mirror/opencv
1
0
Fork 0
mirror of https://github.com/opencv/opencv.git synced 2025-06-17 07:10:51 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

imgcodecs: update documentation for imwrite() to support images formats.

Browse Source
This commit is contained in:
Kumataro 2023-03-26 09:03:16 +09:00
parent 36a03dbdbf
commit 83a49b4f6a
1 changed files with 17 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
modules/imgcodecs/include/opencv2/imgcodecs.hpp
View File

@ -218,17 +218,26 @@ CV_EXPORTS_W bool imreadmulti(const String& filename, CV_OUT std::vector<Mat>& m
/** @brief Saves an image to a specified file. /** @brief Saves an image to a specified file.
The function imwrite saves the image to the specified file. The image format is chosen based on the The function imwrite saves the image to the specified file. The image format is chosen based on the
filename extension (see cv::imread for the list of extensions). In general, only 8-bit filename extension (see cv::imread for the list of extensions). In general, only 8-bit unsigned (CV_8U)
single-channel or 3-channel (with 'BGR' channel order) images single-channel or 3-channel (with 'BGR' channel order) images
can be saved using this function, with these exceptions: can be saved using this function, with these exceptions:
- 16-bit unsigned (CV_16U) images can be saved in the case of PNG, JPEG 2000, and TIFF formats - With OpenEXR encoder, only 32-bit float (CV_32F) images can be saved.
- 32-bit float (CV_32F) images can be saved in TIFF, OpenEXR, and Radiance HDR formats; 3-channel - 8-bit unsigned (CV_8U) images are not supported.
(CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel) - With Radiance HDR encoder, non 64-bit float (CV_64F) images can be saved.
- All images will be converted to 32-bit float (CV_32F).
- With JPEG 2000 encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
- With PAM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
- With PNG encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
- PNG images with an alpha channel can be saved using this function. To do this, create - PNG images with an alpha channel can be saved using this function. To do this, create
8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels
should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below). should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).
- With PGM/PPM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
- With TIFF encoder, 8-bit unsigned (CV_8U), 16-bit unsigned (CV_16U),
32-bit float (CV_32F) and 64-bit float (CV_64F) images can be saved.
- Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below). - Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below).
- 32-bit float 3-channel (CV_32FC3) TIFF images will be saved
using the LogLuv high dynamic range encoding (4 bytes per pixel)
If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way. If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way.