Graphical user interface for editing a palette of colors

Abstract

A graphical user interface is disclosed for interactively editing a palette of colors in response to signals from a user, such as from a pointing device. The interface provides a color space in a color space window on the user's display and draws each color in the palette in its current location in the color space, thereby showing the relationship of each color in the palette with other colors in the palette. The interface stores all color representations as device independent color specifications in the uniform color space. The user edits a color by moving it from its current location to a destination location, or by changing its lightness coordinate. The graphical user interface also provides for storing a plurality of colorimetrically measured colors representing the display gamut. When the user edits a color, a gamut clipping process ensures that the modified color is producible in the display gamut. The user may select a color space from several color spaces available for display in the color space window, and may flexibly and conveniently display and edit the palette of colors to any of the available color spaces. One of the color spaces available is the uniform CIELAB color space. Another color space available displays a histogram of palette color lightness frequencies.

What is claimed is: 
     
       1. A processor-controlled system for modifying a plurality of colors, each color being represented by a set of color information signals; said processor-controlled system comprising a display device for displaying the plurality of colors;   an input device for receiving input signals from a system user;   a processor connected for receiving said input signals from said input device and for providing the color information siqnals representing each of the plurality of colors to said display device; and   a memory device for storing data therein; the data stored in the memory device including the color information signals representing the plurality of colors and data indicating instructions the processor executes;   the processor being further connected for accessing the instruction data stored in the memory device; the processor executing the instructions indicated by the instruction data; the processor, in executing the instructions, presenting on said display device a graphical representation of a color space; the graphical representation of said color space including a graphical representation of each respective color of the plurality of colors; the graphical representation of each color being presented in a current location in said color space having coordinates determined from the set of color information signals representing each respective color;   the processor, further in executing the instructions, receiving said input signals from said input device indicating a movement action by the system user moving the graphical representation of one color of the plurality of colors from said current location to a destination location in said color space;   the processor, further in executing the instructions, responding to said input signals indicating the movement action by determining from color space coordinates of said destination location a set of modified color information signals representing a modified color;   presenting on said display device a graphical representation of said modified color in the destination location in said color space; and   storing the set of modified color information signals representing the modified color in the memory device.   
     
     
       2. The processor-controlled system of claim 1 wherein the set of color information signals for each color includes a lightness signal, and wherein the processor, further in executing the instructions, receives a second input signal from said input device indicating a lightness modifying request by the system user; the lightness modifying request including a selected one of the plurality of colors; the processor, in response to said second input signal, changing said lightness signal of the selected color to produce said set of modified color information signals. 
     
     
       3. The processor-controlled system of claim 2 further wherein the data stored in the memory device further includes a plurality of colorimetrically measured colors representing a display gamut of colors reproducible by said display device, and wherein the processor, further in executing the instructions, adjusts said set of modified color information signals representing said modified color in said graphical representation of said color space to produce a reproducible color in said display gamut using said display gamut of colors stored in the memory device. 
     
     
       4. The processor-controlled system of claim 8 wherein the processor, further in executing the instructions, receives a third input signal from said input device indicating a selected color space display request by the system user; said selected color space being selected by the system user from a plurality of color spaces; the processor, in response to said third input signal, presenting a graphical representation of said selected color space on said display device; the graphical representation of said selected color space including a graphical representation of each respective color of the plurality of colors. 
     
     
       5. The processor-controlled system of claim 4 wherein one of said plurality of color spaces is a lightness frequency distribution color space, and wherein, when the selected color space is the liqhtness frequency distribution color space, the processor, further in executing the instructions, presents the graphical representation of each of the plurality of colors according to said lightness signal thereof in said lightness frequency distribution color space. 
     
     
       6. The system of claim 4 wherein said selected color space selected by the system user is a uniform color space. 
     
     
       7. A method for modifying the appearance of a plurality of colors in a color display system having input signal receiving means for receiving signals from a user, a display device, and a memory for storing a set of color information signals corresponding to each color of the plurality of colors, the method comprising the steps of: drawing on the display device a graphical representation of a colorspace;   plotting the plurality of colors in said color space, each color being plotted in a current location in said color space, said current location having coordinates defined by the set of color information signals of each color of the plurality of colors;   modifying any one of the plurality of colors in response to signals received from the input signal receiving means, said modifying step including the step of moving the one color from said current location to a destination location in said color space, said destination location having coordinates defining a set of modified color information signals representing a modified color in said color space; and   storing said set of modified color information signals in the color display system memory.   
     
     
       8. The method of claim 7 wherein the set of color information signals of each color includes a lightness signal, and wherein said modifying step further includes a lightness modifying step of modifying said lightness signal, in response to at least one of said input signals, to produce said set of modified color information signals. 
     
     
       9. The method of claim 7 further including the steps of colorimetrically measuring a plurality of colors representing the gamut of reproducible colors of the display device; and   storing said display gamut in the color display system memory;   and wherein said modifying step further includes adjusting said set of modified color information signals representing said modified color to represent a reproducible color in said display gamut.   
     
     
       10. The method of claim 7 wherein said color space is a uniform colorspace. 
     
     
       11. The method of claim 7 further including, prior to the step of drawing on the display device the graphical representation of the color space, selecting said color space for display on the display device from a plurality of color spaces in response to at least one of the input signals; said drawing step thereby drawing the graphical representation of said selected color space on the display device; said plotting step thereby plotting the plurality of colors in said selected color space. 
     
     
       12. The method of claim 11 wherein the set of color information signals for each color includes a lightness signal; one of said plurality of color spaces is a lightness frequency distribution color space; and   when said selected color space is the lightness frequency distribution color space, the step of plotting the plurality of colors in said selected color space further includes plotting the plurality of colors according to said lightness signal thereof in said lightness frequency distribution color space.