Delphi Graphics
Delphi
Graphics
Color
Image Processing

Alpha Blending
www.optimalcode.com/exalpha.zip 

IA graphics library, optimized for very fast 32-bit bitmap handling, including alpha blending and antialiasing.
http://delphi.icm.edu.pl/ftp/d50free/g32_09.zip

  efg's Chromaticity Lab Report

Also see Brightness on Image Processing page

Bob Villiers' UseNet Post about how to change a single color in a pallete

Dean Verhoeven's E-mail about using SetDIBColorTable to alter palette of pf8bit bitmap

Ed Harmon's UseNet Post:
MyBitmap.Handle := CreateMappedBitmap(MyBitmap.Handle, [clLime], [NewColor]);

Damon Chandler's (TeamB) UseNet Post about changing palette entry in pf8bit bmp

efg's Color Range Lab Report: Select or exclude range of colors in an image and replace with specified color.

// Change one color to another
// Use this only for small bitmaps, or to avoid working with palettes
procedure TForm1.Button1Click(Sender: TObject);
  VAR
  Bitmap: TBitmap;
  i,j   : INTEGER;
begin 
  Bitmap := TBitmap.Create;
  TRY
    Bitmap.LoadFromFile('C:\Program Files\Borland\Delphi 3\Images\Buttons\Alarm.BMP');
    // Change "red" part of alarm to "blue"
    FOR j := 0 TO Bitmap.Height-1 DO
    BEGIN
      FOR i := 0 TO Bitmap.Width-1 DO
      BEGIN
        IF   Bitmap.Canvas.Pixels[i,j] = clRed
        THEN Bitmap.Canvas.Pixels[i,j] := clBlue
      END
    END;
    Bitmap.SaveToFile('C:\Temp\BlueAlarm.BMP');
    Image2.Picture.Graphic := Bitmap
  FINALLY
    Bitmap.Free
  END;
end;

cworn's UseNet Post with TGradient class and assembly code in the GetColorBetween function

Jean-Yves Quéinec's demo program showing gradient examples  (TBitmap, TImage, TPaintBox)
degrad.zip

Peter Söderman's UseNet Post with example of using GradientFill API call

256-Color Mode:  Since in 256-color video mode many video adapters use 18 bits/pixel, there are only 6 bits of red, green, and blue.  (See COLORRES under GetDeviceCaps for the actual value).  With only 6-bits of R, G, and B, only 64 distinct shades are possible.  That is, 64 shades of gray are possible.  Likewise, 64 shades of red are possible, etc.

Gradient Fill
www.openinfo.se/martin/texterdelphi/gradientfillex.htm

Ray Lischner's "Palettes Made Plain:  Demystifying Microsoft Windows Palettes" shows gradient palette and palette animation demo, Delphi Informant, July 1998.

GradBtn.  Button that can have a gradient fill.
www.users.uswest.net/~sharman1/gradbutt.zip

HarmGradient.  A TGraphicControl descendent.
www.users.uswest.net/~sharman1/HarmGradient.zip

"Creating a gradient fill background," pp. 329-333
Delphi Programming Problem Solver, Neil Rubenking

Gradient Panel
www.geocities.com/SiliconValley/Grid/3989/gradientpnl.htm

Create any combination of R, G, B color gradients in efg's Palette Lab or Scanline Tech Note

See gradients used in Lyapunov and Fractals Show2 Lab Reports

Also see "Spectrum/Rainbow".

lcms implements fast transforms between ICC profiles.
For win95/98/2000/NT.   A wide subset of the ICC International color consortium profile format is supported. The use of ICC profiles enables developers to access the inmense quantity of existing profiles. lcms is free and source code is also provided. This package contains source code, documentation, testbed and profile checking utility.  www.littlecms.com 

Sample lcms application by Armindo Da Silva

Here's how to use the MouseDown event of a TShape to define the TColorPicker brush color:

procedure TFormFractalsShow2.ShapeColorMouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  IF   ColorDialog.Execute
  THEN (Sender AS TShape).Brush.Color := ColorDialog.Color;

  UpdateColorScheme
end;

Mike Lischke's TColorPickerButton is a special speed button which can be used  to let the user select a specific color. The control does not  use the standard Windows color dialog, but uses a popup window   very similar to the one in Office97, which has been improved a  lot to support the task of picking one color out of millions.  
http://delphi.icm.edu.pl/ftp/d40free/colorpb.zip
www.lischke-online.de/Controls.html 

Color Cop v4.0 converts RGB decimal values to RGB Hexadecimal Triplets. It has a built in color picker, color preview, auto copy to clipboard, and an eyedropper to choose colors anywhere on the screen. Color Cop can make text and background colors very easy to manipulate in HTML documents. It now has support for Delphi Hex codes.  
www.datastic.com/tools/colorcop.html 

  HSV (see Alexei Puzikov's HSV/RGB Color Chooser Project)

Color reduction techniques for graphics (FAQ972D)

Demonstrate the different color reduction options that can be used when converting images with more than 256 colors to GIFs, www.melander.dk/delphi/gifimage;
Anders Melander's UseNet Post about 24-bit bitmap to 256-color GIF;

Displaying a 24 bit True Color bitmap image on a 256 color display (FAQ 996D) by Joe Hecht

Harm's UseNet Post with ConvertAndSave8BitBitmap

Create8bitFrom 24bitBitmap in Robert Roßmair's UseNet Post

Phil McRevis' UseNet Post with suggestion on best approach to reduce 24-bit pixels to 15-/16-bit pixels using Floyd-Steinberg dithering

See the Gervautz-Purgathofer Octree Color Quantization algorithm adapted from October 1997 Microsoft Systems Journal in efg's ShowDemoOne and ShowDemoMany Lab Reports.   (These projects only display pf24bit bitmaps in 256 color mode -- they do not convert a bitmap to pf8bit PixelFormat.)

efg's UseNet Post about converting 256-color bitmap to pf1bit 

Collection of color utility routines

• RGB/HLS-conversion, both integer and floating-point unctions (RGB = red, green, blue; HLS = hue, luminance, saturation);
• Windows controls: compute 3D-color shades (highlight, shadow) for a given face color;
• get / set DIB color table of a TBitmap object, map specified bitmap colors to other colors (Delphi 3 and above only);
• Gamma correction; you need the Math unit

http://home.t-online.de/home/Robert.Rossmair/#rrColors

[Foley96, pp. 585-587, Plate II.4]

Gernot Hoffmann Color Order Systems RGB, HLS, HSB
www.fho-emden.de/~hoffmann/hlscone03052001.pdf 

HLS:
- [Foley96, pp. 592-595, Plate II.9]
- Colors (HLS), http://digilander.iol.it/gensavas/francosava/grafica/docs/c_grafica3/i_coloriHLS_English.htm 

HSL
Colin Wilson's UseNet Post with RGB/HSL conversion routines

HSL/RGB:  Michael Tihon's Spectroscope Project

HSL, HSV/ HSB and RGB components
http://web.tiscalinet.it/encomps 

HSV:
- Using a background thread to compute and display a Mandelbrot set using HSVcolor scheme, Delphi in a Nutshell, pp. 148-151

RGB/HLS (D6/D7)

The following routines mimic the like named routines from Shlwapi.dll except these routines do not rely on any specific version of IE being installed. 

//  Calculates Hue, Luminance and Saturation for the clrRGB value
procedure ColorRGBToHLS(clrRGB: COLORREF; var Hue, Luminance, Saturation: Word);

// Calculates a color given Hue, Luminance and Saturation values
function ColorHLSToRGB(Hue, Luminance, Saturation: Word): TColorRef; 

efg's Lab Reports:

Show Image HSV YUV RGB Colors Color Mix

[Foley96, pp. 590-592, Plate II.7-II.8]

GraphicEx:  various color space conversions
http://www.lischke-online.de/Graphics.html#GraphicEx 

CMY, CMYK (subtractive color):
- Converting a RGB color to a CMYK color, Borland  (FAQ 2948D)
- Steve Schafer's UseNet Post showing conversions both ways
- efg's Show Image Lab Report
- [Foley96, pp. 587-588, Plate II.6]

L*a*b*
- Steve Schafer's UseNet Post

L*u*v*:
- [Foley96, pp. 584]

RGB Konvertierungen (RGB Conversions)
- http://home.t-online.de/home/PeterJHaas/bitmap.htm#RGB

XYZ:
- [Foley96, pp. 580-581, 586-587]
- Steve Schafer's UseNet Post

  YUV
- efg's YUV Lab Reports
- efg's YUVRGB code in UseNet post

YIQ: [Foley96, pp. 589-590]

"Putting Colors in Order."  A new method of looking at RGB color space as Hue, Value and Chroma (HVC) Dr. Dobb's Journal, Issue 202, July 1993, page 40.
http://pw1.netcom.com/~hjsmith/ColorOrd/ColorDoc.html
Pascal Code:  http://pw1.netcom.com/~hjsmith/ColorOrd/Listings.html

efg's Color Reference Library

Hitting the Highlights:  Center Stage for Data-entry Controls, Delphi Informant, Jan 1998

function ColorAdjustLuma(clrRGB: TColorRef; n: Integer; fScale: BOOL): TColorRef; 

Given a color and a luminance change "n" this routine returns a color whose luminance has been changed accordingly.

procedure ColorRGBToHLS(clrRGB: COLORREF; var Hue, Luminance, Saturation: Word); 

Calculates a color given Hue, Luminance and Saturation values

procedure ColorRGBToHLS(clrRGB: COLORREF; var Hue, Luminance, Saturation: Word); 

Calculates Hue, Luminance and Saturation for the clrRGB value

FUNCTION  ColorToRGBTriple(CONST Color:  TColor):  TRGBTriple;
BEGIN
  WITH RESULT DO
  BEGIN
    rgbtRed   := GetRValue(Color);
    rgbtGreen := GetGValue(Color);
    rgbtBlue  := GetBValue(Color)
  END
END {ColorToRGBTriple};

Also see GetHighLightColor and GetShadowColor.

Download the whole project from PC Mag in the cdance.zip file.  Unzip cdance.zip and you'll see a curd_src.zip.  Unzip curd_src.zip and you'll see an Images.zip.  Unzip Images.zip and you'll see the Resmake.bat file.  This is a clever trick by Neil to define a .RC file and a "make" file all inside a single .BAT file.  This creates the .RES file used by the Cursor Dance project.

Also see Cursors on the Graphics Algorithms page.

Can your video handle 16, 256, 32768, 16777216, or more colors?
www.chami.com/tips/delphi/121896D.html

Determine the RGB Bits-Per-Pixel for the Display
http://support.microsoft.com/support/kb/articles/q195/8/29.asp

Charles Hacker's UseNet Post calculating ColorDepth

Displaying a 24 bit True Color bitmap image on a 256 color display (FAQ 996D). See efg's ShowDemoOne Lab Report for an alternative in displaying 24-bit BMPs in 256-color display mode.

Gordy's Usenet Post about dithered grayscale

Non-Delphi:
Video for Windows DrawDIBDraw example (near bottom of True-Color Tyranny section).  DrawDib apparently uses some kind of pattern dither (Bayer?) to display images, but it does a surprisingly good job.
www.geocities.com/SiliconValley/2151/dibs.html 

[Foley96, pp. 568-573]

Philipp Pammler's Usenet Post with example of using GetDeviceGammaRamp and SetDeviceGammaRamp API calls. Michael Warner's reply that API gamma functions work with few video cards.

TGammaPanel is a True Color Select Panel like a Paint Shop Pro 5 Color Panel. www.abcnet.de/TRSOFT/Download/Gamma.zip

[Foley96, pp. 564-568]
See Gamma section on efg's Color Reference Library Page

VAR  value;
... 
DeviceContext := GetDC(hWnd_DeskTop);
TRY
  value := GetDeviceCaps(DeviceContext, <constant>)
FINALLY   
  ReleaseDC(0, DeviceContext)
END;

Color specific "caps" include:

GetHighLightColor and GetShadowColor take a Color and calculate an "appropriate" highlight/shadow color for that value. If the color's saturation is beyond 220 then it's lumination is decreased rather than
increased. 

GetHighLightColor and GetShadowColor take a Color and calculate an "appropriate" highlight/shadow color for that value. If the color's saturation is beyond 220 then it's lumination is decreased rather than
increased. 

See Usenet Post with "common formula" by Steve Schafer and Harm's reply with integer math suggested optimzation.

Charles Hacker's UseNet Post with GrayScale procedure

Steve Schafer's Usenet Post about gamma correction including routines to linearize and unlinearize RGB values.

Create a gray-scale palette, Delphi in a Nutshell, p. 19
efg's UseNet Post about how to create TBitmap with 256 shades of gray.

Davie Reed's UseNet Post  about "How to set gray-scale bitmap"
Gordy's Usenet Post about dithered grayscale

Y8 Gray Scale Lab Report

   
How to create a Bitmap from numeric data? (D5)  Shows gray scale vs. spectrum.

Also see Monochrome checkbox in each of the following:
efg's ShowImage Lab Report or Slide Show Tech Note

Michael Christopher's C++ Builder component  for simple image processing with 8 bit-images (invert and contrast enhancement).  MichaelChristopher_IP_Image.zip

Before reassigning the hue of each pixel from the TrackBar, the saturation must be boosted (by the value in the SpinEditBox) in a gray image, or there isn't "enough" color (otherwise the color still appears as a "gray hue"). 

In the above image, each "Original" RGB pixel is converted to HSV.  S is boosted by the "Delta Saturation" amount to give S'.  H is assigned a new value, H', from the TrackBar.  The resulting H'S'V values are converted back to the RGB values in the "New Hue" image.

Complete D3 example with source code:  ChangeHueSaturation.ZIP

D3-D5 example of inverting pf24bit bitmap:  InvertBitmap.ZIP

C  = 255 - R
M = 255 - G
Y  = 255 - B

// Based on 1 June 2000 post to borland.public.delphi.multimedia
// by Robert Roßmair
...
  VAR
    R:  TRect;
...
  WITH Image1.Picture.Bitmap DO
  BEGIN
    R := Rect(0, 0, Width, Height);
    InvertRect(Canvas.Handle, R);
  END;
  Image1.Invalidate

// Show bitmap (BMP file) and its color inverse in two TImages.
// Based on 1 June 2000 post to borland.public.delphi.multimedia
// by Robert Roßmair.

procedure TFormInvertBitmap.ButtonLoadBMPClick(Sender: TObject);
  VAR
    Bitmap:  TBitmap;
begin
  IF   OpenPictureDialog.Execute
  THEN BEGIN
    Bitmap := TBitmap.Create;
    TRY
      Bitmap.LoadFromFile(OpenPictureDialog.Filename);
      Bitmap.PixelFormat := pf24bit;  // avoid using palettes

      Image1.Picture.Graphic := Bitmap;

      InvertRect(Bitmap.Canvas.Handle, Bitmap.Canvas.ClipRect);
      Image2.Picture.Graphic := Bitmap
    FINALLY
      Bitmap.Free
    END
  END
end;

Also see   Color Mix

http://www.govst.edu/users/gsmpati/delphi 

For palette problems when loading DIBs from a resource file, see 
TI1081D, "Loading Bitmaps and Cursors from RES files"
http://community.borland.com/article/0,1410,16081,00.html 

Joe Hecht's UseNet Post that there is no "standard" Windows palette

The Microsoft Windows Palette Manager
www.compuphase.com/palette.htm

The Palette Manager:  How and Why It Does What It Does
http://support.microsoft.com/support/kb/articles/q137/3/72.asp
(download Palman.EXE and review the file PalMan.WRI.)

GetPalette and PaletteChanged, pp. 211-212.
Delphi Component Design by Danny Thorpe

Ray Lischner's "Palettes Made Plain:  Demystifying Microsoft Windows Palettes" shows gradient palette and palette animation demo, Delphi Informant, July 1998.

Processing WM_PALETTECHANGED and WM_QUERYNEWPALETTE
Microsoft's Knowledge Base:  http://support.microsoft.com/support/kb/articles/Q77/7/02.ASP

Safety Palette
http://msdn.microsoft.com/workshop/design/color/safety.asp

The Hardware Palette is the color lookup table found in the hardware.

A System Palette is the copy of the hardware palette maintained in software by the Palette Manager.  (But actually, the hardware often does not use a palette.  Windows maintains a system palette for compatibility with 256-color mode.)

A Logical Palette is a Windows palette object created using the CreatePalette API call.

A Foreground Palette (a logical palette) may overwrite all entries of the sysetm palette, except the static system colors.

A Background Palette (a logical palette) can only set "free" entries in the system palette or map colors in the logical palette to entries in the system palette.

SelectPalette:  Win32 API call to mark palette as either "background" or "possibly-foreground."  Reselecting a palette that is already selected causes no harm.

RealizePalette:  Win 32 API call that creates a mapping table -- each color in the logical palette is color-matched to every color in the system palette. "Realization" is the process of mapping a logical palette to the system palette.   This process is quite involved since the Windows Palette Manager must deal with multiple applications. The foreground palette only has priority, not exclusivity.   Drawing will be relative to the logical palette only after realization of the palette.  Re-realizing a palette that is already realized causes no harm.

Normally SelectPalette/RealizePalette occur as a pair of calls, but RealizePalette is only needed for "display" device contexts.  RealizePalette is not needed for "memory" device contexts.  In summary, SelectPalette is needed for all device contexts and RealizePalette is needed only for a device that really supports palette operations in hardware.

"More Fun with MFC: DIBs, Palettes, Subclassing, and a Gamut of Reusable Goodies", Part I (Jan 97), www.microsoft.com/MSJ/0197/mfcp1/mfcp1.htm 
www.microsoft.com/msj/code1993to1997/MSJJAN97.EXE

More Fun With MFC: DIBs, Palettes, Subclassing and a Gamut of Goodies, Part II (Mar 97)
www.microsoft.com/msj/0397/mfcp2/mfcp2.htm
www.microsoft.com/msj/code1993to1997/MSJMAR97.EXE

More Fun with MFC: DIBs, Palettes, Subclassing, and a Gamut of Goodies, Part III (Jun 97)
www.microsoft.com/msj/0697/mfc3/mfc3.htm 

An 8-bit image that does not contain all the static colors in its original color table loses whatever colors could not be set directly in the system palette (but only in palette mode, i.e., 256-color display mode).

IsPaletteDevice
// Adapted from Joe C. Hecht's UseNet Post
FUNCTION IsPaletteDevice: BOOLEAN;
  VAR
    DeviceContext: hDC;
BEGIN
  DeviceContext := GetDC(hWnd_DeskTop);
  TRY
    RESULT := GetDeviceCaps(DeviceContext, RASTERCAPS) AND RC_PALETTE = RC_PALETTE
  FINALLY
    // Give back the screen DC
    ReleaseDC(0, DeviceContext)
  END
END {IsPaletteDevice};

In The Microsoft Windows Palette Manager there is a "Does the video card support a palette?" section.  The IsPaletteDevice code there checks RC_PALETTE as shown above, but further restricts the test for when the number of bits per pixel is 8.  The comments there:  "The only hardware modes that use a pallete are modes with 2, 4, 16 and 256 colours.  Microsoft Windows supports palette operations only on displays with 256 colours.  That is, in 16-colour mode, you cannot use the palette.  So you only need to check for the RC_PALETTE bit if the number of bits per pixel is 8."  Here's the equivalent code:

FUNCTION IsPaletteDevice:  BOOLEAN;
  VAR
    Bits         :  INTEGER;
    DeviceContext:  hDC;
    ReturnCode   :  INTEGER;
BEGIN
  DeviceContext := GetDC(hWnd_DeskTop);
  TRY
    bits := GetDeviceCaps(DeviceContext, BITSPIXEL) *
            GetDeviceCaps(DeviceContext, PLANES);
    ReturnCode := GetDeviceCaps(DeviceContext, RASTERCAPS);
  FINALLY
    ReleaseDC(0, DeviceContext)
  END;

  RESULT := ((ReturnCode AND RC_PALETTE) <> 0) AND (Bits = 8)
END {IsPaletteDevice};                         

efg's Lab Reports
	Combine pf4Bit Bitmaps
	Palette Lab (WM_PALETTECHANGED and WM_QUERY NEWPALETTE messages)
	Y8 Gray Scale (pf8bit vs pf24bit approach in displaying grayscale data)

Danny Thorpe's UseNet Post about why transparency often fails on paletted devices

see
- CreatePalette API call and AnimatePalette on Delphi Graphics Win32API page

Create a gray-scale palette, Delphi in a Nutshell, p. 19

efg's UseNet Post about how to create TBitmap with 256 shades of gray.

Gradient Palettes, Halftone Palette, 22 FracInt .PAL files ,
  efg's Palette Lab Report

See Scanline Tech Note for pf8bit bitmaps with palettes

  efg's pf1bit  Lab Report

efg's UseNet Post about converting 256-color bitmap to pf1bit 

David Ullrich's UseNet Post about Gray and Black/White Palettes
Eddie Shipman's UseNet Post about making a rainbow background on a form
Ignacio Alvarez's UseNet Post about Palette Created for pf24bit bitmap when using 256 color display mode.

Creating a palette with more than one entry (FAQ 890D)

Damon Chandler's (Team B) UseNet Post about modifying a palette.  
Damon Chandler's (TeamB) UseNet Post about changing palette entry in pf8bit bmp
Also discusses GetDIBColorTable and SetDIBColorTable.
Bob Villiers' UseNet Post about how to change a single color in a pallete

Dean Verhoeven's E-mail about using SetDIBColorTable to alter palette of pf8bit bitmap

Ray Lischner's Palette Animation Demo, pal10.zip at www.tempest-sw.com/freeware or via ftp at ftp://ftp.tempest-sw.com/pub/delphi/pal10.zip, Delphi 1.

Ray Lischner's "Palettes Made Plain:  Demystifying Microsoft Windows Palettes" shows gradient palette and palette animation demo, Delphi Informant, July 1998.

Palette Management in VCL Components, Visual Developer, pp. 110-113, Builder C++ example, www.visual-developer.com/code/vdm/vdmv9n2.zip

Wandlung in Graustufen und Ändern der Palette
(Transformation in gray tones and modifying of the pallet)
http://home.t-online.de/home/PeterJHaas/bitmap.htm#Graustufen

How to respond to QueryNewPalette and PaletteChanged messages
www.lmc-mediaagentur.de/dpool/tips04/0358.htm 

Screen Capture
www.xploiter.com/programming/delphi/tips3.shtml#tip25

Laurie's UseNet Post with Change256ColorBitmapPalette procedure

Sean Dockery's UseNet Post asking how to reliably get windowed controls to abide by changes to the system palette.  (Sean's examples are very good, but his question went unanswered.)

PALDEMO1. A tutorial program by Eric Engler that shows you how to handle Windows palette messages in a 256 color screen mode. Delphi 1.
www.geocities.com/SiliconValley/Network/2114/paldemo1.zip

Palette Experiments, pp. 296-311, Delphi 2 Multimedia. (out of print)

"Working with Color Palettes," pp. 209-211, How to Program Delphi 3 (out of print)
Suggests using Image.BringToFront to control precedence in z-order when multiple images with palettes are displayed.

1. Use a rainbow palette.  A rainbow of colors allows all images to be displayed with approximae colors.  See Color Gradients and Spectrum/Rainbow.
   
2. Use a conglomerate palette.  Combine all palettes into a combined, conglomerate palette.
   
3. Use prioritized palettes.  Force all but one of the palettes to be realized in the background.  (The third parameter to SelectPalette is FALSE on the first and highest priority bitmap and TRUE on all subsequent, priortized SelectPalette calls.  Only the dominant image is displayed optimally.
   
   For example:
   // Select the chosen dominant palette
   SelectPalette(hDC, hDominantPalette, FALSE);
   RealizePalette(hDC);
   
   // Select a lower priority palette
   SelectPalette(hDc, hLowlyPalette, TRUE);
   RealizedPaletted(hDC);
   
   When an application realizes its dominant palette in response to the WM_QUERYNEWPALETTE message, the application needs to realized its secondary palettes in response to the resulting WM_PALETTECHANGED message.  Otherwise, all of the applications have a chance to realize their palettes first, and the foreground application loses out.  For a complete example see
   The Palette Manager:  How and Why It Does What It Does
   http://support.microsoft.com/support/kb/articles/q137/3/72.asp
   
4. Use color analysis (see "Palettes, Optimized" below)

Gervautz-Purgathofer Octree Color Quantization algorithm adapted from October 1997 Microsoft Systems Journal (www.microsoft.com/MSJ/1097/MSJoct97.zip). See efg's ShowDemoOne Lab Report or www.geocities.com/Athens/Delphi/9072/download.htm#genpal

ReduceColors function.  See Anders Melander's UseNet Post about using TGIFImage to reduce colors.

efg's Lab Reports
	Display Single 24-bit color image in 256-color mode Display Several 24-bit color images in 256-color mode

efg's Color Reference Library

Print In Color (FAQ 1650D)

FUNCTION  RGBTripleToColor(CONST Triple:  TRGBTriple):  TColor;
BEGIN
  RESULT := RGB(Triple.rgbtRed, Triple.rgbtGreen, Triple.rgbtBlue)
END {RGBTripleToColor};

Eddie Shipman's UseNet Post about making a rainbow background on a form

   How to create a Bitmap from numeric data? (D5)

  efg's Spectra Lab Report

Also, see "Color Gradients".

System Palette and Static Colors
http://msdn.microsoft.com/library/psdk/gdi/colors_1r3n.htm

According to the Microsoft Systems Journal, Sept. 91, p. 119, the table below is the Windows 3.0 Default Palette.  These colors should never dither in 256-color mode.

The placement of the static colors is at the beginning and end of the palette table so that common raster operations such as XOR will behave correctly.  With the static colors in slots 0..9 and 246..255, the inverse index of one of the static colors results in another static color.

The colors marked with an asterisk (*) below are part of Windows 95 "theme" colors.  So these specific theme colors may not be defined in all configurations of Windows.

I am not sure why RxLib uses different definitions for clSkyBlue and clCream than the values given by  Microsoft.

Printing System Colors using various brush styles:  efg's Printer Demo #2

From www.seanet.com/Users/bradford/ntscvideo.html:
A vectorscope is a specialized oscilloscope that measures color information in the subcarrier of the main signal. Instead of measuring brightness,  a vectorscope indicates saturation and hue. Positions closer to the center are less saturated, while positions closer to the outer edge are more saturated colors. All shades of gray (white to black) are be a dot at the center.

Also see:  www.tektronix.com/Measurement/App_Notes/NTSC_Video_Msmt/vectorscope.html

Check the Show Color Chart box to see the following  diagram overlaid on the above.

Thanks to Richard Jungert for coaching me through this project.

Color Messages
http://msdn.microsoft.com/library/psdk/gdi/colors_8alv.htm

See alternative to XORing,
  efg's   Line Stretch Lab Report