TMemo Question

[Leroy1981]

Does anyone know how I might get ahold of the TCanvas of
a TMemo component. All I really need is to be able to
check the pixels.

 

[onrdbandit]

Do they even have a TCanvas?

 

[Supernat03]

Unfortunately, the TMemo has no canvas. It is derived from a windowed control, which doesn't support that. You can use GDI functions to get the color of a pixel on the screen at a point though if you'd like.

COLORREF GetPixel(

HDC hdc, // handle of device context
int XPos, // x-coordinate of pixel
int nYPos // y-coordinate of pixel
);

COLORREF contains the r, g, and b value of the pixel.

HDC can be obtained by calling GetDeviceContext() from a TWinControl or TControl. Unforunately, again, it's not accessible from TMemo! So you have to grab the HDC yourself.

HDC dc = GetDC(MainForm->Handle);
COLORREF color = GetPixel(dc, xCoord, yCoord);
ReleaseDC(MainForm->Handle, dc);

Byte Red = GetRValue(color);
Byte Green = GetGValue(color);
Byte Blue = GetBValue(color);

I haven't tried this, if it doesn't work, let me know, and I'll see what I did wrong.

Chris

 

[Leroy1981]

Thanks supernat.

That is exactly what I was looking for