TColorDialog

This is a very useful color dialog box that you can use in your Delphi applications so that your program users can choose a color for something you specify, like a forms color or a panels color.

To run up the ColorDialog you use the execute function.

function Execute: Boolean; override;

Like this:

begin
    ColorDialog1.Execute;
end;

You can use this code to change a panels color:

begin
    if ColorDialog1.Execute then
     Panel1.Color := ColorDialog1.Color;
end;

If you want to be able to let your program users use Custom Color Options you can use this code:

begin
    ColorDialog1.Options := [cdFullOpen];
    if ColorDialog1.Execute then
     begin
         Panel1.Color := ColorDialog1.Color;
     end;
end;

TColorDialog.Options:

All the TColorDialog options are set to off by default.
 
 

cdFullOpen	Is used to show the full ColorDialog box with the custom color options available.
cdPreventFullOpen	Is used to disable the Custom Colors button in the dialog, so users cannot choose  and define custom colors.
cdSolidColor	Is used to tell Windows to use the nearest solid color it can find to the color chosen.
cdShowHelp	Adds the Help button to the dialog.
cdAnyColor	The user can select colors that are non-solid (These might have to be approximated by dithering).

To select cdFullOpen and cdShowHelp you can do this:

begin
    ColorDialog1.Options := [cdFullOpen, cdShowHelp];
    if ColorDialog1.Execute then
     begin
         Panel1.Color := ColorDialog1.Color;
     end;
end;

Show the Panel1.Color as the selected color in a TColorDialog:

The code ColorDialog1.Color := Panel1.Color; as shown below in the example will show the current color of Panel1 as the selected color in the TColorDialog.

begin
    ColorDialog1.Options := [cdFullOpen, cdShowHelp];
    ColorDialog1.Color := Panel1.Color;
    if ColorDialog1.Execute then
     begin
         Panel1.Color := ColorDialog1.Color;
     end;
end;

You can also specify a color as well:

ColorDialog1.Color := clBlue;

Have you ever wondered how they fill those little boxes in a TColorDialog with colours (Colors)?

Here is how you could do it.

Drop the TColorDialog on a Form (Form1).

In the Object Inspector for the ColorDialog double-click on the CustomColors property.
This will open the 'String list editor'.

Paste in these lines:

ColorE=EABCCA
ColorF=FBBCCA
ColorG=ACBBCA
ColorH=BDBCCA
ColorI=DEBCCA
ColorJ=EFBCCA
ColorK=BBBAAA
ColorL=DDDAAA
ColorM=EEEAAA
ColorN=ABCDEF
ColorO=FEDCBA
ColorP=CDBEFA

Click 'OK' to save your changes to the String list editor.

Drop Shape1 (TShape) on Form1.
Drop a Button on Form1.

DoubleClick on the Button and type this code:
if ColorDialog1.Execute then
  begin
    Shape1.Brush.Color := ColorDialog1.Color;
  end;

Run the program. Click on the button, click on a color and Shape1 will change to that color.

Notice you will have many new colors available to choose from.