Colors

From Free Pascal wiki
Jump to navigationJump to search

│ Deutsch (de) │ English (en) │ español (es) │ suomi (fi) │ français (fr) │ 日本語 (ja) │ русский (ru) │ 中文（中国大陆） (zh_CN) │

Overview

Since FPC 3.2.0, Free Pascal defines TColor and TColorRec as well as the 140 standard Color names in the Delphi compatible System.UItypes unit, to allow non visual code to use the same type as visual code. Lazarus hasn't caught on yet, because the current Lazarus versions still support 3.0.x.

In the LCL TColor is the standard color type. It is compatible with Delphi's TColor. TColor can represent either an RGB (3x8bit) value, or a system color like clDefault. The LCL can also work with the fpImage system which uses the TFPColor type (which is RGBA (4x16bit), not RGB (3x8bit) like TColor).

Conversions between TColor and RGB values

The Graphics unit provides the following functions: 

function ColorToRGB(Color: TColor): Longint;
function Blue(rgb: TColor): BYTE; // does not work on system color
function Green(rgb: TColor): BYTE; // does not work on system color
function Red(rgb: TColor): BYTE; // does not work on system color
function RGBToColor(R, G, B: Byte): TColor;
procedure RedGreenBlue(rgb: TColor; out Red, Green, Blue: Byte); // does not work on system color
function FPColorToTColor(const FPColor: TFPColor): TColor;
function TColorToFPColor(const c: TColor): TFPColor; // does not work on system color
function IsSysColor(AColor: TColorRef): Boolean;

Convert TColor to/from string

Functions to convert strings like "25500" or "$AA0088" or "clNavy" to TColor:

  • StringToColor
  • StringToColorDef

To convert TColor to a nice string like "clNavy" or "$AA0002":

  • ColorToString

Convert TColor to/from HTML string #rrggbb

See code in Convert color to/from HTML.

Table of standard colors

About 20 predefined color constants are provided, which are Delphi-compatible:

Colour constant Meaning Hexadecimal value for use with TColor Example
clBlack Black TColor($000000);
clMaroon Maroon TColor($000080);
clGreen Green TColor($008000);
clOlive Olive Green TColor($008080);
clNavy Navy Blue TColor($800000);
clPurple Purple TColor($800080);
clTeal Teal TColor($808000);
clGray Grey TColor($808080);
clSilver Silver TColor($C0C0C0);
clRed Red TColor($0000FF);
clLime Lime Green TColor($00FF00);
clYellow Yellow TColor($00FFFF);
clBlue Blue TColor($FF0000);
clFuchsia Fuchsia TColor($FF00FF);
clAqua Aqua TColor($FFFF00);
clLtGray Light Grey TColor($C0C0C0); clSilver alias
clDkGray Dark Grey TColor($808080); clGray alias
clWhite White TColor($FFFFFF);
clCream Cream TColor($F0FBFF); Lazarus 1.2 and newer
clMedGray Medium Grey TColor($A4A0A0); Lazarus 1.2 and newer
clMoneyGreen Mint Green TColor($C0DCC0); Lazarus 1.2 and newer
clSkyBlue Sky Blue TColor($F0CAA6); Lazarus 1.2 and newer


In FPC 3.2.0+ defines some other constants for w3c colors in System.Uitypes. Note that in FPC 3.2.0 and 3.2.2 the red and blue bytes are exchanged. This has been corrected in FPC 3.2.4+. The following table shows the correct byte order:

Colour constant Meaning Hexadecimal value for use with TColor Example
AntiqueWhite AntiqueWhite TColor($D7EBFA); FPC 3.2.0 and newer
Aqua Aqua TColor($FFFF00); FPC 3.2.0 and newer
Aquamarine Aquamarine TColor($D4FF7F); FPC 3.2.0 and newer
Azure Azure TColor($FFFFF0); FPC 3.2.0 and newer
Beige Beige TColor($DCF5F5); FPC 3.2.0 and newer
Bisque Bisque TColor($C4E4FF); FPC 3.2.0 and newer
Black Black TColor($000000); FPC 3.2.0 and newer
BlanchedAlmond BlanchedAlmond TColor($CDEBFF); FPC 3.2.0 and newer
Blue Blue TColor($FF0000); FPC 3.2.0 and newer
BlueViolet BlueViolet TColor($E22B8A); FPC 3.2.0 and newer
Brown Brown TColor($2A2AA5); FPC 3.2.0 and newer
BurlyWood BurlyWood TColor($87B8DE); FPC 3.2.0 and newer
CadetBlue CadetBlue TColor($A09E5F); FPC 3.2.0 and newer
Chartreuse Chartreuse TColor($00FF7F); FPC 3.2.0 and newer
Chocolate Chocolate TColor($1E69D2); FPC 3.2.0 and newer
Coral Coral TColor($FF7F50); FPC 3.2.0 and newer
CornflowerBlue CornflowerBlue TColor($ED9564); FPC 3.2.0 and newer
Cornsilk Cornsilk TColor($DCF8FF); FPC 3.2.0 and newer
Crimson Crimson TColor($3C14DC); FPC 3.2.0 and newer
Cyan Cyan TColor($FFFF00); FPC 3.2.0 and newer
DarkBlue DarkBlue TColor($8B0000); FPC 3.2.0 and newer
DarkCyan DarkCyan TColor($8B8B00); FPC 3.2.0 and newer
DarkGoldenRod DarkGoldenRod TColor($0B86B8); FPC 3.2.0 and newer
DarkGray DarkGray TColor($A9A9A9); FPC 3.2.0 and newer
DarkGreen DarkGreen TColor($006400); FPC 3.2.0 and newer
DarkGrey DarkGrey TColor($A9A9A9); FPC 3.2.0 and newer
DarkKhaki DarkKhaki TColor($6BB7BD); FPC 3.2.0 and newer
DarkMagenta DarkMagenta TColor($8B008B); FPC 3.2.0 and newer
DarkOliveGreen DarkOliveGreen TColor($2F6B55); FPC 3.2.0 and newer
DarkOrange DarkOrange TColor($008CFF); FPC 3.2.0 and newer
DarkOrchid DarkOrchid TColor($CC3299); FPC 3.2.0 and newer
DarkRed DarkRed TColor($00008B); FPC 3.2.0 and newer
DarkSalmon DarkSalmon TColor($7A96E9); FPC 3.2.0 and newer
DarkSeaGreen DarkSeaGreen TColor($8FBC8F); FPC 3.2.0 and newer
DarkSlateBlue DarkSlateBlue TColor($8B3D48); FPC 3.2.0 and newer
DarkSlateGray DarkSlateGray TColor($4F4F2F); FPC 3.2.0 and newer
DarkSlateGrey DarkSlateGrey TColor($4F4F2F); FPC 3.2.0 and newer
DarkTurquoise DarkTurquoise TColor($D1CE00); FPC 3.2.0 and newer
DarkViolet DarkViolet TColor($D30094); FPC 3.2.0 and newer
DeepPink DeepPink TColor($9314FF); FPC 3.2.0 and newer
DeepSkyBlue DeepSkyBlue TColor($FFBF00); FPC 3.2.0 and newer
DimGray DimGray TColor($696969); FPC 3.2.0 and newer
DimGrey DimGrey TColor($696969); FPC 3.2.0 and newer
DodgerBlue DodgerBlue TColor($FF901E); FPC 3.2.0 and newer
FireBrick FireBrick TColor($2222B2); FPC 3.2.0 and newer
FloralWhite FloralWhite TColor($F0FAFF); FPC 3.2.0 and newer
ForestGreen ForestGreen TColor($228B22); FPC 3.2.0 and newer
Fuchsia Fuchsia TColor($FF00FF); FPC 3.2.0 and newer
Gainsboro Gainsboro TColor($DCDCDC); FPC 3.2.0 and newer
GhostWhite GhostWhite TColor($FFF8F8); FPC 3.2.0 and newer
Gold Gold TColor($00D7FF); FPC 3.2.0 and newer
GoldenRod GoldenRod TColor($20A5DA); FPC 3.2.0 and newer
Gray Gray TColor($808080); FPC 3.2.0 and newer
Green Green TColor($008000); FPC 3.2.0 and newer
GreenYellow GreenYellow TColor($2FFFAD); FPC 3.2.0 and newer
Grey Grey TColor($808080); FPC 3.2.0 and newer
HoneyDew HoneyDew TColor($F0FFF0); FPC 3.2.0 and newer
HotPink HotPink TColor($B469FF); FPC 3.2.0 and newer
IndianRed IndianRed TColor($5C5CCD); FPC 3.2.0 and newer
Indigo Indigo TColor($82004B); FPC 3.2.0 and newer
Ivory Ivory TColor($F0FFFF); FPC 3.2.0 and newer
Khaki Khaki TColor($8CE6F0); FPC 3.2.0 and newer
Lavender Lavender TColor($FAE6E6); FPC 3.2.0 and newer
LavenderBlush LavenderBlush TColor($F5F0FF); FPC 3.2.0 and newer
LawnGreen LawnGreen TColor($00FC7C); FPC 3.2.0 and newer
LemonChiffon LemonChiffon TColor($CDFAFF); FPC 3.2.0 and newer
LightBlue LightBlue TColor($E6D8AD); FPC 3.2.0 and newer
LightCoral LightCoral TColor($8080F0); FPC 3.2.0 and newer
LightCyan LightCyan TColor($FFFFE0); FPC 3.2.0 and newer
LightGoldenRodYellow LightGoldenRodYellow TColor($D2FAFA); FPC 3.2.0 and newer
LightGray LightGray TColor($D3D3D3); FPC 3.2.0 and newer
LightGreen LightGreen TColor($90EE90); FPC 3.2.0 and newer
LightGrey LightGrey TColor($D3D3D3); FPC 3.2.0 and newer
LightPink LightPink TColor($C1B6FF); FPC 3.2.0 and newer
LightSalmon LightSalmon TColor($7AA0FF); FPC 3.2.0 and newer
LightSeaGreen LightSeaGreen TColor($AAB220); FPC 3.2.0 and newer
LightSkyBlue LightSkyBlue TColor($FACE87); FPC 3.2.0 and newer
LightSlateGray LightSlateGray TColor($998877); FPC 3.2.0 and newer
LightSlateGrey LightSlateGrey TColor($998877); FPC 3.2.0 and newer
LightSteelBlue LightSteelBlue TColor($B0C4DE); FPC 3.2.0 and newer
LightYellow LightYellow TColor($E0FFFF); FPC 3.2.0 and newer
Lime Lime TColor($00FF00); FPC 3.2.0 and newer
LimeGreen LimeGreen TColor($32CD32); FPC 3.2.0 and newer
Linen Linen TColor($E6F0FA); FPC 3.2.0 and newer
Magenta Magenta TColor($FF00FF); FPC 3.2.0 and newer
Maroon Maroon TColor($000080); FPC 3.2.0 and newer
MediumAquaMarine MediumAquaMarine TColor($AACD66); FPC 3.2.0 and newer
MediumBlue MediumBlue TColor($CD0000); FPC 3.2.0 and newer
MediumOrchid MediumOrchid TColor($D355BA); FPC 3.2.0 and newer
MediumPurple MediumPurple TColor($DB7093); FPC 3.2.0 and newer
MediumSeaGreen MediumSeaGreen TColor($71B33C); FPC 3.2.0 and newer
MediumSlateBlue MediumSlateBlue TColor($EE687B); FPC 3.2.0 and newer
MediumSpringGreen MediumSpringGreen TColor($9AFA00); FPC 3.2.0 and newer
MediumTurquoise MediumTurquoise TColor($CCD148); FPC 3.2.0 and newer
MediumVioletRed MediumVioletRed TColor($8515C7); FPC 3.2.0 and newer
MidnightBlue MidnightBlue TColor($701919); FPC 3.2.0 and newer
MintCream MintCream TColor($FAFFF5); FPC 3.2.0 and newer
MistyRose MistyRose TColor($E1E4FF); FPC 3.2.0 and newer
Moccasin Moccasin TColor($B5E4FF); FPC 3.2.0 and newer
NavajoWhite NavajoWhite TColor($ADDEFF); FPC 3.2.0 and newer
Navy Navy TColor($800000); FPC 3.2.0 and newer
OldLace OldLace TColor($E6F5FD); FPC 3.2.0 and newer
Olive Olive TColor($008080); FPC 3.2.0 and newer
OliveDrab OliveDrab TColor($238E6B); FPC 3.2.0 and newer
Orange Orange TColor($00A5FF); FPC 3.2.0 and newer
OrangeRed OrangeRed TColor($0045FF); FPC 3.2.0 and newer
Orchid Orchid TColor($D670DA); FPC 3.2.0 and newer
PaleGoldenRod PaleGoldenRod TColor($AAE8EE); FPC 3.2.0 and newer
PaleGreen PaleGreen TColor($98FB98); FPC 3.2.0 and newer
PaleTurquoise PaleTurquoise TColor($EEEEAF); FPC 3.2.0 and newer
PaleVioletRed PaleVioletRed TColor($9370DB); FPC 3.2.0 and newer
PapayaWhip PapayaWhip TColor($D5EFFF); FPC 3.2.0 and newer
PeachPuff PeachPuff TColor($B9DAFF); FPC 3.2.0 and newer
Peru Peru TColor($3F85CD); FPC 3.2.0 and newer
Pink Pink TColor($CBC0FF); FPC 3.2.0 and newer
Plum Plum TColor($DDA0DD); FPC 3.2.0 and newer
PowderBlue PowderBlue TColor($E6E0B0); FPC 3.2.0 and newer
Purple Purple TColor($800080); FPC 3.2.0 and newer
RebeccaPurple RebeccaPurple TColor($993366); FPC 3.2.0 and newer
Red Red TColor($0000FF); FPC 3.2.0 and newer
RosyBrown RosyBrown TColor($8F8FBC); FPC 3.2.0 and newer
RoyalBlue RoyalBlue TColor($E16941); FPC 3.2.0 and newer
SaddleBrown SaddleBrown TColor($13458B); FPC 3.2.0 and newer
Salmon Salmon TColor($7280FA); FPC 3.2.0 and newer
SandyBrown SandyBrown TColor($60A4F4); FPC 3.2.0 and newer
SeaGreen SeaGreen TColor($578B2E); FPC 3.2.0 and newer
SeaShell SeaShell TColor($EEF5FF); FPC 3.2.0 and newer
Sienna Sienna TColor($2D52A0); FPC 3.2.0 and newer
Silver Silver TColor($C0C0C0); FPC 3.2.0 and newer
SkyBlue SkyBlue TColor($EBCE87); FPC 3.2.0 and newer
SlateBlue SlateBlue TColor($CD5A6A); FPC 3.2.0 and newer
SlateGray SlateGray TColor($908070); FPC 3.2.0 and newer
SlateGrey SlateGrey TColor($908070); FPC 3.2.0 and newer
Snow Snow TColor($FAFAFF); FPC 3.2.0 and newer
SpringGreen SpringGreen TColor($7FFF00); FPC 3.2.0 and newer
SteelBlue SteelBlue TColor($B48246); FPC 3.2.0 and newer
Tan Tan TColor($8CB4D2); FPC 3.2.0 and newer
Teal Teal TColor($808000); FPC 3.2.0 and newer
Thistle Thistle TColor($D8BFD8); FPC 3.2.0 and newer
Tomato Tomato TColor($4763FF); FPC 3.2.0 and newer
Turquoise Turquoise TColor($D0E040); FPC 3.2.0 and newer
Violet Violet TColor($EE82EE); FPC 3.2.0 and newer
Wheat Wheat TColor($B3DEF5); FPC 3.2.0 and newer
White White TColor($FFFFFF); FPC 3.2.0 and newer
WhiteSmoke WhiteSmoke TColor($F5F5F5); FPC 3.2.0 and newer
Yellow Yellow TColor($00FFFF); FPC 3.2.0 and newer
YellowGreen YellowGreen TColor($32CD9A); FPC 3.2.0 and newer

System colors

Example: clInfoBk, clInfoText

System colors are color constants with a special meaning. Their real value depends on the context and theme. They are not simple colors. For example clInfoBk: 

Form1.Canvas.Brush.Color:=clInfoBk;  // use the default background brush of a hint window
Form1.Canvas.FillRect(10,10,50,50);

A hint window on MS Windows might have a white background so the above will draw white. On Linux/gtk2 it might be a metallic texture, so the above will draw the texture. If you want to put some text onto this you need a corresponding color like clInfoText, otherwise your text might be unreadable for the user. For example: 

Form1.Canvas.Brush.Color:=clInfoBk;  // use the default background brush of a hint window
Form1.Canvas.FillRect(10,10,50,50);
Form1.Canvas.Font.Color:=clInfoText;  // use the default text color of a hint window
Form1.Canvas.TextOut(10,10,'Hint');

The system color clInfoBk can not be used for Pen.Color and not for Font.Color. If you do so the result is undefined and depends on the widgetset and user theme. The same for clInfoText: It can only be used as a Font.Color. Using it as Brush.Color may not work. At the moment all widgetsets allow to use it as Pen.Color too.

Theme changes

When the user switches the theme the system colors changes. A clInfoBk might change from white to blue or from a color to a texture. This change will happen when you allocate a new Brush handle. Keep in mind that a simple assignment Brush.Color:=clInfoBk does not allocate a Brush Handle. The Brush Handle is allocated on use. For example: 

Form1.Canvas.Brush.Color:=clInfoBk; // this will not create a new brush handle
Form1.Canvas.FillRect(10,10,50,50); // this will create the brush handle with the currently active theme brush for hint windows
...
// if the theme changes in this moment the Brush.Handle is still allocated with the old values
...
Form1.Canvas.FillRect(10,10,50,50); // this will paint with the old theme brush
Form1.Canvas.Brush.Color:=clInfoBk; // assigning the old value will not create a new brush handle
Form1.Canvas.FillRect(10,10,50,50); // this will paint with the old theme brush
Form1.Canvas.Brush.Color:=clRed;    // assigning a new color, old Handle invalid
Form1.Canvas.Brush.Color:=clInfoBk; // assigning a new color, old Handle invalid
Form1.Canvas.FillRect(10,10,50,50); // this will create a new handle and paint with the new theme

Table of system colors

The following table lists the system colors and their meaning. Using them outside the scope of the definition is undefined and the result depends on the widgetset and theme. For example clDefault is the normal background brush of the used device context. If you want to paint button elements on your own custom controls use the drawing functions of the unit Themes.

Constant LCL definition Delphi notes Supported Widgetsets
clNone Indicates "do not paint". Using it as Control's color is undefined. The control will not get transparent. - all
clDefault Using it for Brush will use the normal background brush of the target DC (device context).
  • On a Form's canvas a FillRect will paint a rectangular area filled with the normal background of a standard window. This is whatever the widgetset and theme defines. This might be the color gray or a gradient or a picture.
  • Using clDefault on the Canvas of a TListBox will paint with the normal background, which is normally white on Windows. So in a TListBox clDefault is the same as clWindow.
  • Using it as Pen color will use the default line color for the device context.
  • Using it as Font color will use the normal text color of the device context.
 - all
clScrollBar Scrollbar body - all
clBackground Desktop background color - all
clActiveCaption Active window titlebar - none
clInactiveCaption Inactive window titlebar - none
clMenu Regular menu item background color - none
clWindow The normal background brush of unselected text. Defined for controls like TEdit, TComboBox, TMemo, TListBox, TTreeView. - none
clWindowFrame Color of frame around the window - none
clMenuText The font color to use together with clMenu - none
clWindowText Font color to use together with clWindow - none
clCaptionText Active window titlebar text color - none
clActiveBorder ? - none
clInactiveBorder ? - none
clAppWorkspace MDIMain form background - none
clHighlight The brush color of selected element - none
clHighlightText Font color of selected text (to use together with clHighligh). - none
clBtnFace Button background - none
clBtnShadow Button shadow color (bottom right) used to achieve 3D effect - none
clGrayText The font color of disabled element - none
clBtnText Button font color to use together with clBtnFace - none
clInactiveCaptionText Inactive window titlebar text color - none
clBtnHighlight Button highlight color (top left) used to achieve 3D effect - none
cl3DDkShadow ? - none
cl3DLight ? - none
clInfoText Font color for hints. Use together with clInfoBk - all
clInfoBk Brush color for hints. Use together with clInfoText - all
clHotLight ? - none
clGradientActiveCaption The second color used to make gradient of active window titlebar - none
clGradientInactiveCaption The second color used to make gradient for inactive window titlebar - none
clMenuHighlight The background color of selected menu item - none
clMenuBar The Backround color of menu bar - none
clForm ? - none
clColorDesktop ? - none
cl3DFace ? - none
cl3DShadow ? - none
cl3DHiLight ? - none
clBtnHiLight Same as clBtnHighlight - none

Finding the rgb values of a system color

Use the function ColorToRGB (in unit Graphics to determine the rgb components of a system color. This functions detects whether a color is a system color and, if this is true, looks up the system color in the themes color. The returned Longint can be understood as a normal color: 

// This example has a TColorBox on a form and uses this OnChange handler for the TColorbox:
procedure TForm1.ColorBox1Change(Sender: TObject);
var
  c: TColor;
begin
  c := ColorToRGB(ColorBox1.Selected);
  Caption := Format('R%d G%d B%d', [Red(c), Green(c), Blue(c)]);
end;

Drawing theme elements on your custom controls

The unit Themes provides functions to draw single elements of standard controls. For example to draw an expand sign like a TTreeView use the following code: 

uses Themes;

...

procedure TYourCustomControl.Paint;
const
  PlusMinusDetail: array[Boolean {Hot}, Boolean {Expanded}] of TThemedTreeview =
  (
    (ttGlyphClosed, ttGlyphOpened),
    (ttHotGlyphClosed, ttHotGlyphOpened)
  );
var
  Details: TThemedElementDetails;
  R: TRect;
  Collapse: boolean;
begin
  ...
  //draw a themed expand sign.
  Details := ThemeServices.GetElementDetails(PlusMinusDetail[False, Collapse]);
  R := Rect(ALeft, ATop, ARight + 1, ABottom + 1);
  ThemeServices.DrawElement(Canvas.Handle, Details, R, nil);
  ...
end;
Retrieved from "https://wiki.freepascal.org/index.php?title=Colors&oldid=161056"