Visual C++ and MFC Programming 2nd Edition

Visual C++ and MFC Fundamentals Chapter 8 GDI Orientation and Transformations

reserved colors as default. A logical palette is a palette that an application creates for a

specific device context.

7.2 Drawing With Colors...................................................................................

7.2.1 Coloring a Pixel....................................................................................

As mentioned above, a pixel is the real object that holds a color. Although it is so small,

you can access a pixel and change its color. The pixels are stored in an array of [x][y]

value. In fact, when you try accessing a pixel, you would be asked to provide a color for

it. To change the color of a pixel, you can call the CDC::SetPixel() method. Its syntaxes

are:

COLORREF SetPixel(int x, int y, COLORREF crColor);

COLORREF SetPixel(POINT point, COLORREF crColor);

The pixel you want to access is defined by its x and y coordinates, which can also be

specified with a POINT or CPoint object as the point argument. The color you want to

specify is the crColor argument.

7.2.2 Rectangles With 3-D Effect...............................................................

Using colors, you can draw a rectangle with a 3-D effect. To do this, the CDC class

provides the Draw3dRect() method. Its syntaxes are:

void Draw3dRect(LPCRECT lpRect,
COLORREF clrTopLeft, COLORREF clrBottomRight);
void Draw3dRect(int x, int y, int cx, int cy,
COLORREF clrTopLeft, COLORREF clrBottomRight);

The rectangle to draw can be provided by its location and size through the x, y, cx, and cy

arguments. You can also pass it as a pointer to RECT or CRect for the lpRect argument.

Specify a color for the top and left sides of the rectangle as the clrTopLeft argument. The

clrBottomRight argument holds the color of the right and bottom sides of the rectangle.

Here is an example:

void CExoView::OnDraw(CDC* pDC)

{

pDC->Draw3dRect(20, 24, 238, 108, RGB(192, 192, 192), RGB(128, 128, 128));

}