14.Windows Drawing

1. Drawing-related

Drawing device DC (device context), drawing context/Drawing Description table

HDC-DC handle, representing the drawing device

Gdi-windows Graphics Device Interface,win32 provides a drawing API

2. Color

(1) The expression of color

Computer use red, green, blue: R-0 ~ 255

G-0 ~ 255

B-0 ~ 255

Each color dot is 3 bytes 24 bits, save 0-2^24-1

16-bit: 5, 5, 6-red, green, blue

32-bit: 8, 8, 8, 8-red, green, blue, transparency

(2) Use of color

COLORREF-Actual DWORD, for example: colorref ncolor = 0;

Assign values using RGB macros, for example: Ncolor = RGB (0, 0, 255);

Gets the RGB value, Getrvalue/getgvalue/getbvalue, for example: BYTE nred = Getrvalue (Ncolor);

3. Use of points

(1) GetPixel gets the color of the specified point

COLORREF GetPixel (HDC hdc,//

int Nxpos,//

int nypos); //

(2) SetPixel set the specified color

COLORREF SetPixel (HDC hdc,//

int X,//

int Y,//

COLORREF crcolor); //

Returns the original color of the point

4. Use of lines (lines, arcs)

Moves the current point to the specified point: BOOL movetoex (HDC hdc,

int X,

int Y,

Lppoint lppoint);

Draws a line from the current point to the specified point: BOOL LineTo (HDC hdc,

int Nxend,

int nyend);

14.Windows Drawing