我尝试使用jpeglib-turbo压缩rgb数据
void jpeg_compress(const char* jpegFileName, unsigned char* inputData,
int nWidth, int nHeight, int nChannel, int nQuality)
{
/* This struct contains the JPEG compression parameters and pointers to
* working space (which is allocated as needed by the JPEG library).
* It is possible to have several such structures, representing multiple
* compression/decompression processes, in existence at once. We refer
* to any one struct (and its associated working data) as a "JPEG object".
*/
struct jpeg_compress_struct cinfo;
/* This struct represents a JPEG error handler. It is declared separately
* because applications often want to supply a specialized error handler
* (see the second half of this file for an example). But here we just
* take the easy way out and use the standard error handler, which will
* print a message on stderr and call exit() if compression fails.
* Note that this struct must live as long as the main JPEG parameter
* struct, to avoid dangling-pointer problems.
*/
struct jpeg_error_mgr jerr;
/* More stuff */
FILE* outfile; /* target file */
JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */
int row_stride; /* physical row width in image buffer */
/* Step 1: allocate and initialize JPEG compression object */
/* We have to set up the error handler first, in case the initialization
* step fails. (Unlikely, but it could happen if you are out of memory.)
* This routine fills in the contents of struct jerr, and returns jerr's
* address which we place into the link field in cinfo.
*/
cinfo.err = jpeg_std_error(&jerr);
/* Now we can initialize the JPEG compression object. */
jpeg_create_compress(&cinfo); /* Now we can initialize the JPEG compression object. */
/* Step 2: specify data destination (eg, a file) */
/* Note: steps 2 and 3 can be done in either order. */
/* Here we use the library-supplied code to send compressed data to a
* stdio stream. You can also write your own code to do something else.
* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
* requires it in order to write binary files.
*/
if ((outfile = fopen(jpegFileName, "wb")) == NULL)
{
fprintf(stderr, "can't open %s\n", jpegFileName);
return;
}
jpeg_stdio_dest(&cinfo, outfile);
/* Step 3: set parameters for compression */
/* First we supply a description of the input image.
* Four fields of the cinfo struct must be filled in:
*/
cinfo.image_width = nWidth; /* image width and height, in pixels */
cinfo.image_height = nHeight;
cinfo.input_components = nChannel; /* # of color components per pixel */
if (nChannel == 1)
{
cinfo.in_color_space = JCS_GRAYSCALE; /* colorspace of input image */
}
else if (nChannel == 3)
{
cinfo.in_color_space = JCS_RGB; /* colorspace of input image */
}
else if (nChannel == 4) {
cinfo.in_color_space = JCS_EXT_RGBA;
}
/* Now use the library's routine to set default compression parameters.
* (You must set at least cinfo.in_color_space before calling this,
* since the defaults depend on the source color space.)
*/
jpeg_set_defaults(&cinfo);
// Now you can set any non-default parameters you wish to.
// Here we just illustrate the use of quality (quantization table) scaling:
jpeg_set_quality(&cinfo, nQuality, TRUE); /* limit to baseline-JPEG values */
/* Step 4: Start compressor */
/* TRUE ensures that we will write a complete interchange-JPEG file.
* Pass TRUE unless you are very sure of what you're doing.
*/
jpeg_start_compress(&cinfo, TRUE);
/* Step 5: while (scan lines remain to be written) */
/* jpeg_write_scanlines(...); */
/* Here we use the library's state variable cinfo.next_scanline as the
* loop counter, so that we don't have to keep track ourselves.
* To keep things simple, we pass one scanline per call; you can pass
* more if you wish, though.
*/
row_stride = nWidth * nChannel; /* JSAMPLEs per row in image_buffer */
while (cinfo.next_scanline < cinfo.image_height)
{
/* jpeg_write_scanlines expects an array of pointers to scanlines.
* Here the array is only one element long, but you could pass
* more than one scanline at a time if that's more convenient.
*/
row_pointer[0] = &inputData[cinfo.next_scanline * row_stride];
(void)jpeg_write_scanlines(&cinfo, row_pointer, 1);
}
/* Step 6: Finish compression */
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
/* After finish_compress, we can close the output file. */
fclose(outfile);
}
使用DXGI截图来获取RGBA数据
void SaveDesktopImage(ID3D11Texture2D* texture2D, DXGIDuplicator* duplicator, const char* filename,int quality)
{
D3D11_TEXTURE2D_DESC desc;
texture2D->GetDesc(&desc);
D3D11_MAPPED_SUBRESOURCE mappedResource;
duplicator->deviceContext_->Map(texture2D, 0, D3D11_MAP_READ, 0, &mappedResource);
//swap_red_blue_channels((unsigned char*)mappedResource.pData, desc.Width, desc.Height);
//size_t imageSize = desc.Width * desc.Height * 4;
jpeg_compress(filename,(uint8_t*)mappedResource.pData, desc.Width, desc.Height, 4, quality);
}
结果报错了：
0x00007FFD6C911208 (ucrtbase.dll) (HostA.exe 中)处有未经处理的异常: 将一个无效参数传递给了将无效参数视为严重错误的函数。
