Merge pull request opencv#25691 from redhecker:gifSupport

[GSoC] Add GIF decode and encode for imgcodecs opencv#25691

this is related to opencv#24855 

we add  gif support for `imread`, `imreadmulti`, `imwrite` and `imwritemulti`

opencv_extra: opencv/opencv_extra#1203

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

Author: redhecker

CMakeLists.txt

@@ -432,6 +432,9 @@ OCV_OPTION(WITH_ITT "Include Intel ITT support" ON
 OCV_OPTION(WITH_PROTOBUF "Enable libprotobuf" ON
   VISIBLE_IF TRUE
   VERIFY HAVE_PROTOBUF)
+OCV_OPTION(WITH_IMGCODEC_GIF "Include GIF support" OFF
+  VISIBLE_IF TRUE
+  VERIFY HAVE_IMGCODEC_GIF)
 OCV_OPTION(WITH_IMGCODEC_HDR "Include HDR support" ON
   VISIBLE_IF TRUE
   VERIFY HAVE_IMGCODEC_HDR)
@@ -1557,6 +1560,10 @@ if(WITH_GDCM OR HAVE_GDCM)
   status("    GDCM:" HAVE_GDCM THEN "YES (${GDCM_VERSION})" ELSE "NO")
 endif()
 
+if(WITH_IMGCODEC_GIF OR DEFINED HAVE_IMGCODEC_GIF)
+  status("    GIF:" HAVE_IMGCODEC_GIF THEN "YES" ELSE "NO")
+endif()
+
 if(WITH_IMGCODEC_HDR OR DEFINED HAVE_IMGCODEC_HDR)
   status("    HDR:" HAVE_IMGCODEC_HDR THEN "YES" ELSE "NO")
 endif()

cmake/OpenCVFindLibsGrfmt.cmake

@@ -371,6 +371,11 @@ if(WITH_GDCM)
   endif()
 endif()
 
+if(WITH_IMGCODEC_GIF)
+  set(HAVE_IMGCODEC_GIF ON)
+elseif(DEFINED WITH_IMGCODEC_GIF)
+  set(HAVE_IMGCODEC_GIF OFF)
+endif()
 if(WITH_IMGCODEC_HDR)
   set(HAVE_IMGCODEC_HDR ON)
 elseif(DEFINED WITH_IMGCODEC_HDR)

modules/imgcodecs/CMakeLists.txt

@@ -88,6 +88,10 @@ if(HAVE_GDAL)
   list(APPEND GRFMT_LIBS ${GDAL_LIBRARY})
 endif()
 
+if(HAVE_IMGCODEC_GIF)
+  add_definitions(-DHAVE_IMGCODEC_GIF)
+endif()
+
 if(HAVE_IMGCODEC_HDR)
   add_definitions(-DHAVE_IMGCODEC_HDR)
 endif()

modules/imgcodecs/include/opencv2/imgcodecs.hpp

@@ -111,7 +111,13 @@ enum ImwriteFlags {
        IMWRITE_JPEG2000_COMPRESSION_X1000 = 272,//!< For JPEG2000, use to specify the target compression rate (multiplied by 1000). The value can be from 0 to 1000. Default is 1000.
        IMWRITE_AVIF_QUALITY        = 512,//!< For AVIF, it can be a quality between 0 and 100 (the higher the better). Default is 95.
        IMWRITE_AVIF_DEPTH          = 513,//!< For AVIF, it can be 8, 10 or 12. If >8, it is stored/read as CV_32F. Default is 8.
-       IMWRITE_AVIF_SPEED          = 514 //!< For AVIF, it is between 0 (slowest) and (fastest). Default is 9.
+       IMWRITE_AVIF_SPEED          = 514,//!< For AVIF, it is between 0 (slowest) and (fastest). Default is 9.
+       IMWRITE_GIF_LOOP            = 1024,//!< For GIF, it can be a loop flag from 0 to 65535. Default is 0 - loop forever.
+       IMWRITE_GIF_SPEED           = 1025,//!< For GIF, it is between 1 (slowest) and 100 (fastest). Default is 96.
+       IMWRITE_GIF_QUALITY         = 1026, //!< For GIF, it can be a quality from 1 to 8. Default is 2. See cv::ImwriteGifCompressionFlags.
+       IMWRITE_GIF_DITHER          = 1027, //!< For GIF, it can be a quality from -1(most dither) to 3(no dither). Default is 0.
+       IMWRITE_GIF_TRANSPARENCY    = 1028, //!< For GIF, the alpha channel lower than this will be set to transparent. Default is 1.
+       IMWRITE_GIF_COLORTABLE      = 1029  //!< For GIF, 0 means global color table is used, 1 means local color table is used. Default is 0.
      };
 
 enum ImwriteJPEGSamplingFactorParams {
@@ -216,6 +222,18 @@ enum ImwriteHDRCompressionFlags {
     IMWRITE_HDR_COMPRESSION_RLE = 1
 };
 
+//! Imwrite GIF specific values for IMWRITE_GIF_QUALITY parameter key, if larger than 3, then its related to the size of the color table.
+enum ImwriteGIFCompressionFlags {
+    IMWRITE_GIF_FAST_NO_DITHER       = 1,
+    IMWRITE_GIF_FAST_FLOYD_DITHER    = 2,
+    IMWRITE_GIF_COLORTABLE_SIZE_8    = 3,
+    IMWRITE_GIF_COLORTABLE_SIZE_16   = 4,
+    IMWRITE_GIF_COLORTABLE_SIZE_32   = 5,
+    IMWRITE_GIF_COLORTABLE_SIZE_64   = 6,
+    IMWRITE_GIF_COLORTABLE_SIZE_128  = 7,
+    IMWRITE_GIF_COLORTABLE_SIZE_256  = 8
+};
+
 //! @} imgcodecs_flags
 
 /** @brief Loads an image from a file.
@@ -229,6 +247,7 @@ returns an empty matrix.
 Currently, the following file formats are supported:
 
 -   Windows bitmaps - \*.bmp, \*.dib (always supported)
+-   GIF files - \*.gif (always supported)
 -   JPEG files - \*.jpeg, \*.jpg, \*.jpe (see the *Note* section)
 -   JPEG 2000 files - \*.jp2 (see the *Note* section)
 -   Portable Network Graphics - \*.png (see the *Note* section)