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HistogramFormat enumeration (gdipluscolormatrix.h)

  • Article

The HistogramFormat enumeration specifies the number and type of histograms that represent the color channels of a bitmap. This enumeration is used with the Bitmap::GetHistogram method.

Syntax

typedef enum HistogramFormat {
  HistogramFormatARGB,
  HistogramFormatPARGB,
  HistogramFormatRGB,
  HistogramFormatGray,
  HistogramFormatB,
  HistogramFormatG,
  HistogramFormatR,
  HistogramFormatA
} ;

Constants

 
HistogramFormatARGB
Specifies that the Bitmap::GetHistogram method returns four histograms: one each for the alpha, red, green, and blue channels. The alpha-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The red-channel histogram is written to the buffer pointed to by the channel1 parameter. The green-channel histogram is written to the buffer pointed to by the channel2 parameter. The blue-channel histogram is written to the buffer pointed to by the channel3 parameter.
HistogramFormatPARGB
Specifies that the Bitmap::GetHistogram method returns four histograms: one each for the alpha, red, green, and blue channels. The red, green, and blue channels are each multiplied by the alpha channel before the histograms are created. The bitmap is not permanently altered when the color channels are multiplied by the alpha channel; that multiplication is only for the purpose of creating the histograms. The alpha-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The red-channel histogram is written to the buffer pointed to by the channel1 parameter. The green-channel histogram is written to the buffer pointed to by the channel2 parameter. The blue-channel histogram is written to the buffer pointed to by the channel3 parameter.
HistogramFormatRGB
Specifies that the Bitmap::GetHistogram method returns three histograms: one each for the red, green, and blue channels. The red-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The green-channel histogram is written to the buffer pointed to by the channel1 parameter. The blue-channel histogram is written to the buffer pointed to by the channel2 parameter. The channel3 parameter must be set to NULL.
HistogramFormatGray
Specifies that each pixel is converted to a grayscale value in the range 0 through 255, and then one histogram, based on those grayscale value, is returned. The bitmap is not permanently altered by the conversion to grayscale values; those values are calculated only for the purpose of creating the histogram. The grayscale histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The channel1, channel2, and channel3 parameters must be set to NULL.
HistogramFormatB
Specifies that the Bitmap::GetHistogram method returns a histogram for the blue channel. The blue-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The channel1, channel2, and channel3 parameters must be set to NULL.
HistogramFormatG
Specifies that the Bitmap::GetHistogram method returns a histogram for the green channel. The green-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The channel1, channel2, and channel3 parameters must be set to NULL.
HistogramFormatR
Specifies that the Bitmap::GetHistogram method returns a histogram for the red channel. The red-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The channel1, channel2, and channel3 parameters must be set to NULL.
HistogramFormatA
Specifies that the Bitmap::GetHistogram method returns a histogram for the alpha channel. The alpha-channel histogram is written to the buffer pointed to by the channel0 parameter of the Bitmap::GetHistogram method. The channel1, channel2, and channel3 parameters must be set to NULL.

Requirements

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