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LevelsParams structure (gdipluseffects.h)

  • Article

The LevelsParams structure contains members that specify adjustments to the light, midtone, or dark areas of a bitmap.

You can adjust the light, midtone, or dark areas of a bitmap by following these steps.

  1. Create and initialize a LevelsParams structure.
  2. Pass the address of the LevelsParams structure to the Levels::SetParameters method of a Levels object.
  3. Pass the address of the Levels object to the Graphics::DrawImage method or to the Bitmap::ApplyEffect method.

Syntax

struct LevelsParams {
  INT highlight;
  INT midtone;
  INT shadow;
};

Members

highlight

Type: INT

Integer in the range 0 through 100 that specifies which pixels should be lightened. You can use this adjustment to lighten pixels that are already lighter than a certain threshold. Setting highlight to 100 specifies no change. Setting highlight to t specifies that a color channel value is increased if it is already greater than t percent of full intensity. For example, setting highlight to 90 specifies that all color channel values greater than 90 percent of full intensity are increased.

midtone

Type: INT

Integer in the range -100 through 100 that specifies how much to lighten or darken 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. 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.

shadow

Type: INT

Integer in the range 0 through 100 that specifies which pixels should be darkened. You can use this adjustment to darken pixels that are already darker than a certain threshold. Setting shadow to 0 specifies no change. Setting shadow to t specifies that a color channel value is decreased if it is already less than t percent of full intensity. For example, setting shadow to 10 specifies that all color channel values less than 10 percent of full intensity are decreased.

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)