How to paint color Text on background DC

[uni8931]

I want to draw text or image on background DC, so i write code as below. But the output text is also mono. why and how to modify my program. Thanks a lot.

g_PCanvas.cdc = new CDC;
g_PCanvas.cdc->CreateCompatibleDC(NULL);
g_PCanvas.hDC = g_PCanvas.cdc->Detach();
g_PCanvas.hBitmap = CreateCompatibleBitmap(g_PCanvas.hDC, EVOLIS_MAX_WIDTH, EVOLIS_MAX_HEIGHT);
SelectObject(g_PCanvas.hDC, g_PCanvas.hBitmap);
...
...
SetTextColor(hDc, RGB(0xff,0,0xff);
retval = ExtTextOutA(hDc, x, y, ETO_CLIPPED, &rc, szText, strlen(szText), NULL);

..

best regard.

[zerver]

Hi!

Try

GetDC(NULL); // this DC will draw to the entire screen

or

CPaintDC(this); // this == a CWnd derived class

or

CClientDC(this);

and I also wonder what is the purpose of this line:

g_PCanvas.hDC = g_PCanvas.cdc->Detach();

[Skizmo]

Are you painting in the OnPaint or OnDraw function ?

[uni8931]

Thanks for your reply,
I want to write a indepandent DLL API but under OnDraw or OnPaint .
Below is my program source. I define SHOW_WND is available, but this window will splash on screen.


PAINT_CANVAS g_PCanvas;

DWORD CreateCanvas()
{
HINSTANCE hInst = AfxGetInstanceHandle();
g_PCanvas.rc.left=g_PCanvas.rc.top=0;
g_PCanvas.rc.right = EVOLIS_MAX_WIDTH;
g_PCanvas.rc.bottom = EVOLIS_MAX_HEIGHT;

#ifdef SHOW_WND
g_PCanvas.hWnd = uniCreateWindow(hInst, g_PCanvas.rc); // will create a window by another function
g_PCanvas.cWnd.Attach(g_PCanvas.hWnd);
g_PCanvas.cdc = g_PCanvas.cWnd.GetDC();

g_PCanvas.hDC = g_PCanvas.cdc->Detach();
#else // only mono available, why?
// g_PCanvas.hbmColor = CreateBitmap(EVOLIS_MAX_WIDTH, EVOLIS_MAX_HEIGHT, 1, 24, NULL);
g_PCanvas.cdc = new CDC;
g_PCanvas.cdc->CreateCompatibleDC(NULL);
g_PCanvas.hDC = g_PCanvas.cdc->Detach();
g_PCanvas.hBitmap = CreateCompatibleBitmap(g_PCanvas.hDC, EVOLIS_MAX_WIDTH, EVOLIS_MAX_HEIGHT);
SelectObject(g_PCanvas.hDC, g_PCanvas.hBitmap);
#endif
g_PCanvas.hBrush = CreateSolidBrush(RGB(0xff,0xff,0xff));
SelectObject(g_PCanvas.hDC, g_PCanvas.hBrush);

FillRect(g_PCanvas.hDC, &g_PCanvas.rc, g_PCanvas.hBrush);
DeleteObject(g_PCanvas.hBrush);
g_PCanvas.cdc->Attach(g_PCanvas.hDC);
return 0;
}

typedef struct _PAINT_CANVAS
{
RECT rc;
CWnd cWnd;
HWND hWnd;
CDC *cdc;
HDC hDC;
HBRUSH hBrush;
HBITMAP hBitmap, hbmColor, hbmColorOld;
DWORD dwPartial;
DWORD dwStartLine; // partial printing
DWORD dwAreaWidth; // partial printing
DWORD dwColorSmooth; // bit 5 / 6 / 7
} PAINT_CANVAS;