CurveAdjustments enumeration (gdipluseffects.h)

The ColorCurve class encompasses the eight bitmap adjustments listed in the CurveAdjustments enumeration.

To apply one of the eight adjustments to a bitmap, follow these steps.

1. Create a ColorCurveParams structure, and set its adjustment member to one of the elements of the CurveAdjustments enumeration.
2. Set the other two members (adjustValue and channel) of the ColorCurveParams structure.
3. Pass the address of the ColorCurveParams structure to the ColorCurve::SetParameters method of a ColorCurve object.
4. Pass the address of the ColorCurve object to the Graphics::DrawImage method or to the Bitmap::ApplyEffect method.

Syntax

typedef enum CurveAdjustments {
  AdjustExposure,
  AdjustDensity,
  AdjustContrast,
  AdjustHighlight,
  AdjustShadow,
  AdjustMidtone,
  AdjustWhiteSaturation,
  AdjustBlackSaturation
} ;

Constants

AdjustExposure Simulates increasing or decreasing the exposure of a photograph. When you set the adjustment member of a ColorCurveParams object to AdjustExposure, you should set the adjustValue member to an integer in the range -255 through 255. A value of 0 specifies no change in exposure. Positive values specify increased exposure and negative values specify decreased exposure.
AdjustDensity Simulates increasing or decreasing the film density of a photograph. When you set the adjustment member of a ColorCurveParams object to AdjustDensity, you should set the adjustValue member to an integer in the range -255 through 255. A value of 0 specifies no change in density. Positive values specify increased density (lighter picture) and negative values specify decreased density (darker picture).
AdjustContrast Increases or decreases the contrast of a bitmap. When you set the adjustment member of a ColorCurveParams object to AdjustContrast, you should set the adjustValue member to an integer in the range -100 through 100. A value of 0 specifies no change in contrast. Positive values specify increased contrast and negative values specify decreased contrast.
AdjustHighlight Increases or decreases the value of a color channel if that channel already has a value that is above half intensity. You can use this adjustment to get more definition in the light areas of an image without affecting the dark areas. When you set the adjustment member of a ColorCurveParams object to AdjustHighlight, you should set the adjustValue member to an integer in the range -100 through 100. A value of 0 specifies no change. Positive values specify that the light areas are made lighter, and negative values specify that the light areas are made darker.
AdjustShadow Increases or decreases the value of a color channel if that channel already has a value that is below half intensity. You can use this adjustment to get more definition in the dark areas of an image without affecting the light areas. When you set the adjustment member of a ColorCurveParams object to AdjustShadow, you should set the adjustValue member to an integer in the range -100 through 100. A value of 0 specifies no change. Positive values specify that the dark areas are made lighter, and negative values specify that the dark areas are made darker.
AdjustMidtone Lightens or darkens an image. Color channel values in the middle of the intensity range are altered more than color channel values near the minimum or maximum intensity. You can use this adjustment to lighten (or darken) an image without loosing the contrast between the darkest and lightest portions of the image. When you set the adjustment member of a ColorCurveParams object to AdjustMidtone, you should set the adjustValue member to an integer in the range -100 through 100. A value of 0 specifies no change. Positive values specify that the midtones are made lighter, and negative values specify that the midtones are made darker.
AdjustWhiteSaturation When you set the adjustment member of a ColorCurveParams object to AdjustWhiteSaturation, you should set the adjustValue member to an integer in the range 0 through 255. A value of t specifies that the interval [0, t] is mapped linearly to the interval [0, 255]. For example, if adjustValue is equal to 240, then color channel values in the interval [0, 240] are adjusted so that they spread out over the interval [0, 255]. Color channel values greater than 240 are set to 255.
AdjustBlackSaturation When you set the adjustment member of a ColorCurveParams object to AdjustBlackSaturation, you should set the adjustValue member to an integer in the range 0 through 255. A value of t specifies that the interval [t, 255] is mapped linearly to the interval [0, 255]. For example, if adjustValue is equal to 15, then color channel values in the interval [15, 255] are adjusted so that they spread out over the interval [0, 255]. Color channel values less than 15 are set to 0.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Header	gdipluseffects.h (include Gdiplus.h)