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所以我寫了一個加載位圖的應用程序。但我想拉伸加載的位圖，使它們都具有相同的大小。我怎樣才能用StretchBlt來實現這樣的事情？這是我的功能，處理位圖：如何使用StretchBlt拉伸位圖？
hBitmap = (HBITMAP)::LoadImageA(NULL, userSelectedFile, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
if (hBitmap == NULL)
{
::MessageBox(NULL, TEXT("LoadImage Failed"), TEXT("Error"), MB_OK);
return false;
}
HDC hLocalDC;
hLocalDC = ::CreateCompatibleDC(hWinDC);
if (hLocalDC == NULL)
{
::MessageBox(NULL, TEXT("CreateCompatibleDC Failed"), TEXT("Error"), MB_OK);
return false;
}
BITMAP qBitmap;
int iReturn = GetObject(reinterpret_cast<HGDIOBJ>(hBitmap), sizeof(BITMAP), reinterpret_cast<LPVOID>(&qBitmap));
if (!iReturn)
{
::MessageBox(NULL, TEXT("GetObject Failed"), TEXT("Error"), MB_OK);
return false;
}
HBITMAP hOldBmp = (HBITMAP)::SelectObject(hLocalDC, hBitmap);
if (hOldBmp == NULL)
{
::MessageBox(NULL, TEXT("SelectObject Failed"), TEXT("Error"), MB_OK);
return false;
}
BOOL qRetBlit = ::BitBlt(hWinDC, 0, 0, qBitmap.bmWidth, qBitmap.bmHeight, hLocalDC, 0, 0, SRCCOPY);
if (!qRetBlit)
{
::MessageBox(NULL, TEXT("Blit Failed"), TEXT("Error"), MB_OK);
return false;
}
::SelectObject(hLocalDC, hOldBmp);
::DeleteDC(hLocalDC);
::DeleteObject(hBitmap);
return true;
將我必須替換StretchBlt與BitBlt？
更新：我已經設法讓StretchBlt工作，但顯然我的所有圖像都互相重疊。以下是目前爲止的代碼：
hBitmap = (HBITMAP)::LoadImageA(NULL, myFile, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
// Verify that the image was loaded
if (hBitmap == NULL)
{
::MessageBox(NULL, TEXT("LoadImage Failed"), TEXT("Error"), MB_OK);
return false;
}
HDC hLocalDC;
hLocalDC = ::CreateCompatibleDC(hWinDC);
// Verify that the device context was created
if (hLocalDC == NULL)
{
::MessageBox(NULL, TEXT("CreateCompatibleDC Failed"), TEXT("Error"), MB_OK);
return false;
}
BITMAP qBitmap;
int iReturn = GetObject(reinterpret_cast<HGDIOBJ>(hBitmap), sizeof(BITMAP), reinterpret_cast<LPVOID>(&qBitmap));
if (!iReturn)
{
::MessageBox(NULL, TEXT("GetObject Failed"), TEXT("Error"), MB_OK);
return false;
}
HBITMAP hOldBmp = (HBITMAP)::SelectObject(hLocalDC, hBitmap);
if (hOldBmp == NULL)
{
::MessageBox(NULL, TEXT("SelectObject Failed"), TEXT("Error"), MB_OK);
return false;
}
/*BOOL qRetBlit = ::BitBlt(hWinDC, xPos, yPos, qBitmap.bmWidth, qBitmap.bmHeight, hLocalDC, 0, 0, SRCCOPY);
if (!qRetBlit)
{
::MessageBox(NULL, TEXT("Blit Failed"), TEXT("Error"), MB_OK);
return false;
}*/
sx = GetSystemMetrics(SM_CXSCREEN);
sy = GetSystemMetrics(SM_CXSCREEN);
BOOL qStretchBlit = StretchBlt(hWinDC, 0, 0, sx/2, sy/2, hLocalDC, 0, 0, sx, sy, SRCCOPY);
if (!qStretchBlit)
{
MessageBox(NULL, TEXT("StretchBlt Failed"), TEXT("Error"), MB_OK);
return false;
}
// Adjust positioning (not perfect)
if (iOldCounter > iCounter)
{
xPos += MOVE_X_POS;
if (xPos >= NEW_ROW_POS)
{
xPos = 0;
yPos += MOVE_Y_POS;
}
}
::SelectObject(hLocalDC, hOldBmp);
::DeleteDC(hLocalDC);
::DeleteObject(hBitmap);
return true;
想法？
你的意思是「用'StrechBlt'替換'BitBlt'」（因爲你已經在使用前者）。你檢查[MSDN：縮放圖像]（https://msdn.microsoft.com/en-us/library/windows/desktop/dd162950（v = vs.85）.aspx）（雖然它有點長）？ – CristiFati
@CristiFati我有，但喜歡它是這樣一個巨大的例子，我真的不明白這一切。我希望這裏有人會給我一個提示，但顯然沒有人喜歡WinAPI（; p） – WaveOnyx
我喜歡_WinAPI_：d。在hWinDC上繪畫時，你是否嘗試用'StretchBlt'替換'BitBlt'（別忘了2個額外的參數）？此外，我不確定什麼插值技術'StretchBlt'使用，但作爲替代，你可以看看[SO：這個答案]（https://stackoverflow.com/questions/41861274/scaling-up-an-image- using-nearest-neighbor/41879669＃41879669），它使用_nearest neighbor_（這是最簡單但也是最差的）手動縮放圖像。 – CristiFati