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  • efg's Color Reference Library -- Color Science / Color Theory
    Research and Application Vol 21 No 4 Feb 1996 pp 310 313 Color Models See Color Spaces below Color Rendering Color Rendeing Asking the Question text figures Color Rendering a calculation that estimates colorimetric shifts text figures www jimworthey com Color Rendering Index Color Rendering Index Calculating CRI www kruschwitz com cri htm Hunt87 Appendix 7 Color Spaces ColorSpace program www couleur org RGB Colour Space http paulbourke net texture colour colourspace index html Historical Color Systems www uni mannheim de fakul psycho irtel colsys Charles Poynton s Gamma FAQ and Color FAQ www poynton com The Decoding Model a Symmetrical Model of Color Vision www survivor99 com colorforum The 20Decoding 20Model html Section 7 3 High Performance Computer Imaging Working with color spaces Shows diagrams 7 9 and7 10 of device independent and device dependent colors spaces Mentions applications for L a b XYZ L u v Linear RGB and variants R G B RGB 709 YUV YIQ YCbCr 601 YCbCr 709 PhotoYCC CMY CMYK RGB CMY CMYK RYB YIQ HSI HSV HSB HLS Fortner97 Chapter 6 pp 119 Section 4 6 2 Color Models pp 225 237 Digital Image Processing 2nd edition Gernot Hoffman s Color Order Systems RGB HLS HSB http www fho emden de hoffmann hlscone03052001 pdf Gernot Hoffmann s UseNet Post about problems with CMYK when converting form RGB in particular note this CMY to RGB depends on gamut compression gamut clipping RGB primaries definition white point definition RGB CMY RGB is NOT reversible The naive formula R 1 C and so on is wrong Natural Color System Scandinavian Colour Institute A Centre for Colour www ncscolour com Anders Hård et al NCS Natural Color System from Concept to Research and Applications Part I Color Research and Application Vol 21 No 3 June 1996 p 180 205 Anders Hård et al NCS Natural Color System from Concept to Research and Applications Part II Color Research and Application Vol 21 No 3 June 1996 p 206 208 Color Spaces pp 47 55 RGB YIQ HSI Lab The Image Processing Handbook Section 7 3 Working with color spaces pp 219 239 XYZ L a b L u v RGB YUV YIQ CMY CMYK High Performance Computer Imaging Graphic CIE L a b Calculator http colorpro com info tools labcalc htm CIE Lab L 80 Munsel Value 8 Danny Rich s UseNet Post L u v Computer Graphics Principles and Practice p 584 I1I2I3 Color Space Walter Hafner s UseNet Post about Colour Image Segmentation UVW Color Space Joann Taylor s UseNet Post A model of colour vision for predicting colour appearance Hunt87 Chapter 8 efg s ShowImage Lab Report shows coordinates RGB HSV HLS CMYK Intensity Lightness YIQ counts unique RGB colors in image displays prints histograms efg s ColorRange Lab Report shows how to include exclude regions of an image based on RGB or HSV quantities efg s HSV Lab Report efg s YUV Lab Report Color Temperature What Color are the Stars some pixel RGB values www vendian org mncharity dir3 starcolor What Color is a Blackbody some pixel RGB values www vendian org mncharity dir3 blackbody Black Body Radiation www egglescliffe org uk physics astronomy blackbody bbody html Martí Maria s UseNet Post about obtaining white point from color temperature Neil Okamoto s UseNet Post with a C program to compute correlated color temperature based on Robertson s method in Wyszecki Stiles p 224 229 Ákos Borbély et al The Concept of Correlated Colour Temperature Revisited Color Research and Application Vol 26 No 6 Dec 2001 Correlated colour temperature is a one dimensional description of the colour of near white light sources We recommend changing the definition of correlated colour temperature from a visual definition to a mathematical one J Schanda M Meszaros G Czibula Calculating Correlated Color Temperature with a Desktop Programmable Calculator Color Research and Application Vol 3 No 2 Summer 1978 pp 65 69 F Grum S B Saunders D L MacAdam Concept of Correlated Color Temperature Color Research and Application Vol 3 No 1 Spring 1978 pp 17 21 J Schanda and M Danyi Correlated Color Temperature Calculations in the CIE 1976 Chromaticity Diagram Color Research and Application Vol 2 No 4 Winter 1977 pp 161 163 Spectra wavelength to RGB Chromaticity Diagram Blackbody Radiation excellent Dan Bruton s Color Science page http www midnightkite com color html Colour Rendering of Spectra www fourmilab ch documents specrend Mitchell N Charity s comments about this article Rendering Spectra http mintaka sdsu edu GF explain optics rendering html Daylight Education page www solux net edu2 htm White Points Defined in CIE 1931 Standard Name x y Color Temperature Comments A 0 4476 0 4075 2854 K Incandescent Light B 0 3840 0 3516 4874 K Direct Sunlight C 0 3101 0 3162 6774 K Indirect Sunlight D5000 0 3457 0 3586 5000 K Bright Incandescent Light D6500 0 3127 0 3297 6504 K Natural Daylight E 0 3333 0 3333 5500 K Normalized Reference See Sun Color on General Color Info page Fortner97 pp 76 79 109 110 MacAdam85 Chapter 6 Color Theory Online Graphic Design Degree Color Theory and Application http www onlinegraphicdesigndegree com resources color theory Color Theory is a set of principles used to create harmonious color combinations Color relationships can be visually represented with a color wheel the color spectrum wrapped onto a circle www color wheel pro com color theory basics html efg s ColorMix Lab Report demonstrates additive and subtractive color primaries efg s RGBColors Lab Report shows display of up to 16 8 million colors efg s Maxwell Triangle Lab Report shows mixing of primary colors efg s Spectra Lab Report shows wavelength to RGB calculations and hydrogen emission absorption spectra efg s Split Lab Report shows how to splie a 24 bits pixel image into RGB or HSV color planes Fundamentals of Color Science Nassau98 Chapter 1 Color Theory What were early studies of Color http www webexhibits org causesofcolor 1B html Color Science

    Original URL path: http://www.efg2.com/Lab/Library/Color/Science.htm (2016-02-14)
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  • efg's ShowDemoMany Lab Report
    view Solar System images from NASA are included for test purposes Only the images with a checked Include in Palette checkboxes are included in the optimized palette Check and uncheck the Include inPalette checkboxes to see how each image contributes to the optimized palette If all checkboxes are unchecked the Windows halftone palette is used Select the Palette Tabsheet at any time to view the palette being use to display the images Note the location of the 20 fixed Windows palette entries The palette is displayed in a paintbox Discussion When a single image has thousands of colors finding the optimal 236 colors for a set of images can be difficult Unfortunately both Microsoft and Borland ignored this issue in Windows 95 and Delphi and left the problem for developers to suffer through This Delphi 3 example implements the Gervautz Purgathofer Octree Color Quantization algorithm as described in Jeff Prosise s Wicked Code Microsoft Systems Journal October 1997 pp 79 84 To see a palette conflict load all six images and uncheck each checkbox except for Jupiter s Red Spot image The optimized palette for this single image is not very good for all the other images The GetBitmap Procedure is a callback that is used to create an optimized palette for any number of bitmaps This example shows how to create an ARRAY of TComponentSet with each array element a RECORD containing a TBitmap TImage TLabel and TCheckBox This construct allows any of these objects to be indexed via an array element Optimized palettes are not needed for high color or true color displays See also ShowDemoOne for how to display only a single 24 bit image on a 256 color display See E mail note from Andrew Rybenkov with Process32BitDIB addition to TColorQuantizer in the ColorQuantizationLibrary Nov 2002

    Original URL path: http://www.efg2.com/Lab/Graphics/Colors/ShowDemoMany.htm (2016-02-14)
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  • efg's Printer Projects -- Printer Demo #2
    rectangular region of the upper half of the vertical area from 20 to 80 of the horizontal area Region1 CreateRectRgn Width DIV 5 0 4 Width DIV 5 Height DIV 2 Create elliptical region of the lower half of the vertical area Region2 CreateEllipticRgn Width DIV 4 Height DIV 2 3 Width DIV 4 Height TRY Add Region 2 to Region 1 CombineRgn Region1 Region1 Region2 RGN OR SelectClipRgn Canvas Handle Region1 Show Outline of Clipping Area Canvas Brush Color clRed FrameRgn Canvas Handle Region1 Canvas Brush Handle 2 2 FINALLY DeleteObject Region2 END See final DeleteObject statement at end of routine END A big red X formed by diagonals is drawn as is a box around the edges Big X Canvas Pen Color clRed Canvas MoveTo 0 0 Canvas LineTo Width 1 Height 1 Canvas MoveTo 0 Height 1 Canvas LineTo Width 1 0 A Box the hard way Canvas Pen Color clBlack Canvas MoveTo 0 0 Canvas LineTo 0 Height 1 Canvas LineTo Width 1 Height 1 Canvas LineTo Width 1 0 Canvas LineTo 0 0 Use something like MulDiv Width percent 100 to position to a particular horizontal location in a device independent way Likewise use something like MulDiv Height percent 100 to position to a particular vertical location in a device independent way Set Font Height instead of Font Size for better device independence in the display of text In fact it s a good idea to never use Font Size because of various bugs in printer drivers Set the Height in a device independent way and never use the font size Printer Canvas Font Height MulDiv GetDeviceCaps Printer Canvas Handle LOGPIXELSY FontSize 72 Line Styles yDelta MulDiv Height 125 10000 1 25 Canvas Font Height MulDiv Height 2 100 Canvas Font Name Arial Canvas Font Color clBLack Canvas Font Style fsItalic fsbold Canvas Brush Style bsClear s efg s Computer Lab Printer Demo 2 Canvas TextOut Width Canvas TextWidth s DIV 2 MulDiv Height 1 100 s Canvas Font Name Times New Roman Canvas Font Style Canvas Font Height MulDiv Height 15 1000 s www efg2 com Lab Canvas TextOut Width Canvas TextWidth s DIV 2 MulDiv Height 3 100 s Canvas Font Height MulDiv Height 2 100 Canvas Font Color clBlue Canvas Font Height MulDiv Height 1 100 s Line Styles by pen width Canvas TextOut MulDiv Width 76 100 MulDiv Height 7 100 3 Canvas TextHeight s DIV 2 s The various Pen Style s are set by typecasting an integer namely TPenStyle style MOD 7 returned the various Pen Style s psSolid 0 psDash 1 psDot 2 psDashDot 3 psDashDotDot 4 psClear 5 and psInsideFrame 6 Canvas Pen Color clBlack FOR PenWidth 1 TO 4 DO BEGIN FOR style 0 TO 6 DO BEGIN Style is psSolid psDash psDot psDashDot psDashDotDot psClear psInsideFrame Canvas Pen Style TPenStyle style MOD 7 Canvas Pen Width PenWidth y MulDiv Height 7 100 10 PenWidth 1 style yDelta Canvas MoveTo MulDiv Width 76 100 y Canvas LineTo MulDiv Width 87 100 y END END Canvas Pen Color clRed FOR PenWidth 1 TO 4 DO BEGIN FOR style 0 TO 6 DO BEGIN Style is psSolid psDash psDot psDashDot psDashDotDot psClear psInsideFrame Canvas Pen Style TPenStyle style MOD 7 Canvas Pen Width PenWidth y MulDiv Height 7 100 10 PenWidth 1 style yDelta Canvas MoveTo MulDiv Width 88 100 y Canvas LineTo MulDiv Width 99 100 y END END Draw the color boxes with the various brush styles Rectangles Vary Colors and Brush Styles Canvas Pen Style psInsideFrame Canvas Pen Color clBlack Canvas Pen Width 1 xDelta MulDiv Width 35 1000 3 5 yDelta MulDiv Height 50 1000 5 xBase MulDiv Width 2 100 2 yBase MulDiv Height 7 100 7 s Brush Styles Canvas TextOut XBase YBase 3 Canvas TextHeight s DIV 2 s FOR color Low Colors TO High Colors DO BEGIN x xBase color xDelta FOR brush 0 TO 7 DO See p 764 VCL Ref Delphi 1 BEGIN Per E mail from Thérèse Hanquet always assign Brush Color before assigning Brush Style March 2001 Canvas Brush Color colors color Canvas Brush Style TBrushStyle brush y yBase brush yDelta Canvas Rectangle x y x xDelta y yDelta END END The various Brush Style s are set by typecasting an integer namely TBrushStyle brush returned the various brush styles bsSolid 0 bsClear 1 bsHorizontal 2 bsVertical 3 bsFDiagonal 4 bsBDiagonal 5 bsCross 6 bsDiagCross 7 Here s what these rectangles with various colors and brush styles look like If the order of the assignments to Brush Color and Brush Style were reversed in the code above the bsClear row above the second row would also be a solid color like the first row Perhaps this is a bug Thank you Thérèse Hanquet for bringing this to my attention This has affected this example since D1 efg March 2001 The two rows of shades of gray boxes are created with this code The function call RGB i i i for i 0 255 gives the possible 256 shades of gray colors Rectangles Shades of Gray yBase MulDiv Height 87 100 yDelta MulDiv Height 4 100 s Shades of Gray Canvas TextOut MulDiv Width 1 63 YBase 3 Canvas TextHeight s DIV 2 s Canvas Brush Style bsSolid FOR GrayShade 0 TO 60 DO BEGIN x1 MulDiv Width GrayShade 1 63 x2 MulDiv Width GrayShade 2 63 Canvas Brush Color RGB 4 GrayShade 4 GrayShade 4 GrayShade Canvas Rectangle x1 yBase x2 yBase yDelta END yBase yBase yDelta FOR GrayShade 0 TO 60 DO BEGIN x1 MulDiv Width GrayShade 1 63 x2 MulDiv Width GrayShade 2 63 Canvas Brush Color RGB 195 GrayShade 195 GrayShade 195 GrayShade Canvas Rectangle x1 yBase x2 yBase yDelta END Ellipses chords and pies are drawn next Ellipses Canvas Pen Color clWhite Canvas Brush Style bsSolid Canvas Brush Color clRed Canvas Ellipse MulDiv Width 55 100 MulDiv Height 55 100 MulDiv Width 85 100 MulDiv Height 85 100 Canvas Brush Color clLime

    Original URL path: http://www.efg2.com/Lab/OtherProjects/PrinterDemo2.htm (2016-02-14)
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  • containing bitmap size format and color data UINT iUsage color data type indicator RGB values or palette indices VOID ppvBits pointer to variable to receive a pointer to the bitmap s bit values HANDLE hSection optional handle to a file mapping object using this I successfully got 1GB image 32700x32700x8bit DWORD dwOffset offset to the bitmap bit values within the file mapping object WIN NT 4 0 ws sp4 RAM

    Original URL path: http://www.efg2.com/Lab/Graphics/TarasBreginFeedback.TXT (2016-02-14)
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  • subscripts as Eudora does not allow me to do so but you ll understand anyway This is nice for X and Y values lower than say 1 0E6 like pixel coordinates However when this theorem is used to calculate the area of polygons that have vertices that represent real data e g map absolute coordinate points that represent a gas cloud contour that exceed 1 0E6 the error will quickly

    Original URL path: http://www.efg2.com/Lab/Graphics/Frank_van_het_Veld.txt (2016-02-14)
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  • say 1 0E7 the result will lose accuracy because of size of numbers in any computer Same is said for any other formula such as SQR A B B C When working with geometry a simple method can be applied to improve not solve accuracy work with relative coordinates So calling X A A Y B A Z C A this is substract a medium origin Xo value to all

    Original URL path: http://www.efg2.com/Lab/Graphics/ManuelMartin.txt (2016-02-14)
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  • efg's Graphics -- Circle Word Wrap
    LineCount Diameter Height 1 For the given assumptions LineCount 240 20 1 11 These 11 lines will require 11 20 220 pixels The remaining space 240 220 20 pixels will be divided between the top and bottom of the circle The top of the first text line will be y 10 pixels from the top of the circle The Canvas TextOut methods assumes the starting point of a text box is at the upper left y 10 Line 1 Font Height x SQRT Radius² y yMiddle ² based on the equation for a circle x² y² R² Max Text Width 2x pixels Text Line y x Max Text Width 1 10 48 96 2 30 79 158 3 50 97 194 4 70 109 218 5 90 116 232 6 110 120 240 7 130 120 240 8 150 116 232 9 170 109 218 10 190 97 194 11 210 79 158 Each text line must fit into the text box with coordinates xMiddle x y at the upper left and xMiddle x y Font Height at the lower right An arbitrary string of characters with a specified font will not fit into a specified width A function GetStringThatFits was written to fetch a string of a specified pixel width Assuming the string contains words these words are parsed from the string until adding another word would exceed the specified width In the event that the input string does not contain words that is the input string doesn t contain any spaces the function GetStringThatFits then finds the number of characters that will fit into the specified pixel width When the lines are broken into words there is usually some white space on the left and right if the string is centered around the x xMiddle line The x

    Original URL path: http://www.efg2.com/Lab/Graphics/CircleWordWrap.htm (2016-02-14)
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  • efg's Graphics -- Gordon's Snappy Line
    drag to draw lines Lines will either snap to another which is in the cursor rectangle or start and finish at the X and Y co ordinates Use the trackbar to select and erase lines Measure angles between pairs of interconnected lines by Clicking Measure Angle then selecting first the junction of the two lines and then the ends Discussion The LineTestUnit PAS unit contains the basic drawing functions ProFuncUnit Pas contains the text alignment AlignAngleText and SetStatusPanelText procedures The program uses a number of math functions and demonstrates how to align dimension text with a vector Rubber banding of lines is also demonstrated The scroll bar is used to highlight the indexed line and delete the selected line OnMouseUp The scroll bar isn t the best choice for this function separate up and down buttons would have been a better choice It s been left in as much to show why it s a poor choice for this function The LineTest RES file contains a user defined cursor that is used while drawing Note Always use a name for a RES file that is not the same as the RES file for any form If you do working with

    Original URL path: http://www.efg2.com/Lab/Graphics/SnappyLine.htm (2016-02-14)
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