A display device, comprising: a color controller configured to receive first image data (DATA1) from outside the display device, to generate second image data (DATA2) by converting a color gamut of the first image data (DATA1), wherein, for each of the first and second image data (DATA1, DATA2), the color controller is configured to determine first chromaticity coordinates of a predetermined color in the first image data in a first viewing direction and second chromaticity coordinates of the predetermined color in a second viewing direction based on primary-color-viewing-angle data and using a preset conversion equation, wherein the primary-color-viewing-angle data includes chromaticity coordinates of each of multiple primary colors for the display panel in a first viewing direction and chromaticity coordinates thereof in a second viewing direction, wherein the color controller is further configured to determine a change in the chromaticity coordinates (Δu'v' 45) of the predetermined color in the first image data (DATA1) based on a difference between the first chromaticity coordinates and the second chromaticity coordinates for the predetermined color in the first image data (DATA1), and a change in the chromaticity coordinates (Δu'v' 45) of the predetermined color in the second image data (DATA2) based on a difference between the first chromaticity coordinates and the second chromaticity coordinates for the predetermined color in the second image data (DATA2), wherein the color controller is configured to determine a viewing angle variation (Δang) for the predetermined color between the first image data (DATA1) and the second image data (DATA2) based on a difference between the change in the chromaticity coordinates (Δu'v' 45) of the first image data (DATA1) and the change in the chromaticity coordinates (Δu'v' 45) of the second image data (DATA2), and wherein the color controller is configured, when the viewing angle variation for the predetermined color is less than or equal to a first threshold, to generate a third image data (DATA3) by correcting chromaticity coordinates of the predetermined color in the first image data (DATA1) or the second image data (DATA2) such that a hue variation (ΔHUE) between a hue of the predetermined color in the first image data (DATA1) and a hue of the predetermined color in the third image data (DATA3) is equal to or less than a second threshold value; and a display panel configured to display an image based on the second image data (DATA2) when the third image data (DATA3) is not generated by the color controller, and display the image based on the third image data (DATA3) when the third image data (DATA3) is generated by the color controller. a color controller configured to receive first image data (DATA1) from outside the display device, to generate second image data (DATA2) by converting a color gamut of the first image data (DATA1), wherein, for each of the first and second image data (DATA1, DATA2), the color controller is configured to determine first chromaticity coordinates of a predetermined color in the first image data in a first viewing direction and second chromaticity coordinates of the predetermined color in a second viewing direction based on primary-color-viewing-angle data and using a preset conversion equation, wherein the primary-color-viewing-angle data includes chromaticity coordinates of each of multiple primary colors for the display panel in a first viewing direction and chromaticity coordinates thereof in a second viewing direction, wherein the color controller is further configured to determine a change in the chromaticity coordinates (Δu'v' 45) of the predetermined color in the first image data (DATA1) based on a difference between the first chromaticity coordinates and the second chromaticity coordinates for the predetermined color in the first image data (DATA1), and a change in the chromaticity coordinates (Δu'v' 45) of the predetermined color in the second image data (DATA2) based on a difference between the first chromaticity coordinates and the second chromaticity coordinates for the predetermined color in the second image data (DATA2), wherein the color controller is configured to determine a viewing angle variation (Δang) for the predetermined color between the first image data (DATA1) and the second image data (DATA2) based on a difference between the change in the chromaticity coordinates (Δu'v' 45) of the first image data (DATA1) and the change in the chromaticity coordinates (Δu'v' 45) of the second image data (DATA2), and wherein the color controller is configured, when the viewing angle variation for the predetermined color is less than or equal to a first threshold, to generate a third image data (DATA3) by correcting chromaticity coordinates of the predetermined color in the first image data (DATA1) or the second image data (DATA2) such that a hue variation (ΔHUE) between a hue of the predetermined color in the first image data (DATA1) and a hue of the predetermined color in the third image data (DATA3) is equal to or less than a second threshold value; and a display panel configured to display an image based on the second image data (DATA2) when the third image data (DATA3) is not generated by the color controller, and display the image based on the third image data (DATA3) when the third image data (DATA3) is generated by the color controller.