OpenCV  4.5.4 Open Source Computer Vision
Flags used for image file reading and writing

## Enumerations

}

enum  cv::ImwriteEXRCompressionFlags {
cv::IMWRITE_EXR_COMPRESSION_NO = 0,
cv::IMWRITE_EXR_COMPRESSION_RLE = 1,
cv::IMWRITE_EXR_COMPRESSION_ZIPS = 2,
cv::IMWRITE_EXR_COMPRESSION_ZIP = 3,
cv::IMWRITE_EXR_COMPRESSION_PIZ = 4,
cv::IMWRITE_EXR_COMPRESSION_PXR24 = 5,
cv::IMWRITE_EXR_COMPRESSION_B44 = 6,
cv::IMWRITE_EXR_COMPRESSION_B44A = 7,
cv::IMWRITE_EXR_COMPRESSION_DWAA = 8,
cv::IMWRITE_EXR_COMPRESSION_DWAB = 9
}

enum  cv::ImwriteEXRTypeFlags {
cv::IMWRITE_EXR_TYPE_HALF = 1,
cv::IMWRITE_EXR_TYPE_FLOAT = 2
}

enum  cv::ImwriteFlags {
cv::IMWRITE_JPEG_QUALITY = 1,
cv::IMWRITE_JPEG_PROGRESSIVE = 2,
cv::IMWRITE_JPEG_OPTIMIZE = 3,
cv::IMWRITE_JPEG_RST_INTERVAL = 4,
cv::IMWRITE_JPEG_LUMA_QUALITY = 5,
cv::IMWRITE_JPEG_CHROMA_QUALITY = 6,
cv::IMWRITE_PNG_COMPRESSION = 16,
cv::IMWRITE_PNG_STRATEGY = 17,
cv::IMWRITE_PNG_BILEVEL = 18,
cv::IMWRITE_PXM_BINARY = 32,
cv::IMWRITE_EXR_TYPE = (3 << 4) + 0,
cv::IMWRITE_EXR_COMPRESSION = (3 << 4) + 1,
cv::IMWRITE_WEBP_QUALITY = 64,
cv::IMWRITE_PAM_TUPLETYPE = 128,
cv::IMWRITE_TIFF_RESUNIT = 256,
cv::IMWRITE_TIFF_XDPI = 257,
cv::IMWRITE_TIFF_YDPI = 258,
cv::IMWRITE_TIFF_COMPRESSION = 259,
cv::IMWRITE_JPEG2000_COMPRESSION_X1000 = 272
}
Imwrite flags. More...

enum  cv::ImwritePAMFlags {
cv::IMWRITE_PAM_FORMAT_NULL = 0,
cv::IMWRITE_PAM_FORMAT_BLACKANDWHITE = 1,
cv::IMWRITE_PAM_FORMAT_GRAYSCALE = 2,
cv::IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA = 3,
cv::IMWRITE_PAM_FORMAT_RGB = 4,
cv::IMWRITE_PAM_FORMAT_RGB_ALPHA = 5
}
Imwrite PAM specific tupletype flags used to define the 'TUPETYPE' field of a PAM file. More...

enum  cv::ImwritePNGFlags {
cv::IMWRITE_PNG_STRATEGY_DEFAULT = 0,
cv::IMWRITE_PNG_STRATEGY_FILTERED = 1,
cv::IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY = 2,
cv::IMWRITE_PNG_STRATEGY_RLE = 3,
cv::IMWRITE_PNG_STRATEGY_FIXED = 4
}
Imwrite PNG specific flags used to tune the compression algorithm. More...

## Enumeration Type Documentation

#include <opencv2/imgcodecs.hpp>

Enumerator

If set, return the loaded image as is (with alpha channel, otherwise it gets cropped). Ignore EXIF orientation.

If set, always convert image to the single channel grayscale image (codec internal conversion).

If set, always convert image to the 3 channel BGR color image.

If set, return 16-bit/32-bit image when the input has the corresponding depth, otherwise convert it to 8-bit.

If set, the image is read in any possible color format.

If set, always convert image to the single channel grayscale image and the image size reduced 1/2.

If set, always convert image to the 3 channel BGR color image and the image size reduced 1/2.

If set, always convert image to the single channel grayscale image and the image size reduced 1/4.

If set, always convert image to the 3 channel BGR color image and the image size reduced 1/4.

If set, always convert image to the single channel grayscale image and the image size reduced 1/8.

If set, always convert image to the 3 channel BGR color image and the image size reduced 1/8.

If set, do not rotate the image according to EXIF's orientation flag.

## ◆ ImwriteEXRCompressionFlags

#include <opencv2/imgcodecs.hpp>

Enumerator
IMWRITE_EXR_COMPRESSION_NO
Python: cv.IMWRITE_EXR_COMPRESSION_NO

no compression

IMWRITE_EXR_COMPRESSION_RLE
Python: cv.IMWRITE_EXR_COMPRESSION_RLE

run length encoding

IMWRITE_EXR_COMPRESSION_ZIPS
Python: cv.IMWRITE_EXR_COMPRESSION_ZIPS

zlib compression, one scan line at a time

IMWRITE_EXR_COMPRESSION_ZIP
Python: cv.IMWRITE_EXR_COMPRESSION_ZIP

zlib compression, in blocks of 16 scan lines

IMWRITE_EXR_COMPRESSION_PIZ
Python: cv.IMWRITE_EXR_COMPRESSION_PIZ

piz-based wavelet compression

IMWRITE_EXR_COMPRESSION_PXR24
Python: cv.IMWRITE_EXR_COMPRESSION_PXR24

lossy 24-bit float compression

IMWRITE_EXR_COMPRESSION_B44
Python: cv.IMWRITE_EXR_COMPRESSION_B44

lossy 4-by-4 pixel block compression, fixed compression rate

IMWRITE_EXR_COMPRESSION_B44A
Python: cv.IMWRITE_EXR_COMPRESSION_B44A

lossy 4-by-4 pixel block compression, flat fields are compressed more

IMWRITE_EXR_COMPRESSION_DWAA
Python: cv.IMWRITE_EXR_COMPRESSION_DWAA

lossy DCT based compression, in blocks of 32 scanlines. More efficient for partial buffer access. Supported since OpenEXR 2.2.0.

IMWRITE_EXR_COMPRESSION_DWAB
Python: cv.IMWRITE_EXR_COMPRESSION_DWAB

lossy DCT based compression, in blocks of 256 scanlines. More efficient space wise and faster to decode full frames than DWAA_COMPRESSION. Supported since OpenEXR 2.2.0.

## ◆ ImwriteEXRTypeFlags

#include <opencv2/imgcodecs.hpp>

Enumerator
IMWRITE_EXR_TYPE_HALF
Python: cv.IMWRITE_EXR_TYPE_HALF

store as HALF (FP16)

IMWRITE_EXR_TYPE_FLOAT
Python: cv.IMWRITE_EXR_TYPE_FLOAT

store as FP32 (default)

## ◆ ImwriteFlags

 enum cv::ImwriteFlags

#include <opencv2/imgcodecs.hpp>

Imwrite flags.

Enumerator
IMWRITE_JPEG_QUALITY
Python: cv.IMWRITE_JPEG_QUALITY

For JPEG, it can be a quality from 0 to 100 (the higher is the better). Default value is 95.

IMWRITE_JPEG_PROGRESSIVE
Python: cv.IMWRITE_JPEG_PROGRESSIVE

Enable JPEG features, 0 or 1, default is False.

IMWRITE_JPEG_OPTIMIZE
Python: cv.IMWRITE_JPEG_OPTIMIZE

Enable JPEG features, 0 or 1, default is False.

IMWRITE_JPEG_RST_INTERVAL
Python: cv.IMWRITE_JPEG_RST_INTERVAL

JPEG restart interval, 0 - 65535, default is 0 - no restart.

IMWRITE_JPEG_LUMA_QUALITY
Python: cv.IMWRITE_JPEG_LUMA_QUALITY

Separate luma quality level, 0 - 100, default is 0 - don't use.

IMWRITE_JPEG_CHROMA_QUALITY
Python: cv.IMWRITE_JPEG_CHROMA_QUALITY

Separate chroma quality level, 0 - 100, default is 0 - don't use.

IMWRITE_PNG_COMPRESSION
Python: cv.IMWRITE_PNG_COMPRESSION

For PNG, it can be the compression level from 0 to 9. A higher value means a smaller size and longer compression time. If specified, strategy is changed to IMWRITE_PNG_STRATEGY_DEFAULT (Z_DEFAULT_STRATEGY). Default value is 1 (best speed setting).

IMWRITE_PNG_STRATEGY
Python: cv.IMWRITE_PNG_STRATEGY

One of cv::ImwritePNGFlags, default is IMWRITE_PNG_STRATEGY_RLE.

IMWRITE_PNG_BILEVEL
Python: cv.IMWRITE_PNG_BILEVEL

Binary level PNG, 0 or 1, default is 0.

IMWRITE_PXM_BINARY
Python: cv.IMWRITE_PXM_BINARY

For PPM, PGM, or PBM, it can be a binary format flag, 0 or 1. Default value is 1.

IMWRITE_EXR_TYPE
Python: cv.IMWRITE_EXR_TYPE
IMWRITE_EXR_COMPRESSION
Python: cv.IMWRITE_EXR_COMPRESSION

override EXR storage type (FLOAT (FP32) is default)

IMWRITE_WEBP_QUALITY
Python: cv.IMWRITE_WEBP_QUALITY

override EXR compression type (ZIP_COMPRESSION = 3 is default)

For WEBP, it can be a quality from 1 to 100 (the higher is the better). By default (without any parameter) and for quality above 100 the lossless compression is used.

IMWRITE_PAM_TUPLETYPE
Python: cv.IMWRITE_PAM_TUPLETYPE

For PAM, sets the TUPLETYPE field to the corresponding string value that is defined for the format.

IMWRITE_TIFF_RESUNIT
Python: cv.IMWRITE_TIFF_RESUNIT

For TIFF, use to specify which DPI resolution unit to set; see libtiff documentation for valid values.

IMWRITE_TIFF_XDPI
Python: cv.IMWRITE_TIFF_XDPI

For TIFF, use to specify the X direction DPI.

IMWRITE_TIFF_YDPI
Python: cv.IMWRITE_TIFF_YDPI

For TIFF, use to specify the Y direction DPI.

IMWRITE_TIFF_COMPRESSION
Python: cv.IMWRITE_TIFF_COMPRESSION

For TIFF, use to specify the image compression scheme. See libtiff for integer constants corresponding to compression formats. Note, for images whose depth is CV_32F, only libtiff's SGILOG compression scheme is used. For other supported depths, the compression scheme can be specified by this flag; LZW compression is the default.

IMWRITE_JPEG2000_COMPRESSION_X1000
Python: cv.IMWRITE_JPEG2000_COMPRESSION_X1000

For JPEG2000, use to specify the target compression rate (multiplied by 1000). The value can be from 0 to 1000. Default is 1000.

## ◆ ImwritePAMFlags

 enum cv::ImwritePAMFlags

#include <opencv2/imgcodecs.hpp>

Imwrite PAM specific tupletype flags used to define the 'TUPETYPE' field of a PAM file.

Enumerator
IMWRITE_PAM_FORMAT_NULL
Python: cv.IMWRITE_PAM_FORMAT_NULL
IMWRITE_PAM_FORMAT_BLACKANDWHITE
Python: cv.IMWRITE_PAM_FORMAT_BLACKANDWHITE
IMWRITE_PAM_FORMAT_GRAYSCALE
Python: cv.IMWRITE_PAM_FORMAT_GRAYSCALE
IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA
Python: cv.IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA
IMWRITE_PAM_FORMAT_RGB
Python: cv.IMWRITE_PAM_FORMAT_RGB
IMWRITE_PAM_FORMAT_RGB_ALPHA
Python: cv.IMWRITE_PAM_FORMAT_RGB_ALPHA

## ◆ ImwritePNGFlags

 enum cv::ImwritePNGFlags

#include <opencv2/imgcodecs.hpp>

Imwrite PNG specific flags used to tune the compression algorithm.

These flags will be modify the way of PNG image compression and will be passed to the underlying zlib processing stage.

• The effect of IMWRITE_PNG_STRATEGY_FILTERED is to force more Huffman coding and less string matching; it is somewhat intermediate between IMWRITE_PNG_STRATEGY_DEFAULT and IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY.
• IMWRITE_PNG_STRATEGY_RLE is designed to be almost as fast as IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY, but give better compression for PNG image data.
• The strategy parameter only affects the compression ratio but not the correctness of the compressed output even if it is not set appropriately.
• IMWRITE_PNG_STRATEGY_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.
Enumerator
IMWRITE_PNG_STRATEGY_DEFAULT
Python: cv.IMWRITE_PNG_STRATEGY_DEFAULT

Use this value for normal data.

IMWRITE_PNG_STRATEGY_FILTERED
Python: cv.IMWRITE_PNG_STRATEGY_FILTERED

Use this value for data produced by a filter (or predictor).Filtered data consists mostly of small values with a somewhat random distribution. In this case, the compression algorithm is tuned to compress them better.

IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY
Python: cv.IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY

Use this value to force Huffman encoding only (no string match).

IMWRITE_PNG_STRATEGY_RLE
Python: cv.IMWRITE_PNG_STRATEGY_RLE

Use this value to limit match distances to one (run-length encoding).

IMWRITE_PNG_STRATEGY_FIXED
Python: cv.IMWRITE_PNG_STRATEGY_FIXED

Using this value prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.