Access Whole Channels of an Image
[Image Package]

Enumerations
enum	Gan_ImageChannelType {   GAN_INTENSITY_CHANNEL, GAN_RED_CHANNEL, GAN_GREEN_CHANNEL, GAN_BLUE_CHANNEL,   GAN_ALPHA_CHANNEL, GAN_X_CHANNEL, GAN_Y_CHANNEL, GAN_Z_CHANNEL,   GAN_ALL_COLOUR_CHANNELS, GAN_ALL_CHANNELS }
	Image channel types for extracting individual channels. More...
Functions
Gan_Image *	gan_image_extract_channel_q (const Gan_Image *source, Gan_ImageChannelType channel, unsigned r0, unsigned c0, unsigned height, unsigned width, Gan_Image *dest)
	Extracts a specific channel from part of an image.
Gan_Bool	gan_image_insert_channel (const Gan_Image *source, Gan_ImageChannelType schannel, Gan_Image *dest, Gan_ImageChannelType dchannel)
	Inserts a specific channel from one image into another.
Gan_Bool	gan_image_fill_channel_const (Gan_Image *image, Gan_ImageChannelType channel, Gan_Pixel *pixel)
	Sets a single channel of an image to a constant value.
Gan_Bool	gan_image_get_minimum_channel_value (Gan_Image *image, Gan_Image *mask, Gan_ImageChannelType channel, Gan_Pixel *minval)
	Finds the minimum value in the specified channel of an image.
Gan_Bool	gan_image_get_maximum_channel_value (Gan_Image *image, Gan_Image *mask, Gan_ImageChannelType channel, Gan_Pixel *maxval)
	Finds the maximum value in the specified channel of an image.
Gan_Image *	gan_image_threshold_channel_q (const Gan_Image *source, const Gan_Image *mask, Gan_ImageChannelType channel, float threshold, Gan_Image *dest)
	Thresholds a channel of an image.
Gan_Image *	gan_image_extract_channel_s (const Gan_Image *source, Gan_ImageChannelType channel, unsigned r0, unsigned c0, unsigned height, unsigned width)
	Macro: Extracts a specific channel from part of an image.
Gan_Image *	gan_image_fill_channel_zero (Gan_Image *image, Gan_ImageChannelType channel)
	Macro: Sets a single channel of an image to zero.
Gan_Image *	gan_image_threshold_channel_s (const Gan_Image *source, const Gan_Image *mask, Gan_ImageChannelType channel, float threshold)
	Macro: Thresholds a channel of an image.
Gan_Bool	gan_image_has_alpha_channel (const Gan_Image *img)
	Returns value indicating whether an image has an alpha channel.

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Enumeration Type Documentation

enum Gan_ImageChannelType

Image channel types for extracting individual channels. Enumeration values: GAN_INTENSITY_CHANNEL  for grey-level/alpha images GAN_RED_CHANNEL  for RGB and RGB/alpha images GAN_ALPHA_CHANNEL  for grey-level/alpha and RGB/alpha images GAN_X_CHANNEL  for 2D and 3D vector field images GAN_Y_CHANNEL  likewise GAN_Z_CHANNEL  for 3D vector field images GAN_ALL_COLOUR_CHANNELS  all colour channels, e.g. R,G,B but not A GAN_ALL_CHANNELS  all channels

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Function Documentation

Gan_Image * gan_image_extract_channel_q (  const Gan_Image *  source, Gan_ImageChannelType  channel, unsigned  r0, unsigned  c0, unsigned  height, unsigned  width, Gan_Image *  dest )

Extracts a specific channel from part of an image. Parameters: source  The input image channel  The channel to extract from the image r0  Vertical offset of start of region c0  Horizontal offset of start of region height  Height of region in pixels width  Width of region in pixels dest  The destination image Returns: A pointer to the extracted image, or NULL on failure. Extracts a specific channel in a sub-part of an image, See also: gan_image_extract_channel_s().

Gan_Image* gan_image_extract_channel_s (  const Gan_Image *  source, Gan_ImageChannelType  channel, unsigned  r0, unsigned  c0, unsigned  height, unsigned  width )

Macro: Extracts a specific channel from part of an image. Parameters: source  The input image channel  The channel to extract from the image r0  Vertical offset of start of region c0  Horizontal offset of start of region height  Height of region in pixels width  Width of region in pixels Returns: A pointer to the extracted image, or NULL on failure. Extracts a specific channel in a sub-part of an image, This is a macro call to gan_image_extract_channel_q(). See also: gan_image_extract_channel_q().

Gan_Bool gan_image_fill_channel_const (  Gan_Image *  image, Gan_ImageChannelType  channel, Gan_Pixel *  pixel )

Sets a single channel of an image to a constant value. Parameters: image  The input image channel  The channel to set to constant value pixel  Pointer to grey-level pixel value Returns: GAN_TRUE on success, GAN_FALSE on failure. Sets a single channel of an image to a constant value. The channel should correspond to one of the available channels in the image. The type of the pixel structure should be the same as the image, and the format should be GAN_GREY_LEVEL_IMAGE. If pixel is passed as NULL, the channel is filled with zeros. See also: gan_image_fill_channel_zero().

Gan_Image* gan_image_fill_channel_zero (  Gan_Image *  image, Gan_ImageChannelType  channel )

Macro: Sets a single channel of an image to zero. Parameters: image  The input image channel  The channel to set to zero Returns: GAN_TRUE on success, or GAN_FALSE on failure. Sets a single channel of an image to zero. This is a macro call to gan_image_fill_channel_const(). See also: gan_image_fill_channel_const().

Gan_Bool gan_image_get_maximum_channel_value (  Gan_Image *  image, Gan_Image *  mask, Gan_ImageChannelType  channel, Gan_Pixel *  maxval )

Finds the maximum value in the specified channel of an image. Parameters: image  The input image mask  Only test pixels in this mask (may be NULL) channel  The channel to set to constant value maxval  Pointer to the result maximum pixel value Returns: GAN_TRUE on success, GAN_FALSE on failure. Finds the maximum value in the specified channel of an image.

Gan_Bool gan_image_get_minimum_channel_value (  Gan_Image *  image, Gan_Image *  mask, Gan_ImageChannelType  channel, Gan_Pixel *  minval )

Finds the minimum value in the specified channel of an image. Parameters: image  The input image mask  Only test pixels in this mask (may be NULL) channel  The channel to set to constant value minval  Pointer to the result minimum pixel value Returns: GAN_TRUE on success, GAN_FALSE on failure. Finds the minimum value in the specified channel of an image.

Gan_Bool gan_image_has_alpha_channel (  const Gan_Image *  img  )

Returns value indicating whether an image has an alpha channel. Parameters: img  Input image Returns: GAN_TRUE if the image has an alpha channel, GAN_FALSE if it doesn't

Gan_Bool gan_image_insert_channel (  const Gan_Image *  source, Gan_ImageChannelType  schannel, Gan_Image *  dest, Gan_ImageChannelType  dchannel )

Inserts a specific channel from one image into another. Parameters: source  The input image schannel  The channel in the input image dest  The output image dchannel  The channel in the output image Returns: A pointer to the extracted image, or NULL on failure. Extracts a specific channel in a sub-part of an image, See also: gan_image_extract_channel_s().

Gan_Image * gan_image_threshold_channel_q (  const Gan_Image *  source, const Gan_Image *  mask, Gan_ImageChannelType  channel, float  threshold, Gan_Image *  dest )

Thresholds a channel of an image. Parameters: source  The input image mask  Mask of pixels to test channel  The channel to extract from the image threshold  The threshold in the range [0..1] dest  Destination mask image Thresholds a specific channel of an image and returns a mask of pixels above the threshold. If a mask is specified, all pixels in dest outside the mask are set to zero. See also: gan_image_threshold_channel_s().

Gan_Image* gan_image_threshold_channel_s (  const Gan_Image *  source, const Gan_Image *  mask, Gan_ImageChannelType  channel, float  threshold )

Macro: Thresholds a channel of an image. Parameters: source  The input image mask  Mask of pixels to test channel  The channel to extract from the image threshold  The threshold in the range [0..1] Thresholds a specific channel of an image and returns a mask of pixels above the threshold, If a mask is specified, all pixels in dest outside the mask are set to zero. This is a macro call to gan_image_threshold_channel_q(). See also: gan_image_threshold_channel_q().

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