Windows color system is based on RGB values, R=red, G=Green, B=Blue. If you want to specify a color in Windows, you must state your desired color in terms of these three major colors. Each color value has a range from 0 to 255 (a byte value). For example, if you want pure red color, you should use 255,0,0. Or if you want pure white color, you must use 255,255,255. You can see from the examples that getting the color you need is very difficult with this system since you have to have a good grasp of how to mix and match colors.

For text color and background, you use SetTextColor and SetBkColor, both of them require a handle to device context and a 32-bit RGB value. The 32-bit RGB value's structure is defined as:

RGB_value struct

unused db 0

    blue       db ?
green     db ?
red        db ?

RGB_value ends

Note that the first byte is not used and should be zero. The order of the remaining three bytes is reversed,ie. blue, green, red. However, we will not use this structure since it's cumbersome to initialize and use. We will create a macro instead. The macro will receive three parameters: red, green and blue values. It'll produce the desired 32-bit RGB value and store it in eax. The macro is as follows:

RGB macro red,green,blue

xor eax,eax
mov ah,blue
shl eax,8
mov ah,green
mov al,red
endm

You can put this macro in the include file for future use.

You can "create" a font by calling CreateFont or CreateFontIndirect. The difference between the two functions is that CreateFontIndirect receives only one parameter: a pointer to a logical font structure, LOGFONT. CreateFontIndirect is the more flexible of the two especially if your programs need to change fonts frequently. However, in our example, we will "create" only one font for demonstration, we can get away with CreateFont. After the call to CreateFont, it will return a handle to a font which you must select into the device context. After that, every text API function will use the font we have selected into the device context.

Below is our source code:
;======================================================================TEXT.ASM include windows.inc
includelib user32.lib
includelib kernel32.lib
includelib gdi32.lib

RGB macro red,green,blue

        xor eax,eax
mov ah,blue
shl eax,8
mov ah,green
mov al,red

endm

.data
ClassName db "SimpleWinClass",0
AppName db "Our First Window",0
TestString db "Win32 assembly is great and easy!",0 FontName db "script",0

.data?
hInstance HINSTANCE ?
CommandLine LPSTR ?

.code

WinMain proc
hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:LPSTR,CmdShow:SDWORD

LOCAL wc:WNDCLASSEX
LOCAL msg:MSG
LOCAL hwnd:HWND
mov wc.cbSize,SIZEOF WNDCLASSEX
mov wc.style, CS_HREDRAW or CS_VREDRAW mov wc.lpfnWndProc, OFFSET WndProc mov wc.cbClsExtra,NULL
mov wc.cbWndExtra,NULL
push hInstance
pop wc.hInstance
mov wc.hbrBackground,COLOR_WINDOW+1 mov wc.lpszMenuName,NULL
mov wc.lpszClassName,OFFSET ClassName invoke LoadIcon,NULL,IDI_APPLICATION mov wc.hIcon,eax
mov wc.hIconSm,0
invoke LoadCursor,NULL,IDC_ARROW
mov wc.hCursor,eax
invoke RegisterClassEx, addr wc
invoke CreateWindowEx,NULL,ADDR ClassName,ADDR AppName,\

           WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,\
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,\
hInst,NULL

mov hwnd,eax
invoke ShowWindow, hwnd,SW_SHOWNORMAL invoke UpdateWindow, hwnd

        .WHILE TRUE
invoke GetMessage, ADDR msg,NULL,0,0
.BREAK .IF (!eax)
invoke TranslateMessage, ADDR msg
invoke DispatchMessage, ADDR msg
.ENDW
mov     eax,msg.wParam
ret

WinMain endp

WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM

LOCAL hdc:HDC
LOCAL ps:PAINTSTRUCT
LOCAL hfont:HFONT

mov eax,uMsg
.IF eax==WM_DESTROY

invoke PostQuitMessage,NULL
.ELSEIF eax==WM_PAINT

        invoke BeginPaint,hWnd, ADDR ps
mov    hdc,eax
invoke CreateFont,24,16,0,0,400,0,0,0,OEM_CHARSET,\

OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,\

DEFAULT_QUALITY,DEFAULT_PITCH or FF_SCRIPT,\

                                       ADDR FontName
invoke SelectObject, hdc, eax
mov    hfont,eax
RGB    200,200,50
invoke SetTextColor,hdc,eax
RGB    0,0,255
invoke SetBkColor,hdc,eax
invoke TextOut,hdc,0,0,ADDR TestString,SIZEOF TestString
invoke SelectObject,hdc, hfont
invoke EndPaint,hWnd, ADDR ps
.ELSE
invoke DefWindowProc,hWnd,uMsg,wParam,lParam
ret

.ENDIF
xor eax,eax
ret
WndProc endp

end start
;===========================================================================EOF

Let's begin our analysis : )

        invoke CreateFont,24,16,0,0,400,0,0,0,OEM_CHARSET,\
OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,\
DEFAULT_QUALITY,DEFAULT_PITCH or FF_SCRIPT,\
ADDR FontName

CreateFont creates a logical font that is the closest match to the given parameters and the font data available. This function has more parameters than any other function in Windows. It returns a handle to logical font to be used by SelectObject function. We will examine its parameters in detail.

HFONT CreateFont(int nHeight, int nWidth, int nEscapement, int

        nOrientation, int nWeight, BYTE cItalic, BYTE cUnderline, BYTE cStrikeOut,
BYTE cCharSet, BYTE cOutputPrecision, BYTE cClipPrecision, BYTE cQuality,
BYTE cPitchAndFamily, LPSTR lpFacename);

nHeight --> The desired height of the characters . 0 means use default size. nWidth --> The desired width of the characters. Normally this value should be

        0 which allows Windows to match the width to the height. However, in our
example, the default width makes the characters hard to read, so I use the
width of 16 instead.
nEscapement -->  Specifies the orientation of the next character output
relative to the previous one in tenths of a degree. Normally, set to 0. Set
to 900 to have all the characters go upward from the first character, 1800
to write backwards, or 2700 to write each character from the top down.
nOrientation -->  Specifies how much the character should be rotated when
output in tenths of a degree. Set to 900 to have all the characters lying
on their backs, 1800 for upside-down writing, etc.
nWeight -->  Sets the line thickness of each character. Windows defines the
following sizes:
FW_DONTCARE        equ 0
FW_THIN            equ 100
FW_EXTRALIGHT      equ 200
FW_ULTRALIGHT      equ 200
FW_LIGHT           equ 300
FW_NORMAL          equ 400
FW_REGULAR         equ 400
FW_MEDIUM          equ 500
FW_SEMIBOLD        equ 600
FW_DEMIBOLD        equ 600
FW_BOLD            equ 700
FW_EXTRABOLD       equ 800
FW_ULTRABOLD       equ 800
FW_HEAVY           equ 900
FW_BLACK           equ 900

cItalic --> 0 for normal, any other value for italic characters. cUnderline --> 0 for normal, any other value for underlined characters. cStrikeOut --> 0 for normal, any other value for characters with a line

through the center.
cCharSet --> The character set of the font. Normally should be OEM_CHARSET

which allows Windows to select font which is operating system-dependent. cOutputPrecision --> Specifies how much the selected font must be closely

        matched to the characteristics we want. Normally should be
OUT_DEFAULT_PRECIS which defines default font mapping behavior.
cClipPrecision --> Specifies the clipping precision. The clipping precision
defines how to clip characters that are partially outside the clipping
region. You should be able to get by with CLIP_DEFAULT_PRECIS which defines
the default clipping behavior.
cQuality  -->Specifies the output quality. The output quality defines how
carefully GDI must attempt to match the logical-font attributes to those of
an actual physical font. There are three choices: DEFAULT_QUALITY,
PROOF_QUALITY and  DRAFT_QUALITY.
cPitchAndFamily --> Specifies pitch and family of the font. You must combine
the pitch value and the family value with "or" operator.
lpFacename  A pointer to a null-terminated string that specifies the
typeface of the font.

The description above is by no means comprehensive. You should refer to your Win32 API reference for more details.

        invoke SelectObject, hdc, eax
mov    hfont,eax

After we get the handle to the logical font, we must use it to select the font into the device context by calling SelectObject. SelectObject puts the new GDI objects such as pens, brushs, and fonts into the device context to be used by GDI functions. It returns the handle to the replaced object which we should save for future SelectObject call. After SelectObject call, any text output function will use the font we just selected into the device context.

        RGB    200,200,50
invoke SetTextColor,hdc,eax
RGB    0,0,255
invoke SetBkColor,hdc,eax

Use RGB macro to create a 32-bit RGB value to be used by SetColorText and SetBkColor.

invoke TextOut,hdc,0,0,ADDR TestString,SIZEOF TestString

Call TextOut function to draw the text on the client area. The text will be in the font and color we specified previously. The syntax of TextOut is as follows:

BOOL TextOut(

    HDC  hdc,                  // handle of device context
int  nXStart,               // x-coordinate of starting position
int  nYStart,               // y-coordinate of starting position
LPCTSTR  lpString, // address of string
int  cbString               // number of characters in string

);

invoke SelectObject,hdc, hfont

When we are through with the font, we should restore the old font back into the device context. You should always restore the object that you replaced in the device context.