EmWin - loading from external SD card dta file

BitmapConverter are .dta files. Those are almost the same as the c-files, just in a binary form.
Take a look at functions like GUI_DrawStreamedBitmapExAuto() and at chapter 8.1.5 'Drawing streamed bitmaps'. 

To use them you have to set a get data function which reads the data from the .dta file.
Besides of the .dta files you can also draw BMP, JPEG, or PNG files. 

But those have the disadvantage that they need to be decoded which is slower than using the .dta files.
Here is a short example on how to draw a .dta file. 

This is for windows filesystem but it should be easy to adapt for any other filesystem.
Of course you need a .dta file and set the proper path in MainTask.

#include <windows.h>
#include "GUI.h"

/*********************************************************************
*
*    _GetData
*/
static int _GetData(void * p, const U8 ** ppData, unsigned NumBytesReq, U32 Off) {
  HANDLE * phFile;
  DWORD NumBytesRead;
  U8  * pData;

  pData  = (U8 *)*ppData;
  phFile = (HANDLE *)p;
  //
  // Set file pointer to the required position
  //
  SetFilePointer(*phFile, Off, 0, FILE_BEGIN);
  //
  // Read data into buffer
  //
  ReadFile(*phFile, pData, NumBytesReq, &NumBytesRead, NULL);
  //
  // Return number of available bytes
  //
  return NumBytesRead;
}

/*********************************************************************
*
*    Public code
*
**********************************************************************
*/
/*********************************************************************
*
*    MainTask
*/
void MainTask(void) {
  HANDLE hFile;
  char   acPath[] = "Path to .dta file";

  GUI_Init();
  hFile = CreateFile(acPath, GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  GUI_DrawStreamedBitmapExAuto(_GetData, (void *)&hFile, 0, 0);
  CloseHandle(hFile);
  while (1) {
 GUI_Delay(100);
  }
}