How to maka characters dim?

Edited text of question

Unfortunately, I stopped programming in Borland C two years ago.
Nevertheless, I want to help you !
I dug up some old sources and realized that I had been using the bgi library for 16 color and the SVGA library for 256 colors. A fading as you would want it is probably nicer to do with 256 colors. I also did some direct BIOS programming, which is faster but riskier and you can only set pixels ! I could send you the BIOS functions, and also search the SVGA library on the Borland WWW page.

Are you programming this under DOS ? Which gfx library are you using ? If you want to do this under Win, I cannot help you specifically, since I have never done any Win programming.

I have done this palette fading before, but its no use if I send you the code if you don't have the library to go with it.

Edited text of question

svga library:

-------------- svgalib.h --------------------
#include <graphics.h>
#include <process.h>
#include "d:\BORLANDC\BGI\VGAPALET.C"

int init_svga(int mode);
int outit_svga(void);
void getvgapalette16(DacPalette16 *PalBuf);
void getvgapalette256(DacPalette256 *PalBuf);
void setvgapalette16(DacPalette16 *PalBuf);
void setvgapalette256(DacPalette256 *PalBuf);

-----------------------------------------------

---------- svgalib.c --------------------------
#include "svgalib.h"

int init_svga(int gmode)
{
        int gdriver;

        gdriver = installuserdriver("SVGA256",0);
        initgraph(&gdriver,&gmode,"d:\\borlandc\\bgi\\");

        if (graphresult()!=grOk)
                exit(1);

        return 0;
}
int outit_svga()
{
        closegraph();
        return 0;
}

void getvgapalette16(DacPalette16 *PalBuf)
{
  struct REGPACK reg;

  reg.r_ax = 0x1017;
  reg.r_bx = 0;
  reg.r_cx = 16;
  reg.r_es = FP_SEG(PalBuf);
  reg.r_dx = FP_OFF(PalBuf);
  intr(0x10,&reg);
}

void getvgapalette256(DacPalette256 *PalBuf)
{
  struct REGPACK reg;

  reg.r_ax = 0x1017;
  reg.r_bx = 0;
  reg.r_cx = 256;
  reg.r_es = FP_SEG(PalBuf);
  reg.r_dx = FP_OFF(PalBuf);
  intr(0x10,&reg);
}

void setvgapalette16(DacPalette16 *PalBuf)
{
  struct REGPACK reg;

  reg.r_ax = 0x1012;
  reg.r_bx = 0;
  reg.r_cx = 16;
  reg.r_es = FP_SEG(PalBuf);
  reg.r_dx = FP_OFF(PalBuf);
  intr(0x10,&reg);
}

void setvgapalette256(DacPalette256 *PalBuf)
{
  struct REGPACK reg;

  reg.r_ax = 0x1012;
  reg.r_bx = 0;
  reg.r_cx = 256;
  reg.r_es = FP_SEG(PalBuf);
  reg.r_dx = FP_OFF(PalBuf);
  intr(0x10,&reg);
}

-----------------------------------------------

code, needs to include 'svgalib.c':

----------------------------------------

#include "svgalib.h"

main()
{
  int num;
  init_svga(SVGA800x600x256);
  set_palette();

  num=15;

  setcolor(num); /* set current drawing color to color cell 15 */
  /* draw something */
  fade(15);
  /* etc */
}

void set_palette()
{
  DacPalette256 palette;

  palette[0][0]=0; /* red component of color cell 0 */
  palette[0][1]=0; /* green component of color cell 0 */
  palette[0][2]=0; /* blue component of color cell 0 */
  /* rgb entries range from 0 to 255 */
  /* 000 eq black, 255 255 255 eq white */

  palette[1][0]=1;
  palette[1][1]=1;
  palette[1][2]=1;
  /* etc */
  palette[255][1]=255;
  palette[255][2]=255;
  palette[255][3]=255;

  /* this has immediate effect */
  setvgapalette256(&palette);
}

/* example for fading any colorcell entry to black */
void fade(int num)
{
  int i,r,g,b;
  int step=10;
  float rf,gf,bf;
  DacPalette256 palette;

  getvgapalette256(&palette);

  r=palette[num][0];
  g=palette[num][1];
  b=palette[num][2];

  rf=(float)r/(float)step;
  gf=(float)g/(float)step;
  bf=(float)b/(float)step;

  for(i=0;i<step;i++){
    palette[num][0]=r-(int)((float)i*rf);
    palette[num][1]=g-(int)((float)i*gf);
    palette[num][1]=b-(int)((float)i*bf);
    setvgapalette256(&palette);
    /* add some delay */
  }
}

-------------------------
You realize of course that this is a very crude example, and I have just typed this from memory, not beeing able to actually test the code. There are lot of things to refine, e.g. checking that palette entries stay in the range 0-255 etc...

But I guess the principal is clear! Hope that gets you going !