cdk_display - Man Page

Cdk has the capability to display colors in almost every string type displayed in a Cdk widget.

Normally the color pairs are accessed via the COLOR_PAIR macro. You can still do this, but creating a string with multiple colors is tedious. That is why the color commands were created. Use initCDKColor to create up to 64 color pairs which you can refer to by number in strings.

The color settings are stored directly in the string. When the widget is created or activated, the string is converted to take advantage of any color commands in the string.

• To turn on a color pair insert </XX> into the string; where XX is a numeric value from 0 to the maximum color pair.

  Color pair 0 is the standard default color pair for the screen.

  If you used initCDKColor, the maximum value for XX is 63 for terminals supporting 8 ANSI colors.

  If you created color pairs directly using init_pair, the maximum value for XX is implementation-dependent, e.g., 63 (for Unix systems) and 255 for ncurses.

  If the terminal does not support color, Cdk uses the bold attribute.

• To turn off a color pair use the format command <!XX> where XX is a numeric value from 0 to the maximum color pair.

The following example demonstrates the use of the color commands.

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#include <cdk/cdk.h>

void main()
{
   CDKSCREEN	*cdkscreen;
   CDKLABEL	*demo;
   char		*mesg[4];

   cdkscreen = initCDKScreen (NULL);

   /* Start CDK Colors */
   initCDKColor();

   /* Set the labels up.		*/
   mesg[0] = "</31>This line should have a yellow foreground and a cyan background.<!31>";
   mesg[1] = "</05>This line should have a white  foreground and a blue background.<!05>";
   mesg[2] = "</26>This line should have a yellow foreground and a red  background.<!26>";
   mesg[3] = "<C>This line should be set to whatever the screen default is.";

   /* Declare the labels.	*/
   demo	= newCDKLabel (cdkscreen, CENTER, CENTER, mesg, 4, TRUE, TRUE);

   /* Draw the label		*/
   drawCDKLabel (demo, TRUE);
   waitCDKLabel (demo, ' ');

   /* Clean up			*/
   destroyCDKLabel (demo);
   destroyCDKScreen (cdkscreen);
   endCDK();
   exit (0);
}

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Cdk also provides attribute commands which allow different character attributes to be displayed in a Cdk widget. To use a character attribute the format command is </X> where X is one of several command characters. To turn a attribute off use the command <!X>. The following table outlines the command characters:

The following example demonstrates the use of character display attributes.

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#include <cdk/cdk.h>

void main()
{
   CDKSCREEN    *cdkscreen;
   CDKLABEL     *demo;
   char         *mesg[4];

   cdkscreen = initCDKScreen (NULL);

   /* Start CDK Colors */
   initCDKColor();

   /* Set the labels up.  */
   mesg[0] = "</B/31>Bold text            yellow foreground / blue background.<!31>";
   mesg[1] = "</U/05>Underlined text      white  foreground / blue background.<!05>";
   mesg[2] = "</K/26>Blinking text        yellow foreground / red  background.<!26>";
   mesg[3] = "<C>This line uses the screen default colors.";

   /* Declare the labels.  */
   demo = newCDKLabel (cdkscreen, CENTER, CENTER, mesg, 4, TRUE, TRUE);

   /* Draw the label */
   drawCDKLabel (demo, TRUE);
   waitCDKLabel (demo, ' ');

   /* Clean up */
   destroyCDKLabel (demo);
   destroyCDKScreen (cdkscreen);
   endCDK();
   exit (0);
}
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Note that color commands and format commands can be mixed inside the same format marker. The above example underlines the label marker, which also sets color pair number 2.

Justification commands can left justify, right justify, or center a string of text. To use a justification format in a string the command <X> is used. The following table lists the format commands:

The following example demonstrates how to use the justification commands in a Cdk widget.

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#include <cdk/cdk.h>

void main()
{
   CDKSCREEN    *cdkscreen;
   CDKLABEL     *demo;
   char         *mesg[5];

   cdkscreen = initCDKScreen (NULL);

   /* Start CDK Colors */
   initCDKColor();

   /* Set the labels up.  */
   mesg[0] = "<R></B/31>This line should have a yellow foreground and a blue background.<!31>";
   mesg[1] = "</U/05>This line should have a white  foreground and a blue background.<!05>";
   mesg[2] = "<B=+>This is a bullet.";
   mesg[3] = "<I=10>This is indented 10 characters.";
   mesg[4] = "<C>This line should be set to whatever the screen default is.";

   /* Declare the labels.  */
   demo = newCDKLabel (cdkscreen, CENTER, CENTER, mesg, 5, TRUE, TRUE);

   /* Draw the label */
   drawCDKLabel (demo, TRUE);
   waitCDKLabel (demo, ' ');

   /* Clean up */
   destroyCDKLabel (demo);
   destroyCDKScreen (cdkscreen);
   endCDK();
   exit (0);
}

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The bullet format command can take either a single character or a string. The bullet in the above example would look like

but if we were to use the following command instead

it would look like

A format command must be at the beginning of the string.

Cdk has a set of special drawing characters which can be inserted into any ASCII file. These characters are encoded using the format command “<#XX>” where XX is a two-character name. The char2Chtype and chtype2String functions provide conversion to/from curses chtype data (see cdk_util(3)).

The following table lists the supported special character commands.

The character formats can be repeated using an optional numeric repeat value. To repeat a character add the repeat count within parentheses to the end of the character format. The following example draws 10 horizontal-line characters:

<#HL(10)>

The following example draws a box within a label window:

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#include <cdk/cdk.h>

void main()
{
   /* Declare variables.  */
   CDKSCREEN    *cdkscreen;
   CDKLABEL     *demo;
   char         *mesg[4];

   cdkscreen = initCDKScreen (NULL);

   /* Start CDK Colors */
   initCDKColor();

   /* Set the labels up.  */
   mesg[0] = "<C><#UL><#HL(26)><#UR>";
   mesg[1] = "<C><#VL></R>This text should be boxed.<!R><#VL>";
   mesg[2] = "<C><#LL><#HL(26)><#LR>";
   mesg[3] = "<C>While this is not.";

   /* Declare the labels.  */
   demo = newCDKLabel (cdkscreen, CENTER, CENTER, mesg, 4, TRUE, TRUE);

   /* Is the label NULL???  */
   if (demo == (CDKLABEL *)NULL)
   {
      /* Clean up the memory.  */
      destroyCDKScreen (cdkscreen);

      /* End curses...  */
      endCDK();

      /* Spit out a message.  */
      printf ("Oops. Can't seem to create the label. Is the window too small?\n");
      exit (1);
   }

   /* Draw the CDK screen.  */
   refreshCDKScreen (cdkscreen);
   waitCDKLabel (demo, ' ');

   /* Clean up */
   destroyCDKLabel (demo);
   destroyCDKScreen (cdkscreen);
   endCDK();
   exit (0);
}

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Notice that drawn text can also be justified.