OleLoadPicturePath
API 函数可以加载 JPEG 文件。
那么这只是访问位的问题。
还有Windows Imaging Component API,但我没有使用过。
不过,我怀疑它也可以工作,而且它可能比处理 OLE 的东西更简单,但我在这里举例说明OleLoadPicturePath
.
在尝试修改下面的代码之前,您应该:
#include <header_wrapper/olectl_h.h> // IPicture
#include <header_wrapper/windows_h.h>
#include "resource.h" // IDD_DEMO_DIALOG, IDC_PICTURE
#include <progrock/cppx/throwx.h> // hopefully, throwX, std::exception
#include <progrock/cppx/size.h> // size
#include <progrock/winapi/path.h> // *
#include <progrock/winapi/ComPointer.h> // ComPointer
using namespace progrock;
#include <assert.h> // assert
#include <iostream>
#include <stdlib.h> // EXIT_FAILURE, EXIT_SUCCESS
using namespace std;
using cppx::hopefully;
using cppx::size;
using cppx::throwX;
using winapi::String;
struct IsHrSuccess
{
friend bool operator>>( HRESULT const hr, IsHrSuccess const& )
{
return SUCCEEDED( hr );
}
};
IsHrSuccess const isHrSuccess = IsHrSuccess();
short kindOf( IPicture const& pic )
{
short kind = 0;
const_cast< IPicture& >( pic ).get_Type( &kind )
>> isHrSuccess || throwX( "kindOf: IPicture::get_Type failed" );
return kind;
}
bool isBitmap( IPicture const& pic )
{
return (kindOf( pic ) == PICTYPE_BITMAP);
}
OLE_HANDLE handleOf( IPicture const& pic )
{
OLE_HANDLE result = 0;
const_cast< IPicture& >( pic ).get_Handle( &result )
>> isHrSuccess || throwX( "handleOf: IPicture::get_Handle failed" );
return result;
}
HBITMAP bmpHandle( IPicture const& pic )
{
assert( isBitmap( pic ) );
return reinterpret_cast< HBITMAP >( handleOf( pic ) );
}
namespace g {
winapi::ComPointer<IPicture> pPicture;
} // namespace g
INT_PTR CALLBACK demoDialogProc(
HWND const window,
UINT const messageId,
WPARAM const wParam,
LPARAM const lParam
)
{
switch( messageId )
{
case WM_INITDIALOG:
::SendDlgItemMessage(
window, IDC_PICTURE, STM_SETIMAGE,
IMAGE_BITMAP,
reinterpret_cast< LPARAM >( bmpHandle( *g::pPicture ) )
);
break;
case WM_CLOSE:
::EndDialog( window, IDCANCEL );
break;
case WM_COMMAND:
::EndDialog( window, wParam );
break;
}
return 0;
}
struct Com
{
Com() { ::CoInitialize( 0 ) >> isHrSuccess || throwX( "::CoInitialize failed" ); }
~Com() { ::CoUninitialize(); }
};
void cppMain()
{
Com usingCom;
String const picFileName = L"image.jpg";
String const picFilePath = winapi::path::combine( winapi::exeFolder(), picFileName );
::OleLoadPicturePath(
const_cast< wchar_t* >( picFilePath.c_str() ),
nullptr, 0, 0,
IID_IPicture,
g::pPicture.asOutArgument()
)
>> isHrSuccess || throwX( "OleLoadPicturePath failed" );
assert( isBitmap( *g::pPicture ) );
::DialogBox( ::GetModuleHandle( 0 ), MAKEINTRESOURCE( IDD_DEMO_DIALOG ), 0, demoDialogProc );
}
int main()
{
try
{
cppMain();
return EXIT_SUCCESS;
}
catch( exception const& x )
{
wcout << "!" << x.what() << endl;
}
return EXIT_FAILURE;
}