Windows GDI screenshot uses Libjpeg to save JPG files

/** Windows GDI screenshot save JPG file using Libjpeg */#include "stdio.h" #include "windows.h" #include "libjpeg/jpeglib.h" #pragma comment (Lib, "Libjpeg/libjpeg.lib") void Bgr_to_jpgfile (BYTE *rgb,int size,int w,int h,char *jpgfile) {struct JPEG_ERROR_MGR Jerr;jpeg_std_error (&jerr); struct Jpeg_compress_struct cinfo;cinfo.err = &jerr;jpeg_create_compress (& Cinfo); FILE *FP = fopen (Jpgfile, "wb+"); Jpeg_stdio_dest (&AMP;CINFO,FP); cinfo.image_width = W;cinfo.image_height = h; cinfo.input_components = 3;cinfo.in_color_space = Jcs_rgb;jpeg_set_defaults (&cinfo); Jpeg_set_quality (& Cinfo, +, TRUE); jpeg_start_compress (&cinfo,true); int row_stride = cinfo.image_width*cinfo.input_components; Jsamprow Row_pointer[1];while (Cinfo.next_scanline < Cinfo.image_height) {row_pointer[0] = & Rgb[cinfo.next_ Scanline * Row_stride];//row_pointer[0] = & rgb[(cinfo.image_height-cinfo.next_scanline-1) *row_stride];(void) Jpeg_write_scanlines (&cinfo, Row_pointer, 1);} Jpeg_finish_compress (&cinfo); jpeg_destRoy_compress (&cinfo); fclose (FP);} int main (int argc,char *argv) {HWND Dthwnd = GetDesktopWindow (); HDC DTHDC = GetDC (dthwnd); int dtwidth = GetSystemMetrics (sm_cxscreen); int dtheight = GetSystemMetrics (Sm_cyscreen); HDC dthdcbuf = CreateCompatibleDC (NULL); Hbitmap hbitmap = CreateCompatibleBitmap (dthdc,dtwidth,dtheight); SelectObject (Dthdcbuf, HBITMAP); BitBlt (dthdcbuf, 0, 0, dtwidth, dtheight, DTHDC, 0, 0, srccopy); int bitsize = dtwidth*dtheight*4; BYTE *bit = new Byte[bitsize]; LONG re = getbitmapbits (Hbitmap, bitsize, bit), if (bit && re) {BYTE *buf = bit; for (int i=0, j=0; j < Bitsize; i+ =3, j+=4) {* (buf+i) = * (BUF+J); * (buf+i+1) = * (buf+j+1); * (buf+i+2) = * (buf+j+2);} bgr_to_jpgfile (bit,dtwidth*dtheight*3 , Dtwidth, Dtheight, "gdi_libjpeg.jpg"); free (bit);} DeleteObject (HBITMAP);D Eletedc (DTHDCBUF); ReleaseDC (DTHWND,DTHDC); return 1;}

Gdi_jpg.cpp

Windows GDI screenshot uses Libjpeg to save JPG files