Documentation for <libdisplay-info/info.h>

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struct di_chromaticity_cie1931 

struct di_chromaticity_cie1931 {
	float x;
	float y;
};

CIE 1931 2-degree observer chromaticity coordinates

struct di_color_primaries 

struct di_color_primaries {
	/* Are primary[] given */
	 bool has_primaries;
	
	/* Is default_white given */
	 bool has_default_white_point;
	
	/* Chromaticities of the primaries in RGB order
	 *
	 * Either all values are given, or they are all zeroes.
	 */
	struct di_chromaticity_cie1931 primary[];
	
	/* Default white point chromaticity
	 *
	 * If non-zero, this should be the display white point when it has
	 * been reset to its factory defaults. Either both x and y are given,
	 * or they are both zero.
	 */
	struct di_chromaticity_cie1931 default_white;
};

Display color primaries and default white point

struct di_hdr_static_metadata 

struct di_hdr_static_metadata {
	/* Desired content max luminance (cd/m²), zero if unset */
	float desired_content_max_luminance;
	/* Desired content max frame-average luminance (cd/m²), zero if unset */
	float desired_content_max_frame_avg_luminance;
	/* Desired content min luminance (cd/m²), zero if unset */
	float desired_content_min_luminance;
	
	/* Supported metadata types: */
	
	/* Static Metadata Type 1 */
	 bool type1;
	
	/* Supported EOFTs: */
	
	/* Traditional gamma - SDR luminance range */
	 bool traditional_sdr;
	/* Traditional gamma - HDR luminance range */
	 bool traditional_hdr;
	/* Perceptual Quantization (PQ) based on SMPTE ST 2084 */
	 bool pq;
	/* Hybrid Log-Gamma (HLG) based on Rec. ITU-R BT.2100 */
	 bool hlg;
};

Display HDR static metadata

struct di_info 

struct di_info;

Information about a display device.

This includes at least one EDID or DisplayID blob.

Use di_info_parse_edid() to create a struct di_info from an EDID blob. DisplayID blobs are not yet supported.

di_info_destroy() 

void di_info_destroy(​struct di_info *info);

Destroy a display device information structure.

di_info_get_default_color_primaries() 

const struct di_color_primaries *di_info_get_default_color_primaries(​const struct di_info *info);

Get display color primaries and default white point

Get the parameters of the default RGB colorimetry mode which is always supported. Primaries for monochrome displays might be all zeroes.

These primaries might not be display's physical primaries, but only the primaries of the default RGB colorimetry signal when using IT Video Format (ANSI/CTA-861-H, Section 5).

The returned pointer is owned by the struct di_info passed in. It remains valid only as long as the di_info exists, and must not be freed by the caller.

This function does not return NULL.

di_info_get_default_gamma() 

float di_info_get_default_gamma(​const struct di_info *info);

Get display default transfer characteristic exponent (gamma)

This should be the display gamma value when the display has been reset to its factory defaults, and it is driven with the default RGB colorimetry. The value is zero when unknown.

di_info_get_edid() 

const struct di_edid *di_info_get_edid(​const struct di_info *info);

Returns the EDID the display device information was constructed with.

The returned struct di_edid can be used to query low-level EDID information, see <libdisplay-info/edid.h>. Users should prefer the high-level API if possible.

NULL is returned if the struct di_info doesn't contain an EDID. The returned struct di_edid is valid until di_info_destroy().

di_info_get_failure_msg() 

const char *di_info_get_failure_msg(​const struct di_info *info);

Get the failure messages for this blob.

NULL is returned if the blob conforms to the relevant specifications.

di_info_get_hdr_static_metadata() 

const struct di_hdr_static_metadata *di_info_get_hdr_static_metadata(​const struct di_info *info);

Get HDR static metadata support information as defined in ANSI/CTA-861-H as HDR Static Metadata Data Block.

The returned pointer is owned by the struct di_info passed in. It remains valid only as long as the di_info exists, and must not be freed by the caller.

This function does not return NULL. When HDR static metadata does not exist, all luminance fields are zero and only traditional_sdr is flagged as supported.

di_info_get_make() 

char *di_info_get_make(​const struct di_info *info);

Get the make of the display device.

This is the manufacturer name, either company name or PNP ID. This string is informational and not meant to be used in programmatic decisions, configuration keys, etc.

The string is in UTF-8 and may contain any characters except ASCII control codes.

The caller is responsible for free'ing the returned string. NULL is returned if the information is not available.

di_info_get_model() 

char *di_info_get_model(​const struct di_info *info);

Get the model of the display device.

This is the product name/model string or product number. This string is informational and not meant to be used in programmatic decisions, configuration keys, etc.

The string is in UTF-8 and may contain any characters except ASCII control codes.

The caller is responsible for free'ing the returned string. NULL is returned if the information is not available.

di_info_get_serial() 

char *di_info_get_serial(​const struct di_info *info);

Get the serial of the display device.

This is the product serial string or the serial number. This string is informational and not meant to be used in programmatic decisions, configuration keys, etc.

The string is in UTF-8 and may contain any characters except ASCII control codes.

The caller is responsible for free'ing the returned string. NULL is returned if the information is not available.

di_info_get_supported_signal_colorimetry() 

const struct di_supported_signal_colorimetry *di_info_get_supported_signal_colorimetry(​const struct di_info *info);

Get signal colorimetry encodings supported by the display

These signal colorimetry encodings are supported in addition to the display's default RGB colorimetry. When you wish to use one of the additional encodings, they need to be explicitly enabled in the video signal. How to do that is specific to the signalling used, e.g. HDMI.

Signal colorimetry encoding provides the color space that the signal is encoded for. This includes primary and white point chromaticities, and the YCbCr-RGB conversion if necessary. Also the transfer function is implied unless explicitly set otherwise, e.g. with HDR static metadata. See ANSI/CTA-861-H for details.

The signal color volume can be considerably larger than the physically displayable color volume.

The returned pointer is owned by the struct di_info passed in. It remains valid only as long as the di_info exists, and must not be freed by the caller.

This function does not return NULL.

di_info_parse_edid() 

struct di_info *di_info_parse_edid(​const void *data, size_t size);

Parse an EDID blob.

Callers do not need to keep the provided data pointer valid after calling this function. Callers should destroy the returned pointer via di_info_destroy().

struct di_supported_signal_colorimetry 

struct di_supported_signal_colorimetry {
	/* Rec. ITU-R BT.2020 constant luminance YCbCr */
	 bool bt2020_cycc;
	/* Rec. ITU-R BT.2020 non-constant luminance YCbCr */
	 bool bt2020_ycc;
	/* Rec. ITU-R BT.2020 RGB */
	 bool bt2020_rgb;
	/* SMPTE ST 2113 RGB: P3D65 and P3DCI */
	 bool st2113_rgb;
	/* Rec. ITU-R BT.2100 ICtCp HDR (with PQ and/or HLG) */
	 bool ictcp;
};

Additional signal colorimetry encodings supported by the display