x > 0;x=x-2)
{
for(int y = 0;y < imageHeight/2;y++)
{
yuv[i] = data[(imageWidth*imageHeight)+(y*imageWidth)+x];
i--;
yuv[i] = data[(imageWidth*imageHeight)+(y*imageWidth)+(x-1)];
i--;
}
}
return yuv;
}
private byte[] rotateYUV420Degree180(byte[] data, int imageWidth, int imageHeight)
{
byte [] yuv = new byte[imageWidth*imageHeight*3/2];
int i = 0;
int count = 0;
for (i = imageWidth * imageHeight - 1; i >= 0; i--) {
yuv[count] = data[i];
count++;
}
i = imageWidth * imageHeight * 3 / 2 - 1;
for (i = imageWidth * imageHeight * 3 / 2 - 1; i >= imageWidth
* imageHeight; i -= 2) {
yuv[count++] = data[i - 1];
yuv[count++] = data[i];
}
return yuv;
}
private byte[] rotateYUV420Degree270(byte[] data, int imageWidth, int imageHeight)
{
byte [] yuv = new byte[imageWidth*imageHeight*3/2];
int nWidth = 0, nHeight = 0;
int wh = 0;
int uvHeight = 0;
if(imageWidth != nWidth || imageHeight != nHeight)
{
nWidth = imageWidth;
nHeight = imageHeight;
wh = imageWidth * imageHeight;
uvHeight = imageHeight >> 1;//uvHeight = height / 2
}
//–˝◊™Y
int k = 0;
for(int i = 0; i < imageWidth; i++) {
int nPos = 0;
for(int j = 0; j < imageHeight; j++) {
yuv[k] = data[nPos + i];
k++;
nPos += imageWidth;
}
}
for(int i = 0; i < imageWidth; i+=2){
int nPos = wh;
for(int j = 0; j < uvHeight; j++) {
yuv[k] = data[nPos + i];
yuv[k + 1] = data[nPos + i + 1];
k += 2;
nPos += imageWidth;
}
}
return rotateYUV420Degree180(yuv,imageWidth,imageHeight);
}
关于android - 从 android 相机解码 NV21 图像，但它的颜色不适合图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26604983/